writersmugs.com >  Audio Books >  Bertrand-Russell >  The Analysis of Mind
download audio


An admirable statement of the aims of the Library of Philosophy
was provided by the first editor, the late Professor J. H.
Muirhead, in his description of the original programme printed in
Erdmann's History of Philosophy under the date 1890. This was
slightly modified in subsequent volumes to take the form of the
following statement:

"The Muirhead Library of Philosophy was designed as a
contribution to the History of Modern Philosophy under the heads:
first of Different Schools of Thought--Sensationalist, Realist,
Idealist, Intuitivist; secondly of different
Subjects--Psychology, Ethics, Aesthetics, Political Philosophy,
Theology. While much had been done in England in tracing the
course of evolution in nature, history, economics, morals and
religion, little had been done in tracing the development of
thought on these subjects. Yet 'the evolution of opinion is part
of the whole evolution'.

"By the co-operation of different writers in carrying out this
plan it was hoped that a thoroughness and completeness of
treatment, otherwise unattainable, might be secured. It was
believed also that from writers mainly British and American
fuller consideration of English Philosophy than it had hitherto
received might be looked for. In the earlier series of books
containing, among others, Bosanquet's "History of Aesthetic,"
Pfleiderer's "Rational Theology since Kant," Albee's "History of
English Utilitarianism," Bonar's "Philosophy and Political
Economy," Brett's "History of Psychology," Ritchie's "Natural
Rights," these objects were to a large extent effected.

"In the meantime original work of a high order was being produced
both in England and America by such writers as Bradley, Stout,
Bertrand Russell, Baldwin, Urban, Montague, and others, and a new
interest in foreign works, German, French and Italian, which had
either become classical or were attracting public attention, had
developed. The scope of the Library thus became extended into
something more international, and it is entering on the fifth
decade of its existence in the hope that it may contribute to
that mutual understanding between countries which is so pressing
a need of the present time."

The need which Professor Muirhead stressed is no less pressing
to-day, and few will deny that philosophy has much to do with
enabling us to meet it, although no one, least of all Muirhead
himself, would regard that as the sole, or even the main, object
of philosophy. As Professor Muirhead continues to lend the
distinction of his name to the Library of Philosophy it seemed
not inappropriate to allow him to recall us to these aims in his
own words. The emphasis on the history of thought also seemed to
me very timely; and the number of important works promised for
the Library in the very near future augur well for the continued
fulfilment, in this and other ways, of the expectations of the
original editor.

H. D. Lewis


This book has grown out of an attempt to harmonize two different
tendencies, one in psychology, the other in physics, with both of
which I find myself in sympathy, although at first sight they
might seem inconsistent. On the one hand, many psychologists,
especially those of the behaviourist school, tend to adopt what
is essentially a materialistic position, as a matter of method if
not of metaphysics. They make psychology increasingly dependent
on physiology and external observation, and tend to think of
matter as something much more solid and indubitable than mind.
Meanwhile the physicists, especially Einstein and other exponents
of the theory of relativity, have been making "matter" less and
less material. Their world consists of "events," from which
"matter" is derived by a logical construction. Whoever reads, for
example, Professor Eddington's "Space, Time and Gravitation"
(Cambridge University Press, 1920), will see that an
old-fashioned materialism can receive no support from modern
physics. I think that what has permanent value in the outlook of
the behaviourists is the feeling that physics is the most
fundamental science at present in existence. But this position
cannot be called materialistic, if, as seems to be the case,
physics does not assume the existence of matter.

The view that seems to me to reconcile the materialistic tendency
of psychology with the anti-materialistic tendency of physics is
the view of William James and the American new realists,
according to which the "stuff" of the world is neither mental nor
material, but a "neutral stuff," out of which both are
constructed. I have endeavoured in this work to develop this view
in some detail as regards the phenomena with which psychology is

My thanks are due to Professor John B. Watson and to Dr. T. P.
Nunn for reading my MSS. at an early stage and helping me with
many valuable suggestions; also to Mr. A. Wohlgemuth for much
very useful information as regards important literature. I have
also to acknowledge the help of the editor of this Library of
Philosophy, Professor Muirhead, for several suggestions by which
I have profited.

The work has been given in the form of lectures both in London
and Peking, and one lecture, that on Desire, has been published
in the Athenaeum.

There are a few allusions to China in this book, all of which
were written before I had been in China, and are not intended to
be taken by the reader as geographically accurate. I have used
"China" merely as a synonym for "a distant country," when I
wanted illustrations of unfamiliar things.

Peking, January 1921.


I.   Recent Criticisms of "Consciousness" II.  Instinct and Habit
III. Desire and Feeling IV.  Influence of Past History on Present
Occurrences in Living      Organisms V.   Psychological and
Physical Causal Laws VI.  Introspection VII. The Definition of
Perception VIII.Sensations and Images IX.  Memory X.   Words and
Meaning XI.  General Ideas and Thought XII. Belief XIII.Truth and
Falsehood XIV. Emotions and Will XV.  Characteristics of Mental


download audio

There are certain occurrences which we are in the habit of
calling "mental." Among these we may take as typical BELIEVING
and DESIRING. The exact definition of the word "mental" will, I
hope, emerge as the lectures proceed; for the present, I shall
mean by it whatever occurrences would commonly be called mental.

I wish in these lectures to analyse as fully as I can what it is
that really takes place when we, e.g. believe or desire. In this
first lecture I shall be concerned to refute a theory which is
widely held, and which I formerly held myself: the theory that
the essence of everything mental is a certain quite peculiar
something called "consciousness," conceived either as a relation
to objects, or as a pervading quality of psychical phenomena.

The reasons which I shall give against this theory will be mainly
derived from previous authors. There are two sorts of reasons,
which will divide my lecture into two parts

(1) Direct reasons, derived from analysis and its difficulties;

(2) Indirect reasons, derived from observation of animals
(comparative psychology) and of the insane and hysterical

Few things are more firmly established in popular philosophy than
the distinction between mind and matter. Those who are not
professional metaphysicians are willing to confess that they do
not know what mind actually is, or how matter is constituted; but
they remain convinced that there is an impassable gulf between
the two, and that both belong to what actually exists in the
world. Philosophers, on the other hand, have maintained often
that matter is a mere fiction imagined by mind, and sometimes
that mind is a mere property of a certain kind of matter. Those
who maintain that mind is the reality and matter an evil dream
are called "idealists"--a word which has a different meaning in
philosophy from that which it bears in ordinary life. Those who
argue that matter is the reality and mind a mere property of
protoplasm are called "materialists." They have been rare among
philosophers, but common, at certain periods, among men of
science. Idealists, materialists, and ordinary mortals have been
in agreement on one point: that they knew sufficiently what they
meant by the words "mind" and "matter" to be able to conduct
their debate intelligently. Yet it was just in this point, as to
which they were at one, that they seem to me to have been all
alike in error.

The stuff of which the world of our experience is composed is, in
my belief, neither mind nor matter, but something more primitive
than either. Both mind and matter seem to be composite, and the
stuff of which they are compounded lies in a sense between the
two, in a sense above them both, like a common ancestor. As
regards matter, I have set forth my reasons for this view on
former occasions,* and I shall not now repeat them. But the
question of mind is more difficult, and it is this question that
I propose to discuss in these lectures. A great deal of what I
shall have to say is not original; indeed, much recent work, in
various fields, has tended to show the necessity of such theories
as those which I shall be advocating. Accordingly in this first
lecture I shall try to give a brief description of the systems of
ideas within which our investigation is to be carried on.

* "Our Knowledge of the External World" (Allen & Unwin), Chapters
III and IV. Also "Mysticism and Logic," Essays VII and VIII.

If there is one thing that may be said, in the popular
estimation, to characterize mind, that one thing is
"consciousness." We say that we are "conscious" of what we see
and hear, of what we remember, and of our own thoughts and
feelings. Most of us believe that tables and chairs are not
"conscious." We think that when we sit in a chair, we are aware
of sitting in it, but it is not aware of being sat in. It cannot
for a moment be doubted that we are right in believing that there
is SOME difference between us and the chair in this respect: so
much may be taken as fact, and as a datum for our inquiry. But as
soon as we try to say what exactly the difference is, we become
involved in perplexities. Is "consciousness" ultimate and simple,
something to be merely accepted and contemplated? Or is it
something complex, perhaps consisting in our way of behaving in
the presence of objects, or, alternatively, in the existence in
us of things called "ideas," having a certain relation to
objects, though different from them, and only symbolically
representative of them? Such questions are not easy to answer;
but until they are answered we cannot profess to know what we
mean by saying that we are possessed of "consciousness."

Before considering modern theories, let us look first at
consciousness from the standpoint of conventional psychology,
since this embodies views which naturally occur when we begin to
reflect upon the subject. For this purpose, let us as a
preliminary consider different ways of being conscious.

First, there is the way of PERCEPTION. We "perceive" tables and
chairs, horses and dogs, our friends, traffic passing in the
street--in short, anything which we recognize through the senses.
I leave on one side for the present the question whether pure
sensation is to be regarded as a form of consciousness: what I am
speaking of now is perception, where, according to conventional
psychology, we go beyond the sensation to the "thing" which it
represents. When you hear a donkey bray, you not only hear a
noise, but realize that it comes from a donkey. When you see a
table, you not only see a coloured surface, but realize that it
is hard. The addition of these elements that go beyond crude
sensation is said to constitute perception. We shall have more to
say about this at a later stage. For the moment, I am merely
concerned to note that perception of objects is one of the most
obvious examples of what is called "consciousness." We are
"conscious" of anything that we perceive.

We may take next the way of MEMORY. If I set to work to recall
what I did this morning, that is a form of consciousness
different from perception, since it is concerned with the past.
There are various problems as to how we can be conscious now of
what no longer exists. These will be dealt with incidentally when
we come to the analysis of memory.

From memory it is an easy step to what are called "ideas"--not in
the Platonic sense, but in that of Locke, Berkeley and Hume, in
which they are opposed to "impressions." You may be conscious of
a friend either by seeing him or by "thinking" of him; and by
"thought" you can be conscious of objects which cannot be seen,
such as the human race, or physiology. "Thought" in the narrower
sense is that form of consciousness which consists in "ideas" as
opposed to impressions or mere memories.

We may end our preliminary catalogue with BELIEF, by which I mean
that way of being conscious which may be either true or false. We
say that a man is "conscious of looking a fool," by which we mean
that he believes he looks a fool, and is not mistaken in this
belief. This is a different form of consciousness from any of the
earlier ones. It is the form which gives "knowledge" in the
strict sense, and also error. It is, at least apparently, more
complex than our previous forms of consciousness; though we shall
find that they are not so separable from it as they might appear
to be.

Besides ways of being conscious there are other things that would
ordinarily be called "mental," such as desire and pleasure and
pain. These raise problems of their own, which we shall reach in
Lecture III. But the hardest problems are those that arise
concerning ways of being "conscious." These ways, taken together,
are called the "cognitive" elements in mind, and it is these that
will occupy us most during the following lectures.

There is one element which SEEMS obviously in common among the
different ways of being conscious, and that is, that they are all
directed to OBJECTS. We are conscious "of" something. The
consciousness, it seems, is one thing, and that of which we are
conscious is another thing. Unless we are to acquiesce in the
view that we can never be conscious of anything outside our own
minds, we must say that the object of consciousness need not be
mental, though the consciousness must be. (I am speaking within
the circle of conventional doctrines, not expressing my own
beliefs.) This direction towards an object is commonly regarded
as typical of every form of cognition, and sometimes of mental
life altogether. We may distinguish two different tendencies in
traditional psychology. There are those who take mental phenomena
naively, just as they would physical phenomena. This school of
psychologists tends not to emphasize the object. On the other
hand, there are those whose primary interest is in the apparent
fact that we have KNOWLEDGE, that there is a world surrounding us
of which we are aware. These men are interested in the mind
because of its relation to the world, because knowledge, if it is
a fact, is a very mysterious one. Their interest in psychology is
naturally centred in the relation of consciousness to its object,
a problem which, properly, belongs rather to theory of knowledge.
We may take as one of the best and most typical representatives
of this school the Austrian psychologist Brentano, whose
"Psychology from the Empirical Standpoint,"* though published in
1874, is still influential and was the starting-point of a great
deal of interesting work. He says (p. 115):

* "Psychologie vom empirischen Standpunkte," vol. i, 1874. (The
second volume was never published.)

"Every psychical phenomenon is characterized by what the
scholastics of the Middle Ages called the intentional (also the
mental) inexistence of an object, and what we, although with not
quite unambiguous expressions, would call relation to a content,
direction towards an object (which is not here to be understood
as a reality), or immanent objectivity. Each contains something
in itself as an object, though not each in the same way. In
presentation something is presented, in judgment something is
acknowledged or rejected, in love something is loved, in hatred
hated, in desire desired, and so on.

"This intentional inexistence is exclusively peculiar to
psychical phenomena. No physical phenomenon shows anything
similar. And so we can define psychical phenomena by saying that
they are phenomena which intentionally contain an object in

The view here expressed, that relation to an object is an
ultimate irreducible characteristic of mental phenomena, is one
which I shall be concerned to combat. Like Brentano, I am
interested in psychology, not so much for its own sake, as for
the light that it may throw on the problem of knowledge. Until
very lately I believed, as he did, that mental phenomena have
essential reference to objects, except possibly in the case of
pleasure and pain. Now I no longer believe this, even in the case
of knowledge. I shall try to make my reasons for this rejection
clear as we proceed. It must be evident at first glance that the
analysis of knowledge is rendered more difficult by the
rejection; but the apparent simplicity of Brentano's view of
knowledge will be found, if I am not mistaken, incapable of
maintaining itself either against an analytic scrutiny or against
a host of facts in psycho-analysis and animal psychology. I do
not wish to minimize the problems. I will merely observe, in
mitigation of our prospective labours, that thinking, however it
is to be analysed, is in itself a delightful occupation, and that
there is no enemy to thinking so deadly as a false simplicity.
Travelling, whether in the mental or the physical world, is a
joy, and it is good to know that, in the mental world at least,
there are vast countries still very imperfectly explored.

The view expressed by Brentano has been held very generally, and
developed by many writers. Among these we may take as an example
his Austrian successor Meinong.* According to him there are three
elements involved in the thought of an object. These three he
calls the act, the content and the object. The act is the same in
any two cases of the same kind of consciousness; for instance, if
I think of Smith or think of Brown, the act of thinking, in
itself, is exactly similar on both occasions. But the content of
my thought, the particular event that is happening in my mind, is
different when I think of Smith and when I think of Brown. The
content, Meinong argues, must not be confounded with the object,
since the content must exist in my mind at the moment when I have
the thought, whereas the object need not do so. The object may be
something past or future; it may be physical, not mental; it may
be something abstract, like equality for example; it may be
something imaginary, like a golden mountain; or it may even be
something self-contradictory, like a round square. But in all
these cases, so he contends, the content exists when the thought
exists, and is what distinguishes it, as an occurrence, from
other thoughts.

* See, e.g. his article: "Ueber Gegenstande hoherer Ordnung und
deren Verhaltniss zur inneren Wahrnehmung," "Zeitschrift fur
Psychologie and Physiologie der Sinnesorgane," vol. xxi, pp.
182-272 (1899), especially pp. 185-8.

To make this theory concrete, let us suppose that you are
thinking of St. Paul's. Then, according to Meinong, we have to
distinguish three elements which are necessarily combined in
constituting the one thought. First, there is the act of
thinking, which would be just the same whatever you were thinking
about. Then there is what makes the character of the thought as
contrasted with other thoughts; this is the content. And finally
there is St. Paul's, which is the object of your thought. There
must be a difference between the content of a thought and what it
is about, since the thought is here and now, whereas what it is
about may not be; hence it is clear that the thought is not
identical with St. Paul's. This seems to show that we must
distinguish between content and object. But if Meinong is right,
there can be no thought without an object: the connection of the
two is essential. The object might exist without the thought, but
not the thought without the object: the three elements of act,
content and object are all required to constitute the one single
occurrence called "thinking of St. Paul's."

The above analysis of a thought, though I believe it to be
mistaken, is very useful as affording a schema in terms of which
other theories can be stated. In the remainder of the present
lecture I shall state in outline the view which I advocate, and
show how various other views out of which mine has grown result
from modifications of the threefold analysis into act, content
and object.

The first criticism I have to make is that the ACT seems
unnecessary and fictitious. The occurrence of the content of a
thought constitutes the occurrence of the thought. Empirically, I
cannot discover anything corresponding to the supposed act; and
theoretically I cannot see that it is indispensable. We say: "_I_
think so-and-so," and this word "I" suggests that thinking is the
act of a person. Meinong's "act" is the ghost of the subject, or
what once was the full-blooded soul. It is supposed that thoughts
cannot just come and go, but need a person to think them. Now, of
course it is true that thoughts can be collected into bundles, so
that one bundle is my thoughts, another is your thoughts, and a
third is the thoughts of Mr. Jones. But I think the person is not
an ingredient in the single thought: he is rather constituted by
relations of the thoughts to each other and to the body. This is
a large question, which need not, in its entirety, concern us at
present. All that I am concerned with for the moment is that the
grammatical forms "I think," "you think," and "Mr. Jones thinks,"
are misleading if regarded as indicating an analysis of a single
thought. It would be better to say "it thinks in me," like "it
rains here"; or better still, "there is a thought in me." This is
simply on the ground that what Meinong calls the act in thinking
is not empirically discoverable, or logically deducible from what
we can observe.

The next point of criticism concerns the relation of content and
object. The reference of thoughts to objects is not, I believe,
the simple direct essential thing that Brentano and Meinong
represent it as being. It seems to me to be derivative, and to
consist largely in BELIEFS: beliefs that what constitutes the
thought is connected with various other elements which together
make up the object. You have, say, an image of St. Paul's, or
merely the word "St. Paul's" in your head. You believe, however
vaguely and dimly, that this is connected with what you would see
if you went to St. Paul's, or what you would feel if you touched
its walls; it is further connected with what other people see and
feel, with services and the Dean and Chapter and Sir Christopher
Wren. These things are not mere thoughts of yours, but your
thought stands in a relation to them of which you are more or
less aware. The awareness of this relation is a further thought,
and constitutes your feeling that the original thought had an
"object." But in pure imagination you can get very similar
thoughts without these accompanying beliefs; and in this case
your thoughts do not have objects or seem to have them. Thus in
such instances you have content without object. On the other
hand, in seeing or hearing it would be less misleading to say
that you have object without content, since what you see or hear
is actually part of the physical world, though not matter in the
sense of physics. Thus the whole question of the relation of
mental occurrences to objects grows very complicated, and cannot
be settled by regarding reference to objects as of the essence of
thoughts. All the above remarks are merely preliminary, and will
be expanded later.

Speaking in popular and unphilosophical terms, we may say that
the content of a thought is supposed to be something in your head
when you think the thought, while the object is usually something
in the outer world. It is held that knowledge of the outer world
is constituted by the relation to the object, while the fact that
knowledge is different from what it knows is due to the fact that
knowledge comes by way of contents. We can begin to state the
difference between realism and idealism in terms of this
opposition of contents and objects. Speaking quite roughly and
approximately, we may say that idealism tends to suppress the
object, while realism tends to suppress the content. Idealism,
accordingly, says that nothing can be known except thoughts, and
all the reality that we know is mental; while realism maintains
that we know objects directly, in sensation certainly, and
perhaps also in memory and thought. Idealism does not say that
nothing can be known beyond the present thought, but it maintains
that the context of vague belief, which we spoke of in connection
with the thought of St. Paul's, only takes you to other thoughts,
never to anything radically different from thoughts. The
difficulty of this view is in regard to sensation, where it seems
as if we came into direct contact with the outer world. But the
Berkeleian way of meeting this difficulty is so familiar that I
need not enlarge upon it now. I shall return to it in a later
lecture, and will only observe, for the present, that there seem
to me no valid grounds for regarding what we see and hear as not
part of the physical world.

Realists, on the other hand, as a rule, suppress the content, and
maintain that a thought consists either of act and object alone,
or of object alone. I have been in the past a realist, and I
remain a realist as regards sensation, but not as regards memory
or thought. I will try to explain what seem to me to be the
reasons for and against various kinds of realism.

Modern idealism professes to be by no means confined to the
present thought or the present thinker in regard to its
knowledge; indeed, it contends that the world is so organic, so
dove-tailed, that from any one portion the whole can be inferred,
as the complete skeleton of an extinct animal can be inferred
from one bone. But the logic by which this supposed organic
nature of the world is nominally demonstrated appears to
realists, as it does to me, to be faulty. They argue that, if we
cannot know the physical world directly, we cannot really know
any thing outside our own minds: the rest of the world may be
merely our dream. This is a dreary view, and they there fore seek
ways of escaping from it. Accordingly they maintain that in
knowledge we are in direct contact with objects, which may be,
and usually are, outside our own minds. No doubt they are
prompted to this view, in the first place, by bias, namely, by
the desire to think that they can know of the existence of a
world outside themselves. But we have to consider, not what led
them to desire the view, but whether their arguments for it are

There are two different kinds of realism, according as we make a
thought consist of act and object, or of object alone. Their
difficulties are different, but neither seems tenable all
through. Take, for the sake of definiteness, the remembering of a
past event. The remembering occurs now, and is therefore
necessarily not identical with the past event. So long as we
retain the act, this need cause no difficulty. The act of
remembering occurs now, and has on this view a certain essential
relation to the past event which it remembers. There is no
LOGICAL objection to this theory, but there is the objection,
which we spoke of earlier, that the act seems mythical, and is
not to be found by observation. If, on the other hand, we try to
constitute memory without the act, we are driven to a content,
since we must have something that happens NOW, as opposed to the
event which happened in the past. Thus, when we reject the act,
which I think we must, we are driven to a theory of memory which
is more akin to idealism. These arguments, however, do not apply
to sensation. It is especially sensation, I think, which is
considered by those realists who retain only the object.* Their
views, which are chiefly held in America, are in large measure
derived from William James, and before going further it will be
well to consider the revolutionary doctrine which he advocated. I
believe this doctrine contains important new truth, and what I
shall have to say will be in a considerable measure inspired by

* This is explicitly the case with Mach's "Analysis of
Sensations," a book of fundamental importance in the present
connection. (Translation of fifth German edition, Open Court Co.,
1914. First German edition, 1886.)

William James's view was first set forth in an essay called "Does
'consciousness' exist?"* In this essay he explains how what used
to be the soul has gradually been refined down to the
"transcendental ego," which, he says, "attenuates itself to a
thoroughly ghostly condition, being only a name for the fact that
the 'content' of experience IS KNOWN. It loses personal form and
activity--these passing over to the content--and becomes a bare
Bewusstheit or Bewusstsein uberhaupt, of which in its own right
absolutely nothing can be said. I believe (he continues) that
'consciousness,' when once it has evaporated to this estate of
pure diaphaneity, is on the point of disappearing altogether. It
is the name of a nonentity, and has no right to a place among
first principles. Those who still cling to it are clinging to a
mere echo, the faint rumour left behind by the disappearing
'soul' upon the air of philosophy"(p. 2).

* "Journal of Philosophy, Psychology and Scientific Methods,"
vol. i, 1904. Reprinted in "Essays in Radical Empiricism"
(Longmans, Green & Co., 1912), pp. 1-38, to which references in
what follows refer.

He explains that this is no sudden change in his opinions. "For
twenty years past," he says, "I have mistrusted 'consciousness'
as an entity; for seven or eight years past I have suggested its
non-existence to my students, and tried to give them its
pragmatic equivalent in realities of experience. It seems to me
that the hour is ripe for it to be openly and universally
discarded"(p. 3).

His next concern is to explain away the air of paradox, for James
was never wilfully paradoxical. "Undeniably," he says,
"'thoughts' do exist." "I mean only to deny that the word stands
for an entity, but to insist most emphatically that it does stand
for a function. There is, I mean, no aboriginal stuff or quality
of being, contrasted with that of which material objects are
made, out of which our thoughts of them are made; but there is a
function in experience which thoughts perform, and for the
performance of which this quality of being is invoked. That
function is KNOWING"(pp. 3-4).

James's view is that the raw material out of which the world is
built up is not of two sorts, one matter and the other mind, but
that it is arranged in different patterns by its inter-relations,
and that some arrangements may be called mental, while others may
be called physical.

"My thesis is," he says, "that if we start with the supposition
that there is only one primal stuff or material in the world, a
stuff of which everything is composed, and if we call that stuff
'pure experience,' then knowing can easily be explained as a
particular sort of relation towards one another into which
portions of pure experience may enter. The relation itself is a
part of pure experience; one of its 'terms' becomes the subject
or bearer of the knowledge, the knower, the other becomes the
object known"(p. 4).

After mentioning the duality of subject and object, which is
supposed to constitute consciousness, he proceeds in italics:

He illustrates his meaning by the analogy of paint as it appears
in a paint-shop and as it appears in a picture: in the one case
it is just "saleable matter," while in the other it "performs a
spiritual function. Just so, I maintain (he continues), does a
given undivided portion of experience, taken in one context of
associates, play the part of a knower, of a state of mind, of
'consciousness'; while in a different context the same undivided
bit of experience plays the part of a thing known, of an
objective 'content.' In a word, in one group it figures as a
thought, in another group as a thing"(pp. 9-10).

He does not believe in the supposed immediate certainty of
thought. "Let the case be what it may in others," he says, "I am
as confident as I am of anything that, in myself, the stream of
thinking (which I recognize emphatically as a phenomenon) is only
a careless name for what, when scrutinized, reveals itself to
consist chiefly of the stream of my breathing. The 'I think'
which Kant said must be able to accompany all my objects, is the
'I breathe' which actually does accompany them"(pp. 36-37).

The same view of "consciousness" is set forth in the succeeding
essay, "A World of Pure Experience" (ib., pp. 39-91). The use of
the phrase "pure experience" in both essays points to a lingering
influence of idealism. "Experience," like "consciousness," must
be a product, not part of the primary stuff of the world. It must
be possible, if James is right in his main contentions, that
roughly the same stuff, differently arranged, would not give rise
to anything that could be called "experience." This word has been
dropped by the American realists, among whom we may mention
specially Professor R. B. Perry of Harvard and Mr. Edwin B. Holt.
The interests of this school are in general philosophy and the
philosophy of the sciences, rather than in psychology; they have
derived a strong impulsion from James, but have more interest
than he had in logic and mathematics and the abstract part of
philosophy. They speak of "neutral" entities as the stuff out of
which both mind and matter are constructed. Thus Holt says: "If
the terms and propositions of logic must be substantialized, they
are all strictly of one substance, for which perhaps the least
dangerous name is neutral- stuff. The relation of neutral-stuff
to matter and mind we shall have presently to consider at
considerable length." *

* "The Concept of Consciousness" (Geo. Allen & Co., 1914), p. 52.

My own belief--for which the reasons will appear in subsequent
lectures--is that James is right in rejecting consciousness as an
entity, and that the American realists are partly right, though
not wholly, in considering that both mind and matter are composed
of a neutral-stuff which, in isolation, is neither mental nor
material. I should admit this view as regards sensations: what is
heard or seen belongs equally to psychology and to physics. But I
should say that images belong only to the mental world, while
those occurrences (if any) which do not form part of any
"experience" belong only to the physical world. There are, it
seems to me, prima facie different kinds of causal laws, one
belonging to physics and the other to psychology. The law of
gravitation, for example, is a physical law, while the law of
association is a psychological law. Sensations are subject to
both kinds of laws, and are therefore truly "neutral" in Holt's
sense. But entities subject only to physical laws, or only to
psychological laws, are not neutral, and may be called
respectively purely material and purely mental. Even those,
however, which are purely mental will not have that intrinsic
reference to objects which Brentano assigns to them and which
constitutes the essence of "consciousness" as ordinarily
understood. But it is now time to pass on to other modern
tendencies, also hostile to "consciousness."

There is a psychological school called "Behaviourists," of whom
the protagonist is Professor John B. Watson,* formerly of the
Johns Hopkins University. To them also, on the whole, belongs
Professor John Dewey, who, with James and Dr. Schiller, was one
of the three founders of pragmatism. The view of the
"behaviourists" is that nothing can be known except by external
observation. They deny altogether that there is a separate source
of knowledge called "introspection," by which we can know things
about ourselves which we could never observe in others. They do
not by any means deny that all sorts of things MAY go on in our
minds: they only say that such things, if they occur, are not
susceptible of scientific observation, and do not therefore
concern psychology as a science. Psychology as a science, they
say, is only concerned with BEHAVIOUR, i.e. with what we DO; this
alone, they contend, can be accurately observed. Whether we think
meanwhile, they tell us, cannot be known; in their observation of
the behaviour of human beings, they have not so far found any
evidence of thought. True, we talk a great deal, and imagine that
in so doing we are showing that we can think; but behaviourists
say that the talk they have to listen to can be explained without
supposing that people think. Where you might expect a chapter on
"thought processes" you come instead upon a chapter on "The
Language Habit." It is humiliating to find how terribly adequate
this hypothesis turns out to be.

* See especially his "Behavior: an Introduction to Comparative
Psychology," New York, 1914.

Behaviourism has not, however, sprung from observing the folly of
men. It is the wisdom of animals that has suggested the view. It
has always been a common topic of popular discussion whether
animals "think." On this topic people are prepared to take sides
without having the vaguest idea what they mean by "thinking."
Those who desired to investigate such questions were led to
observe the behaviour of animals, in the hope that their
behaviour would throw some light on their mental faculties. At
first sight, it might seem that this is so. People say that a dog
"knows" its name because it comes when it is called, and that it
"remembers" its master, because it looks sad in his absence, but
wags its tail and barks when he returns. That the dog behaves in
this way is matter of observation, but that it "knows" or
"remembers" anything is an inference, and in fact a very doubtful
one. The more such inferences are examined, the more precarious
they are seen to be. Hence the study of animal behaviour has been
gradually led to abandon all attempt at mental interpretation.
And it can hardly be doubted that, in many cases of complicated
behaviour very well adapted to its ends, there can be no
prevision of those ends. The first time a bird builds a nest, we
can hardly suppose it knows that there will be eggs to be laid in
it, or that it will sit on the eggs, or that they will hatch into
young birds. It does what it does at each stage because instinct
gives it an impulse to do just that, not because it foresees and
desires the result of its actions.*

* An interesting discussion of the question whether instinctive
actions, when first performed, involve any prevision, however
vague, will be found in Lloyd Morgan's "Instinct and Experience"
(Methuen, 1912), chap. ii.

Careful observers of animals, being anxious to avoid precarious
inferences, have gradually discovered more and more how to give
an account of the actions of animals without assuming what we
call "consciousness." It has seemed to the behaviourists that
similar methods can be applied to human behaviour, without
assuming anything not open to external observation. Let us give a
crude illustration, too crude for the authors in question, but
capable of affording a rough insight into their meaning. Suppose
two children in a school, both of whom are asked "What is six
times nine?" One says fifty-four, the other says fifty-six. The
one, we say, "knows" what six times nine is, the other does not.
But all that we can observe is a certain language-habit. The one
child has acquired the habit of saying "six times nine is
fifty-four"; the other has not. There is no more need of
"thought" in this than there is when a horse turns into his
accustomed stable; there are merely more numerous and complicated
habits. There is obviously an observable fact called "knowing"
such-and-such a thing; examinations are experiments for
discovering such facts. But all that is observed or discovered is
a certain set of habits in the use of words. The thoughts (if
any) in the mind of the examinee are of no interest to the
examiner; nor has the examiner any reason to suppose even the
most successful examinee capable of even the smallest amount of

Thus what is called "knowing," in the sense in which we can
ascertain what other people "know," is a phenomenon exemplified
in their physical behaviour, including spoken and written words.
There is no reason--so Watson argues--to suppose that their
knowledge IS anything beyond the habits shown in this behaviour:
the inference that other people have something nonphysical called
"mind" or "thought" is therefore unwarranted.

So far, there is nothing particularly repugnant to our prejudices
in the conclusions of the behaviourists. We are all willing to
admit that other people are thoughtless. But when it comes to
ourselves, we feel convinced that we can actually perceive our
own thinking. "Cogito, ergo sum" would be regarded by most people
as having a true premiss. This, however, the behaviourist denies.
He maintains that our knowledge of ourselves is no different in
kind from our knowledge of other people. We may see MORE, because
our own body is easier to observe than that of other people; but
we do not see anything radically unlike what we see of others.
Introspection, as a separate source of knowledge, is entirely
denied by psychologists of this school. I shall discuss this
question at length in a later lecture; for the present I will
only observe that it is by no means simple, and that, though I
believe the behaviourists somewhat overstate their case, yet
there is an important element of truth in their contention, since
the things which we can discover by introspection do not seem to
differ in any very fundamental way from the things which we
discover by external observation.

So far, we have been principally concerned with knowing. But it
might well be maintained that desiring is what is really most
characteristic of mind. Human beings are constantly engaged in
achieving some end they feel pleasure in success and pain in
failure. In a purely material world, it may be said, there would
be no opposition of pleasant and unpleasant, good and bad, what
is desired and what is feared. A man's acts are governed by
purposes. He decides, let us suppose, to go to a certain place,
whereupon he proceeds to the station, takes his ticket and enters
the train. If the usual route is blocked by an accident, he goes
by some other route. All that he does is determined--or so it
seems--by the end he has in view, by what lies in front of him,
rather than by what lies behind. With dead matter, this is not
the case. A stone at the top of a hill may start rolling, but it
shows no pertinacity in trying to get to the bottom. Any ledge or
obstacle will stop it, and it will exhibit no signs of discontent
if this happens. It is not attracted by the pleasantness of the
valley, as a sheep or cow might be, but propelled by the
steepness of the hill at the place where it is. In all this we
have characteristic differences between the behaviour of animals
and the behaviour of matter as studied by physics.

Desire, like knowledge, is, of course, in one sense an observable
phenomenon. An elephant will eat a bun, but not a mutton chop; a
duck will go into the water, but a hen will not. But when we
think of our own. desires, most people believe that we can know
them by an immediate self-knowledge which does not depend upon
observation of our actions. Yet if this were the case, it would
be odd that people are so often mistaken as to what they desire.
It is matter of common observation that "so-and-so does not know
his own motives," or that "A is envious of B and malicious about
him, but quite unconscious of being so." Such people are called
self-deceivers, and are supposed to have had to go through some
more or less elaborate process of concealing from themselves what
would otherwise have been obvious. I believe that this is an
entire mistake. I believe that the discovery of our own motives
can only be made by the same process by which we discover other
people's, namely, the process of observing our actions and
inferring the desire which could prompt them. A desire is
"conscious" when we have told ourselves that we have it. A hungry
man may say to himself: "Oh, I do want my lunch." Then his desire
is "conscious." But it only differs from an "unconscious" desire
by the presence of appropriate words, which is by no means a
fundamental difference.

The belief that a motive is normally conscious makes it easier to
be mistaken as to our own motives than as to other people's. When
some desire that we should be ashamed of is attributed to us, we
notice that we have never had it consciously, in the sense of
saying to ourselves, "I wish that would happen." We therefore
look for some other interpretation of our actions, and regard our
friends as very unjust when they refuse to be convinced by our
repudiation of what we hold to be a calumny. Moral considerations
greatly increase the difficulty of clear thinking in this matter.
It is commonly argued that people are not to blame for
unconscious motives, but only for conscious ones. In order,
therefore, to be wholly virtuous it is only necessary to repeat
virtuous formulas. We say: "I desire to be kind to my friends,
honourable in business, philanthropic towards the poor,
public-spirited in politics." So long as we refuse to allow
ourselves, even in the watches of the night, to avow any contrary
desires, we may be bullies at home, shady in the City, skinflints
in paying wages and profiteers in dealing with the public; yet,
if only conscious motives are to count in moral valuation, we
shall remain model characters. This is an agreeable doctrine, and
it is not surprising that men are un willing to abandon it. But
moral considerations are the worst enemies of the scientific
spirit and we must dismiss them from our minds if we wish to
arrive at truth.

I believe--as I shall try to prove in a later lecture -that
desire, like force in mechanics, is of the nature of a convenient
fiction for describing shortly certain laws of behaviour. A
hungry animal is restless until it finds food; then it becomes
quiescent. The thing which will bring a restless condition to an
end is said to be what is desired. But only experience can show
what will have this sedative effect, and it is easy to make
mistakes. We feel dissatisfaction, and think that such and-such a
thing would remove it; but in thinking this, we are theorizing,
not observing a patent fact. Our theorizing is often mistaken,
and when it is mistaken there is a difference between what we
think we desire and what in fact will bring satisfaction. This is
such a common phenomenon that any theory of desire which fails to
account for it must be wrong.

What have been called "unconscious" desires have been brought
very much to the fore in recent years by psycho-analysis.
Psycho-analysis, as every one knows, is primarily a method of
understanding hysteria and certain forms of insanity*; but it has
been found that there is much in the lives of ordinary men and
women which bears a humiliating resemblance to the delusions of
the insane. The connection of dreams, irrational beliefs and
foolish actions with unconscious wishes has been brought to
light, though with some exaggeration, by Freud and Jung and their
followers. As regards the nature of these unconscious wishes, it
seems to me--though as a layman I speak with diffidence--that
many psycho-analysts are unduly narrow; no doubt the wishes they
emphasize exist, but others, e.g. for honour and power, are
equally operative and equally liable to concealment. This,
however, does not affect the value of their general theories from
the point of view of theoretic psychology, and it is from this
point of view that their results are important for the analysis
of mind.

* There is a wide field of "unconscious" phenomena which does not
depend upon psycho-analytic theories. Such occurrences as
automatic writing lead Dr. Morton Prince to say: "As I view this
question of the subconscious, far too much weight is given to the
point of awareness or not awareness of our conscious processes.
As a matter of fact, we find entirely identical phenomena, that
is, identical in every respect but one-that of awareness in which
sometimes we are aware of these conscious phenomena and sometimes
not"(p. 87 of "Subconscious Phenomena," by various authors,
Rebman). Dr. Morton Price conceives that there may be
"consciousness" without "awareness." But this is a difficult
view, and one which makes some definition of "consciousness"
imperative. For nay part, I cannot see how to separate
consciousness from awareness.

What, I think, is clearly established, is that a man's actions
and beliefs may be wholly dominated by a desire of which he is
quite unconscious, and which he indignantly repudiates when it is
suggested to him. Such a desire is generally, in morbid cases, of
a sort which the patient would consider wicked; if he had to
admit that he had the desire, he would loathe himself. Yet it is
so strong that it must force an outlet for itself; hence it
becomes necessary to entertain whole systems of false beliefs in
order to hide the nature of what is desired. The resulting
delusions in very many cases disappear if the hysteric or lunatic
can be made to face the facts about himself. The consequence of
this is that the treatment of many forms of insanity has grown
more psychological and less physiological than it used to be.
Instead of looking for a physical defect in the brain, those who
treat delusions look for the repressed desire which has found
this contorted mode of expression. For those who do not wish to
plunge into the somewhat repulsive and often rather wild theories
of psychoanalytic pioneers, it will be worth while to read a
little book by Dr. Bernard Hart on "The Psychology of Insanity."*
On this question of the mental as opposed to the physiological
study of the causes of insanity, Dr. Hart says:

* Cambridge, 1912; 2nd edition, 1914. The following references
are to the second edition.

"The psychological conception [of insanity] is based on the view
that mental processes can be directly studied without any
reference to the accompanying changes which are presumed to take
place in the brain, and that insanity may therefore be properly
attacked from the standpoint of psychology"(p. 9).

This illustrates a point which I am anxious to make clear from
the outset. Any attempt to classify modern views, such as I
propose to advocate, from the old standpoint of materialism and
idealism, is only misleading. In certain respects, the views
which I shall be setting forth approximate to materialism; in
certain others, they approximate to its opposite. On this
question of the study of delusions, the practical effect of the
modern theories, as Dr. Hart points out, is emancipation from the
materialist method. On the other hand, as he also points out (pp.
38-9), imbecility and dementia still have to be considered
physiologically, as caused by defects in the brain. There is no
inconsistency in this If, as we maintain, mind and matter are
neither of them the actual stuff of reality, but different
convenient groupings of an underlying material, then, clearly,
the question whether, in regard to a given phenomenon, we are to
seek a physical or a mental cause, is merely one to be decided by
trial. Metaphysicians have argued endlessly as to the interaction
of mind and matter. The followers of Descartes held that mind and
matter are so different as to make any action of the one on the
other impossible. When I will to move my arm, they said, it is
not my will that operates on my arm, but God, who, by His
omnipotence, moves my arm whenever I want it moved. The modern
doctrine of psychophysical parallelism is not appreciably
different from this theory of the Cartesian school.
Psycho-physical parallelism is the theory that mental and
physical events each have causes in their own sphere, but run on
side by side owing to the fact that every state of the brain
coexists with a definite state of the mind, and vice versa. This
view of the reciprocal causal independence of mind and matter has
no basis except in metaphysical theory.* For us, there is no
necessity to make any such assumption, which is very difficult to
harmonize with obvious facts. I receive a letter inviting me to
dinner: the letter is a physical fact, but my apprehension of its
meaning is mental. Here we have an effect of matter on mind. In
consequence of my apprehension of the meaning of the letter, I go
to the right place at the right time; here we have an effect of
mind on matter. I shall try to persuade you, in the course of
these lectures, that matter is not so material and mind not so
mental as is generally supposed. When we are speaking of matter,
it will seem as if we were inclining to idealism; when we are
speaking of mind, it will seem as if we were inclining to
materialism. Neither is the truth. Our world is to be constructed
out of what the American realists call "neutral" entities, which
have neither the hardness and indestructibility of matter, nor
the reference to objects which is supposed to characterize mind.

* It would seem, however, that Dr. Hart accepts this theory as 8
methodological precept. See his contribution to "Subconscious
Phenomena" (quoted above), especially pp. 121-2.

There is, it is true, one objection which might be felt, not
indeed to the action of matter on mind, but to the action of mind
on matter. The laws of physics, it may be urged, are apparently
adequate to explain everything that happens to matter, even when
it is matter in a man's brain. This, however, is only a
hypothesis, not an established theory. There is no cogent
empirical reason for supposing that the laws determining the
motions of living bodies are exactly the same as those that apply
to dead matter. Sometimes, of course, they are clearly the same.
When a man falls from a precipice or slips on a piece of orange
peel, his body behaves as if it were devoid of life. These are
the occasions that make Bergson laugh. But when a man's bodily
movements are what we call "voluntary," they are, at any rate
prima facie, very different in their laws from the movements of
what is devoid of life. I do not wish to say dogmatically that
the difference is irreducible; I think it highly probable that it
is not. I say only that the study of the behaviour of living
bodies, in the present state of our knowledge, is distinct from
physics. The study of gases was originally quite distinct from
that of rigid bodies, and would never have advanced to its
present state if it had not been independently pursued. Nowadays
both the gas and the rigid body are manufactured out of a more
primitive and universal kind of matter. In like manner, as a
question of methodology, the laws of living bodies are to be
studied, in the first place, without any undue haste to
subordinate them to the laws of physics. Boyle's law and the rest
had to be discovered before the kinetic theory of gases became
possible. But in psychology we are hardly yet at the stage of
Boyle's law. Meanwhile we need not be held up by the bogey of the
universal rigid exactness of physics. This is, as yet, a mere
hypothesis, to be tested empirically without any preconceptions.
It may be true, or it may not. So far, that is all we can say.

Returning from this digression to our main topic, namely, the
criticism of "consciousness," we observe that Freud and his
followers, though they have demonstrated beyond dispute the
immense importance of "unconscious" desires in determining our
actions and beliefs, have not attempted the task of telling us
what an "unconscious" desire actually is, and have thus invested
their doctrine with an air of mystery and mythology which forms a
large part of its popular attractiveness. They speak always as
though it were more normal for a desire to be conscious, and as
though a positive cause had to be assigned for its being
unconscious. Thus "the unconscious" becomes a sort of underground
prisoner, living in a dungeon, breaking in at long intervals upon
our daylight respectability with dark groans and maledictions and
strange atavistic lusts. The ordinary reader, almost inevitably,
thinks of this underground person as another consciousness,
prevented by what Freud calls the "censor" from making his voice
heard in company, except on rare and dreadful occasions when he
shouts so loud that every one hears him and there is a scandal.
Most of us like the idea that we could be desperately wicked if
only we let ourselves go. For this reason, the Freudian
"unconscious" has been a consolation to many quiet and
well-behaved persons.

I do not think the truth is quite so picturesque as this. I
believe an "unconscious" desire is merely a causal law of our
behaviour,* namely, that we remain restlessly active until a
certain state of affairs is realized, when we achieve temporary
equilibrium If we know beforehand what this state of affairs is,
our desire is conscious; if not, unconscious. The unconscious
desire is not something actually existing, but merely a tendency
to a certain behaviour; it has exactly the same status as a force
in dynamics. The unconscious desire is in no way mysterious; it
is the natural primitive form of desire, from which the other has
developed through our habit of observing and theorizing (often
wrongly). It is not necessary to suppose, as Freud seems to do,
that every unconscious wish was once conscious, and was then, in
his terminology, "repressed" because we disapproved of it. On the
contrary, we shall suppose that, although Freudian "repression"
undoubtedly occurs and is important, it is not the usual reason
for unconsciousness of our wishes. The usual reason is merely
that wishes are all, to begin with, unconscious, and only become
known when they are actively noticed. Usually, from laziness,
people do not notice, but accept the theory of human nature which
they find current, and attribute to themselves whatever wishes
this theory would lead them to expect. We used to be full of
virtuous wishes, but since Freud our wishes have become, in the
words of the Prophet Jeremiah, "deceitful above all things and
desperately wicked." Both these views, in most of those who have
held them, are the product of theory rather than observation, for
observation requires effort, whereas repeating phrases does not.

* Cf. Hart, "The Psychology of Insanity," p. 19.

The interpretation of unconscious wishes which I have been
advocating has been set forth briefly by Professor John B. Watson
in an article called "The Psychology of Wish Fulfilment," which
appeared in "The Scientific Monthly" in November, 1916. Two
quotations will serve to show his point of view:

"The Freudians (he says) have made more or less of a
'metaphysical entity' out of the censor. They suppose that when
wishes are repressed they are repressed into the 'unconscious,'
and that this mysterious censor stands at the trapdoor lying
between the conscious and the unconscious. Many of us do not
believe in a world of the unconscious (a few of us even have
grave doubts about the usefulness of the term consciousness),
hence we try to explain censorship along ordinary biological
lines. We believe that one group of habits can 'down' another
group of habits--or instincts. In this case our ordinary system
of habits--those which we call expressive of our 'real selves'--
inhibit or quench (keep inactive or partially inactive) those
habits and instinctive tendencies which belong largely in the
past"(p. 483).

Again, after speaking of the frustration of some impulses which
is involved in acquiring the habits of a civilized adult, he

"It is among these frustrated impulses that I would find the
biological basis of the unfulfilled wish. Such 'wishes' need
never have been 'conscious,' and NEED NEVER HAVE BEEN SUPPRESSED
this that there is no particular reason for applying the term
'wish' to such tendencies"(p. 485).

One of the merits of the general analysis of mind which we shall
be concerned with in the following lectures is that it removes
the atmosphere of mystery from the phenomena brought to light by
the psycho-analysts. Mystery is delightful, but unscientific,
since it depends upon ignorance. Man has developed out of the
animals, and there is no serious gap between him and the amoeba.
Something closely analogous to knowledge and desire, as regards
its effects on behaviour, exists among animals, even where what
we call "consciousness" is hard to believe in; something equally
analogous exists in ourselves in cases where no trace of
"consciousness" can be found. It is therefore natural to suppose
that, what ever may be the correct definition of "consciousness,"
"consciousness" is not the essence of life or mind. In the
following lectures, accordingly, this term will disappear until
we have dealt with words, when it will re-emerge as mainly a
trivial and unimportant outcome of linguistic habits.

download audio

In attempting to understand the elements out of which mental
phenomena are compounded, it is of the greatest importance to
remember that from the protozoa to man there is nowhere a very
wide gap either in structure or in behaviour. From this fact it
is a highly probable inference that there is also nowhere a very
wide mental gap. It is, of course, POSSIBLE that there may be, at
certain stages in evolution, elements which are entirely new from
the standpoint of analysis, though in their nascent form they
have little influence on behaviour and no very marked
correlatives in structure. But the hypothesis of continuity in
mental development is clearly preferable if no psychological
facts make it impossible. We shall find, if I am not mistaken,
that there are no facts which refute the hypothesis of mental
continuity, and that, on the other hand, this hypothesis affords
a useful test of suggested theories as to the nature of mind.

The hypothesis of mental continuity throughout organic evolution
may be used in two different ways. On the one hand, it may be
held that we have more knowledge of our own minds than those of
animals, and that we should use this knowledge to infer the
existence of something similar to our own mental processes in
animals and even in plants. On the other hand, it may be held
that animals and plants present simpler phenomena, more easily
analysed than those of human minds; on this ground it may be
urged that explanations which are adequate in the case of animals
ought not to be lightly rejected in the case of man. The
practical effects of these two views are diametrically opposite:
the first leads us to level up animal intelligence with what we
believe ourselves to know about our own intelligence, while the
second leads us to attempt a levelling down of our own
intelligence to something not too remote from what we can observe
in animals. It is therefore important to consider the relative
justification of the two ways of applying the principle of

It is clear that the question turns upon another, namely, which
can we know best, the psychology of animals or that of human
beings? If we can know most about animals, we shall use this
knowledge as a basis for inference about human beings; if we can
know most about human beings, we shall adopt the opposite
procedure. And the question whether we can know most about the
psychology of human beings or about that of animals turns upon
yet another, namely: Is introspection or external observation the
surer method in psychology? This is a question which I propose to
discuss at length in Lecture VI; I shall therefore content myself
now with a statement of the conclusions to be arrived at.

We know a great many things concerning ourselves which we cannot
know nearly so directly concerning animals or even other people.
We know when we have a toothache, what we are thinking of, what
dreams we have when we are asleep, and a host of other
occurrences which we only know about others when they tell us of
them, or otherwise make them inferable by their behaviour. Thus,
so far as knowledge of detached facts is concerned, the advantage
is on the side of self-knowledge as against external observation.

But when we come to the analysis and scientific understanding of
the facts, the advantages on the side of self-knowledge become
far less clear. We know, for example, that we have desires and
beliefs, but we do not know what constitutes a desire or a
belief. The phenomena are so familiar that it is difficult to
realize how little we really know about them. We see in animals,
and to a lesser extent in plants, behaviour more or less similar
to that which, in us, is prompted by desires and beliefs, and we
find that, as we descend in the scale of evolution, behaviour
becomes simpler, more easily reducible to rule, more
scientifically analysable and predictable. And just because we
are not misled by familiarity we find it easier to be cautious in
interpreting behaviour when we are dealing with phenomena remote
from those of our own minds: Moreover, introspection, as
psychoanalysis has demonstrated, is extraordinarily fallible even
in cases where we feel a high degree of certainty. The net result
seems to be that, though self-knowledge has a definite and
important contribution to make to psychology, it is exceedingly
misleading unless it is constantly checked and controlled by the
test of external observation, and by the theories which such
observation suggests when applied to animal behaviour. On the
whole, therefore, there is probably more to be learnt about human
psychology from animals than about animal psychology from human
beings; but this conclusion is one of degree, and must not be
pressed beyond a point.

It is only bodily phenomena that can be directly observed in
animals, or even, strictly speaking, in other human beings. We
can observe such things as their movements, their physiological
processes, and the sounds they emit. Such things as desires and
beliefs, which seem obvious to introspection, are not visible
directly to external observation. Accordingly, if we begin our
study of psychology by external observation, we must not begin by
assuming such things as desires and beliefs, but only such things
as external observation can reveal, which will be characteristics
of the movements and physiological processes of animals. Some
animals, for example, always run away from light and hide
themselves in dark places. If you pick up a mossy stone which is
lightly embedded in the earth, you will see a number of small
animals scuttling away from the unwonted daylight and seeking
again the darkness of which you have deprived them. Such animals
are sensitive to light, in the sense that their movements are
affected by it; but it would be rash to infer that they have
sensations in any way analogous to our sensations of sight. Such
inferences, which go beyond the observable facts, are to be
avoided with the utmost care.

It is customary to divide human movements into three classes,
voluntary, reflex and mechanical. We may illustrate the
distinction by a quotation from William James ("Psychology," i,

"If I hear the conductor calling 'all aboard' as I enter the
depot, my heart first stops, then palpitates, and my legs respond
to the air-waves falling on my tympanum by quickening their
movements. If I stumble as I run, the sensation of falling
provokes a movement of the hands towards the direction of the
fall, the effect of which is to shield the body from too sudden a
shock. If a cinder enter my eye, its lids close forcibly and a
copious flow of tears tends to wash it out.

"These three responses to a sensational stimulus differ, however,
in many respects. The closure of the eye and the lachrymation are
quite involuntary, and so is the disturbance of the heart. Such
involuntary responses we know as 'reflex' acts. The motion of the
arms to break the shock of falling may also be called reflex,
since it occurs too quickly to be deliberately intended. Whether
it be instinctive or whether it result from the pedestrian
education of childhood may be doubtful; it is, at any rate, less
automatic than the previous acts, for a man might by conscious
effort learn to perform it more skilfully, or even to suppress it
altogether. Actions of this kind, with which instinct and
volition enter upon equal terms, have been called 'semi-reflex.'
The act of running towards the train, on the other hand, has no
instinctive element about it. It is purely the result of
education, and is preceded by a consciousness of the purpose to
be attained and a distinct mandate of the will. It is a
'voluntary act.' Thus the animal's reflex and voluntary
performances shade into each other gradually, being connected by
acts which may often occur automatically, but may also be
modified by conscious intelligence.

"An outside observer, unable to perceive the accompanying
consciousness, might be wholly at a loss to discriminate between
the automatic acts and those which volition escorted. But if the
criterion of mind's existence be the choice of the proper means
for the attainment of a supposed end, all the acts alike seem to
be inspired by intelligence, for APPROPRIATENESS characterizes
them all alike. "

There is one movement, among those that James mentions at first,
which is not subsequently classified, namely, the stumbling. This
is the kind of movement which may be called "mechanical"; it is
evidently of a different kind from either reflex or voluntary
movements, and more akin to the movements of dead matter. We may
define a movement of an animal's body as "mechanical" when it
proceeds as if only dead matter were involved. For example, if
you fall over a cliff, you move under the influence of
gravitation, and your centre of gravity describes just as correct
a parabola as if you were already dead. Mechanical movements have
not the characteristic of appropriateness, unless by accident, as
when a drunken man falls into a waterbutt and is sobered. But
reflex and voluntary movements are not ALWAYS appropriate, unless
in some very recondite sense. A moth flying into a lamp is not
acting sensibly; no more is a man who is in such a hurry to get
his ticket that he cannot remember the name of his destination.
Appropriateness is a complicated and merely approximate idea, and
for the present we shall do well to dismiss it from our thoughts.

As James states, there is no difference, from the point of view
of the outside observer, between voluntary and reflex movements.
The physiologist can discover that both depend upon the nervous
system, and he may find that the movements which we call
voluntary depend upon higher centres in the brain than those that
are reflex. But he cannot discover anything as to the presence or
absence of "will" or "consciousness," for these things can only
be seen from within, if at all. For the present, we wish to place
ourselves resolutely in the position of outside observers; we
will therefore ignore the distinction between voluntary and
reflex movements. We will call the two together "vital"
movements. We may then distinguish "vital" from mechanical
movements by the fact that vital movements depend for their
causation upon the special properties of the nervous system,
while mechanical movements depend only upon the properties which
animal bodies share with matter in general.

There is need for some care if the distinction between mechanical
and vital movements is to be made precise. It is quite likely
that, if we knew more about animal bodies, we could deduce all
their movements from the laws of chemistry and physics. It is
already fairly easy to see how chemistry reduces to physics, i.e.
how the differences between different chemical elements can be
accounted for by differences of physical structure, the
constituents of the structure being electrons which are exactly
alike in all kinds of matter. We only know in part how to reduce
physiology to chemistry, but we know enough to make it likely
that the reduction is possible. If we suppose it effected, what
would become of the difference between vital and mechanical

Some analogies will make the difference clear. A shock to a mass
of dynamite produces quite different effects from an equal shock
to a mass of steel: in the one case there is a vast explosion,
while in the other case there is hardly any noticeable
disturbance. Similarly, you may sometimes find on a mountain-side
a large rock poised so delicately that a touch will set it
crashing down into the valley, while the rocks all round are so
firm that only a considerable force can dislodge them What is
analogous in these two cases is the existence of a great store of
energy in unstable equilibrium ready to burst into violent motion
by the addition of a very slight disturbance. Similarly, it
requires only a very slight expenditure of energy to send a
post-card with the words "All is discovered; fly!" but the effect
in generating kinetic energy is said to be amazing. A human body,
like a mass of dynamite, contains a store of energy in unstable
equilibrium, ready to be directed in this direction or that by a
disturbance which is physically very small, such as a spoken
word. In all such cases the reduction of behaviour to physical
laws can only be effected by entering into great minuteness; so
long as we confine ourselves to the observation of comparatively
large masses, the way in which the equilibrium will be upset
cannot be determined. Physicists distinguish between macroscopic
and microscopic equations: the former determine the visible
movements of bodies of ordinary size, the latter the minute
occurrences in the smallest parts. It is only the microscopic
equations that are supposed to be the same for all sorts of
matter. The macroscopic equations result from a process of
averaging out, and may be different in different cases. So, in
our instance, the laws of macroscopic phenomena are different for
mechanical and vital movements, though the laws of microscopic
phenomena may be the same.

We may say, speaking somewhat roughly, that a stimulus applied to
the nervous system, like a spark to dynamite, is able to take
advantage of the stored energy in unstable equilibrium, and thus
to produce movements out of proportion to the proximate cause.
Movements produced in this way are vital movements, while
mechanical movements are those in which the stored energy of a
living body is not involved. Similarly dynamite may be exploded,
thereby displaying its characteristic properties, or may (with
due precautions) be carted about like any other mineral. The
explosion is analogous to vital movements, the carting about to
mechanical movements.

Mechanical movements are of no interest to the psychologist, and
it has only been necessary to define them in order to be able to
exclude them. When a psychologist studies behaviour, it is only
vital movements that concern him. We shall, therefore, proceed to
ignore mechanical movements, and study only the properties of the

The next point is to distinguish between movements that are
instinctive and movements that are acquired by experience. This
distinction also is to some extent one of degree. Professor Lloyd
Morgan gives the following definition of "instinctive behaviour":

"That which is, on its first occurrence, independent of prior
experience; which tends to the well-being of the individual and
the preservation of the race; which is similarly performed by all
members of the same more or less restricted group of animals; and
which may be subject to subsequent modification under the
guidance of experience." *

* "Instinct and Experience" (Methuen, 1912) p. 5.

This definition is framed for the purposes of biology, and is in
some respects unsuited to the needs of psychology. Though perhaps
unavoidable, allusion to "the same more or less restricted group
of animals" makes it impossible to judge what is instinctive in
the behaviour of an isolated individual. Moreover, "the
well-being of the individual and the preservation of the race" is
only a usual characteristic, not a universal one, of the sort of
movements that, from our point of view, are to be called
instinctive; instances of harmful instincts will be given
shortly. The essential point of the definition, from our point of
view, is that an instinctive movement is in dependent of prior

We may say that an "instinctive" movement is a vital movement
performed by an animal the first time that it finds itself in a
novel situation; or, more correctly, one which it would perform
if the situation were novel.* The instincts of an animal are
different at different periods of its growth, and this fact may
cause changes of behaviour which are not due to learning. The
maturing and seasonal fluctuation of the sex-instinct affords a
good illustration. When the sex-instinct first matures, the
behaviour of an animal in the presence of a mate is different
from its previous behaviour in similar circumstances, but is not
learnt, since it is just the same if the animal has never
previously been in the presence of a mate.

* Though this can only be decided by comparison with other
members of the species, and thus exposes us to the need of
comparison which we thought an objection to Professor Lloyd
Morgan's definition.

On the other hand, a movement is "learnt," or embodies a "habit,"
if it is due to previous experience of similar situations, and is
not what it would be if the animal had had no such experience.

There are various complications which blur the sharpness of this
distinction in practice. To begin with, many instincts mature
gradually, and while they are immature an animal may act in a
fumbling manner which is very difficult to distinguish from
learning. James ("Psychology," ii, 407) maintains that children
walk by instinct, and that the awkwardness of their first
attempts is only due to the fact that the instinct has not yet
ripened. He hopes that "some scientific widower, left alone with
his offspring at the critical moment, may ere long test this
suggestion on the living subject." However this may be, he quotes
evidence to show that "birds do not LEARN to fly," but fly by
instinct when they reach the appropriate age (ib., p. 406). In
the second place, instinct often gives only a rough outline of
the sort of thing to do, in which case learning is necessary in
order to acquire certainty and precision in action. In the third
place, even in the clearest cases of acquired habit, such as
speaking, some instinct is required to set in motion the process
of learning. In the case of speaking, the chief instinct involved
is commonly supposed to be that of imitation, but this may be
questioned. (See Thorndike's "Animal Intelligence," p. 253 ff.)

In spite of these qualifications, the broad distinction between
instinct and habit is undeniable. To take extreme cases, every
animal at birth can take food by instinct, before it has had
opportunity to learn; on the other hand, no one can ride a
bicycle by instinct, though, after learning, the necessary
movements become just as automatic as if they were instinctive.

The process of learning, which consists in the acquisition of
habits, has been much studied in various animals.* For example:
you put a hungry animal, say a cat, in a cage which has a door
that can be opened by lifting a latch; outside the cage you put
food. The cat at first dashes all round the cage, making frantic
efforts to force a way out. At last, by accident, the latch is
lifted. and the cat pounces on the food. Next day you repeat the
experiment, and you find that the cat gets out much more quickly
than the first time, although it still makes some random
movements. The third day it gets out still more quickly, and
before long it goes straight to the latch and lifts it at once.
Or you make a model of the Hampton Court maze, and put a rat in
the middle, assaulted by the smell of food on the outside. The
rat starts running down the passages, and is constantly stopped
by blind alleys, but at last, by persistent attempts, it gets
out. You repeat this experiment day after day; you measure the
time taken by the rat in reaching the food; you find that the
time rapidly diminishes, and that after a while the rat ceases to
make any wrong turnings. It is by essentially similar processes
that we learn speaking, writing, mathematics, or the government
of an empire.

* The scientific study of this subject may almost be said to
begin with Thorndike's "Animal Intelligence" (Macmillan, 1911).

Professor Watson ("Behavior," pp. 262-3) has an ingenious theory
as to the way in which habit arises out of random movements. I
think there is a reason why his theory cannot be regarded as
alone sufficient, but it seems not unlikely that it is partly
correct. Suppose, for the sake of simplicity, that there are just
ten random movements which may be made by the animal--say, ten
paths down which it may go--and that only one of these leads to
food, or whatever else represents success in the case in
question. Then the successful movement always occurs during the
animal's attempts, whereas each of the others, on the average,
occurs in only half the attempts. Thus the tendency to repeat a
previous performance (which is easily explicable without the
intervention of "consciousness") leads to a greater emphasis on
the successful movement than on any other, and in time causes it
alone to be performed. The objection to this view, if taken as
the sole explanation, is that on improvement ought to set in till
after the SECOND trial, whereas experiment shows that already at
the second attempt the animal does better than the first time.
Something further is, therefore, required to account for the
genesis of habit from random movements; but I see no reason to
suppose that what is further required involves "consciousness."

Mr. Thorndike (op. cit., p. 244) formulates two "provisional laws
of acquired behaviour or learning," as follows:

"The Law of Effect is that: Of several responses made to the same
situation, those which are accompanied or closely followed by
satisfaction to the animal will, other things being equal, be
more firmly connected with the situation, so that, when it
recurs, they will be more likely to recur; those which are
accompanied or closely followed by discomfort to the animal will,
other things being equal, have their connections with that
situation weakened, so that, when it recurs, they will be less
likely to occur. The greater the satisfaction or discomfort, the
greater the strengthening or weakening of the bond.

"The Law of Exercise is that: Any response to a situation will,
other things being equal, be more strongly connected with the
situation in proportion to the number of times it has been
connected with that situation and to the average vigour and
duration of the connections."

With the explanation to be presently given of the meaning of
"satisfaction" and "discomfort," there seems every reason to
accept these two laws.

What is true of animals, as regards instinct and habit, is
equally true of men. But the higher we rise in the evolutionary
scale, broadly speaking, the greater becomes the power of
learning, and the fewer are the occasions when pure instinct is
exhibited unmodified in adult life. This applies with great force
to man, so much so that some have thought instinct less important
in the life of man than in that of animals. This, however, would
be a mistake. Learning is only possible when instinct supplies
the driving-force. The animals in cages, which gradually learn to
get out, perform random movements at first, which are purely
instinctive. But for these random movements, they would never
acquire the experience which afterwards enables them to produce
the right movement. (This is partly questioned by Hobhouse*--
wrongly, I think.) Similarly, children learning to talk make all
sorts of sounds, until one day the right sound comes by accident.
It is clear that the original making of random sounds, without
which speech would never be learnt, is instinctive. I think we
may say the same of all the habits and aptitudes that we acquire
in all of them there has been present throughout some instinctive
activity, prompting at first rather inefficient movements, but
supplying the driving force while more and more effective methods
are being acquired. A cat which is hungry smells fish, and goes
to the larder. This is a thoroughly efficient method when there
is fish in the larder, and it is often successfully practised by
children. But in later life it is found that merely going to the
larder does not cause fish to be there; after a series of random
movements it is found that this result is to be caused by going
to the City in the morning and coming back in the evening. No one
would have guessed a priori that this movement of a middle-aged
man's body would cause fish to come out of the sea into his
larder, but experience shows that it does, and the middle-aged
man therefore continues to go to the City, just as the cat in the
cage continues to lift the latch when it has once found it. Of
course, in actual fact, human learning is rendered easier, though
psychologically more complex, through language; but at bottom
language does not alter the essential character of learning, or
of the part played by instinct in promoting learning. Language,
however, is a subject upon which I do not wish to speak until a
later lecture.

* "Mind in Evolution" (Macmillan, 1915), pp. 236-237.

The popular conception of instinct errs by imagining it to be
infallible and preternaturally wise, as well as incapable of
modification. This is a complete delusion. Instinct, as a rule,
is very rough and ready, able to achieve its result under
ordinary circumstances, but easily misled by anything unusual.
Chicks follow their mother by instinct, but when they are quite
young they will follow with equal readiness any moving object
remotely resembling their mother, or even a human being (James,
"Psychology," ii, 396). Bergson, quoting Fabre, has made play
with the supposed extraordinary accuracy of the solitary wasp
Ammophila, which lays its eggs in a caterpillar. On this subject
I will quote from Drever's "Instinct in Man," p. 92:

"According to Fabre's observations, which Bergson accepts, the
Ammophila stings its prey EXACTLY and UNERRINGLY in EACH of the
nervous centres. The result is that the caterpillar is paralyzed,
but not immediately killed, the advantage of this being that the
larva cannot be injured by any movement of the caterpillar, upon
which the egg is deposited, and is provided with fresh meat when
the time comes.

"Now Dr. and Mrs. Peckham have shown that the sting of the wasp
is NOT UNERRING, as Fabre alleges, that the number of stings is
NOT CONSTANT, that sometimes the caterpillar is NOT PARALYZED,
and sometimes it is KILLED OUTRIGHT, and that THE DIFFERENT
which is not injured by slight movements of the caterpillar, nor
by consuming food decomposed rather than fresh caterpillar."

This illustrates how love of the marvellous may mislead even so
careful an observer as Fabre and so eminent a philosopher as

In the same chapter of Dr. Drever's book there are some
interesting examples of the mistakes made by instinct. I will
quote one as a sample:

"The larva of the Lomechusa beetle eats the young of the ants, in
whose nest it is reared. Nevertheless, the ants tend the
Lomechusa larvae with the same care they bestow on their own
young. Not only so, but they apparently discover that the methods
of feeding, which suit their own larvae, would prove fatal to the
guests, and accordingly they change their whole system of
nursing" (loc. cit., p. 106).

Semon ("Die Mneme," pp. 207-9) gives a good illustration of an
instinct growing wiser through experience. He relates how hunters
attract stags by imitating the sounds of other members of their
species, male or female, but find that the older a stag becomes
the more difficult it is to deceive him, and the more accurate
the imitation has to be. The literature of instinct is vast, and
illustrations might be multiplied indefinitely. The main points
as regards instinct, which need to be emphasized as against the
popular conceptions of it, are:

(1) That instinct requires no prevision of the biological end
which it serves;

(2) That instinct is only adapted to achieve this end in the
usual circumstances of the animal in question, and has no more
precision than is necessary for success AS A RULE;

(3) That processes initiated by instinct often come to be
performed better after experience;

(4) That instinct supplies the impulses to experimental movements
which are required for the process of learning;

(5) That instincts in their nascent stages are easily modifiable,
and capable of being attached to various sorts of objects.

All the above characteristics of instinct can be established by
purely external observation, except the fact that instinct does
not require prevision. This, though not strictly capable of being
PROVED by observation, is irresistibly suggested by the most
obvious phenomena. Who can believe, for example, that a new-born
baby is aware of the necessity of food for preserving life? Or
that insects, in laying eggs, are concerned for the preservation
of their species? The essence of instinct, one might say, is that
it provides a mechanism for acting without foresight in a manner
which is usually advantageous biologically. It is partly for this
reason that it is so important to understand the fundamental
position of instinct in prompting both animal and human

download audio

Desire is a subject upon which, if I am not mistaken, true views
can only be arrived at by an almost complete reversal of the
ordinary unreflecting opinion. It is natural to regard desire as
in its essence an attitude towards something which is imagined,
not actual; this something is called the END or OBJECT of the
desire, and is said to be the PURPOSE of any action resulting
from the desire. We think of the content of the desire as being
just like the content of a belief, while the attitude taken up
towards the content is different. According to this theory, when
we say: "I hope it will rain," or "I expect it will rain," we
express, in the first case, a desire, and in the second, a
belief, with an identical content, namely, the image of rain. It
would be easy to say that, just as belief is one kind of feeling
in relation to this content, so desire is another kind. According
to this view, what comes first in desire is something imagined,
with a specific feeling related to it, namely, that specific
feeling which we call "desiring" it. The discomfort associated
with unsatisfied desire, and the actions which aim at satisfying
desire, are, in this view, both of them effects of the desire. I
think it is fair to say that this is a view against which common
sense would not rebel; nevertheless, I believe it to be radically
mistaken. It cannot be refuted logically, but various facts can
be adduced which make it gradually less simple and plausible,
until at last it turns out to be easier to abandon it wholly and
look at the matter in a totally different way.

The first set of facts to be adduced against the common sense
view of desire are those studied by psycho-analysis. In all human
beings, but most markedly in those suffering from hysteria and
certain forms of insanity, we find what are called "unconscious"
desires, which are commonly regarded as showing self-deception.
Most psycho-analysts pay little attention to the analysis of
desire, being interested in discovering by observation what it is
that people desire, rather than in discovering what actually
constitutes desire. I think the strangeness of what they report
would be greatly diminished if it were expressed in the language
of a behaviourist theory of desire, rather than in the language
of every-day beliefs. The general description of the sort of
phenomena that bear on our present question is as follows: A
person states that his desires are so-and-so, and that it is
these desires that inspire his actions; but the outside observer
perceives that his actions are such as to realize quite different
ends from those which he avows, and that these different ends are
such as he might be expected to desire. Generally they are less
virtuous than his professed desires, and are therefore less
agreeable to profess than these are. It is accordingly supposed
that they really exist as desires for ends, but in a subconscious
part of the mind, which the patient refuses to admit into
consciousness for fear of having to think ill of himself. There
are no doubt many cases to which such a supposition is applicable
without obvious artificiality. But the deeper the Freudians delve
into the underground regions of instinct, the further they travel
from anything resembling conscious desire, and the less possible
it becomes to believe that only positive self-deception conceals
from us that we really wish for things which are abhorrent to our
explicit life.

In the cases in question we have a conflict between the outside
observer and the patient's consciousness. The whole tendency of
psycho-analysis is to trust the outside observer rather than the
testimony of introspection. I believe this tendency to be
entirely right, but to demand a re-statement of what constitutes
desire, exhibiting it as a causal law of our actions, not as
something actually existing in our minds.

But let us first get a clearer statement of the essential
characteristic of the phenomena.

A person, we find, states that he desires a certain end A, and
that he is acting with a view to achieving it. We observe,
however, that his actions are such as are likely to achieve a
quite different end B, and that B is the sort of end that often
seems to be aimed at by animals and savages, though civilized
people are supposed to have discarded it. We sometimes find also
a whole set of false beliefs, of such a kind as to persuade the
patient that his actions are really a means to A, when in fact
they are a means to B. For example, we have an impulse to inflict
pain upon those whom we hate; we therefore believe that they are
wicked, and that punishment will reform them. This belief enables
us to act upon the impulse to inflict pain, while believing that
we are acting upon the desire to lead sinners to repentance. It
is for this reason that the criminal law has been in all ages
more severe than it would have been if the impulse to ameliorate
the criminal had been what really inspired it. It seems simple to
explain such a state of affairs as due to "self-deception," but
this explanation is often mythical. Most people, in thinking
about punishment, have had no more need to hide their vindictive
impulses from themselves than they have had to hide the
exponential theorem. Our impulses are not patent to a casual
observation, but are only to be discovered by a scientific study
of our actions, in the course of which we must regard ourselves
as objectively as we should the motions of the planets or the
chemical reactions of a new element.

The study of animals reinforces this conclusion, and is in many
ways the best preparation for the analysis of desire. In animals
we are not troubled by the disturbing influence of ethical
considerations. In dealing with human beings, we are perpetually
distracted by being told that such-and-such a view is gloomy or
cynical or pessimistic: ages of human conceit have built up such
a vast myth as to our wisdom and virtue that any intrusion of the
mere scientific desire to know the facts is instantly resented by
those who cling to comfortable illusions. But no one cares
whether animals are virtuous or not, and no one is under the
delusion that they are rational. Moreover, we do not expect them
to be so "conscious," and are prepared to admit that their
instincts prompt useful actions without any prevision of the ends
which they achieve. For all these reasons, there is much in the
analysis of mind which is more easily discovered by the study of
animals than by the observation of human beings.

We all think that, by watching the behaviour of animals, we can
discover more or less what they desire. If this is the case--and
I fully agree that it is--desire must be capable of being
exhibited in actions, for it is only the actions of animals that
we can observe. They MAY have minds in which all sorts of things
take place, but we can know nothing about their minds except by
means of inferences from their actions; and the more such
inferences are examined, the more dubious they appear. It would
seem, therefore, that actions alone must be the test of the
desires of animals. From this it is an easy step to the
conclusion that an animal's desire is nothing but a
characteristic of a certain series of actions, namely, those
which would be commonly regarded as inspired by the desire in
question. And when it has been shown that this view affords a
satisfactory account of animal desires, it is not difficult to
see that the same explanation is applicable to the desires of
human beings.

We judge easily from the behaviour of an animal of a familiar
kind whether it is hungry or thirsty, or pleased or displeased,
or inquisitive or terrified. The verification of our judgment, so
far as verification is possible, must be derived from the
immediately succeeding actions of the animal. Most people would
say that they infer first something about the animal's state of
mind--whether it is hungry or thirsty and so on--and thence
derive their expectations as to its subsequent conduct. But this
detour through the animal's supposed mind is wholly unnecessary.
We can say simply: The animal's behaviour during the last minute
has had those characteristics which distinguish what is called
"hunger," and it is likely that its actions during the next
minute will be similar in this respect, unless it finds food, or
is interrupted by a stronger impulse, such as fear. An animal
which is hungry is restless, it goes to the places where food is
often to be found, it sniffs with its nose or peers with its eyes
or otherwise increases the sensitiveness of its sense-organs; as
soon as it is near enough to food for its sense-organs to be
affected, it goes to it with all speed and proceeds to eat; after
which, if the quantity of food has been sufficient, its whole
demeanour changes it may very likely lie down and go to sleep.
These things and others like them are observable phenomena
distinguishing a hungry animal from one which is not hungry. The
characteristic mark by which we recognize a series of actions
which display hunger is not the animal's mental state, which we
cannot observe, but something in its bodily behaviour; it is this
observable trait in the bodily behaviour that I am proposing to
call "hunger," not some possibly mythical and certainly
unknowable ingredient of the animal's mind.

Generalizing what occurs in the case of hunger, we may say that
what we call a desire in an animal is always displayed in a cycle
of actions having certain fairly well marked characteristics.
There is first a state of activity, consisting, with
qualifications to be mentioned presently, of movements likely to
have a certain result; these movements, unless interrupted,
continue until the result is achieved, after which there is
usually a period of comparative quiescence. A cycle of actions of
this sort has marks by which it is broadly distinguished from the
motions of dead matter. The most notable of these marks are--(1)
the appropriateness of the actions for the realization of a
certain result; (2) the continuance of action until that result
has been achieved. Neither of these can be pressed beyond a
point. Either may be (a) to some extent present in dead matter,
and (b) to a considerable extent absent in animals, while
vegetable are intermediate, and display only a much fainter form
of the behaviour which leads us to attribute desire to animals.
(a) One might say rivers "desire" the sea water, roughly
speaking, remains in restless motion until it reaches either the
sea or a place from which it cannot issue without going uphill,
and therefore we might say that this is what it wishes while it
is flowing. We do not say so, because we can account for the
behaviour of water by the laws of physics; and if we knew more
about animals, we might equally cease to attribute desires to
them, since we might find physical and chemical reactions
sufficient to account for their behaviour. (b) Many of the
movements of animals do not exhibit the characteristics of the
cycles which seem to embody desire. There are first of all the
movements which are "mechanical," such as slipping and falling,
where ordinary physical forces operate upon the animal's body
almost as if it were dead matter. An animal which falls over a
cliff may make a number of desperate struggles while it is in the
air, but its centre of gravity will move exactly as it would if
the animal were dead. In this case, if the animal is killed at
the end of the fall, we have, at first sight, just the
characteristics of a cycle of actions embodying desire, namely,
restless movement until the ground is reached, and then
quiescence. Nevertheless, we feel no temptation to say that the
animal desired what occurred, partly because of the obviously
mechanical nature of the whole occurrence, partly because, when
an animal survives a fall, it tends not to repeat the experience.

There may be other reasons also, but of them I do not wish to
speak yet. Besides mechanical movements, there are interrupted
movements, as when a bird, on its way to eat your best peas, is
frightened away by the boy whom you are employing for that
purpose. If interruptions are frequent and completion of cycles
rare, the characteristics by which cycles are observed may become
so blurred as to be almost unrecognizable. The result of these
various considerations is that the differences between animals
and dead matter, when we confine ourselves to external
unscientific observation of integral behaviour, are a matter of
degree and not very precise. It is for this reason that it has
always been possible for fanciful people to maintain that even
stocks and stones have some vague kind of soul. The evidence that
animals have souls is so very shaky that, if it is assumed to be
conclusive, one might just as well go a step further and extend
the argument by analogy to all matter. Nevertheless, in spite of
vagueness and doubtful cases, the existence of cycles in the
behaviour of animals is a broad characteristic by which they are
prima facie distinguished from ordinary matter; and I think it is
this characteristic which leads us to attribute desires to
animals, since it makes their behaviour resemble what we do when
(as we say) we are acting from desire.

I shall adopt the following definitions for describing the
behaviour of animals:

A "behaviour-cycle" is a series of voluntary or reflex movements
of an animal, tending to cause a certain result, and continuing
until that result is caused, unless they are interrupted by
death, accident, or some new behaviour-cycle. (Here "accident"
may be defined as the intervention of purely physical laws
causing mechanical movements.)

The "purpose" of a behaviour-cycle is the result which brings it
to an end, normally by a condition of temporary
quiescence-provided there is no interruption.

An animal is said to "desire" the purpose of a behaviour cycle
while the behaviour-cycle is in progress.

I believe these definitions to be adequate also to human purposes
and desires, but for the present I am only occupied with animals
and with what can be learnt by external observation. I am very
anxious that no ideas should be attached to the words "purpose"
and "desire" beyond those involved in the above definitions.

We have not so far considered what is the nature of the initial
stimulus to a behaviour-cycle. Yet it is here that the usual view
of desire seems on the strongest ground. The hungry animal goes
on making movements until it gets food; it seems natural,
therefore, to suppose that the idea of food is present throughout
the process, and that the thought of the end to be achieved sets
the whole process in motion. Such a view, however, is obviously
untenable in many cases, especially where instinct is concerned.
Take, for example, reproduction and the rearing of the young.
Birds mate, build a nest, lay eggs in it, sit on the eggs, feed
the young birds, and care for them until they are fully grown. It
is totally impossible to suppose that this series of actions,
which constitutes one behaviour-cycle, is inspired by any
prevision of the end, at any rate the first time it is
performed.* We must suppose that the stimulus to the performance
of each act is an impulsion from behind, not an attraction from
the future. The bird does what it does, at each stage, because it
has an impulse to that particular action, not because it
perceives that the whole cycle of actions will contribute to the
preservation of the species. The same considerations apply to
other instincts. A hungry animal feels restless, and is led by
instinctive impulses to perform the movements which give it
nourishment; but the act of seeking food is not sufficient
evidence from which to conclude that the animal has the thought
of food in its "mind."

* For evidence as to birds' nests, cf. Semon, "Die Mneme," pp.
209, 210.

Coming now to human beings, and to what we know about our own
actions, it seems clear that what, with us, sets a
behaviour-cycle in motion is some sensation of the sort which we
call disagreeable. Take the case of hunger: we have first an
uncomfortable feeling inside, producing a disinclination to sit
still, a sensitiveness to savoury smells, and an attraction
towards any food that there may be in our neighbourhood. At any
moment during this process we may become aware that we are
hungry, in the sense of saying to ourselves, "I am hungry"; but
we may have been acting with reference to food for some time
before this moment. While we are talking or reading, we may eat
in complete unconsciousness; but we perform the actions of eating
just as we should if we were conscious, and they cease when our
hunger is appeased. What we call "consciousness" seems to be a
mere spectator of the process; even when it issues orders, they
are usually, like those of a wise parent, just such as would have
been obeyed even if they had not been given. This view may seem
at first exaggerated, but the more our so-called volitions and
their causes are examined, the more it is forced upon us. The
part played by words in all this is complicated, and a potent
source of confusions; I shall return to it later. For the
present, I am still concerned with primitive desire, as it exists
in man, but in the form in which man shows his affinity to his
animal ancestors.

Conscious desire is made up partly of what is essential to
desire, partly of beliefs as to what we want. It is important to
be clear as to the part which does not consist of beliefs.

The primitive non-cognitive element in desire seems to be a push,
not a pull, an impulsion away from the actual, rather than an
attraction towards the ideal. Certain sensations and other mental
occurrences have a property which we call discomfort; these cause
such bodily movements as are likely to lead to their cessation.
When the discomfort ceases, or even when it appreciably
diminishes, we have sensations possessing a property which we
call PLEASURE. Pleasurable sensations either stimulate no action
at all, or at most stimulate such action as is likely to prolong
them. I shall return shortly to the consideration of what
discomfort and pleasure are in themselves; for the present, it is
their connection with action and desire that concerns us.
Abandoning momentarily the standpoint of behaviourism, we may
presume that hungry animals experience sensations involving
discomfort, and stimulating such movements as seem likely to
bring them to the food which is outside the cages. When they have
reached the food and eaten it, their discomfort ceases and their
sensations become pleasurable. It SEEMS, mistakenly, as if the
animals had had this situation in mind throughout, when in fact
they have been continually pushed by discomfort. And when an
animal is reflective, like some men, it comes to think that it
had the final situation in mind throughout; sometimes it comes to
know what situation will bring satisfaction, so that in fact the
discomfort does bring the thought of what will allay it.
Nevertheless the sensation involving discomfort remains the prime

This brings us to the question of the nature of discomfort and
pleasure. Since Kant it has been customary to recognize three
great divisions of mental phenomena, which are typified by
knowledge, desire and feeling, where "feeling" is used to mean
pleasure and discomfort. Of course, "knowledge" is too definite a
word: the states of mind concerned are grouped together as
"cognitive," and are to embrace not only beliefs, but
perceptions, doubts, and the understanding of concepts. "Desire,"
also, is narrower than what is intended: for example, WILL is to
be included in this category, and in fact every thing that
involves any kind of striving, or "conation" as it is technically
called. I do not myself believe that there is any value in this
threefold division of the contents of mind. I believe that
sensations (including images) supply all the "stuff" of the mind,
and that everything else can be analysed into groups of
sensations related in various ways, or characteristics of
sensations or of groups of sensations. As regards belief, I shall
give grounds for this view in later lectures. As regards desires,
I have given some grounds in this lecture. For the present, it is
pleasure and discomfort that concern us. There are broadly three
theories that might be held in regard to them. We may regard them
as separate existing items in those who experience them, or we
may regard them as intrinsic qualities of sensations and other
mental occurrences, or we may regard them as mere names for the
causal characteristics of the occurrences which are uncomfortable
or pleasant. The first of these theories, namely, that which
regards discomfort and pleasure as actual contents in those who
experience them, has, I think, nothing conclusive to be said in
its favour.* It is suggested chiefly by an ambiguity in the word
"pain," which has misled many people, including Berkeley, whom it
supplied with one of his arguments for subjective idealism. We
may use "pain" as the opposite of "pleasure," and "painful" as
the opposite of "pleasant," or we may use "pain" to mean a
certain sort of sensation, on a level with the sensations of heat
and cold and touch. The latter use of the word has prevailed in
psychological literature, and it is now no longer used as the
opposite of "pleasure." Dr. H. Head, in a recent publication, has
stated this distinction as follows:**

* Various arguments in its favour are advanced by A. Wohlgemuth,
"On the feelings and their neural correlate, with an examination
of the nature of pain," "British Journal of Psychology," viii, 4.
(1917). But as these arguments are largely a reductio ad absurdum
of other theories, among which that which I am advocating is not
included, I cannot regard them as establishing their contention.

** "Sensation and the Cerebral Cortex," "Brain," vol. xli, part
ii (September, 1918), p. 90. Cf. also Wohlgemuth, loc. cit. pp.
437, 450.

"It is necessary at the outset to distinguish clearly between
'discomfort' and 'pain.' Pain is a distinct sensory quality
equivalent to heat and cold, and its intensity can be roughly
graded according to the force expended in stimulation.
Discomfort, on the other hand, is that feeling-tone which is
directly opposed to pleasure. It may accompany sensations not in
themselves essentially painful; as for instance that produced by
tickling the sole of the foot. The reaction produced by repeated
pricking contains both these elements; for it evokes that sensory
quality known as pain, accompanied by a disagreeable
feeling-tone, which we have called discomfort. On the other hand,
excessive pressure, except when applied directly over some
nerve-trunk, tends to excite more discomfort than pain."

The confusion between discomfort and pain has made people regard
discomfort as a more substantial thing than it is, and this in
turn has reacted upon the view taken of pleasure, since
discomfort and pleasure are evidently on a level in this respect.
As soon as discomfort is clearly distinguished from the sensation
of pain, it becomes more natural to regard discomfort and
pleasure as properties of mental occurrences than to regard them
as separate mental occurrences on their own account. I shall
therefore dismiss the view that they are separate mental
occurrences, and regard them as properties of such experiences as
would be called respectively uncomfortable and pleasant.

It remains to be examined whether they are actual qualities of
such occurrences, or are merely differences as to causal
properties. I do not myself see any way of deciding this
question; either view seems equally capable of accounting for the
facts. If this is true, it is safer to avoid the assumption that
there are such intrinsic qualities of mental occurrences as are
in question, and to assume only the causal differences which are
undeniable. Without condemning the intrinsic theory, we can
define discomfort and pleasure as consisting in causal
properties, and say only what will hold on either of the two
theories. Following this course, we shall say:

"Discomfort" is a property of a sensation or other mental
occurrence, consisting in the fact that the occurrence in
question stimulates voluntary or reflex movements tending to
produce some more or less definite change involving the cessation
of the occurrence.

"Pleasure" is a property of a sensation or other mental
occurrence, consisting in the fact that the occurrence in
question either does not stimulate any voluntary or reflex
movement, or, if it does, stimulates only such as tend to prolong
the occurrence in question.*

* Cf. Thorndike, op. cit., p. 243.

"Conscious" desire, which we have now to consider, consists of
desire in the sense hitherto discussed, together with a true
belief as to its "purpose," i.e. as to the state of affairs that
will bring quiescence with cessation of the discomfort. If our
theory of desire is correct, a belief as to its purpose may very
well be erroneous, since only experience can show what causes a
discomfort to cease. When the experience needed is common and
simple, as in the case of hunger, a mistake is not very probable.
But in other cases--e.g. erotic desire in those who have had
little or no experience of its satisfaction--mistakes are to be
expected, and do in fact very often occur. The practice of
inhibiting impulses, which is to a great extent necessary to
civilized life, makes mistakes easier, by preventing experience
of the actions to which a desire would otherwise lead, and by
often causing the inhibited impulses themselves to be unnoticed
or quickly forgotten. The perfectly natural mistakes which thus
arise constitute a large proportion of what is, mistakenly in
part, called self-deception, and attributed by Freud to the

But there is a further point which needs emphasizing, namely,
that a belief that something is desired has often a tendency to
cause the very desire that is believed in. It is this fact that
makes the effect of "consciousness" on desire so complicated.

When we believe that we desire a certain state of affairs, that
often tends to cause a real desire for it. This is due partly to
the influence of words upon our emotions, in rhetoric for
example, and partly to the general fact that discomfort normally
belongs to the belief that we desire such-and-such a thing that
we do not possess. Thus what was originally a false opinion as to
the object of a desire acquires a certain truth: the false
opinion generates a secondary subsidiary desire, which
nevertheless becomes real. Let us take an illustration. Suppose
you have been jilted in a way which wounds your vanity. Your
natural impulsive desire will be of the sort expressed in Donne's

     When by thy scorn, O Murderess, I am dead,

in which he explains how he will haunt the poor lady as a ghost,
and prevent her from enjoying a moment's peace. But two things
stand in the way of your expressing yourself so naturally: on the
one hand, your vanity, which will not acknowledge how hard you
are hit; on the other hand, your conviction that you are a
civilized and humane person, who could not possibly indulge so
crude a desire as revenge. You will therefore experience a
restlessness which will at first seem quite aimless, but will
finally resolve itself in a conscious desire to change your
profession, or go round the world, or conceal your identity and
live in Putney, like Arnold Bennett's hero. Although the prime
cause of this desire is a false judgment as to your previous
unconscious desire, yet the new conscious desire has its own
derivative genuineness, and may influence your actions to the
extent of sending you round the world. The initial mistake,
however, will have effects of two kinds. First, in uncontrolled
moments, under the influence of sleepiness or drink or delirium,
you will say things calculated to injure the faithless deceiver.
Secondly, you will find travel disappointing, and the East less
fascinating than you had hoped--unless, some day, you hear that
the wicked one has in turn been jilted. If this happens, you will
believe that you feel sincere sympathy, but you will suddenly be
much more delighted than before with the beauties of tropical
islands or the wonders of Chinese art. A secondary desire,
derived from a false judgment as to a primary desire, has its own
power of influencing action, and is therefore a real desire
according to our definition. But it has not the same power as a
primary desire of bringing thorough satisfaction when it is
realized; so long as the primary desire remains unsatisfied,
restlessness continues in spite of the secondary desire's
success. Hence arises a belief in the vanity of human wishes: the
vain wishes are those that are secondary, but mistaken beliefs
prevent us from realizing that they are secondary.

What may, with some propriety, be called self-deception arises
through the operation of desires for beliefs. We desire many
things which it is not in our power to achieve: that we should be
universally popular and admired, that our work should be the
wonder of the age, and that the universe should be so ordered as
to bring ultimate happiness to all, though not to our enemies
until they have repented and been purified by suffering. Such
desires are too large to be achieved through our own efforts. But
it is found that a considerable portion of the satisfaction which
these things would bring us if they were realized is to be
achieved by the much easier operation of believing that they are
or will be realized. This desire for beliefs, as opposed to
desire for the actual facts, is a particular case of secondary
desire, and, like all secondary desire its satisfaction does not
lead to a complete cessation of the initial discomfort.
Nevertheless, desire for beliefs, as opposed to desire for facts,
is exceedingly potent both individually and socially. According
to the form of belief desired, it is called vanity, optimism, or
religion. Those who have sufficient power usually imprison or put
to death any one who tries to shake their faith in their own
excellence or in that of the universe; it is for this reason that
seditious libel and blasphemy have always been, and still are,
criminal offences.

It is very largely through desires for beliefs that the primitive
nature of desire has become so hidden, and that the part played
by consciousness has been so confusing and so exaggerated.

We may now summarize our analysis of desire and feeling.

A mental occurrence of any kind--sensation, image, belief, or
emotion--may be a cause of a series of actions, continuing,
unless interrupted, until some more or less definite state of
affairs is realized. Such a series of actions we call a
"behaviour-cycle." The degree of definiteness may vary greatly:
hunger requires only food in general, whereas the sight of a
particular piece of food raises a desire which requires the
eating of that piece of food. The property of causing such a
cycle of occurrences is called "discomfort"; the property of the
mental occurrences in which the cycle ends is called " pleasure."
The actions constituting the cycle must not be purely mechanical,
i.e. they must be bodily movements in whose causation the special
properties of nervous tissue are involved. The cycle ends in a
condition of quiescence, or of such action as tends only to
preserve the status quo. The state of affairs in which this
condition of quiescence is achieved is called the "purpose" of
the cycle, and the initial mental occurrence involving discomfort
is called a "desire" for the state of affairs that brings
quiescence. A desire is called "conscious" when it is accompanied
by a true belief as to the state of affairs that will bring
quiescence; otherwise it is called "unconscious." All primitive
desire is unconscious, and in human beings beliefs as to the
purposes of desires are often mistaken. These mistaken beliefs
generate secondary desires, which cause various interesting
complications in the psychology of human desire, without
fundamentally altering the character which it shares with animal

download audio

In this lecture we shall be concerned with a very general
characteristic which broadly, though not absolutely,
distinguishes the behaviour of living organisms from that of dead
matter. The characteristic in question is this:

The response of an organism to a given stimulus is very often
dependent upon the past history of the organism, and not merely
upon the stimulus and the HITHERTO DISCOVERABLE present state of
the organism.

This characteristic is embodied in the saying "a burnt child
fears the fire." The burn may have left no visible traces, yet it
modifies the reaction of the child in the presence of fire. It is
customary to assume that, in such cases, the past operates by
modifying the structure of the brain, not directly. I have no
wish to suggest that this hypothesis is false; I wish only to
point out that it is a hypothesis. At the end of the present
lecture I shall examine the grounds in its favour. If we confine
ourselves to facts which have been actually observed, we must say
that past occurrences, in addition to the present stimulus and
the present ascertainable condition of the organism, enter into
the causation of the response.

The characteristic is not wholly confined to living organisms.
For example, magnetized steel looks just like steel which has not
been magnetized, but its behaviour is in some ways different. In
the case of dead matter, however, such phenomena are less
frequent and important than in the case of living organisms, and
it is far less difficult to invent satisfactory hypotheses as to
the microscopic changes of structure which mediate between the
past occurrence and the present changed response. In the case of
living organisms, practically everything that is distinctive both
of their physical and of their mental behaviour is bound up with
this persistent influence of the past. Further, speaking broadly,
the change in response is usually of a kind that is biologically
advantageous to the organism.

Following a suggestion derived from Semon ("Die Mneme," Leipzig,
1904; 2nd edition, 1908, English translation, Allen & Unwin,
1921; "Die mnemischen Empfindungen," Leipzig, l909), we will give
the name of "mnemic phenomena" to those responses of an organism
which, so far as hitherto observed facts are concerned, can only
be brought under causal laws by including past occurrences in the
history of the organism as part of the causes of the present
response. I do not mean merely--what would always be the
case--that past occurrences are part of a CHAIN of causes leading
to the present event. I mean that, in attempting to state the
PROXIMATE cause of the present event, some past event or events
must be included, unless we take refuge in hypothetical
modifications of brain structure.) For example: you smell
peat-smoke, and you recall some occasion when you smelt it
before. The cause of your recollection, so far as hitherto observ
able phenomena are concerned, consists both of the peat smoke
(present stimulus) and of the former occasion (past experience).
The same stimulus will not produce the same recollection in
another man who did not share your former experience, although
the former experience left no OBSERVABLE traces in the structure
of the brain. According to the maxim "same cause, same effect,"
we cannot therefore regard the peat-smoke alone as the cause of
your recollection, since it does not have the same effect in
other cases. The cause of your recollection must be both the
peat-smoke and the past occurrence. Accordingly your recollection
is an instance of what we are calling "mnemic phenomena."

Before going further, it will be well to give illustrations of
different classes of mnemic phenomena.

(a) ACQUIRED HABITS.--In Lecture II we saw how animals can learn
by experience how to get out of cages or mazes, or perform other
actions which are useful to them but not provided for by their
instincts alone. A cat which is put into a cage of which it has
had experience behaves differently from the way in which it
behaved at first. We can easily invent hypotheses, which are
quite likely to be true, as to connections in the brain caused by
past experience, and themselves causing the different response.
But the observable fact is that the stimulus of being in the cage
produces differing results with repetition, and that the
ascertainable cause of the cat's behaviour is not merely the cage
and its own ascertainable organization, but also its past history
in regard to the cage. From our present point of view, the matter
is independent of the question whether the cat's behaviour is due
to some mental fact called "knowledge," or displays a merely
bodily habit. Our habitual knowledge is not always in our minds,
but is called up by the appropriate stimuli. If we are asked
"What is the capital of France?" we answer "Paris," because of
past experience; the past experience is as essential as the
present question in the causation of our response. Thus all our
habitual knowledge consists of acquired habits, and comes under
the head of mnemic phenomena.

(b) IMAGES.--I shall have much to say about images in a later
lecture; for the present I am merely concerned with them in so
far as they are "copies" of past sensations. When you hear New
York spoken of, some image probably comes into your mind, either
of the place itself (if you have been there), or of some picture
of it (if you have not). The image is due to your past
experience, as well as to the present stimulus of the words "New
York." Similarly, the images you have in dreams are all dependent
upon your past experience, as well as upon the present stimulus
to dreaming. It is generally believed that all images, in their
simpler parts, are copies of sensations; if so, their mnemic
character is evident. This is important, not only on its own
account, but also because, as we shall see later, images play an
essential part in what is called "thinking."

(c) ASSOCIATION.--The broad fact of association, on the mental
side, is that when we experience something which we have
experienced before, it tends to call up the context of the former
experience. The smell of peat-smoke recalling a former scene is
an instance which we discussed a moment ago. This is obviously a
mnemic phenomenon. There is also a more purely physical
association, which is indistinguishable from physical habit. This
is the kind studied by Mr. Thorndike in animals, where a certain
stimulus is associated with a certain act. This is the sort which
is taught to soldiers in drilling, for example. In such a case
there need not be anything mental, but merely a habit of the
body. There is no essential distinction between association and
habit, and the observations which we made concerning habit as a
mnemic phenomenon are equally applicable to association.

object of a familiar kind, much of what appears subjectively to
be immediately given is really derived from past experience. When
we see an object, say a penny, we seem to be aware of its "real"
shape we have the impression of something circular, not of
something elliptical. In learning to draw, it is necessary to
acquire the art of representing things according to the
sensation, not according to the perception. And the visual
appearance is filled out with feeling of what the object would be
like to touch, and so on. This filling out and supplying of the
"real" shape and so on consists of the most usual correlates of
the sensational core in our perception. It may happen that, in
the particular case, the real correlates are unusual; for
example, if what we are seeing is a carpet made to look like
tiles. If so, the non-sensational part of our perception will be
illusory, i.e. it will supply qualities which the object in
question does not in fact have. But as a rule objects do have the
qualities added by perception, which is to be expected, since
experience of what is usual is the cause of the addition. If our
experience had been different, we should not fill out sensation
in the same way, except in so far as the filling out is
instinctive, not acquired. It would seem that, in man, all that
makes up space perception, including the correlation of sight and
touch and so on, is almost entirely acquired. In that case there
is a large mnemic element in all the common perceptions by means
of which we handle common objects. And, to take another kind of
instance, imagine what our astonishment would be if we were to
hear a cat bark or a dog mew. This emotion would be dependent
upon past experience, and would therefore be a mnemic phenomenon
according to the definition.

(e) MEMORY AS KNOWLEDGE.--The kind of memory of which I am now
speaking is definite knowledge of some past event in one's own
experience. From time to time we remember things that have
happened to us, because something in the present reminds us of
them. Exactly the same present fact would not call up the same
memory if our past experience had been different. Thus our
remembering is caused by--

(1) The present stimulus,

(2) The past occurrence.

It is therefore a mnemic phenomenon according to our definition.
A definition of "mnemic phenomena" which did not include memory
would, of course, be a bad one. The point of the definition is
not that it includes memory, but that it includes it as one of a
class of phenomena which embrace all that is characteristic in
the subject matter of psychology.

(f) EXPERIENCE.--The word "experience" is often used very
vaguely. James, as we saw, uses it to cover the whole primal
stuff of the world, but this usage seems objection able, since,
in a purely physical world, things would happen without there
being any experience. It is only mnemic phenomena that embody
experience. We may say that an animal "experiences" an occurrence
when this occurrence modifies the animal's subsequent behaviour,
i.e. when it is the mnemic portion of the cause of future
occurrences in the animal's life. The burnt child that fears the
fire has "experienced" the fire, whereas a stick that has been
thrown on and taken off again has not "experienced" anything,
since it offers no more resistance than before to being thrown
on. The essence of "experience" is the modification of behaviour
produced by what is experienced. We might, in fact, define one
chain of experience, or one biography, as a series of occurrences
linked by mnemic causation. I think it is this characteristic,
more than any other, that distinguishes sciences dealing with
living organisms from physics.

The best writer on mnemic phenomena known to me is Richard Semon,
the fundamental part of whose theory I shall endeavour to
summarize before going further:

When an organism, either animal or plant, is subjected to a
stimulus, producing in it some state of excitement, the removal
of the stimulus allows it to return to a condition of
equilibrium. But the new state of equilibrium is different from
the old, as may be seen by the changed capacity for reaction. The
state of equilibrium before the stimulus may be called the
"primary indifference-state"; that after the cessation of the
stimulus, the "secondary indifference-state." We define the
"engraphic effect" of a stimulus as the effect in making a
difference between the primary and secondary indifference-states,
and this difference itself we define as the "engram" due to the
stimulus. "Mnemic phenomena" are defined as those due to engrams;
in animals, they are specially associated with the nervous
system, but not exclusively, even in man.

When two stimuli occur together, one of them, occurring
afterwards, may call out the reaction for the other also. We call
this an "ekphoric influence," and stimuli having this character
are called "ekphoric stimuli." In such a case we call the engrams
of the two stimuli "associated." All simultaneously generated
engrams are associated; there is also association of successively
aroused engrams, though this is reducible to simultaneous
association. In fact, it is not an isolated stimulus that leaves
an engram, but the totality of the stimuli at any moment;
consequently any portion of this totality tends, if it recurs, to
arouse the whole reaction which was aroused before. Semon holds
that engrams can be inherited, and that an animal's innate habits
may be due to the experience of its ancestors; on this subject he
refers to Samuel Butler.

Semon formulates two "mnemic principles." The first, or "Law of
Engraphy," is as follows: "All simultaneous excitements in an
organism form a connected simultaneous excitement-complex, which
as such works engraphically, i.e. leaves behind a connected
engram-complex, which in so far forms a whole" ("Die mnemischen
Empfindungen," p. 146). The second mnemic principle, or "Law of
Ekphory," is as follows: "The partial return of the energetic
situation which formerly worked engraphically operates
ekphorically on a simultaneous engram-complex" (ib., p. 173).
These two laws together represent in part a hypothesis (the
engram), and in part an observable fact. The observable fact is
that, when a certain complex of stimuli has originally caused a
certain complex of reactions, the recurrence of part of the
stimuli tends to cause the recurrence of the whole of the

Semon's applications of his fundamental ideas in various
directions are interesting and ingenious. Some of them will
concern us later, but for the present it is the fundamental
character of mnemic phenomena that is in question.

Concerning the nature of an engram, Semon confesses that at
present it is impossible to say more than that it must consist in
some material alteration in the body of the organism ("Die
mnemischen Empfindungen," p. 376). It is, in fact, hypothetical,
invoked for theoretical uses, and not an outcome of direct
observation. No doubt physiology, especially the disturbances of
memory through lesions in the brain, affords grounds for this
hypothesis; nevertheless it does remain a hypothesis, the
validity of which will be discussed at the end of this lecture.

I am inclined to think that, in the present state of physiology,
the introduction of the engram does not serve to simplify the
account of mnemic phenomena. We can, I think, formulate the known
laws of such phenomena in terms, wholly, of observable facts, by
recognizing provisionally what we may call "mnemic causation." By
this I mean that kind of causation of which I spoke at the
beginning of this lecture, that kind, namely, in which the
proximate cause consists not merely of a present event, but of
this together with a past event. I do not wish to urge that this
form of causation is ultimate, but that, in the present state of
our knowledge, it affords a simplification, and enables us to
state laws of behaviour in less hypothetical terms than we should
otherwise have to employ.

The clearest instance of what I mean is recollection of a past
event. What we observe is that certain present stimuli lead us to
recollect certain occurrences, but that at times when we are not
recollecting them, there is nothing discoverable in our minds
that could be called memory of them. Memories, as mental facts,
arise from time to time, but do not, so far as we can see, exist
in any shape while they are "latent." In fact, when we say that
they are "latent," we mean merely that they will exist under
certain circumstances. If, then, there is to be some standing
difference between the person who can remember a certain fact and
the person who cannot, that standing difference must be, not in
anything mental, but in the brain. It is quite probable that
there is such a difference in the brain, but its nature is
unknown and it remains hypothetical. Everything that has, so far,
been made matter of observation as regards this question can be
put together in the statement: When a certain complex of
sensations has occurred to a man, the recurrence of part of the
complex tends to arouse the recollection of the whole. In like
manner, we can collect all mnemic phenomena in living organisms
under a single law, which contains what is hitherto verifiable in
Semon's two laws. This single law is:


This law would need to be supplemented by some account of the
influence of frequency, and so on; but it seems to contain the
essential characteristic of mnemic phenomena, without admixture
of anything hypothetical.

Whenever the effect resulting from a stimulus to an organism
differs according to the past history of the organism, without
our being able actually to detect any relevant difference in its
present structure, we will speak of "mnemic causation," provided
we can discover laws embodying the influence of the past. In
ordinary physical causation, as it appears to common sense, we
have approximate uniformities of sequence, such as "lightning is
followed by thunder," "drunkenness is followed by headache," and
so on. None of these sequences are theoretically invariable,
since something may intervene to disturb them. In order to obtain
invariable physical laws, we have to proceed to differential
equations, showing the direction of change at each moment, not
the integral change after a finite interval, however short. But
for the purposes of daily life many sequences are to all in tents
and purposes invariable. With the behaviour of human beings,
however, this is by no means the case. If you say to an
Englishman, "You have a smut on your nose," he will proceed to
remove it, but there will be no such effect if you say the same
thing to a Frenchman who knows no English. The effect of words
upon the hearer is a mnemic phenomena, since it depends upon the
past experience which gave him understanding of the words. If
there are to be purely psychological causal laws, taking no
account of the brain and the rest of the body, they will have to
be of the form, not "X now causes Y now," but--

"A, B, C, . . . in the past, together with X now, cause Y now."
For it cannot be successfully maintained that our understanding
of a word, for example, is an actual existent content of the mind
at times when we are not thinking of the word. It is merely what
may be called a "disposition," i.e. it is capable of being
aroused whenever we hear the word or happen to think of it. A
"disposition" is not something actual, but merely the mnemic
portion of a mnemic causal law.

In such a law as "A, B, C, . . . in the past, together with X
now, cause Y now," we will call A, B, C, . . . the mnemic cause,
X the occasion or stimulus, and Y the reaction. All cases in
which experience influences behaviour are instances of mnemic

Believers in psycho-physical parallelism hold that psychology can
theoretically be freed entirely from all dependence on physiology
or physics. That is to say, they believe that every psychical
event has a psychical cause and a physical concomitant. If there
is to be parallelism, it is easy to prove by mathematical logic
that the causation in physical and psychical matters must be of
the same sort, and it is impossible that mnemic causation should
exist in psychology but not in physics. But if psychology is to
be independent of physiology, and if physiology can be reduced to
physics, it would seem that mnemic causation is essential in
psychology. Otherwise we shall be compelled to believe that all
our knowledge, all our store of images and memories, all our
mental habits, are at all times existing in some latent mental
form, and are not merely aroused by the stimuli which lead to
their display. This is a very difficult hypothesis. It seems to
me that if, as a matter of method rather than metaphysics, we
desire to obtain as much independence for psychology as is
practically feasible, we shall do better to accept mnemic
causation in psychology protem, and therefore reject parallelism,
since there is no good ground for admitting mnemic causation in

It is perhaps worth while to observe that mnemic causation is
what led Bergson to deny that there is causation. at all in the
psychical sphere. He points out, very truly, that the same
stimulus, repeated, does not have the same consequences, and he
argues that this is contrary to the maxim, "same cause, same
effect." It is only necessary, however, to take account of past
occurrences and include them with the cause, in order to
re-establish the maxim, and the possibility of psychological
causal laws. The metaphysical conception of a cause lingers in
our manner of viewing causal laws: we want to be able to FEEL a
connection between cause and effect, and to be able to imagine
the cause as "operating." This makes us unwilling to regard
causal laws as MERELY observed uniformities of sequence; yet that
is all that science has to offer. To ask why such-and-such a kind
of sequence occurs is either to ask a meaningless question, or to
demand some more general kind of sequence which includes the one
in question. The widest empirical laws of sequence known at any
time can only be "explained" in the sense of being subsumed by
later discoveries under wider laws; but these wider laws, until
they in turn are subsumed, will remain brute facts, resting
solely upon observation, not upon some supposed inherent

There is therefore no a priori objection to a causal law in which
part of the cause has ceased to exist. To argue against such a
law on the ground that what is past cannot operate now, is to
introduce the old metaphysical notion of cause, for which science
can find no place. The only reason that could be validly alleged
against mnemic causation would be that, in fact, all the
phenomena can be explained without it. They are explained without
it by Semon's "engram," or by any theory which regards the
results of experience as embodied in modifications of the brain
and nerves. But they are not explained, unless with extreme
artificiality, by any theory which regards the latent effects of
experience as psychical rather than physical. Those who desire to
make psychology as far as possible independent of physiology
would do well, it seems to me, if they adopted mnemic causation.
For my part, however, I have no such desire, and I shall
therefore endeavour to state the grounds which occur to me in
favour of some such view as that of the "engram."

One of the first points to be urged is that mnemic phenomena are
just as much to be found in physiology as in psychology. They are
even to be found in plants, as Sir Francis Darwin pointed out
(cf. Semon, "Die Mneme," 2nd edition, p. 28 n.). Habit is a
characteristic of the body at least as much as of the mind. We
should, therefore, be compelled to allow the intrusion of mnemic
causation, if admitted at all, into non-psychological regions,
which ought, one feels, to be subject only to causation of the
ordinary physical sort. The fact is that a great deal of what, at
first sight, distinguishes psychology from physics is found, on
examination, to be common to psychology and physiology; this
whole question of the influence of experience is a case in point.
Now it is possible, of course, to take the view advocated by
Professor J. S. Haldane, who contends that physiology is not
theoretically reducible to physics and chemistry.* But the weight
of opinion among physiologists appears to be against him on this
point; and we ought certainly to require very strong evidence
before admitting any such breach of continuity as between living
and dead matter. The argument from the existence of mnemic
phenomena in physiology must therefore be allowed a certain
weight against the hypothesis that mnemic causation is ultimate.

* See his "The New Physiology and Other Addresses," Griffin,
1919, also the symposium, "Are Physical, Biological and
Psychological Categories Irreducible?" in "Life and Finite
Individuality," edited for the Aristotelian Society, with an
Introduction. By H. Wildon Carr, Williams & Norgate, 1918.

The argument from the connection of brain-lesions with loss of
memory is not so strong as it looks, though it has also, some
weight. What we know is that memory, and mnemic phenomena
generally, can be disturbed or destroyed by changes in the brain.
This certainly proves that the brain plays an essential part in
the causation of memory, but does not prove that a certain state
of the brain is, by itself, a sufficient condition for the
existence of memory. Yet it is this last that has to be proved.
The theory of the engram, or any similar theory, has to maintain
that, given a body and brain in a suitable state, a man will have
a certain memory, without the need of any further conditions.
What is known, however, is only that he will not have memories if
his body and brain are not in a suitable state. That is to say,
the appropriate state of body and brain is proved to be necessary
for memory, but not to be sufficient. So far, therefore, as our
definite knowledge goes, memory may require for its causation a
past occurrence as well as a certain present state of the brain.

In order to prove conclusively that mnemic phenomena arise
whenever certain physiological conditions are fulfilled, we ought
to be able actually to see differences between the brain of a man
who speaks English and that of a man who speaks French, between
the brain of a man who has seen New York and can recall it, and
that of a man who has never seen that city. It may be that the
time will come when this will be possible, but at present we are
very far removed from it. At present, there is, so far as I am
aware, no good evidence that every difference between the
knowledge possessed by A and that possessed by B is paralleled by
some difference in their brains. We may believe that this is the
case, but if we do, our belief is based upon analogies and
general scientific maxims, not upon any foundation of detailed
observation. I am myself inclined, as a working hypothesis, to
adopt the belief in question, and to hold that past experience
only affects present behaviour through modifications of
physiological structure. But the evidence seems not quite
conclusive, so that I do not think we ought to forget the other
hypothesis, or to reject entirely the possibility that mnemic
causation may be the ultimate explanation of mnemic phenomena. I
say this, not because I think it LIKELY that mnemic causation is
ultimate, but merely because I think it POSSIBLE, and because it
often turns out important to the progress of science to remember
hypotheses which have previously seemed improbable.

download audio

The traditional conception of cause and effect is one which
modern science shows to be fundamentally erroneous, and requiring
to be replaced by a quite different notion, that of LAWS OF
CHANGE. In the traditional conception, a particular event A
caused a particular event B, and by this it was implied that,
given any event B, some earlier event A could be discovered which
had a relation to it, such that--

(1) Whenever A occurred, it was followed by B;

(2) In this sequence, there was something "necessary," not a mere
de facto occurrence of A first and then B.

The second point is illustrated by the old discussion as to
whether it can be said that day causes night, on the ground that
day is always followed by night. The orthodox answer was that day
could not be called the cause of night, because it would not be
followed by night if the earth's rotation were to cease, or
rather to grow so slow that one complete rotation would take a
year. A cause, it was held, must be such that under no
conceivable circumstances could it fail to be followed by its

As a matter of fact, such sequences as were sought by believers
in the traditional form of causation have not so far been found
in nature. Everything in nature is apparently in a state of
continuous change,* so that what we call one "event" turns out to
be really a process. If this event is to cause another event, the
two will have to be contiguous in time; for if there is any
interval between them, something may happen during that interval
to prevent the expected effect. Cause and effect, therefore, will
have to be temporally contiguous processes. It is difficult to
believe, at any rate where physical laws are concerned, that the
earlier part of the process which is the cause can make any
difference to the effect, so long as the later part of the
process which is the cause remains unchanged. Suppose, for
example, that a man dies of arsenic poisoning, we say that his
taking arsenic was the cause of death. But clearly the process by
which he acquired the arsenic is irrelevant: everything that
happened before he swallowed it may be ignored, since it cannot
alter the effect except in so far as it alters his condition at
the moment of taking the dose. But we may go further: swallowing
arsenic is not really the proximate cause of death, since a man
might be shot through the head immediately after taking the dose,
and then it would not be of arsenic that he would die. The
arsenic produces certain physiological changes, which take a
finite time before they end in death. The earlier parts of these
changes can be ruled out in the same way as we can rule out the
process by which the arsenic was acquired. Proceeding in this
way, we can shorten the process which we are calling the cause
more and more. Similarly we shall have to shorten the effect. It
may happen that immediately after the man's death his body is
blown to pieces by a bomb. We cannot say what will happen after
the man's death, through merely knowing that he has died as the
result of arsenic poisoning. Thus, if we are to take the cause as
one event and the effect as another, both must be shortened
indefinitely. The result is that we merely have, as the
embodiment of our causal law, a certain direction of change at
each moment. Hence we are brought to differential equations as
embodying causal laws. A physical law does not say "A will be
followed by B," but tells us what acceleration a particle will
have under given circumstances, i.e. it tells us how the
particle's motion is changing at each moment, not where the
particle will be at some future moment.

* The theory of quanta suggests that the continuity is only
apparent. If so, we shall be able theoretically to reach events
which are not processes. But in what is directly observable there
is still apparent continuity, which justifies the above remarks
for the prevent.

Laws embodied in differential equations may possibly be exact,
but cannot be known to be so. All that we can know empirically is
approximate and liable to exceptions; the exact laws that are
assumed in physics are known to be somewhere near the truth, but
are not known to be true just as they stand. The laws that we
actually know empirically have the form of the traditional causal
laws, except that they are not to be regarded as universal or
necessary. "Taking arsenic is followed by death" is a good
empirical generalization; it may have exceptions, but they will
be rare. As against the professedly exact laws of physics, such
empirical generalizations have the advantage that they deal with
observable phenomena. We cannot observe infinitesimals, whether
in time or space; we do not even know whether time and space are
infinitely divisible. Therefore rough empirical generalizations
have a definite place in science, in spite of not being exact of
universal. They are the data for more exact laws, and the grounds
for believing that they are USUALLY true are stronger than the
grounds for believing that the more exact laws are ALWAYS true.

Science starts, therefore, from generalizations of the form, "A
is usually followed by B." This is the nearest approach that can
be made to a causal law of the traditional sort. It may happen in
any particular instance that A is ALWAYS followed by B, but we
cannot know this, since we cannot foresee all the perfectly
possible circumstances that might make the sequence fail, or know
that none of them will actually occur. If, however, we know of a
very large number of cases in which A is followed by B, and few
or none in which the sequence fails, we shall in PRACTICE be
justified in saying "A causes B," provided we do not attach to
the notion of cause any of the metaphysical superstitions that
have gathered about the word.

There is another point, besides lack of universality and
necessity, which it is important to realize as regards causes in
the above sense, and that is the lack of uniqueness. It is
generally assumed that, given any event, there is some one
phenomenon which is THE cause of the event in question. This
seems to be a mere mistake. Cause, in the only sense in which it
can be practically applied, means "nearly invariable antecedent."
We cannot in practice obtain an antecedent which is QUITE
invariable, for this would require us to take account of the
whole universe, since something not taken account of may prevent
the expected effect. We cannot distinguish, among nearly
invariable antecedents, one as THE cause, and the others as
merely its concomitants: the attempt to do this depends upon a
notion of cause which is derived from will, and will (as we shall
see later) is not at all the sort of thing that it is generally
supposed to be, nor is there any reason to think that in the
physical world there is anything even remotely analogous to what
will is supposed to be. If we could find one antecedent, and only
one, that was QUITE invariable, we could call that one THE cause
without introducing any notion derived from mistaken ideas about
will. But in fact we cannot find any antecedent that we know to
be quite invariable, and we can find many that are nearly so. For
example, men leave a factory for dinner when the hooter sounds at
twelve o'clock. You may say the hooter is THE cause of their
leaving. But innumerable other hooters in other factories, which
also always sound at twelve o'clock, have just as good a right to
be called the cause. Thus every event has many nearly invariable
antecedents, and therefore many antecedents which may be called
its cause.

The laws of traditional physics, in the form in which they deal
with movements of matter or electricity, have an apparent
simplicity which somewhat conceals the empirical character of
what they assert. A piece of matter, as it is known empirically,
is not a single existing thing, but a system of existing things.
When several people simultaneously see the same table, they all
see something different; therefore "the" table, which they are
supposed all to see, must be either a hypothesis or a
construction. "The" table is to be neutral as between different
observers: it does not favour the aspect seen by one man at the
expense of that seen by another. It was natural, though to my
mind mistaken, to regard the "real" table as the common cause of
all the appearances which the table presents (as we say) to
different observers. But why should we suppose that there is some
one common cause of all these appearances? As we have just seen,
the notion of "cause" is not so reliable as to allow us to infer
the existence of something that, by its very nature, can never be

Instead of looking for an impartial source, we can secure
neutrality by the equal representation of all parties. Instead of
supposing that there is some unknown cause, the "real" table,
behind the different sensations of those who are said to be
looking at the table, we may take the whole set of these
sensations (together possibly with certain other particulars) as
actually BEING the table. That is to say, the table which is
neutral as between different observers (actual and possible) is
the set of all those particulars which would naturally be called
"aspects" of the table from different points of view. (This is a
first approximation, modified later.)

It may be said: If there is no single existent which is the
source of all these "aspects," how are they collected together?
The answer is simple: Just as they would be if there were such a
single existent. The supposed "real" table underlying its
appearances is, in any case, not itself perceived, but inferred,
and the question whether such-and-such a particular is an
"aspect" of this table is only to be settled by the connection of
the particular in question with the one or more particulars by
which the table is defined. That is to say, even if we assume a
"real" table, the particulars which are its aspects have to be
collected together by their relations to each other, not to it,
since it is merely inferred from them. We have only, therefore,
to notice how they are collected together, and we can then keep
the collection without assuming any "real" table as distinct from
the collection. When different people see what they call the same
table, they see things which are not exactly the same, owing to
difference of point of view, but which are sufficiently alike to
be described in the same words, so long as no great accuracy or
minuteness is sought. These closely similar particulars are
collected together by their similarity primarily and, more
correctly, by the fact that they are related to each other
approximately according to the laws of perspective and of
reflection and diffraction of light. I suggest, as a first
approximation, that these particulars, together with such
correlated others as are unperceived, jointly ARE the table; and
that a similar definition applies to all physical objects.*

*See "Our Knowledge of the External World" (Allen & Unwin),
chaps. iii and iv.

In order to eliminate the reference to our perceptions, which
introduces an irrelevant psychological suggestion, I will take a
different illustration, namely, stellar photography. A
photographic plate exposed on a clear night reproduces the
appearance of the portion of the sky concerned, with more or
fewer stars according to the power of the telescope that is being
used. Each separate star which is photographed produces its
separate effect on the plate, just as it would upon ourselves if
we were looking at the sky. If we assume, as science normally
does, the continuity of physical processes, we are forced to
conclude that, at the place where the plate is, and at all places
between it and a star which it photographs, SOMETHING is
happening which is specially connected with that star. In the
days when the aether was less in doubt, we should have said that
what was happening was a certain kind of transverse vibration in
the aether. But it is not necessary or desirable to be so
explicit: all that we need say is that SOMETHING happens which is
specially connected with the star in question. It must be
something specially connected with that star, since that star
produces its own special effect upon the plate. Whatever it is
must be the end of a process which starts from the star and
radiates outwards, partly on general grounds of continuity,
partly to account for the fact that light is transmitted with a
certain definite velocity. We thus arrive at the conclusion that,
if a certain star is visible at a certain place, or could be
photographed by a sufficiently sensitive plate at that place,
something is happening there which is specially connected with
that star. Therefore in every place at all times a vast multitude
of things must be happening, namely, at least one for every
physical object which can be seen or photographed from that
place. We can classify such happenings on either of two

(1) We can collect together all the happenings in one place, as
is done by photography so far as light is concerned;

(2) We can collect together all the happenings, in different
places, which are connected in the way that common sense regards
as being due to their emanating from one object.

Thus, to return to the stars, we can collect together either--

(1) All the appearances of different stars in a given place, or,

(2) All the appearances of a given star in different places.

But when I speak of "appearances," I do so only for brevity: I do
not mean anything that must "appear" to somebody, but only that
happening, whatever it may be, which is connected, at the place
in question, with a given physical object--according to the old
orthodox theory, it would be a transverse vibration in the
aether. Like the different appearances of the table to a number
of simultaneous observers, the different particulars that belong
to one physical object are to be collected together by continuity
and inherent laws of correlation, not by their supposed causal
connection with an unknown assumed existent called a piece of
matter, which would be a mere unnecessary metaphysical thing in
itself. A piece of matter, according to the definition that I
propose, is, as a first approximation,* the collection of all
those correlated particulars which would normally be regarded as
its appearances or effects in different places. Some further
elaborations are desirable, but we can ignore them for the
present. I shall return to them at the end of this lecture.

*The exact definition of a piece of matter as a construction will
be given later.

According to the view that I am suggesting, a physical object or
piece of matter is the collection of all those correlated
particulars which would be regarded by common sense as its
effects or appearances in different places. On the other hand,
all the happenings in a given place represent what common sense
would regard as the appearances of a number of different objects
as viewed from that place. All the happenings in one place may be
regarded as the view of the world from that place. I shall call
the view of the world from a given place a "perspective." A
photograph represents a perspective. On the other hand, if
photographs of the stars were taken in all points throughout
space, and in all such photographs a certain star, say Sirius,
were picked out whenever it appeared, all the different
appearances of Sirius, taken together, would represent Sirius.
For the understanding of the difference between psychology and
physics it is vital to understand these two ways of classifying
particulars, namely:

(1) According to the place where they occur;

(2) According to the system of correlated particulars in
different places to which they belong, such system being defined
as a physical object.

Given a system of particulars which is a physical object, I shall
define that one of the system which is in a given place (if any)
as the "appearance of that object in that place."

When the appearance of an object in a given place changes, it is
found that one or other of two things occurs. The two
possibilities may be illustrated by an example. You are in a room
with a man, whom you see: you may cease to see him either by
shutting your eyes or by his going out of the room. In the first
case, his appearance to other people remains unchanged; in the
second, his appearance changes from all places. In the first
case, you say that it is not he who has changed, but your eyes;
in the second, you say that he has changed. Generalizing, we

(1) Cases in which only certain appearances of the object change,
while others, and especially appearances from places very near to
the object, do not change;

(2) Cases where all, or almost all, the appearances of the object
undergo a connected change.

In the first case, the change is attributed to the medium between
the object and the place; in the second, it is attributed to the
object itself.*

* The application of this distinction to motion raises
complications due to relativity, but we may ignore these for our
present purposes.

It is the frequency of the latter kind of change, and the
comparatively simple nature of the laws governing the
simultaneous alterations of appearances in such cases, that have
made it possible to treat a physical object as one thing, and to
overlook the fact that it is a system of particulars. When a
number of people at a theatre watch an actor, the changes in
their several perspectives are so similar and so closely
correlated that all are popularly regarded as identical with each
other and with the changes of the actor himself. So long as all
the changes in the appearances of a body are thus correlated
there is no pressing prima facie need to break up the system of
appearances, or to realize that the body in question is not
really one thing but a set of correlated particulars. It is
especially and primarily such changes that physics deals with,
i.e. it deals primarily with processes in which the unity of a
physical object need not be broken up because all its appearances
change simultaneously according to the same law--or, if not all,
at any rate all from places sufficiently near to the object, with
in creasing accuracy as we approach the object.

The changes in appearances of an object which are due to changes
in the intervening medium will not affect, or will affect only
very slightly, the appearances from places close to the object.
If the appearances from sufficiently neighbouring places are
either wholly un changed, or changed to a diminishing extent
which has zero for its limit, it is usually found that the
changes can be accounted for by changes in objects which are
between the object in question and the places from which its
appearance has changed appreciably. Thus physics is able to
reduce the laws of most changes with which it deals to changes in
physical objects, and to state most of its fundamental laws in
terms of matter. It is only in those cases in which the unity of
the system of appearances constituting a piece of matter has to
be broken up, that the statement of what is happening cannot be
made exclusively in terms of matter. The whole of psychology, we
shall find, is included among such cases; hence their importance
for our purposes.

We can now begin to understand one of the fundamental differences
between physics and psychology. Physics treats as a unit the
whole system of appearances of a piece of matter, whereas
psychology is interested in certain of these appearances
themselves. Confining ourselves for the moment to the psychology
of perceptions, we observe that perceptions are certain of the
appearances of physical objects. From the point of view that we
have been hitherto adopting, we might define them as the
appearances of objects at places from which sense-organs and the
suitable parts of the nervous system form part of the intervening
medium. Just as a photographic plate receives a different
impression of a cluster of stars when a telescope is part of the
intervening medium, so a brain receives a different impression
when an eye and an optic nerve are part of the intervening
medium. An impression due to this sort of intervening medium is
called a perception, and is interesting to psychology on its own
account, not merely as one of the set of correlated particulars
which is the physical object of which (as we say) we are having a

We spoke earlier of two ways of classifying particulars. One way
collects together the appearances commonly regarded as a given
object from different places; this is, broadly speaking, the way
of physics, leading to the construction of physical objects as
sets of such appearances. The other way collects together the
appearances of different objects from a given place, the result
being what we call a perspective. In the particular case where
the place concerned is a human brain, the perspective belonging
to the place consists of all the perceptions of a certain man at
a given time. Thus classification by perspectives is relevant to
psychology, and is essential in defining what we mean by one

I do not wish to suggest that the way in which I have been
defining perceptions is the only possible way, or even the best
way. It is the way that arose naturally out of our present topic.
But when we approach psychology from a more introspective
standpoint, we have to distinguish sensations and perceptions, if
possible, from other mental occurrences, if any. We have also to
consider the psychological effects of sensations, as opposed to
their physical causes and correlates. These problems are quite
distinct from those with which we have been concerned in the
present lecture, and I shall not deal with them until a later

It is clear that psychology is concerned essentially with actual
particulars, not merely with systems of particulars. In this it
differs from physics, which, broadly speaking, is concerned with
the cases in which all the particulars which make up one physical
object can be treated as a single causal unit, or rather the
particulars which are sufficiently near to the object of which
they are appearances can be so treated. The laws which physics
seeks can, broadly speaking, be stated by treating such systems
of particulars as causal units. The laws which psychology seeks
cannot be so stated, since the particulars themselves are what
interests the psychologist. This is one of the fundamental
differences between physics and psychology; and to make it clear
has been the main purpose of this lecture.

I will conclude with an attempt to give a more precise definition
of a piece of matter. The appearances of a piece of matter from
different places change partly according to intrinsic laws (the
laws of perspective, in the case of visual shape), partly
according to the nature of the intervening medium--fog, blue
spectacles, telescopes, microscopes, sense-organs, etc. As we
approach nearer to the object, the effect of the intervening
medium grows less. In a generalized sense, all the intrinsic laws
of change of appearance may be called "laws of perspective."
Given any appearance of an object, we can construct
hypothetically a certain system of appearances to which the
appearance in question would belong if the laws of perspective
alone were concerned. If we construct this hypothetical system
for each appearance of the object in turn, the system
corresponding to a given appearance x will be independent of any
distortion due to the medium beyond x, and will only embody such
distortion as is due to the medium between x and the object.
Thus, as the appearance by which our hypothetical system is
defined is moved nearer and nearer to the object, the
hypothetical system of appearances defined by its means embodies
less and less of the effect of the medium. The different sets of
appearances resulting from moving x nearer and nearer to the
object will approach to a limiting set, and this limiting set
will be that system of appearances which the object would present
if the laws of perspective alone were operative and the medium
exercised no distorting effect. This limiting set of appearances
may be defined, for purposes of physics, as the piece of matter

download audio

One of the main purposes of these lectures is to give grounds for
the belief that the distinction between mind and matter is not so
fundamental as is commonly supposed. In the preceding lecture I
dealt in outline with the physical side of this problem. I
attempted to show that what we call a material object is not
itself a substance, but is a system of particulars analogous in
their nature to sensations, and in fact often including actual
sensations among their number. In this way the stuff of which
physical objects are composed is brought into relation with the
stuff of which part, at least, of our mental life is composed.

There is, however, a converse task which is equally necessary for
our thesis, and that is, to show that the stuff of our mental
life is devoid of many qualities which it is commonly supposed to
have, and is not possessed of any attributes which make it
incapable of forming part of the world of matter. In the present
lecture I shall begin the arguments for this view.

Corresponding to the supposed duality of matter and mind, there
are, in orthodox psychology, two ways of knowing what exists. One
of these, the way of sensation and external perception, is
supposed to furnish data for our knowledge of matter, the other,
called "introspection," is supposed to furnish data for knowledge
of our mental processes. To common sense, this distinction seems
clear and easy. When you see a friend coming along the street,
you acquire knowledge of an external, physical fact; when you
realize that you are glad to meet him, you acquire knowledge of a
mental fact. Your dreams and memories and thoughts, of which you
are often conscious, are mental facts, and the process by which
you become aware of them SEEMS to be different from sensation.
Kant calls it the "inner sense"; sometimes it is spoken of as
"consciousness of self"; but its commonest name in modern English
psychology is "introspection." It is this supposed method of
acquiring knowledge of our mental processes that I wish to
analyse and examine in this lecture.

I will state at the outset the view which I shall aim at
establishing. I believe that the stuff of our mental life, as
opposed to its relations and structure, consists wholly of
sensations and images. Sensations are connected with matter in
the way that I tried to explain in Lecture V, i.e. each is a
member of a system which is a certain physical object. Images,
though they USUALLY have certain characteristics, especially lack
of vividness, that distinguish them from sensations, are not
INVARIABLY so distinguished, and cannot therefore be defined by
these characteristics. Images, as opposed to sensations, can only
be defined by their different causation: they are caused by
association with a sensation, not by a stimulus external to the
nervous system--or perhaps one should say external to the brain,
where the higher animals are concerned. The occurrence of a
sensation or image does not in itself constitute knowledge but
any sensation or image may come to be known if the conditions are
suitable. When a sensation--like the hearing of a clap of
thunder--is normally correlated with closely similar sensations
in our neighbours, we regard it as giving knowledge of the
external world, since we regard the whole set of similar
sensations as due to a common external cause. But images and
bodily sensations are not so correlated. Bodily sensations can be
brought into a correlation by physiology, and thus take their
place ultimately among sources of knowledge of the physical
world. But images cannot be made to fit in with the simultaneous
sensations and images of others. Apart from their hypothetical
causes in the brain, they have a causal connection with physical
objects, through the fact that they are copies of past
sensations; but the physical objects with which they are thus
connected are in the past, not in the present. These images
remain private in a sense in which sensations are not. A
sensation SEEMS to give us knowledge of a present physical
object, while an image does not, except when it amounts to a
hallucination, and in this case the seeming is deceptive. Thus
the whole context of the two occurrences is different. But in
themselves they do not differ profoundly, and there is no reason
to invoke two different ways of knowing for the one and for the
other. Consequently introspection as a separate kind of knowledge

The criticism of introspection has been in the main the work of
American psychologists. I will begin by summarizing an article
which seems to me to afford a good specimen of their arguments,
namely, "The Case against Introspection," by Knight Dunlap
("Psychological Review," vol xix, No. 5, pp. 404-413, September,
1912). After a few historical quotations, he comes to two modern
defenders of introspection, Stout and James. He quotes from Stout
such statements as the following: "Psychical states as such
become objects only when we attend to them in an introspective
way. Otherwise they are not themselves objects, but only
constituents of the process by which objects are recognized"
("Manual," 2nd edition, p. 134. The word "recognized" in Dunlap's
quotation should be "cognized.") "The object itself can never be
identified with the present modification of the individual's
consciousness by which it is cognized" (ib. p. 60). This is to be
true even when we are thinking about modifications of our own
consciousness; such modifications are to be always at least
partially distinct from the conscious experience in which we
think of them.

At this point I wish to interrupt the account of Knight Dunlap's
article in order to make some observations on my own account with
reference to the above quotations from Stout. In the first place,
the conception of "psychical states" seems to me one which
demands analysis of a somewhat destructive character. This
analysis I shall give in later lectures as regards cognition; I
have already given it as regards desire. In the second place, the
conception of "objects" depends upon a certain view as to
cognition which I believe to be wholly mistaken, namely, the view
which I discussed in my first lecture in connection with
Brentano. In this view a single cognitive occurrence contains
both content and object, the content being essentially mental,
while the object is physical except in introspection and abstract
thought. I have already criticized this view, and will not dwell
upon it now, beyond saying that "the process by which objects are
cognized" appears to be a very slippery phrase. When we "see a
table," as common sense would say, the table as a physical object
is not the "object" (in the psychological sense) of our
perception. Our perception is made up of sensations, images and
beliefs, but the supposed "object" is something inferential,
externally related, not logically bound up with what is occurring
in us. This question of the nature of the object also affects the
view we take of self-consciousness. Obviously, a "conscious
experience" is different from a physical object; therefore it is
natural to assume that a thought or perception whose object is a
conscious experience must be different from a thought or
perception whose object is a physical object. But if the relation
to the object is inferential and external, as I maintain, the
difference between two thoughts may bear very little relation to
the difference between their objects. And to speak of "the
present modification of the individual's consciousness by which
an object is cognized" is to suggest that the cognition of
objects is a far more direct process, far more intimately bound
up with the objects, than I believe it to be. All these points
will be amplified when we come to the analysis of knowledge, but
it is necessary briefly to state them now in order to suggest the
atmosphere in which our analysis of "introspection" is to be
carried on.

Another point in which Stout's remarks seem to me to suggest what
I regard as mistakes is his use of "consciousness." There is a
view which is prevalent among psychologists, to the effect that
one can speak of "a conscious experience" in a curious dual
sense, meaning, on the one hand, an experience which is conscious
of something, and, on the other hand, an experience which has
some intrinsic nature characteristic of what is called
"consciousness." That is to say, a "conscious experience" is
characterized on the one hand by relation to its object and on
the other hand by being composed of a certain peculiar stuff, the
stuff of "consciousness." And in many authors there is yet a
third confusion: a "conscious experience," in this third sense,
is an experience of which we are conscious. All these, it seems
to me, need to be clearly separated. To say that one occurrence
is "conscious" of another is, to my mind, to assert an external
and rather remote relation between them. I might illustrate it by
the relation of uncle and nephew a man becomes an uncle through
no effort of his own, merely through an occurrence elsewhere.
Similarly, when you are said to be "conscious" of a table, the
question whether this is really the case cannot be decided by
examining only your state of mind: it is necessary also to
ascertain whether your sensation is having those correlates which
past experience causes you to assume, or whether the table
happens, in this case, to be a mirage. And, as I explained in my
first lecture, I do not believe that there is any "stuff" of
consciousness, so that there is no intrinsic character by which a
"conscious" experience could be distinguished from any other.

After these preliminaries, we can return to Knight Dunlap's
article. His criticism of Stout turns on the difficulty of giving
any empirical meaning to such notions as the "mind" or the
"subject"; he quotes from Stout the sentence: "The most important
drawback is that the mind, in watching its own workings, must
necessarily have its attention divided between two objects," and
he concludes: "Without question, Stout is bringing in here
illicitly the concept of a single observer, and his introspection
does not provide for the observation of this observer; for the
process observed and the observer are distinct" (p. 407). The
objections to any theory which brings in the single observer were
considered in Lecture I, and were acknowledged to be cogent. In
so far, therefore, as Stout's theory of introspection rests upon
this assumption, we are compelled to reject it. But it is
perfectly possible to believe in introspection without supposing
that there is a single observer.

William James's theory of introspection, which Dunlap next
examines, does not assume a single observer. It changed after the
publication of his "Psychology," in consequence of his abandoning
the dualism of thought and things. Dunlap summarizes his theory
as follows:

"The essential points in James's scheme of consciousness are
SUBJECT, OBJECT,and a KNOWING of the object by the subject. The
difference between James's scheme and other schemes involving the
same terms is that James considers subject and object to be the
same thing, but at different times In order to satisfy this
requirement James supposes a realm of existence which he at first
called 'states of consciousness' or 'thoughts,' and later, 'pure
experience,' the latter term including both the 'thoughts' and
the 'knowing.' This scheme, with all its magnificent
artificiality, James held on to until the end, simply dropping
the term consciousness and the dualism between the thought and an
external reality"(p. 409).

He adds: "All that James's system really amounts to is the
acknowledgment that a succession of things are known, and that
they are known by something. This is all any one can claim,
except for the fact that the things are known together, and that
the knower for the different items is one and the same" (ib.).

In this statement, to my mind, Dunlap concedes far more than
James did in his later theory. I see no reason to suppose that
"the knower for different items is one and the same," and I am
convinced that this proposition could not possibly be ascertained
except by introspection of the sort that Dunlap rejects. The
first of these points must wait until we come to the analysis of
belief: the second must be considered now. Dunlap's view is that
there is a dualism of subject and object, but that the subject
can never become object, and therefore there is no awareness of
an awareness. He says in discussing the view that introspection
reveals the occurrence of knowledge: "There can be no denial of
the existence of the thing (knowing) which is alleged to be known
or observed in this sort of 'introspection.' The allegation that
the knowing is observed is that which may be denied. Knowing
there certainly is; known, the knowing certainly is not"(p. 410).
And again: "I am never aware of an awareness" (ib.). And on the
next page: "It may sound paradoxical to say that one cannot
observe the process (or relation) of observation, and yet may be
certain that there is such a process: but there is really no
inconsistency in the saying. How do I know that there is
awareness? By being aware of something. There is no meaning in
the term 'awareness' which is not expressed in the statement 'I
am aware of a colour (or what-not).' "

But the paradox cannot be so lightly disposed of. The statement
"I am aware of a colour" is assumed by Knight Dunlap to be known
to be true, but he does not explain how it comes to be known. The
argument against him is not conclusive, since he may be able to
show some valid way of inferring our awareness. But he does not
suggest any such way. There is nothing odd in the hypothesis of
beings which are aware of objects, but not of their own
awareness; it is, indeed, highly probable that young children and
the higher animals are such beings. But such beings cannot make
the statement "I am aware of a colour," which WE can make. We
have, therefore, some knowledge which they lack. It is necessary
to Knight Dunlap's position to maintain that this additional
knowledge is purely inferential, but he makes no attempt to show
how the inference is possible. It may, of course, be possible,
but I cannot see how. To my mind the fact (which he admits) that
we know there is awareness, is ALL BUT decisive against his
theory, and in favour of the view that we can be aware of an

Dunlap asserts (to return to James) that the real ground for
James's original belief in introspection was his belief in two
sorts of objects, namely, thoughts and things. He suggests that
it was a mere inconsistency on James's part to adhere to
introspection after abandoning the dualism of thoughts and
things. I do not wholly agree with this view, but it is difficult
to disentangle the difference as to introspection from the
difference as to the nature of knowing. Dunlap suggests (p. 411)
that what is called introspection really consists of awareness of
"images," visceral sensations, and so on. This view, in essence,
seems to me sound. But then I hold that knowing itself consists
of such constituents suitably related, and that in being aware of
them we are sometimes being aware of instances of knowing. For
this reason, much as I agree with his view as to what are the
objects of which there is awareness, I cannot wholly agree with
his conclusion as to the impossibility of introspection.

The behaviourists have challenged introspection even more
vigorously than Knight Dunlap, and have gone so far as to deny
the existence of images. But I think that they have confused
various things which are very commonly confused, and that it is
necessary to make several distinctions before we can arrive at
what is true and what false in the criticism of introspection.

I wish to distinguish three distinct questions, any one of which
may be meant when we ask whether introspection is a source of
knowledge. The three questions are as follows:

(1) Can we observe anything about ourselves which we cannot
observe about other people, or is everything we can observe
PUBLIC, in the sense that another could also observe it if
suitably placed?

(2) Does everything that we can observe obey the laws of physics
and form part of the physical world, or can we observe certain
things that lie outside physics?

(3) Can we observe anything which differs in its intrinsic nature
from the constituents of the physical world, or is everything
that we can observe composed of elements intrinsically similar to
the constituents of what is called matter?

Any one of these three questions may be used to define
introspection. I should favour introspection in the sense of the
first question, i.e. I think that some of the things we observe
cannot, even theoretically, be observed by any one else. The
second question, tentatively and for the present, I should answer
in favour of introspection; I think that images, in the actual
condition of science, cannot be brought under the causal laws of
physics, though perhaps ultimately they may be. The third
question I should answer adversely to introspection I think that
observation shows us nothing that is not composed of sensations
and images, and that images differ from sensations in their
causal laws, not intrinsically. I shall deal with the three
questions successively.

ourselves, for the moment, to sensations, we find that there are
different degrees of publicity attaching to different sorts of
sensations. If you feel a toothache when the other people in the
room do not, you are in no way surprised; but if you hear a clap
of thunder when they do not, you begin to be alarmed as to your
mental condition. Sight and hearing are the most public of the
senses; smell only a trifle less so; touch, again, a trifle less,
since two people can only touch the same spot successively, not
simultaneously. Taste has a sort of semi-publicity, since people
seem to experience similar taste-sensations when they eat similar
foods; but the publicity is incomplete, since two people cannot
eat actually the same piece of food.

But when we pass on to bodily sensations--headache, toothache,
hunger, thirst, the feeling of fatigue, and so on--we get quite
away from publicity, into a region where other people can tell us
what they feel, but we cannot directly observe their feeling. As
a natural result of this state of affairs, it has come to be
thought that the public senses give us knowledge of the outer
world, while the private senses only give us knowledge as to our
own bodies. As regards privacy, all images, of whatever sort,
belong with the sensations which only give knowledge of our own
bodies, i.e. each is only observable by one observer. This is the
reason why images of sight and hearing are more obviously
different from sensations of sight and hearing than images of
bodily sensations are from bodily sensations; and that is why the
argument in favour of images is more conclusive in such cases as
sight and hearing than in such cases as inner speech.

The whole distinction of privacy and publicity, however, so long
as we confine ourselves to sensations, is one of degree, not of
kind. No two people, there is good empirical reason to think,
ever have exactly similar sensations related to the same physical
object at the same moment; on the other hand, even the most
private sensation has correlations which would theoretically
enable another observer to infer it.

That no sensation is ever completely public, results from
differences of point of view. Two people looking at the same
table do not get the same sensation, because of perspective and
the way the light falls. They get only correlated sensations. Two
people listening to the same sound do not hear exactly the same
thing, because one is nearer to the source of the sound than the
other, one has better hearing than the other, and so on. Thus
publicity in sensations consists, not in having PRECISELY similar
sensations, but in having more or less similar sensations
correlated according to ascertainable laws. The sensations which
strike us as public are those where the correlated sensations are
very similar and the correlations are very easy to discover. But
even the most private sensations have correlations with things
that others can observe. The dentist does not observe your ache,
but he can see the cavity which causes it, and could guess that
you are suffering even if you did not tell him. This fact,
however, cannot be used, as Watson would apparently wish, to
extrude from science observations which are private to one
observer, since it is by means of many such observations that
correlations are established, e.g. between toothaches and
cavities. Privacy, therefore does not by itself make a datum
unamenable to scientific treatment. On this point, the argument
against introspection must be rejected.

now to the second ground of objection to introspection, namely,
that its data do not obey the laws of physics. This, though less
emphasized, is, I think, an objection which is really more
strongly felt than the objection of privacy. And we obtain a
definition of introspection more in harmony with usage if we
define it as observation of data not subject to physical laws
than if we define it by means of privacy. No one would regard a
man as introspective because he was conscious of having a stomach
ache. Opponents of introspection do not mean to deny the obvious
fact that we can observe bodily sensations which others cannot
observe. For example, Knight Dunlap contends that images are
really muscular contractions,* and evidently regards our
awareness of muscular contractions as not coming under the head
of introspection. I think it will be found that the essential
characteristic of introspective data, in the sense which now
concerns us, has to do with LOCALIZATION: either they are not
localized at all, or they are localized, like visual images, in a
place already physically occupied by something which would be
inconsistent with them if they were regarded as part of the
physical world. If you have a visual image of your friend sitting
in a chair which in fact is empty, you cannot locate the image in
your body, because it is visual, nor (as a physical phenomenon)
in the chair, because the chair, as a physical object, is empty.
Thus it seems to follow that the physical world does not include
all that we are aware of, and that images, which are
introspective data, have to be regarded, for the present, as not
obeying the laws of physics; this is, I think, one of the chief
reasons why an attempt is made to reject them. I shall try to
show in Lecture VIII that the purely empirical reasons for
accepting images are overwhelming. But we cannot be nearly so
certain that they will not ultimately be brought under the laws
of physics. Even if this should happen, however, they would still
be distinguishable from sensations by their proximate causal
laws, as gases remain distinguishable from solids.

* "Psychological Review," 1916, "Thought-Content and Feeling," p.
59. See also ib., 1912, "The Nature of Perceived Relations,"
where he says: "'Introspection,' divested of its mythological
suggestion of the observing of consciousness, is really the
observation of bodily sensations (sensibles) and feelings
(feelables)"(p. 427 n.).

SENSATIONS? We come now to our third question concerning
introspection. It is commonly thought that by looking within we
can observe all sorts of things that are radically different from
the constituents of the physical world, e.g. thoughts, beliefs,
desires, pleasures, pains and emotions. The difference between
mind and matter is increased partly by emphasizing these supposed
introspective data, partly by the supposition that matter is
composed of atoms or electrons or whatever units physics may at
the moment prefer. As against this latter supposition, I contend
that the ultimate constituents of matter are not atoms or
electrons, but sensations, and other things similar to sensations
as regards extent and duration. As against the view that
introspection reveals a mental world radically different from
sensations, I propose to argue that thoughts, beliefs, desires,
pleasures, pains and emotions are all built up out of sensations
and images alone, and that there is reason to think that images
do not differ from sensations in their intrinsic character. We
thus effect a mutual rapprochement of mind and matter, and reduce
the ultimate data of introspection (in our second sense) to
images alone. On this third view of the meaning of introspection,
therefore, our decision is wholly against it.

There remain two points to be considered concerning
introspection. The first is as to how far it is trustworthy; the
second is as to whether, even granting that it reveals no
radically different STUFF from that revealed by what might be
called external perception, it may not reveal different
RELATIONS, and thus acquire almost as much importance as is
traditionally assigned to it.

To begin with the trustworthiness of introspection. It is common
among certain schools to regard the knowledge of our own mental
processes as incomparably more certain than our knowledge of the
"external" world; this view is to be found in the British
philosophy which descends from Hume, and is present, somewhat
veiled, in Kant and his followers. There seems no reason whatever
to accept this view. Our spontaneous, unsophisticated beliefs,
whether as to ourselves or as to the outer world, are always
extremely rash and very liable to error. The acquisition of
caution is equally necessary and equally difficult in both
directions. Not only are we often un aware of entertaining a
belief or desire which exists in us; we are often actually
mistaken. The fallibility of introspection as regards what we
desire is made evident by psycho-analysis; its fallibility as to
what we know is easily demonstrated. An autobiography, when
confronted by a careful editor with documentary evidence, is
usually found to be full of obviously inadvertent errors. Any of
us confronted by a forgotten letter written some years ago will
be astonished to find how much more foolish our opinions were
than we had remembered them as being. And as to the analysis of
our mental operations--believing, desiring, willing, or what
not--introspection unaided gives very little help: it is
necessary to construct hypotheses and test them by their
consequences, just as we do in physical science. Introspection,
therefore, though it is one among our sources of knowledge, is
not, in isolation, in any degree more trustworthy than "external"

I come now to our second question: Does introspection give us
materials for the knowledge of relations other than those arrived
at by reflecting upon external perception? It might be contended
that the essence of what is "mental" consists of relations, such
as knowing for example, and that our knowledge concerning these
essentially mental relations is entirely derived from
introspection. If "knowing" were an unanalysable relation, this
view would be incontrovertible, since clearly no such relation
forms part of the subject matter of physics. But it would seem
that "knowing" is really various relations, all of them complex.
Therefore, until they have been analysed, our present question
must remain unanswered I shall return to it at the end of the
present course of lectures.

download audio

In Lecture V we found reason to think that the ultimate
constituents* of the world do not have the characteristics of
either mind or matter as ordinarily understood: they are not
solid persistent objects moving through space, nor are they
fragments of "consciousness." But we found two ways of grouping
particulars, one into "things" or "pieces of matter," the other
into series of "perspectives," each series being what may be
called a "biography." Before we can define either sensations or
images, it is necessary to consider this twofold classification
in somewhat greater detail, and to derive from it a definition of
perception. It should be said that, in so far as the
classification assumes the whole world of physics (including its
unperceived portions), it contains hypothetical elements. But we
will not linger on the grounds for admitting these, which belong
to the philosophy of physics rather than of psychology.

* When I speak of "ultimate constituents," I do not mean
necessarily such as are theoretically incapable of analysis, but
only such as, at present, we can see no means of analysing. I
speak of such constituents as "particulars," or as "RELATIVE
particulars" when I wish to emphasize the fact that they may be
themselves complex.

The physical classification of particulars collects together all
those that are aspects of one "thing." Given any one particular,
it  is found often (we do not say always) that there are a number
of other particulars differing from this one in gradually
increasing degrees. Those (or some of those) that differ from it
only very slightly will be found to differ approximately
according  to certain laws which may be called, in a generalized
sense, the laws of "perspective"; they include the ordinary laws
of  perspective as a special case. This approximation grows more
and more nearly exact as the difference grows less; in technical
language, the laws of perspective account for the differences to
the first order of small quantities, and other laws are only
required to account for second-order differences. That is to say,
as the difference diminishes, the part of the difference which is
not according to the laws of perspective diminishes much more
rapidly, and bears to the total difference a ratio which tends
towards zero as both are made smaller and smaller. By this  means
we can theoretically collect together a number of  particulars
which may be defined as the "aspects" or "appearances" of one
thing at one time. If the laws of  perspective were sufficiently
known, the connection between  different aspects would be
expressed in differential equations.

This gives us, so far, only those particulars which constitute
one thing at one time. This set of particulars may be called a
"momentary thing." To define that series of "momentary things"
that constitute the successive states of one thing is a problem
involving the laws of dynamics. These give the laws governing the
changes of aspects from one time to a slightly later time, with
the same sort of differential approximation to exactness as we
obtained for spatially neighbouring aspects through the laws of
perspective. Thus a momentary thing is a set of particulars,
while a thing (which may be identified with the whole history of
the thing) is a series of such sets of particulars. The
particulars in one set are collected together by the laws of
perspective; the successive sets are collected together by the
laws of dynamics. This is the view of the world which is
appropriate to traditional physics.

The definition of a "momentary thing" involves problems
concerning time, since the particulars constituting a momentary
thing will not be all simultaneous, but will travel outward from
the thing with the velocity of light (in case the thing is in
vacuo). There are complications connected with relativity, but
for our present purpose they are not vital, and I shall ignore

Instead of first collecting together all the particulars
constituting a momentary thing, and then forming the series of
successive sets, we might have first collected together a series
of successive aspects related by the laws of dynamics, and then
have formed the set of such series related by the laws of
perspective. To illustrate by the case of an actor on the stage:
our first plan was to collect together all the aspects which he
presents to different spectators at one time, and then to form
the series of such sets. Our second plan is first to collect
together all the aspects which he presents successively to a
given spectator, and then to do the same thing for the other
spectators, thus forming a set of series instead of a series of
sets. The first plan tells us what he does; the second the
impressions he produces. This second way of classifying
particulars is one which obviously has more relevance to
psychology than the other. It is partly by this second method of
classification that we obtain definitions of one "experience" or
"biography" or "person." This method of classification is also
essential to the definition of sensations and images, as I shall
endeavour to prove later on. But we must first amplify the
definition of perspectives and biographies.

In our illustration of the actor, we spoke, for the moment, as
though each spectator's mind were wholly occupied by the one
actor. If this were the case, it might be possible to define the
biography of one spectator as a series of successive aspects of
the actor related according to the laws of dynamics. But in fact
this is not the case. We are at all times during our waking life
receiving a variety of impressions, which are aspects of a
variety of things. We have to consider what binds together two
simultaneous sensations in one person, or, more generally, any
two occurrences which forte part of one experience. We might say,
adhering to the standpoint of physics, that two aspects of
different things belong to the same perspective when they are in
the same place. But this would not really help us, since a
"place" has not yet been defined. Can we define what is meant by
saying that two aspects are "in the same place," without
introducing anything beyond the laws of perspective and dynamics?

I do not feel sure whether it is possible to frame such a
definition or not; accordingly I shall not assume that it is
possible, but shall seek other characteristics by which a
perspective or biography may be defined.

When (for example) we see one man and hear another speaking at
the same time, what we see and what we hear have a relation which
we can perceive, which makes the two together form, in some
sense, one experience. It is when this relation exists that two
occurrences become associated. Semon's "engram" is formed by all
that we experience at one time. He speaks of two parts of this
total as having the relation of "Nebeneinander" (M. 118; M.E. 33
ff.), which is reminiscent of Herbart's "Zusammen." I think the
relation may be called simply "simultaneity." It might be said
that at any moment all sorts of things that are not part of my
experience are happening in the world, and that therefore the
relation we are seeking to define cannot be merely simultaneity.
This, however, would be an error--the sort of error that the
theory of relativity avoids. There is not one universal time,
except by an elaborate construction; there are only local times,
each of which may be taken to be the time within one biography.
Accordingly, if I am (say) hearing a sound, the only occurrences
that are, in any simple sense, simultaneous with my sensation are
events in my private world, i.e. in my biography. We may
therefore define the "perspective" to which the sensation in
question belongs as the set of particulars that are simultaneous
with this sensation. And similarly we may define the "biography"
to which the sensation belongs as the set of particulars that are
earlier or later than, or simultaneous with, the given sensation.
Moreover, the very same definitions can be applied to particulars
which are not sensations. They are actually required for the
theory of relativity, if we are to give a philosophical
explanation of what is meant by "local time" in that theory The
relations of simultaneity and succession are known to us in our
own experience; they may be analysable, but that does not affect
their suitability for defining perspectives and biographies. Such
time-relations as can be constructed between events in different
biographies are of a different kind: they are not experienced,
and are merely logical, being designed to afford convenient ways
of stating the correlations between different biographies.

It is not only by time-relations that the parts of one biography
are collected together in the case of living beings. In this case
there are the mnemic phenomena which constitute the unity of one
"experience," and transform mere occurrences into "experiences."
I have already dwelt upon the importance of mnemic phenomena for
psychology, and shall not enlarge upon them now, beyond observing
that they are what transforms a biography (in our technical
sense) into a life. It is they that give the continuity of a
"person" or a "mind." But there is no reason to suppose that
mnemic phenomena are associated with biographies except in the
case of animals and plants.

Our two-fold classification of particulars gives rise to the
dualism of body and biography in regard to everything in the
universe, and not only in regard to living things. This arises as
follows. Every particular of the sort considered by physics is a
member of two groups (1) The group of particulars constituting
the other aspects of the same physical object; (2) The group of
particulars that have direct time-relations to the given

Each of these is associated with a place. When I look at a star,
my sensation is (1) A member of the group of particulars which is
the star, and which is associated with the place where the star
is; (2) A member of the group of particulars which is my
biography, and which is associated with the place where I am.*

*I have explained elsewhere the manner in which space is
constructed on this theory, and in which the position of a
perspective is brought into relation with the position of a
physical object ("Our Knowledge of the External World," Lecture
III, pp. 90, 91).

The result is that every particular of the kind relevant to
physics is associated with TWO places; e.g. my sensation of the
star is associated with the place where I am and with the place
where the star is. This dualism has nothing to do with any "mind"
that I may be supposed to possess; it exists in exactly the same
sense if I am replaced by a photographic plate. We may call the
two places the active and passive places respectively.* Thus in
the case of a perception or photograph of a star, the active
place is the place where the star is, while the passive place is
the place where the percipient or photographic plate is.

* I use these as mere names; I do not want to introduce any
notion of "activity."

We can thus, without departing from physics, collect together all
the particulars actively at a given place, or all the particulars
passively at a given place. In our own case, the one group is our
body (or our brain), while the other is our mind, in so far as it
consists of perceptions. In the case of the photographic plate,
the first group is the plate as dealt with by physics, the second
the aspect of the heavens which it photographs. (For the sake of
schematic simplicity, I am ignoring various complications
connected with time, which require some tedious but perfectly
feasible elaborations.) Thus what may be called subjectivity in
the point of view is not a distinctive peculiarity of mind: it is
present just as much in the  photographic plate. And the
photographic plate has its biography as well as its "matter." But
this biography is an affair of physics, and has none of the
peculiar characteristics by which "mental" phenomena are
distinguished, with the sole exception of subjectivity.

Adhering, for the moment, to the standpoint of physics, we may
define a "perception" of an object as the appearance of the
object from a place where there is a brain (or, in lower animals,
some suitable nervous structure), with sense-organs and nerves
forming part of the intervening medium. Such appearances of
objects are distinguished from appearances in other places by
certain peculiarities, namely

(1) They give rise to mnemic phenomena;

(2) They are themselves affected by mnemic phenomena.

That is to say, they may be remembered and associated or
influence our habits, or give rise to images, etc., and they are
themselves different from what they would have been if our past
experience had been different--for example, the effect of a
spoken sentence upon the hearer depends upon whether the hearer
knows the language or not, which is a question of past
experience. It is these two characteristics, both connected with
mnemic phenomena, that distinguish perceptions from the
appearances of objects in places where there is no living being.

Theoretically, though often not practically, we can, in our
perception of an object, separate the part which is due to past
experience from the part which proceeds without mnemic influences
out of the character of the object. We may define as "sensation"
that part which proceeds in this way, while the remainder, which
is a mnemic phenomenon, will have to be added to the sensation to
make up what is called the "perception." According to this
definition, the sensation is a theoretical core in the actual
experience; the actual experience is the perception. It is
obvious that there are grave difficulties in carrying out these
definitions, but we will not linger over them. We have to pass,
as soon as we can, from the physical standpoint, which we have
been hitherto adopting, to the standpoint of psychology, in which
we make more use of introspection in the first of the three
senses discussed in the preceding lecture.

But before making the transition, there are two points which must
be made clear. First: Everything outside my own personal
biography is outside my experience; therefore if anything can be
known by me outside my biography, it can only be known in one of
two ways

(1) By inference from things within my biography, or

(2) By some a priori principle independent of experience.

I do not myself believe that anything approaching certainty is to
be attained by either of these methods, and therefore whatever
lies outside my personal biography must be regarded,
theoretically, as hypothesis. The theoretical argument for
adopting the hypothesis is that it simplifies the statement of
the laws according to which events happen in our experience. But
there is no very good ground for supposing that a simple law is
more likely to be true than a complicated law, though there is
good ground for assuming a simple law in scientific practice, as
a working hypothesis, if it explains the facts as well as another
which is less simple. Belief in the existence of things outside
my own biography exists antecedently to evidence, and can only be
destroyed, if at all, by a long course of philosophic doubt. For
purposes of science, it is justified practically by the
simplification which it introduces into the laws of physics. But
from the standpoint of theoretical logic it must be regarded as a
prejudice, not as a well-grounded theory. With this proviso, I
propose to continue yielding to the prejudice.

The second point concerns the relating of our point of view to
that which regards sensations as caused by stimuli external to
the nervous system (or at least to the brain), and distinguishes
images as "centrally excited," i.e. due to causes in the brain
which cannot be traced back to anything affecting the
sense-organs. It is clear that, if our analysis of physical
objects has been valid, this way of defining sensations needs
reinterpretation. It is also clear that we must be able to find
such a new interpretation if our theory is to be admissible.

To make the matter clear, we will take the simplest possible
illustration. Consider a certain star, and suppose for the moment
that its size is negligible. That is to say, we will regard it
as, for practical purposes, a luminous point. Let us further
suppose that it exists only for a very brief time, say a second.
Then, according to physics, what happens is that a spherical wave
of light travels outward from the star through space, just as,
when you drop a stone into a stagnant pond, ripples travel
outward from the place where the stone hit the water. The wave of
light travels with a certain very nearly constant velocity,
roughly 300,000 kilometres per second. This velocity may be
ascertained by sending a flash of light to a mirror, and
observing how long it takes before the reflected flash reaches
you, just as the velocity of sound may be ascertained by means of
an echo.

What it is that happens when a wave of light reaches a given
place we cannot tell, except in the sole case when the place in
question is a brain connected with an eye which is turned in the
right direction. In this one very special case we know what
happens: we have the sensation called "seeing the star." In all
other cases, though we know (more or less hypothetically) some of
the correlations and abstract properties of the appearance of the
star, we do not know the appearance itself. Now you may, for the
sake of illustration, compare the different appearances of the
star to the conjugation of a Greek verb, except that the number
of its parts is really infinite, and not only apparently so to
the despairing schoolboy. In vacuo, the parts are regular, and
can be derived from the (imaginary) root according to the laws of
grammar, i.e. of perspective. The star being situated in empty
space, it may be defined, for purposes of physics, as consisting
of all those appearances which it presents in vacuo, together
with those which, according to the laws of perspective, it would
present elsewhere if its appearances elsewhere were regular. This
is merely the adaptation of the definition of matter which I gave
in an earlier lecture. The appearance of a star at a certain
place, if it is regular, does not require any cause or
explanation beyond the existence of the star. Every regular
appearance is an actual member of the system which is the star,
and its causation is entirely internal to that system. We may
express this by saying that a regular appearance is due to the
star alone, and is actually part of the star, in the sense in
which a man is part of the human race.

But presently the light of the star reaches our atmosphere. It
begins to be refracted, and dimmed by mist, and its velocity is
slightly diminished. At last it reaches a human eye, where a
complicated process takes place, ending in a sensation which
gives us our grounds for believing in all that has gone before.
Now, the irregular appearances of the star are not, strictly
speaking, members of the system which is the star, according to
our definition of matter. The irregular appearances, however, are
not merely irregular: they proceed according to laws which can be
stated in terms of the matter through which the light has passed
on its way. The sources of an irregular appearance are therefore

(1) The object which is appearing irregularly;

2) The intervening medium.

It should be observed that, while the conception of a regular
appearance is perfectly precise, the conception of an irregular
appearance is one capable of any degree of vagueness. When the
distorting influence of the medium is sufficiently great, the
resulting particular can no longer be regarded as an appearance
of an object, but must be treated on its own account. This
happens especially when the particular in question cannot be
traced back to one object, but is a blend of two or more. This
case is normal in perception: we see as one what the microscope
or telescope reveals to be many different objects. The notion of
perception is therefore not a precise one: we perceive things
more or less, but always with a very considerable amount of
vagueness and confusion.

In considering irregular appearances, there are certain very
natural mistakes which must be avoided. In order that a
particular may count as an irregular appearance of a certain
object, it is not necessary that it should bear any resemblance
to the regular appearances as regard its intrinsic qualities. All
that is necessary is that it should be derivable from the regular
appearances by the laws which express the distorting influence of
the medium. When it is so derivable, the particular in question
may be regarded as caused by the regular appearances, and
therefore by the object itself, together with the modifications
resulting from the medium. In other cases, the particular in
question may, in the same sense, be regarded as caused by several
objects together with the medium; in this case, it may be called
a confused appearance of several objects. If it happens to be in
a brain, it may be called a confused perception of these objects.
All actual perception is confused to a greater or less extent.

We can now interpret in terms of our theory the distinction
between those mental occurrences which are said to have an
external stimulus, and those which are said to be "centrally
excited," i.e. to have no stimulus external to the brain. When a
mental occurrence can be regarded as an appearance of an object
external to the brain, however irregular, or even as a confused
appearance of several such objects, then we may regard it as
having for its stimulus the object or objects in question, or
their appearances at the sense-organ concerned. When, on the
other hand, a mental occurrence has not sufficient connection
with objects external to the brain to be regarded as an
appearance of such objects, then its physical causation (if any)
will have to be sought in the brain. In the former case it can be
called a perception; in the latter it cannot be so called. But
the distinction is one of degree, not of kind. Until this is
realized, no satisfactory theory of perception, sensation, or
imagination is possible.

download audio

The dualism of mind and matter, if we have been right so far,
cannot be allowed as metaphysically valid. Nevertheless, we seem
to find a certain dualism, perhaps not ultimate, within the world
as we observe it. The dualism is not primarily as to the stuff of
the world, but as to causal laws. On this subject we may again
quote William James. He points out that when, as we say, we
merely "imagine" things, there are no such effects as would ensue
if the things were what we call "real." He takes the case of
imagining a fire

"I make for myself an experience of blazing fire; I place it near
my body; but it does not warm me in the least. I lay a stick upon
it and the stick either burns or remains green, as I please. I
call up water, and pour it on the fire, and absolutely no
difference ensues. I account for all such facts by calling this
whole train of experiences unreal, a mental train. Mental fire is
what won't burn real sticks; mental water is what won't
necessarily (though of course it may) put out even a mental
fire.... With 'real' objects, on the contrary, consequences
always accrue; and thus the real experiences get sifted from the
mental ones, the things from our thoughts of them, fanciful or
true, and precipitated together as the stable part of the whole
experience--chaos, under the name of the physical world."*

* "Essays in Radical Empiricism," pp. 32-3.

In this passage James speaks, by mere inadvertence, as though the
phenomena which he is describing as "mental" had NO effects. This
is, of course, not the case: they have their effects, just as
much as physical phenomena do, but their effects follow different
laws. For example, dreams, as Freud has shown, are just as much
subject to laws as are the motions of the planets. But the laws
are different: in a dream you may be transported from one place
to another in a moment, or one person may turn into another under
your eyes. Such differences compel you to distinguish the world
of dreams from the physical world.

If the two sorts of causal laws could be sharply distinguished,
we could call an occurrence "physical" when it obeys causal laws
appropriate to the physical world, and "mental" when it obeys
causal laws appropriate to the mental world. Since the mental
world and the physical world interact, there would be a boundary
between the two: there would be events which would have physical
causes and mental effects, while there would be others which
would have mental causes and physical effects. Those that have
physical causes and mental effects we should define as
"sensations." Those that have mental causes and physical effects
might perhaps be identified with what we call voluntary
movements; but they do not concern us at present.

These definitions would have all the precision that could be
desired if the distinction between physical and psychological
causation were clear and sharp. As a matter of fact, however,
this distinction is, as yet, by no means sharp. It is possible
that, with fuller knowledge, it will be found to be no more
ultimate than the distinction between the laws of gases and the
laws of rigid bodies. It also suffers from the fact that an event
may be an effect of several causes according to several causal
laws we cannot, in general, point to anything unique as THE cause
of such-and-such an event. And finally it is by no means certain
that the peculiar causal laws which govern mental events are not
really physiological. The law of habit, which is one of the most
distinctive, may be fully explicable in terms of the
peculiarities of nervous tissue, and these peculiarities, in
turn, may be explicable by the laws of physics. It seems,
therefore, that we are driven to a different kind of definition.
It is for this reason that it was necessary to develop the
definition of perception. With this definition, we can define a
sensation as the non-mnemic elements in a perception.

When, following our definition, we try to decide what elements in
our experience are of the nature of sensations, we find more
difficulty than might have been expected. Prima facie, everything
is sensation that comes to us through the senses: the sights we
see, the sounds we hear, the smells we smell, and so on; also
such things as headache or the feeling of muscular strain. But in
actual fact so much interpretation, so much of habitual
correlation, is mixed with all such experiences, that the core of
pure sensation is only to be extracted by careful investigation.
To take a simple illustration: if you go to the theatre in your
own country, you seem to hear equally well in the stalls or the
dress circle; in either case you think you miss nothing. But if
you go in a foreign country where you have a fair knowledge of
the language, you will seem to have grown partially deaf, and you
will find it necessary to be much nearer the stage than you would
need to be in your own country. The reason is that, in hearing
our own language spoken, we quickly and unconsciously fill out
what we really hear with inferences to what the man must be
saying, and we never realize that we have not heard the words we
have merely inferred. In a foreign language, these inferences are
more difficult, and we are more dependent upon actual sensation.
If we found ourselves in a foreign world, where tables looked
like cushions and cushions like tables, we should similarly
discover how much of what we think we see is really inference.
Every fairly familiar sensation is to us a sign of the things
that usually go with it, and many of these things will seem to
form part of the sensation. I remember in the early days of
motor-cars being with a friend when a tyre burst with a loud
report. He thought it was a pistol, and supported his opinion by
maintaining that he had seen the flash. But of course there had
been no flash. Nowadays no one sees a flash when a tyre bursts.

In order, therefore, to arrive at what really is sensation in an
occurrence which, at first sight, seems to contain nothing else,
we have to pare away all that is due to habit or expectation or
interpretation. This is a matter for the psychologist, and by no
means an easy matter. For our purposes, it is not important to
determine what exactly is the sensational core in any case; it is
only important to notice that there certainly is a sensational
core, since habit, expectation and interpretation are diversely
aroused on diverse occasions, and the diversity is clearly due to
differences in what is presented to the senses. When you open
your newspaper in the morning, the actual sensations of seeing
the print form a very minute part of what goes on in you, but
they are the starting-point of all the rest, and it is through
them that the newspaper is a means of information or
mis-information. Thus, although it may be difficult to determine
what exactly is sensation in any given experience, it is clear
that there is sensation, unless, like Leibniz, we deny all action
of the outer world upon us.

Sensations are obviously the source of our knowledge of the
world, including our own body. It might seem natural to regard a
sensation as itself a cognition, and until lately I did so regard
it. When, say, I see a person I know coming towards me in the
street, it SEEMS as though the mere seeing were knowledge. It is
of course undeniable that knowledge comes THROUGH the seeing, but
I think it is a mistake to regard the mere seeing itself as
knowledge. If we are so to regard it, we must distinguish the
seeing from what is seen: we must say that, when we see a patch
of colour of a certain shape, the patch of colour is one thing
and our seeing of it is another. This view, however, demands the
admission of the subject, or act, in the sense discussed in our
first lecture. If there is a subject, it can have a relation to
the patch of colour, namely, the sort of relation which we might
call awareness. In that case the sensation, as a mental event,
will consist of awareness of the colour, while the colour itself
will remain wholly physical, and may be called the sense-datum,
to distinguish it from the sensation. The subject, however,
appears to be a logical fiction, like mathematical points and
instants. It is introduced, not because observation reveals it,
but because it is linguistically convenient and apparently
demanded by grammar. Nominal entities of this sort may or may not
exist, but there is no good ground for assuming that they do. The
functions that they appear to perform can always be performed by
classes or series or other logical constructions, consisting of
less dubious entities. If we are to avoid a perfectly gratuitous
assumption, we must dispense with the subject as one of the
actual ingredients of the world. But when we do this, the
possibility of distinguishing the sensation from the sense-datum
vanishes; at least I see no way of preserving the distinction.
Accordingly the sensation that we have when we see a patch of
colour simply is that patch of colour, an actual constituent of
the physical world, and part of what physics is concerned with. A
patch of colour is certainly not knowledge, and therefore we
cannot say that pure sensation is cognitive. Through its
psychological effects, it is the cause of cognitions, partly by
being itself a sign of things that are correlated with it, as
e.g. sensations of sight and touch are correlated, and partly by
giving rise to images and memories after the sensation is faded.
But in itself the pure sensation is not cognitive.

In the first lecture we considered the view of Brentano, that "we
may define psychical phenomena by saying that they are phenomena
which intentionally contain an object." We saw reasons to reject
this view in general; we are now concerned to show that it must
be rejected in the particular case of sensations. The kind of
argument which formerly made me accept Brentano's view in this
case was exceedingly simple. When I see a patch of colour, it
seemed to me that the colour is not psychical, but physical,
while my seeing is not physical, but psychical. Hence I concluded
that the colour is something other than my seeing of the colour.
This argument, to me historically, was directed against idealism:
the emphatic part of it was the assertion that the colour is
physical, not psychical. I shall not trouble you now with the
grounds for holding as against Berkeley that the patch of colour
is physical; I have set them forth before, and I see no reason to
modify them. But it does not follow that the patch of colour is
not also psychical, unless we assume that the physical and the
psychical cannot overlap, which I no longer consider a valid
assumption. If we admit--as I think we should--that the patch of
colour may be both physical and psychical, the reason for
distinguishing the sense-datum from the sensation disappears, and
we may say that the patch of colour and our sensation in seeing
it are identical.

This is the view of William James, Professor Dewey, and the
American realists. Perceptions, says Professor Dewey, are not per
se cases of knowledge, but simply natural events with no more
knowledge status than (say) a shower. "Let them [the realists]
try the experiment of conceiving perceptions as pure natural
events, not cases of awareness or apprehension, and they will be
surprised to see how little they miss."* I think he is right in
this, except in supposing that the realists will be surprised.
Many of them already hold the view he is advocating, and others
are very sympathetic to it. At any rate, it is the view which I
shall adopt in these lectures.

* Dewey, "Essays in Experimental Logic," pp. 253, 262.

The stuff of the world, so far as we have experience of it,
consists, on the view that I am advocating, of innumerable
transient particulars such as occur in seeing, hearing, etc.,
together with images more or less resembling these, of which I
shall speak shortly. If physics is true, there are, besides the
particulars that we experience, others, probably equally (or
almost equally) transient, which make up that part of the
material world that does not come into the sort of contact with a
living body that is required to turn it into a sensation. But
this topic belongs to the philosophy of physics, and need not
concern us in our present inquiry.

Sensations are what is common to the mental and physical worlds;
they may be defined as the intersection of mind and matter. This
is by no means a new view; it is advocated, not only by the
American authors I have mentioned, but by Mach in his Analysis of
Sensations, which was published in 1886. The essence of
sensation, according to the view I am advocating, is its
independence of past experience. It is a core in our actual
experiences, never existing in isolation except possibly in very
young infants. It is not itself knowledge, but it supplies the
data for our knowledge of the physical world, including our own

There are some who believe that our mental life is built up out
of sensations alone. This may be true; but in any case I think
the only ingredients required in addition to sensations are
images. What images are, and how they are to be defined, we have
now to inquire.

The distinction between images and sensations might seem at first
sight by no means difficult. When we shut our eyes and call up
pictures of familiar scenes, we usually have no difficulty, so
long as we remain awake, in discriminating between what we are
imagining and what is really seen. If we imagine some piece of
music that we know, we can go through it in our mind from
beginning to end without any discoverable tendency to suppose
that we are really hearing it. But although such cases are so
clear that no confusion seems possible, there are many others
that are far more difficult, and the definition of images is by
no means an easy problem.

To begin with: we do not always know whether what we are
experiencing is a sensation or an image. The things we see in
dreams when our eyes are shut must count as images, yet while we
are dreaming they seem like sensations. Hallucinations often
begin as persistent images, and only gradually acquire that
influence over belief that makes the patient regard them as
sensations. When we are listening for a faint sound--the striking
of a distant clock, or a horse's hoofs on the road--we think we
hear it many times before we really do, because expectation
brings us the image, and we mistake it for sensation. The
distinction between images and sensations is, therefore, by no
means always obvious to inspection.*

* On the distinction between images and sensation, cf. Semon,
"Die mnemischen Empfindungen," pp. 19-20.

We may consider three different ways in which it has been sought
to distinguish images from sensations, namely:

(1) By the less degree of vividness in images;

(2) By our absence of belief in their "physical reality";

(3) By the fact that their causes and effects are different from
those of sensations.

I believe the third of these to be the only universally
applicable criterion. The other two are applicable in very many
cases, but cannot be used for purposes of definition because they
are liable to exceptions. Nevertheless, they both deserve to be
carefully considered.

(1) Hume, who gives the names "impressions" and "ideas" to what
may, for present purposes, be identified with our "sensations"
and "images," speaks of impressions as "those perceptions which
enter with most force and violence" while he defines ideas as
"the faint images of these (i.e. of impressions) in thinking and
reasoning." His immediately following observations, however, show
the inadequacy of his criteria of "force" and "faintness." He

"I believe it will not be very necessary to employ many words in
explaining this distinction. Every one of himself will readily
perceive the difference betwixt feeling and thinking. The common
degrees of these are easily distinguished, though it is not
impossible but in particular instances they may very nearly
approach to each other. Thus in sleep, in a fever, in madness, or
in any very violent emotions of soul, our ideas may approach to
our impressions; as, on the other hand, it sometimes happens,
that our impressions are so faint and low that we cannot
distinguish them from our ideas. But notwithstanding this near
resemblance in a few instances, they are in general so very
different, that no one can make a scruple to rank them under
distinct heads, and assign to each a peculiar name to mark the
difference" ("Treatise of Human Nature," Part I, Section I).

I think Hume is right in holding that they should be ranked under
distinct heads, with a peculiar name for each. But by his own
confession in the above passage, his criterion for distinguishing
them is not always adequate. A definition is not sound if it only
applies in cases where the difference is glaring: the essential
purpose of a definition is to provide a mark which is applicable
even in marginal cases--except, of course, when we are dealing
with a conception, like, e.g. baldness, which is one of degree
and has no sharp boundaries. But so far we have seen no reason to
think that the difference between sensations and images is only
one of degree.

Professor Stout, in his "Manual of Psychology," after discussing
various ways of distinguishing sensations and images, arrives at
a view which is a modification of Hume's. He says (I quote from
the second edition):

"Our conclusion is that at bottom the distinction between image
and percept, as respectively faint and vivid states, is based on
a difference of quality. The percept has an aggressiveness which
does not belong to the image. It strikes the mind with varying
degrees of force or liveliness according to the varying intensity
of the stimulus. This degree of force or liveliness is part of
what we ordinarily mean by the intensity of a sensation. But this
constituent of the intensity of sensations is absent in mental
imagery"(p. 419).

This view allows for the fact that sensations may reach any
degree of faintness--e.g. in the case of a just visible star or a
just audible sound--without becoming images, and that therefore
mere faintness cannot be the characteristic mark of images. After
explaining the sudden shock of a flash of lightning or a
steam-whistle, Stout says that "no mere image ever does strike
the mind in this manner"(p. 417). But I believe that this
criterion fails in very much the same instances as those in which
Hume's criterion fails in its original form. Macbeth speaks of--

          that suggestion      Whose horrid image doth unfix my
hair      And make my seated heart knock at my ribs      Against
the use of nature.

The whistle of a steam-engine could hardly have a stronger effect
than this. A very intense emotion will often bring with
it--especially where some future action or some undecided issue
is involved--powerful compelling images which may determine the
whole course of life, sweeping aside all contrary solicitations
to the will by their capacity for exclusively possessing the
mind. And in all cases where images, originally recognized as
such, gradually pass into hallucinations, there must be just that
"force or liveliness" which is supposed to be always absent from
images. The cases of dreams and fever-delirium are as hard to
adjust to Professor Stout's modified criterion as to Hume's. I
conclude therefore that the test of liveliness, however
applicable in ordinary instances, cannot be used to define the
differences between sensations and images.

(2) We might attempt to distinguish images from sensations by our
absence of belief in the "physical reality" of images. When we
are aware that what we are experiencing is an image, we do not
give it the kind of belief that we should give to a sensation: we
do not think that it has the same power of producing knowledge of
the "external world." Images are "imaginary"; in SOME sense they
are "unreal." But this difference is hard to analyse or state
correctly. What we call the "unreality" of images requires
interpretation it cannot mean what would be expressed by saying
"there's no such thing." Images are just as truly part of the
actual world as sensations are. All that we really mean by
calling an  image "unreal" is that it does not have the
concomitants which it would have if it were a sensation. When we
call up a visual image of a chair, we do not attempt to sit in
it, because we know that, like Macbeth's dagger, it is not
"sensible to feeling as to sight"-- i.e. it does not have the
correlations with tactile sensations which it would have if it
were a visual sensation and not merely a visual image. But this
means that the so-called "unreality" of images consists merely in
their not obeying the laws of physics, and thus brings us back to
the causal distinction between images and sensations.

This view is confirmed by the fact that we only feel images to be
"unreal" when we already know them to be images. Images cannot be
defined by the FEELING of unreality, because when we falsely
believe an image to be a sensation, as in the case of dreams, it
FEELS just as real as if it were a sensation. Our feeling of
unreality results from our having already realized that we are
dealing with an image, and cannot therefore be the definition of
what we mean by an image. As soon as an image begins to deceive
us as to its status, it also deceives us as to its correlations,
which are what we mean by its "reality."

(3) This brings us to the third mode of distinguishing images
from sensations, namely, by their causes and effects. I believe
this to be the only valid ground of distinction. James, in the
passage about the mental fire which won't burn real sticks,
distinguishes images by their effects, but I think the more
reliable distinction is by their causes. Professor Stout (loc.
cit., p. 127) says: "One characteristic mark of what we agree in
calling sensation is its mode of production. It is caused by what
we call a STIMULUS. A stimulus is always some condition external
to the nervous system itself and operating upon it." I think that
this is the correct view, and that the distinction between images
and sensations can only be made by taking account of their
causation. Sensations come through sense-organs, while images do
not. We cannot have visual sensations in the dark, or with our
eyes shut, but we can very well have visual images under these
circumstances. Accordingly images have been defined as "centrally
excited sensations," i.e. sensations which have their
physiological cause in the brain only, not also in the
sense-organs and the nerves that run from the sense-organs to the
brain. I think the phrase "centrally excited sensations" assumes
more than is necessary, since it takes it for granted that an
image must have a proximate physiological cause. This is probably
true, but it is an hypothesis, and for our purposes an
unnecessary one. It would seem to fit better with what we can
immediately observe if we were to say that an image is
occasioned, through association, by a sensation or another image,
in other words that it has a mnemic cause--which does not prevent
it from also having a physical cause. And I think it will be
found that the causation of an image always proceeds according to
mnemic laws, i.e. that it is governed by habit and past
experience. If you listen to a man playing the pianola without
looking at him, you will have images of his hands on the keys as
if he were playing the piano; if you suddenly look at him while
you are absorbed in the music, you will experience a shock of
surprise when you notice that his hands are not touching the
notes. Your image of his hands is due to the many times that you
have heard similar sounds and at the same time seen the player's
hands on the piano. When habit and past experience play this
part, we are in the region of mnemic as opposed to ordinary
physical causation. And I think that, if we could regard as
ultimately valid the difference between physical and mnemic
causation, we could distinguish images from sensations as having
mnemic causes, though they may also have physical causes.
Sensations, on the other hand, will only have physical causes.

However this may be, the practically effective distinction
between sensations and images is that in the causation of
sensations, but not of images, the stimulation of nerves carrying
an effect into the brain, usually from the surface of the body,
plays an essential part. And this accounts for the fact that
images and sensations cannot always be distinguished by their
intrinsic nature.

Images also differ from sensations as regards their effects.
Sensations, as a rule, have both physical and mental effects. As
you watch the train you meant to catch leaving the station, there
are both the successive positions of the train (physical effects)
and the successive waves of fury and disappointment (mental
effects). Images, on the contrary, though they MAY produce bodily
movements, do so according to mnemic laws, not according to the
laws of physics. All their effects, of whatever nature, follow
mnemic laws. But this difference is less suitable for definition
than the difference as to causes.

Professor Watson, as a logical carrying-out of his behaviourist
theory, denies altogether that there are any observable phenomena
such as images are supposed to be. He replaces them all by faint
sensations, and especially by pronunciation of words sotto voce.
When we "think" of a table (say), as opposed to seeing it, what
happens, according to him, is usually that we are making small
movements of the throat and tongue such as would lead to our
uttering the word "table" if they were more pronounced. I shall
consider his view again in connection with words; for the present
I am only concerned to combat his denial of images. This denial
is set forth both in his book on "Behavior" and in an article
called "Image and Affection in Behavior" in the "Journal of
Philosophy, Psychology and Scientific Methods," vol. x (July,
1913). It seems to me that in this matter he has been betrayed
into denying plain facts in the interests of a theory, namely,
the supposed impossibility of introspection. I dealt with the
theory in Lecture VI; for the present I wish to reinforce the
view that the facts are undeniable.

Images are of various sorts, according to the nature of the
sensations which they copy. Images of bodily movements, such as
we have when we imagine moving an arm or, on a smaller scale,
pronouncing a word, might possibly be explained away on Professor
Watson's lines, as really consisting in small incipient movements
such as, if magnified and prolonged, would be the movements we
are said to be imagining. Whether this is the case or not might
even be decided experimentally. If there were a delicate
instrument for recording small movements in the mouth and throat,
we might place such an instrument in a person's mouth and then
tell him to recite a poem to himself, as far as possible only in
imagination. I should not be at all surprised if it were found
that actual small movements take place while he is "mentally"
saying over the verses. The point is important, because what is
called "thought" consists mainly (though I think not wholly) of
inner speech. If Professor Watson is right as regards inner
speech, this whole region is transferred from imagination to
sensation. But since the question is capable of experimental
decision, it would be gratuitous rashness to offer an opinion
while that decision is lacking.

But visual and auditory images are much more difficult to deal
with in this way, because they lack the connection with physical
events in the outer world which belongs to visual and auditory
sensations. Suppose, for example, that I am sitting in my room,
in which there is an empty arm-chair. I shut my eyes, and call up
a visual image of a friend sitting in the arm-chair. If I thrust
my image into the world of physics, it contradicts all the usual
physical laws. My friend reached the chair without coming in at
the door in the usual way; subsequent inquiry will show that he
was somewhere else at the moment. If regarded as a sensation, my
image has all the marks of the supernatural. My image, therefore,
is regarded as an event in me, not as having that position in the
orderly happenings of the public world that belongs to
sensations. By saying that it is an event in me, we leave it
possible that it may be PHYSIOLOGICALLY caused: its privacy may
be only due to its connection with my body. But in any case it is
not a public event, like an actual person walking in at the door
and sitting down in my chair. And it cannot, like inner speech,
be regarded as a SMALL sensation, since it occupies just as large
an area in my visual field as the actual sensation would do.

Professor Watson says: "I should throw out imagery altogether and
attempt to show that all natural thought goes on in terms of
sensori-motor processes in the larynx." This view seems to me
flatly to contradict experience. If you try to persuade any
uneducated person that she cannot call up a visual picture of a
friend sitting in a chair, but can only use words describing what
such an occurrence would be like, she will conclude that you are
mad. (This statement is based upon experiment.) Galton, as every
one knows, investigated visual imagery, and found that education
tends to kill it: the Fellows of the Royal Society turned out to
have much less of it than their wives. I see no reason to doubt
his conclusion that the habit of abstract pursuits makes learned
men much inferior to the average in power of visualizing, and
much more exclusively occupied with words in their "thinking."
And Professor Watson is a very learned man.

I shall henceforth assume that the existence of images is
admitted, and that they are to be distinguished from sensations
by their causes, as well as, in a lesser degree, by their
effects. In their intrinsic nature, though they often differ from
sensations by being more dim or vague or faint, yet they do not
always or universally differ from sensations in any way that can
be used for defining them. Their privacy need form no bar to the
scientific study of them, any more than the privacy of bodily
sensations does. Bodily sensations are admitted by even the most
severe critics of introspection, although, like images, they can
only be observed by one observer. It must be admitted, however,
that the laws of the appearance and disappearance of images are
little known and difficult to discover, because we are not
assisted, as in the case of sensations, by our knowledge of the
physical world.

There remains one very important point concerning images, which
will occupy us much hereafter, and that is, their resemblance to
previous sensations. They are said to be "copies" of sensations,
always as regards the simple qualities that enter into them,
though not always as regards the manner in which these are put
together. It is generally believed that we cannot imagine a shade
of colour that we have never seen, or a sound that we have never
heard. On this subject Hume is the classic. He says, in the
definitions already quoted:

"Those perceptions, which enter with most force and violence, we
may name IMPRESSIONS; and under this name I comprehend all our
sensations, passions and emotions, as they make their first
appearance in the soul. By IDEAS I mean the faint images of these
in thinking and reasoning."

He next explains the difference between simple and complex ideas,
and explains that a complex idea may occur without any similar
complex impression. But as regards simple ideas, he states that
"every simple idea has a simple impression, which resembles it,
and every simple impression a correspondent idea." He goes on to
enunciate the general principle "that all our simple ideas in
their first appearance are derived from simple impressions, which
are correspondent to them, and which they exactly represent"
("Treatise of Human Nature," Part I, Section I).

It is this fact, that images resemble antecedent sensations,
which enables us to call them images "of" this or that. For the
understanding of memory, and of knowledge generally, the
recognizable resemblance of images and sensations is of
fundamental importance.

There are difficulties in establishing Hume's principles, and
doubts as to whether it is exactly true. Indeed, he himself
signalized an exception immediately after stating his maxim.
Nevertheless, it is impossible to doubt that in the main simple
images are copies of similar simple sensations which have
occurred earlier, and that the same is true of complex images in
all cases of memory as opposed to mere imagination. Our power of
acting with reference to what is sensibly absent is largely due
to this characteristic of images, although, as education
advances, images tend to be more and more replaced by words. We
shall have much to say in the next two lectures on the subject of
images as copies of sensations. What has been said now is merely
by way of reminder that this is their most notable

I am by no means confident that the distinction between images
and sensations is ultimately valid, and I should be glad to be
convinced that images can be reduced to sensations of a peculiar
kind. I think it is clear, however, that, at any rate in the case
of auditory and visual images, they do differ from ordinary
auditory and visual sensations, and therefore form a recognizable
class of occurrences, even if it should prove that they can be
regarded as a sub-class of sensations. This is all that is
necessary to validate the use of images to be made in the sequel.

download audio

Memory, which we are to consider to-day, introduces us to
knowledge in one of its forms. The analysis of knowledge will
occupy us until the end of the thirteenth lecture, and is the
most difficult part of our whole enterprise.

I do not myself believe that the analysis of knowledge can be
effected entirely by means of purely external observation, such
as behaviourists employ. I shall discuss this question in later
lectures. In the present lecture I shall attempt the analysis of
memory-knowledge, both as an introduction to the problem of
knowledge in general, and because memory, in some form, is
presupposed in almost all other knowledge. Sensation, we decided,
is not a form of knowledge. It might, however, have been expected
that we should begin our discussion of knowledge with PERCEPTION,
i.e. with that integral experience of things in the environment,
out of which sensation is extracted by psychological analysis.
What is called perception differs from sensation by the fact that
the sensational ingredients bring up habitual associates--images
and expectations of their usual correlates--all of which are
subjectively indistinguishable from the sensation. The FACT of
past experience is essential in producing this filling-out of
sensation, but not the RECOLLECTION of past experience. The
non-sensational elements in perception can be wholly explained as
the result of habit, produced by frequent correlations.
Perception, according to our definition in Lecture VII, is no
more a form of knowledge than sensation is, except in so far as
it involves expectations. The purely psychological problems which
it raises are not very difficult, though they have sometimes been
rendered artificially obscure by unwillingness to admit the
fallibility of the non-sensational elements of perception. On the
other hand, memory raises many difficult and very important
problems, which it is necessary to consider at the first possible

One reason for treating memory at this early stage is that it
seems to be involved in the fact that images are recognized as
"copies" of past sensible experience. In the preceding lecture I
alluded to Hume's principle "that all our simple ideas in their
first appearance are derived from simple impressions, which are
correspondent to them, and which they exactly represent." Whether
or not this principle is liable to exceptions, everyone would
agree that is has a broad measure of truth, though the word
"exactly" might seem an overstatement, and it might seem more
correct to say that ideas APPROXIMATELY represent impressions.
Such modifications of Hume's principle, however, do not affect
the problem which I wish to present for your consideration,
namely: Why do we believe that images are, sometimes or always,
approximately or exactly, copies of sensations? What sort of
evidence is there? And what sort of evidence is logically
possible? The difficulty of this question arises through the fact
that the sensation which an image is supposed to copy is in the
past when the image exists, and can therefore only be known by
memory, while, on the other hand, memory of past sensations seems
only possible by means of present images. How, then, are we to
find any way of comparing the present image and the past
sensation? The problem is just as acute if we say that images
differ from their prototypes as if we say that they resemble
them; it is the very possibility of comparison that is hard to
understand.* We think we can know that they are alike or
different, but we cannot bring them together in one experience
and compare them. To deal with this problem, we must have a
theory of memory. In this way the whole status of images as
"copies" is bound up with the analysis of memory.

* How, for example, can we obtain such knowledge as the
following: "If we look at, say, a red nose and perceive it, and
after a little while ekphore, its memory-image, we note
immediately how unlike, in its likeness, this memory-image is to
the original perception" (A. Wohlgemuth, "On the Feelings and
their Neural Correlate with an Examination of the Nature of
Pain," "Journal of Psychology," vol. viii, part iv, June, 1917).

In investigating memory-beliefs, there are certain points which
must be borne in mind. In the first place, everything
constituting a memory-belief is happening now, not in that past
time to which the belief is said to refer. It is not logically
necessary to the existence of a memory-belief that the event
remembered should have occurred, or even that the past should
have existed at all. There is no logical impossibility in the
hypothesis that the world sprang into being five minutes ago,
exactly as it then was, with a population that "remembered" a
wholly unreal past. There is no logically necessary connection
between events at different times; therefore nothing that is
happening now or will happen in the future can disprove the
hypothesis that the world began five minutes ago. Hence the
occurrences which are CALLED knowledge of the past are logically
independent of the past; they are wholly analysable into present
contents, which might, theoretically, be just what they are even
if no past had existed.

I am not suggesting that the non-existence of the past should be
entertained as a serious hypothesis. Like all sceptical
hypotheses, it is logically tenable, but uninteresting. All that
I am doing is to use its logical tenability as a help in the
analysis of what occurs when we remember.

In the second place, images without beliefs are insufficient to
constitute memory; and habits are still more insufficient. The
behaviourist, who attempts to make psychology a record of
behaviour, has to trust his memory in making the record. "Habit"
is a concept involving the occurrence of similar events at
different times; if the behaviourist feels confident that there
is such a phenomenon as habit, that can only be because he trusts
his memory, when it assures him that there have been other times.
And the same applies to images. If we are to know as it is
supposed we do--that images are "copies," accurate or inaccurate,
of past events, something more than the mere occurrence of images
must go to constitute this knowledge. For their mere occurrence,
by itself, would not suggest any connection with anything that
had happened before.

Can we constitute memory out of images together with suitable
beliefs? We may take it that memory-images, when they occur in
true memory, are (a) known to be copies, (b) sometimes known to
be imperfect copies (cf. footnote on previous page). How is it
possible to know that a memory-image is an imperfect copy,
without having a more accurate copy by which to replace it? This
would SEEM to suggest that we have a way of knowing the past
which is independent of images, by means of which we can
criticize image-memories. But I do not think such an inference is

What results, formally, from our knowledge of the past through
images of which we recognize the inaccuracy, is that such images
must have two characteristics by which we can arrange them in two
series, of which one corresponds to the more or less remote
period in the past to which they refer, and the other to our
greater or less confidence in their accuracy. We will take the
second of these points first.

Our confidence or lack of confidence in the accuracy of a
memory-image must, in fundamental cases, be based upon a
characteristic of the image itself, since we cannot evoke the
past bodily and compare it with the present image. It might be
suggested that vagueness is the required characteristic, but I do
not think this is the case. We sometimes have images that are by
no means peculiarly vague, which yet we do not trust--for
example, under the influence of fatigue we may see a friend's
face vividly and clearly, but horribly distorted. In such a case
we distrust our image in spite of its being unusually clear. I
think the characteristic by which we distinguish the images we
trust is the feeling of FAMILIARITY that accompanies them. Some
images, like some sensations, feel very familiar, while others
feel strange. Familiarity is a feeling capable of degrees. In an
image of a well-known face, for example, some parts may feel more
familiar than others; when this happens, we have more belief in
the accuracy of the familiar parts than in that of the unfamiliar
parts. I think it is by this means that we become critical of
images, not by some imageless memory with which we compare them.
I shall return to the consideration of familiarity shortly.

I come now to the other characteristic which memory-images must
have in order to account for our knowledge of the past. They must
have some characteristic which makes us regard them as referring
to more or less remote portions of the past. That is to say if we
suppose that A is the event remembered, B the remembering, and t
the interval of time between A and B, there must be some
characteristic of B which is capable of degrees, and which, in
accurately dated memories, varies as t varies. It may increase as
t increases, or diminish as t increases. The question which of
these occurs is not of any importance for the theoretic
serviceability of the characteristic in question.

In actual fact, there are doubtless various factors that concur
in giving us the feeling of greater or less remoteness in some
remembered event. There may be a specific feeling which could be
called the feeling of "pastness," especially where immediate
memory is concerned. But apart from this, there are other marks.
One of these is context. A recent memory has, usually, more
context than a more distant one. When a remembered event has a
remembered context, this may occur in two ways, either (a) by
successive images in the same order as their prototypes, or (b)
by remembering a whole process simultaneously, in the same way in
which a present process may be apprehended, through akoluthic
sensations which, by fading, acquire the mark of just-pastness in
an increasing degree as they fade, and are thus placed in a
series while all sensibly present. It will be context in this
second sense, more specially, that will give us a sense of the
nearness or remoteness of a remembered event.

There is, of course, a difference between knowing the temporal
relation of a remembered event to the present, and knowing the
time-order of two remembered events. Very often our knowledge of
the temporal relation of a remembered event to the present is
inferred from its temporal relations to other remembered events.
It would seem that only rather recent events can be placed at all
accurately by means of feelings giving their temporal relation to
the present, but it is clear that such feelings must play an
essential part in the process of dating remembered events.

We may say, then, that images are regarded by us as more or less
accurate copies of past occurrences because they come to us with
two sorts of feelings: (1) Those that may be called feelings of
familiarity; (2) those that may be collected together as feelings
giving a sense of pastness. The first lead us to trust our
memories, the second to assign places to them in the time-order.

We have now to analyse the memory-belief, as opposed to the
characteristics of images which lead us to base memory-beliefs
upon them.

If we had retained the "subject" or "act" in knowledge, the whole
problem of memory would have been comparatively simple. We could
then have said that remembering is a direct relation between the
present act or subject and the past occurrence remembered: the
act of remembering is present, though its object is past. But the
rejection of the subject renders some more complicated theory
necessary. Remembering has to be a present occurrence in some way
resembling, or related to, what is remembered. And it is
difficult to find any ground, except a pragmatic one, for
supposing that memory is not sheer delusion, if, as seems to be
the case, there is not, apart from memory, any way of
ascertaining that there really was a past occurrence having the
required relation to our present remembering. What, if we
followed Meinong's terminology, we should call the "object" in
memory, i.e. the past event which we are said to be remembering,
is unpleasantly remote from the "content," i.e. the present
mental occurrence in remembering. There is an awkward gulf
between the two, which raises difficulties for the theory of
knowledge. But we must not falsify observation to avoid
theoretical difficulties. For the present, therefore, let us
forget these problems, and try to discover what actually occurs
in memory.

Some points may be taken as fixed, and such as any theory of
memory must arrive at. In this case, as in most others, what may
be taken as certain in advance is rather vague. The study of any
topic is like the continued observation of an object which is
approaching us along a road: what is certain to begin with is the
quite vague knowledge that there is SOME object on the road. If
you attempt to be less vague, and to assert that the object is an
elephant, or a man, or a mad dog, you run a risk of error; but
the purpose of continued observation is to enable you to arrive
at such more precise knowledge. In like manner, in the study of
memory, the certainties with which you begin are very vague, and
the more precise propositions at which you try to arrive are less
certain than the hazy data from which you set out. Nevertheless,
in spite of the risk of error, precision is the goal at which we
must aim.

The first of our vague but indubitable data is that there is
knowledge of the past. We do not yet know with any precision what
we mean by "knowledge," and we must admit that in any given
instance our memory may be at fault. Nevertheless, whatever a
sceptic might urge in theory, we cannot practically doubt that we
got up this morning, that we did various things yesterday, that a
great war has been taking place, and so on. How far our knowledge
of the past is due to memory, and how far to other sources, is of
course a matter to be investigated, but there can be no doubt
that memory forms an indispensable part of our knowledge of the

The second datum is that we certainly have more capacity for
knowing the past than for knowing the future. We know some things
about the future, for example what eclipses there will be; but
this knowledge is a matter of elaborate calculation and
inference, whereas some of our knowledge of the past comes to us
without effort, in the same sort of immediate way in which we
acquire knowledge of occurrences in our present environment. We
might provisionally, though perhaps not quite correctly, define
"memory" as that way of knowing about the past which has no
analogue in our knowledge of the future; such a definition would
at least serve to mark the problem with which we are concerned,
though some expectations may deserve to rank with memory as
regards immediacy.

A third point, perhaps not quite so certain as our previous two,
is that the truth of memory cannot be wholly practical, as
pragmatists wish all truth to be. It seems clear that some of the
things I remember are trivial and without any visible importance
for the future, but that my memory is true (or false) in virtue
of a past event, not in virtue of any future consequences of my
belief. The definition of truth as the correspondence between
beliefs and facts seems peculiarly evident in the case of memory,
as against not only the pragmatist definition but also the
idealist definition by means of coherence. These considerations,
however, are taking us away from psychology, to which we must now

It is important not to confuse the two forms of memory which
Bergson distinguishes in the second chapter of his "Matter and
Memory," namely the sort that consists of habit, and the sort
that consists of independent recollection. He gives the instance
of learning a lesson by heart: when I know it by heart I am said
to "remember" it, but this merely means that I have acquired
certain habits; on the other hand, my recollection of (say) the
second time I read the lesson while I was learning it is the
recollection of a unique event, which occurred only once. The
recollection of a unique event cannot, so Bergson contends, be
wholly constituted by habit, and is in fact something radically
different from the memory which is habit. The recollection alone
is true memory. This distinction is vital to the understanding of
memory. But it is not so easy to carry out in practice as it is
to draw in theory. Habit is a very intrusive feature of our
mental life, and is often present where at first sight it seems
not to be. There is, for example, a habit of remembering a unique
event. When we have once described the event, the words we have
used easily become habitual. We may even have used words to
describe it to ourselves while it was happening; in that case,
the habit of these words may fulfil the function of Bergson's
true memory, while in reality it is nothing but habit-memory. A
gramophone, by the help of suitable records, might relate to us
the incidents of its past; and people are not so different from
gramophones as they like to believe.

In spite, however, of a difficulty in distinguishing the two
forms of memory in practice, there can be no doubt that both
forms exist. I can set to work now to remember things I never
remembered before, such as what I had to eat for breakfast this
morning, and it can hardly be wholly habit that enables me to do
this. It is this sort of occurrence that constitutes the essence
of memory Until we have analysed what happens in such a case as
this, we have not succeeded in understanding memory.

The sort of memory with which we are here concerned is the sort
which is a form of knowledge. Whether knowledge itself is
reducible to habit is a question to which I shall return in a
later lecture; for the present I am only anxious to point out
that, whatever the true analysis of knowledge may be, knowledge
of past occurrences is not proved by behaviour which is due to
past experience. The fact that a man can recite a poem does not
show that he remembers any previous occasion on which he has
recited or read it. Similarly, the performances of animals in
getting out of cages or mazes to which they are accustomed do not
prove that they remember having been in the same situation
before. Arguments in favour of (for example) memory in plants are
only arguments in favour of habit-memory, not of knowledge-
memory. Samuel Butler's arguments in favour of the view that an
animal remembers something of the lives of its ancestors* are,
when examined, only arguments in favour of habit-memory. Semon's
two books, mentioned in an earlier lecture, do not touch
knowledge-memory at all closely. They give laws according to
which images of past occurrences come into our minds, but do not
discuss our belief that these images refer to past occurrences,
which is what constitutes knowledge-memory. It is this that is of
interest to theory of knowledge. I shall speak of it as "true"
memory, to distinguish it from mere habit acquired through past
experience. Before considering true memory, it will be well to
consider two things which are on the way towards memory, namely
the feeling of familiarity and recognition.

* See his "Life and Habit and Unconscious Memory."

We often feel that something in our sensible environment is
familiar, without having any definite recollection of previous
occasions on which we have seen it. We have this feeling normally
in places where we have often been before--at home, or in
well-known streets. Most people and animals find it essential to
their happiness to spend a good deal of their time in familiar
surroundings, which are especially comforting when any danger
threatens. The feeling of familiarity has all sorts of degrees,
down to the stage where we dimly feel that we have seen a person
before. It is by no means always reliable; almost everybody has
at some time experienced the well-known illusion that all that is
happening now happened before at some time. There are occasions
when familiarity does not attach itself to any definite object,
when there is merely a vague feeling that SOMETHING is familiar.
This is illustrated by Turgenev's "Smoke," where the hero is long
puzzled by a haunting sense that something in his present is
recalling something in his past, and at last traces it to the
smell of heliotrope. Whenever the sense of familiarity occurs
without a definite object, it leads us to search the environment
until we are satisfied that we have found the appropriate object,
which leads us to the judgment: "THIS is familiar." I think we
may regard familiarity as a definite feeling, capable of existing
without an object, but normally standing in a specific relation
to some feature of the environment, the relation being that which
we express in words by saying that the feature in question is
familiar. The judgment that what is familiar has been experienced
before is a product of reflection, and is no part of the feeling
of familiarity, such as a horse may be supposed to have when he
returns to his stable. Thus no knowledge as to the past is to be
derived from the feeling of familiarity alone.

A further stage is RECOGNITION. This may be taken in two senses,
the first when a thing not merely feels familiar, but we know it
is such-and-such. We recognize our friend Jones, we know cats and
dogs when we see them, and so on. Here we have a definite
influence of past experience, but not necessarily any actual
knowledge of the past. When we see a cat, we know it is a cat
because of previous cats we have seen, but we do not, as a rule,
recollect at the moment any particular occasion when we have seen
a cat. Recognition in this sense does not necessarily involve
more than a habit of association: the kind of object we are
seeing at the moment is associated with the word "cat," or with
an auditory image of purring, or whatever other characteristic we
may happen to recognize in. the cat of the moment. We are, of
course, in fact able to judge, when we recognize an object, that
we have seen it before, but this judgment is something over and
above recognition in this first sense, and may very probably be
impossible to animals that nevertheless have the experience of
recognition in this first sense of the word.

There is, however, another sense of the word, in which we mean by
recognition, not knowing the name of a thing or some other
property of it, but knowing that we have seen it before In this
sense recognition does involve knowledge about the Fast. This
knowledge is memory in one sense, though in another it is not. It
does not involve a definite memory of a definite past event, but
only the knowledge that something happening now is similar to
something that happened before. It differs from the sense of
familiarity by being cognitive; it is a belief or judgment, which
the sense of familiarity is not. I do not wish to undertake the
analysis of belief at present, since it will be the subject of
the twelfth lecture; for the present I merely wish to emphasize
the fact that recognition, in our second sense, consists in a
belief, which we may express approximately in the words: "This
has existed before."

There are, however, several points in which such an account of
recognition is inadequate. To begin with, it might seem at first
sight more correct to define recognition as "I have seen this
before" than as "this has existed before." We recognize a thing
(it may be urged) as having been in our experience before,
whatever that may mean; we do not recognize it as merely having
been in the world before. I am not sure that there is anything
substantial in this point. The definition of "my experience" is
difficult; broadly speaking, it is everything that is connected
with what I am experiencing now by certain links, of which the
various forms of memory are among the most important. Thus, if I
recognize a thing, the occasion of its previous existence in
virtue of which I recognize it forms part of "my experience" by
DEFINITION: recognition will be one of the marks by which my
experience is singled out from the rest of the world. Of course,
the words "this has existed before" are a very inadequate
translation of what actually happens when we form a judgment of
recognition, but that is unavoidable: words are framed to express
a level of thought which is by no means primitive, and are quite
incapable of expressing such an elementary occurrence as
recognition. I shall return to what is virtually the same
question in connection with true memory, which raises exactly
similar problems.

A second point is that, when we recognize something, it was not
in fact the very same thing, but only something similar, that we
experienced on a former occasion. Suppose the object in question
is a friend's face. A person's face is always changing, and is
not exactly the same on any two occasions. Common sense treats it
as one face with varying expressions; but the varying expressions
actually exist, each at its proper time, while the one face is
merely a logical construction. We regard two objects as the same,
for common-sense purposes, when the reaction they call for is
practically the same. Two visual appearances, to both of which it
is appropriate to say: "Hullo, Jones!" are treated as appearances
of one identical object, namely Jones. The name "Jones" is
applicable to both, and it is only reflection that shows us that
many diverse particulars are collected together to form the
meaning of the name "Jones." What we see on any one occasion is
not the whole series of particulars that make up Jones, but only
one of them (or a few in quick succession). On another occasion
we see another member of the series, but it is sufficiently
similar to count as the same from the standpoint of common sense.
Accordingly, when we judge "I have seen THIS before," we judge
falsely if "this" is taken as applying to the actual constituent
of the world that we are seeing at the moment. The word "this"
must be interpreted vaguely so as to include anything
sufficiently like what we are seeing at the moment. Here, again,
we shall find a similar point as regards true memory; and in
connection with true memory we will consider the point again. It
is sometimes suggested, by those who favour behaviourist views,
that recognition consists in behaving in the same way when a
stimulus is repeated as we behaved on the first occasion when it
occurred. This seems to be the exact opposite of the truth. The
essence of recognition is in the DIFFERENCE between a repeated
stimulus and a new one. On the first occasion there is no
recognition; on the second occasion there is. In fact,
recognition is another instance of the peculiarity of causal laws
in psychology, namely, that the causal unit is not a single
event, but two or more events Habit is the great instance of
this, but recognition is another. A stimulus occurring once has a
certain effect; occurring twice, it has the further effect of
recognition. Thus the phenomenon of recognition has as its cause
the two occasions when the stimulus has occurred; either alone is
insufficient. This complexity of causes in psychology might be
connected with Bergson's arguments against repetition in the
mental world. It does not prove that there are no causal laws in
psychology, as Bergson suggests; but it does prove that the
causal laws of psychology are Prima facie very different from
those of physics. On the possibility of explaining away the
difference as due to the peculiarities of nervous tissue I have
spoken before, but this possibility must not be forgotten if we
are tempted to draw unwarranted metaphysical deductions.

True memory, which we must now endeavour to understand, consists
of knowledge of past events, but not of all such knowledge. Some
knowledge of past events, for example what we learn through
reading history, is on a par with the knowledge we can acquire
concerning the future: it is obtained by inference, not (so to
speak) spontaneously. There is a similar distinction in our
knowledge of the present: some of it is obtained through the
senses, some in more indirect ways. I know that there are at this
moment a number of people in the streets of New York, but I do
not know this in the immediate way in which I know of the people
whom I see by looking out of my window. It is not easy to state
precisely wherein the difference between these two sorts of
knowledge consists, but it is easy to feel the difference. For
the moment, I shall not stop to analyse it, but shall content
myself with saying that, in this respect, memory resembles the
knowledge derived from the senses. It is immediate, not inferred,
not abstract; it differs from perception mainly by being referred
to the past.

In regard to memory, as throughout the analysis of knowledge,
there are two very distinct problems, namely (1) as to the nature
of the present occurrence in knowing; (2) as to the relation of
this occurrence to what is known. When we remember, the knowing
is now, while what is known is in the past. Our two questions
are, in the case of memory

(1) What is the present occurrence when we remember?

(2) What is the relation of this present occurrence to the past
event which is remembered?

Of these two questions, only the first concerns the psychologist;
the second belongs to theory of knowledge. At the same time, if
we accept the vague datum with which we began, to the effect
that, in some sense, there is knowledge of the past, we shall
have to find, if we can, such an account of the present
occurrence in remembering as will make it not impossible for
remembering to give us knowledge of the past. For the present,
however, we shall do well to forget the problems concerning
theory of knowledge, and concentrate upon the purely
psychological problem of memory.

Between memory-image and sensation there is an intermediate
experience concerning the immediate past. For example, a sound
that we have just heard is present to us in a way which differs
both from the sensation while we are hearing the sound and from
the memory-image of something heard days or weeks ago. James
states that it is this way of apprehending the immediate past
that is "the ORIGINAL of our experience of pastness, from whence
we get the meaning of the term"("Psychology," i, p. 604).
Everyone knows the experience of noticing (say) that the clock
HAS BEEN striking, when we did not notice it while it was
striking. And when we hear a remark spoken, we are conscious of
the earlier words while the later ones are being uttered, and
this retention feels different from recollection of something
definitely past. A sensation fades gradually, passing by
continuous gradations to the status of an image. This retention
of the immediate past in a condition intermediate between
sensation and image may be called "immediate memory." Everything
belonging to it is included with sensation in what is called the
"specious present." The specious present includes elements at all
stages on the journey from sensation to image. It is this fact
that enables us to apprehend such things as movements, or the
order of the words in a spoken sentence. Succession can occur
within the specious present, of which we can distinguish some
parts as earlier and others as later. It is to be supposed that
the earliest parts are those that have faded most from their
original force, while the latest parts are those that retain
their full sensational character. At the beginning of a stimulus
we have a sensation; then a gradual transition; and at the end an
image. Sensations while they are fading are called "akoluthic"
sensations.* When the process of fading is completed (which
happens very quickly), we arrive at the image, which is capable
of being revived on subsequent occasions with very little change.
True memory, as opposed to "immediate memory," applies only to
events sufficiently distant to have come to an end of the period
of fading. Such events, if they are represented by anything
present, can only be represented by images, not by those
intermediate stages, between sensations and images, which occur
during the period of fading.

* See Semon, "Die mnemischen Empfindungen," chap. vi.

Immediate memory is important both because it provides experience
of succession, and because it bridges the gulf between sensations
and the images which are their copies. But it is now time to
resume the consideration of true memory.

Suppose you ask me what I ate for breakfast this morning.
Suppose, further, that I have not thought about my breakfast in
the meantime, and that I did not, while I was eating it, put into
words what it consisted of. In this case my recollection will be
true memory, not habit-memory. The process of remembering will
consist of calling up images of my breakfast, which will come to
me with a feeling of belief such as distinguishes memory-images
from mere imagination-images. Or sometimes words may come without
the intermediary of images; but in this case equally the feeling
of belief is essential.

Let us omit from our consideration, for the present, the memories
in which words replace images. These are always, I think, really
habit-memories, the memories that use images being the typical
true memories.

Memory-images and imagination-images do not differ in their
intrinsic qualities, so far as we can discover. They differ by
the fact that the images that constitute memories, unlike those
that constitute imagination, are accompanied by a feeling of
belief which may be expressed in the words "this happened." The
mere occurrence of images, without this feeling of belief,
constitutes imagination; it is the element of belief that is the
distinctive thing in memory.*

* For belief of a specific kind, cf. Dorothy Wrinch "On the
Nature of Memory," "Mind," January, 1920.

There are, if I am not mistaken, at least three different kinds
of belief-feeling, which we may call respectively memory,
expectation and bare assent. In what I call bare assent, there is
no time-element in the feeling of belief, though there may be in
the content of what is believed. If I believe that Caesar landed
in Britain in B.C. 55, the time-determination lies, not in the
feeling of belief, but in what is believed. I do not remember the
occurrence, but have the same feeling towards it as towards the
announcement of an eclipse next year. But when I have seen a
flash of lightning and am waiting for the thunder, I have a
belief-feeling analogous to memory, except that it refers to the
future: I have an image of thunder, combined with a feeling which
may be expressed in the words: "this will happen." So, in memory,
the pastness lies, not in the content of what is believed, but in
the nature of the belief-feeling. I might have just the same
images and expect their realization; I might entertain them
without any belief, as in reading a novel; or I might entertain
them together with a time-determination, and give bare assent, as
in reading history. I shall return to this subject in a later
lecture, when we come to the analysis of belief. For the present,
I wish to make it clear that a certain special kind of belief is
the distinctive characteristic of memory.

The problem as to whether memory can be explained as habit or
association requires to be considered afresh in connection with
the causes of our remembering something. Let us take again the
case of my being asked what I had for breakfast this morning. In
this case the question leads to my setting to work to recollect.
It is a little strange that the question should instruct me as to
what it is that I am to recall. This has to do with understanding
words, which will be the topic of the next lecture; but something
must be said about it now. Our understanding of the words
"breakfast this morning" is a habit, in spite of the fact that on
each fresh day they point to a different occasion. "This morning"
does not, whenever it is used, mean the same thing, as "John" or
"St. Paul's" does; it means a different period of time on each
different day. It follows that the habit which constitutes our
understanding of the words "this morning" is not the habit of
associating the words with a fixed object, but the habit of
associating them with something having a fixed time-relation to
our present. This morning has, to-day, the same time-relation to
my present that yesterday morning had yesterday. In order to
understand the phrase "this morning" it is necessary that we
should have a way of feeling time-intervals, and that this
feeling should give what is constant in the meaning of the words
"this morning." This appreciation of time-intervals is, however,
obviously a product of memory, not a presupposition of it. It
will be better, therefore, if we wish to analyse the causation of
memory by something not presupposing memory, to take some other
instance than that of a question about "this morning."

Let us take the case of coming into a familiar room where
something has been changed--say a new picture hung on the wall.
We may at first have only a sense that SOMETHING is unfamiliar,
but presently we shall remember, and say "that picture was not on
the wall before." In order to make the case definite, we will
suppose that we were only in the room on one former occasion. In
this case it seems fairly clear what happens. The other objects
in the room are associated, through the former occasion, with a
blank space of wall where now there is a picture. They call up an
image of a blank wall, which clashes with perception of the
picture. The image is associated with the belief-feeling which we
found to be distinctive of memory, since it can neither be
abolished nor harmonized with perception. If the room had
remained unchanged, we might have had only the feeling of
familiarity without the definite remembering; it is the change
that drives us from the present to memory of the past.

We may generalize this instance so as to cover the causes of many
memories. Some present feature of the environment is associated,
through past experiences, with something now absent; this absent
something comes before us as an image, and is contrasted with
present sensation. In cases of this sort, habit (or association)
explains why the present feature of the environment brings up the
memory-image, but it does not explain the memory-belief. Perhaps
a more complete analysis could explain the memory-belief also on
lines of association and habit, but the causes of beliefs are
obscure, and we cannot investigate them yet. For the present we
must content ourselves with the fact that the memory-image can be
explained by habit. As regards the memory-belief, we must, at
least provisionally, accept Bergson's view that it cannot be
brought under the head of habit, at any rate when it first
occurs, i.e. when we remember something we never remembered

We must now consider somewhat more closely the content of a
memory-belief. The memory-belief confers upon the memory-image
something which we may call "meaning;" it makes us feel that the
image points to an object which existed in the past. In order to
deal with this topic we must consider the verbal expression of
the memory-belief. We might be tempted to put the memory-belief
into the words: "Something like this image occurred." But such
words would be very far from an accurate translation of the
simplest kind of memory-belief. "Something like this image" is a
very complicated conception. In the simplest kind of memory we
are not aware of the difference between an image and the
sensation which it copies, which may be called its "prototype."
When the image is before us, we judge rather "this occurred." The
image is not distinguished from the object which existed in the
past: the word "this" covers both, and enables us to have a
memory-belief which does not introduce the complicated notion
"something like this."

It might be objected that, if we judge "this occurred" when in
fact "this" is a present image, we judge falsely, and the
memory-belief, so interpreted, becomes deceptive. This, however,
would be a mistake, produced by attempting to give to words a
precision which they do not possess when used by unsophisticated
people. It is true that the image is not absolutely identical
with its prototype, and if the word "this" meant the image to the
exclusion of everything else, the judgment "this occurred" would
be false. But identity is a precise conception, and no word, in
ordinary speech, stands for anything precise. Ordinary speech
does not distinguish between identity and close similarity. A
word always applies, not only to one particular, but to a group
of associated particulars, which are not recognized as multiple
in common thought or speech. Thus primitive memory, when it
judges that "this occurred," is vague, but not false.

Vague identity, which is really close similarity, has been a
source of many of the confusions by which philosophy has lived.
Of a vague subject, such as a "this," which is both an image and
its prototype, contradictory predicates are true simultaneously:
this existed and does not exist, since it is a thing remembered,
but also this exists and did not exist, since it is a present
image. Hence Bergson's interpenetration of the present by the
past, Hegelian continuity and identity-in-diversity, and a host
of other notions which are thought to be profound because they
are obscure and confused. The contradictions resulting from
confounding image and prototype in memory force us to precision.
But when we become precise, our remembering becomes different
from that of ordinary life, and if we forget this we shall go
wrong in the analysis of ordinary memory.

Vagueness and accuracy are important notions, which it is very
necessary to understand. Both are a matter of degree. All
thinking is vague to some extent, and complete accuracy is a
theoretical ideal not practically attainable. To understand what
is meant by accuracy, it will be well to consider first
instruments of measurement, such as a balance or a thermometer.
These are said to be accurate when they give different results
for very slightly different stimuli.* A clinical thermometer is
accurate when it enables us to detect very slight differences in
the temperature of the blood. We may say generally that an
instrument is accurate in proportion as it reacts differently to
very slightly different stimuli. When a small difference of
stimulus produces a great difference of reaction, the instrument
is accurate; in the contrary case it is not.

* This is a necessary but not a sufficient condition. The subject
of accuracy and vagueness will be considered again in Lecture

Exactly the same thing applies in defining accuracy of thought or
perception. A musician will respond differently to very minute
differences in playing which would be quite imperceptible to the
ordinary mortal. A negro can see the difference between one negro
and another one is his friend, another his enemy. But to us such
different responses are impossible: we can merely apply the word
"negro" indiscriminately. Accuracy of response in regard to any
particular kind of stimulus is improved by practice.
Understanding a language is a case in point. Few Frenchmen can
hear any difference between the sounds "hall" and "hole," which
produce quite different impressions upon us. The two statements
"the hall is full of water" and "the hole is full of water" call
for different responses, and a hearing which cannot distinguish
between them is inaccurate or vague in this respect.

Precision and vagueness in thought, as in perception, depend upon
the degree of difference between responses to more or less
similar stimuli. In the case of thought, the response does not
follow immediately upon the sensational stimulus, but that makes
no difference as regards our present question. Thus to revert to
memory: A memory is "vague" when it is appropriate to many
different occurrences: for instance, "I met a man" is vague,
since any man would verify it. A memory is "precise" when the
occurrences that would verify it are narrowly circumscribed: for
instance, "I met Jones" is precise as compared to "I met a man."
A memory is "accurate" when it is both precise and true, i.e. in
the above instance, if it was Jones I met. It is precise even if
it is false, provided some very definite occurrence would have
been required to make it true.

It follows from what has been said that a vague thought has more
likelihood of being true than a precise one. To try and hit an
object with a vague thought is like trying to hit the bull's eye
with a lump of putty: when the putty reaches the target, it
flattens out all over it, and probably covers the bull's eye
along with the rest. To try and hit an object with a precise
thought is like trying to hit the bull's eye with a bullet. The
advantage of the precise thought is that it distinguishes between
the bull's eye and the rest of the target. For example, if the
whole target is represented by the fungus family and the bull's
eye by mushrooms, a vague thought which can only hit the target
as a whole is not much use from a culinary point of view. And
when I merely remember that I met a man, my memory may be very
inadequate to my practical requirements, since it may make a
great difference whether I met Brown or Jones. The memory "I met
Jones" is relatively precise. It is accurate if I met Jones,
inaccurate if I met Brown, but precise in either case as against
the mere recollection that I met a man.

The distinction between accuracy and precision is however, not
fundamental. We may omit precision from out thoughts and confine
ourselves to the distinction between accuracy and vagueness. We
may then set up the following definitions:

An instrument is "reliable" with respect to a given set of
stimuli when to stimuli which are not relevantly different it
gives always responses which are not relevantly different.

An instrument is a "measure" of a set of stimuli which are
serially ordered when its responses, in all cases where they are
relevantly different, are arranged in a series in the same order.

The "degree of accuracy" of an instrument which is a reliable
measurer is the ratio of the difference of response to the
difference of stimulus in cases where the difference of stimulus
is small.* That is to say, if a small difference of stimulus
produces a great difference of response, the instrument is very
accurate; in the contrary case, very inaccurate.

* Strictly speaking, the limit of this, i.e. the derivative of
the response with respect to the stimulus.

A mental response is called "vague" in proportion to its lack of
accuracy, or rather precision.

These definitions will be found useful, not only in the case of
memory, but in almost all questions concerned with knowledge.

It should be observed that vague beliefs, so far from being
necessarily false, have a better chance of truth than precise
ones, though their truth is less valuable than that of precise
beliefs, since they do not distinguish between occurrences which
may differ in important ways.

The whole of the above discussion of vagueness and accuracy was
occasioned by the attempt to interpret the word "this" when we
judge in verbal memory that "this occurred." The word "this," in
such a judgment, is a vague word, equally applicable to the
present memory-image and to the past occurrence which is its
prototype. A vague word is not to be identified with a general
word, though in practice the distinction may often be blurred. A
word is general when it is understood to be applicable to a
number of different objects in virtue of some common property. A
word is vague when it is in fact applicable to a number of
different objects because, in virtue of some common property,
they have not appeared, to the person using the word, to be
distinct. I emphatically do not mean that he has judged them to
be identical, but merely that he has made the same response to
them all and has not judged them to be different. We may compare
a vague word to a jelly and a general word to a heap of shot.
Vague words precede judgments of identity and difference; both
general and particular words are subsequent to such judgments.
The word "this" in the primitive memory-belief is a vague word,
not a general word; it covers both the image and its prototype
because the two are not distinguished.*

* On the vague and the general cf. Ribot: "Evolution of General
Ideas," Open Court Co., 1899, p. 32: "The sole permissible
formula is this: Intelligence progresses from the indefinite to
the definite. If 'indefinite' is taken as synonymous with
general, it may be said that the particular does not appear at
the outset, but neither does the general in any exact sense: the
vague would be more appropriate. In other words, no sooner has
the intellect progressed beyond the moment of perception and of
its immediate reproduction in memory, than the generic image
makes its appearance, i.e. a state intermediate between the
particular and the general, participating in the nature of the
one and of the other--a confused simplification."

But we have not yet finished our analysis of the memory-belief.
The tense in the belief that "this occurred" is provided by the
nature of the belief-feeling involved in memory; the word "this,"
as we have seen, has a vagueness which we have tried to describe.
But we must still ask what we mean by "occurred." The image is,
in one sense, occurring now; and therefore we must find some
other sense in which the past event occurred but the image does
not occur.

There are two distinct questions to be asked: (1) What causes us
to say that a thing occurs? (2) What are we feeling when we say
this? As to the first question, in the crude use of the word,
which is what concerns us, memory-images would not be said to
occur; they would not be noticed in themselves, but merely used
as signs of the past event. Images are "merely imaginary"; they
have not, in crude thought, the sort of reality that belongs to
outside bodies. Roughly speaking, "real" things would be those
that can cause sensations, those that have correlations of the
sort that constitute physical objects. A thing is said to be
"real" or to "occur" when it fits into a context of such
correlations. The prototype of our memory-image did fit into a
physical context, while our memory-image does not. This causes us
to feel that the prototype was "real," while the image is

But the answer to our second question, namely as to what we are
feeling when we say a thing "occurs" or is "real," must be
somewhat different. We do not, unless we are unusually
reflective, think about the presence or absence of correlations:
we merely have different feelings which, intellectualized, may be
represented as expectations of the presence or absence of
correlations. A thing which "feels real" inspires us with hopes
or fears, expectations or curiosities, which are wholly absent
when a thing "feels imaginary." The feeling of reality is a
feeling akin to respect: it belongs PRIMARILY to whatever can do
things to us without our voluntary co-operation. This feeling of
reality, related to the memory-image, and referred to the past by
the specific kind of belief-feeling that is characteristic of
memory, seems to be what constitutes the act of remembering in
its pure form.

We may now summarize our analysis of pure memory.

Memory demands (a) an image, (b) a belief in past existence. The
belief may be expressed in the words "this existed."

The belief, like every other, may be analysed into (1) the
believing, (2) what is believed. The believing is a specific
feeling or sensation or complex of sensations, different from
expectation or bare assent in a way that makes the belief refer
to the past; the reference to the past lies in the
belief-feeling, not in the content believed. There is a relation
between the belief-feeling and the content, making the
belief-feeling refer to the content, and expressed by saying that
the content is what is believed.

The content believed may or may not be expressed in words. Let us
take first the case when it is not. In that case, if we are
merely remembering that something of which we now have an image
occurred, the content consists of (a) the image, (b) the feeling,
analogous to respect, which we translate by saying that something
is "real" as opposed to "imaginary," (c) a relation between the
image and the feeling of reality, of the sort expressed when we
say that the feeling refers to the image. This content does not
contain in itself any time-determination

the time-determination lies in the nature of the belief feeling,
which is that called "remembering" or (better) "recollecting." It
is only subsequent reflection upon this reference to the past
that makes us realize the distinction between the image and the
event recollected. When we have made this distinction, we can say
that the image "means" the past event.

The content expressed in words is best represented by the words
"the existence of this," since these words do not involve tense,
which belongs to the belief-feeling, not to the content.  Here
"this" is a vague term, covering the memory-image and anything
very like it, including its prototype. "Existence" expresses the
feeling of a "reality" aroused primarily by whatever can have
effects upon us without our voluntary co-operation. The word "of"
in the phrase "the existence of this" represents the relation
which subsists between the feeling of reality and the "this."

This analysis of memory is probably extremely faulty, but I do
not know how to improve it.

NOTE.-When I speak of a FEELING of belief, I use the word
"feeling" in a popular sense, to cover a sensation or an image or
a complex of sensations or images or both; I use this word
because I do not wish to commit myself to any special analysis of
the belief-feeling.

download audio

The problem with which we shall be concerned in this lecture is
the problem of determining what is the relation called "meaning."
The word "Napoleon," we say, "means" a certain person. In saying
this, we are asserting a relation between the word "Napoleon" and
the person so designated. It is this relation that we must now

Let us first consider what sort of object a word is when
considered simply as a physical thing, apart from its meaning. To
begin with, there are many instances of a word, namely all the
different occasions when it is employed. Thus a word is not
something unique and particular, but a set of occurrences. If we
confine ourselves to spoken words, a word has two aspects,
according as we regard it from the point of view of the speaker
or from that of the hearer. From the point of view of the
speaker, a single instance of the use of a word consists of a
certain set of movements in the throat and mouth, combined with
breath. From the point of view of the hearer, a single instance
of the use of a word consists of a certain series of sounds, each
being approximately represented by a single letter in writing,
though in practice a letter may represent several sounds, or
several letters may represent one sound. The connection between
the spoken word and the word as it reaches the hearer is causal.
Let us confine ourselves to the spoken word, which is the more
important for the analysis of what is called "thought." Then we
may say that a single instance of the spoken word consists of a
series of movements, and the word consists of a whole set of such
series, each member of the set being very similar to each other
member. That is to say, any two instances of the word "Napoleon"
are very similar, and each instance consists of a series of
movements in the mouth.

A single word, accordingly, is by no means simple it is a class
of similar series of movements (confining ourselves still to the
spoken word). The degree of similarity required cannot be
precisely defined: a man may pronounce the word "Napoleon" so
badly that it can hardly be determined whether he has really
pronounced it or not. The instances of a word shade off into
other movements by imperceptible degrees. And exactly analogous
observations apply to words heard or written or read. But in what
has been said so far we have not even broached the question of
the DEFINITION of a word, since "meaning" is clearly what
distinguishes a word from other sets of similar movements, and
"meaning" remains to be defined.

It is natural to think of the meaning of a word as something
conventional. This, however, is only true with great limitations.
A new word can be added to an existing language by a mere
convention, as is done, for instance, with new scientific terms.
But the basis of a language is not conventional, either from the
point of view of the individual or from that of the community. A
child learning to speak is learning habits and associations which
are just as much determined by the environment as the habit of
expecting dogs to bark and cocks to crow. The community that
speaks a language has learnt it, and modified it by processes
almost all of which are not deliberate, but the results of causes
operating according to more or less ascertainable laws. If we
trace any Indo-European language back far enough, we arrive
hypothetically (at any rate according to some authorities) at the
stage when language consisted only of the roots out of which
subsequent words have grown. How these roots acquired their
meanings is not known, but a conventional origin is clearly just
as mythical as the social contract by which Hobbes and Rousseau
supposed civil government to have been established. We can hardly
suppose a parliament of hitherto speechless elders meeting
together and agreeing to call a cow a cow and a wolf a wolf. The
association of words with their meanings must have grown up by
some natural process, though at present the nature of the process
is unknown.

Spoken and written words are, of course, not the only way of
conveying meaning. A large part of one of Wundt's two vast
volumes on language in his "Volkerpsychologie" is concerned with
gesture-language. Ants appear to be able to communicate a certain
amount of information by means of their antennae. Probably
writing itself, which we now regard as merely a way of
representing speech, was originally an independent language, as
it has remained to this day in China. Writing seems to have
consisted originally of pictures, which gradually became
conventionalized, coming in time to represent syllables, and
finally letters on the telephone principle of "T for Tommy." But
it would seem that writing nowhere began as an attempt to
represent speech it began as a direct pictorial representation of
what was to be expressed. The essence of language lies, not in
the use of this or that special means of communication, but in
the employment of fixed associations (however these may have
originated) in order that something now sensible--a spoken word,
a picture, a gesture, or what not--may call up the "idea" of
something else. Whenever this is done, what is now sensible may
be called a "sign"  or "symbol," and that of which it is intended
to call up the "idea" may be called its "meaning." This is a
rough outline of what constitutes "meaning." But we must fill in
the outline in various ways. And, since we are concerned with
what is called "thought," we must pay more attention than we
otherwise should do to the private as opposed to the social use
of language. Language profoundly affects our thoughts, and it is
this aspect of language that is of most importance to us in our
present inquiry. We are almost more concerned with the internal
speech that is never uttered than we are with the things said out
loud to other people.

When we ask what constitutes meaning, we are not asking what is
the meaning of this or that particular word. The word "Napoleon"
means a certain individual; but we are asking, not who is the
individual meant, but what is the relation of the word to the
individual which makes the one mean the other. But just as it is
useful to realize the nature of a word as part of the physical
world, so it is useful to realize the sort of thing that a word
may mean. When we are clear both as to what a word is in its
physical aspect, and as to what sort of thing it can mean, we are
in a better position to discover the relation of the two which is

The things that words mean differ more than words do. There are
different sorts of words, distinguished by the grammarians; and
there are logical distinctions, which are connected to some
extent, though not so closely as was formerly supposed, with the
grammatical distinctions of parts of speech. It is easy, however,
to be misled by grammar, particularly if all the languages we
know belong to one family. In some languages, according to some
authorities, the distinction of parts of speech does not exist;
in many languages it is widely different from that to which we
are accustomed in the Indo-European languages. These facts have
to be borne in mind if we are to avoid giving metaphysical
importance to mere accidents of our own speech.

In considering what words mean, it is natural to start with
proper names, and we will again take "Napoleon" as our instance.
We commonly imagine, when we use a proper name, that we mean one
definite entity, the particular individual who was called
"Napoleon." But what we know as a person is not simple. There MAY
be a single simple ego which was Napoleon, and remained strictly
identical from his birth to his death. There is no way of proving
that this cannot be the case, but there is also not the slightest
reason to suppose that it is the case. Napoleon as he was
empirically known consisted of a series of gradually changing
appearances: first a squalling baby, then a boy, then a slim and
beautiful youth, then a fat and slothful person very
magnificently dressed This series of appearances, and various
occurrences having certain kinds of causal connections with them,
constitute Napoleon as empirically known, and therefore are
Napoleon in so far as he forms part of the experienced world.
Napoleon is a complicated series of occurrences, bound together
by causal laws, not, like instances of a word, by similarities.
For although a person changes gradually, and presents similar
appearances on two nearly contemporaneous occasions, it is not
these similarities that constitute the person, as appears from
the "Comedy of Errors" for example.

Thus in the case of a proper name, while the word is a set of
similar series of movements, what it means is a series of
occurrences bound together by causal laws of that special kind
that makes the occurrences taken together constitute what we call
one person, or one animal or thing, in case the name applies to
an animal or thing instead of to a person. Neither the word nor
what it names is one of the ultimate indivisible constituents of
the world. In language there is no direct way of designating one
of the ultimate brief existents that go to make up the
collections we call things or persons. If we want to speak of
such existentswhich hardly happens except in philosophy-we have
to do it by means of some elaborate phrase, such as "the visual
sensation which occupied the centre of my field of vision at noon
on January 1, 1919." Such ultimate simples I call "particulars."
Particulars MIGHT have proper names, and no doubt would have if
language had been invented by scientifically trained observers
for purposes of philosophy and logic. But as language was
invented for practical ends, particulars have remained one and
all without a name.

We are not, in practice, much concerned with the actual
particulars that come into our experience in sensation; we are
concerned rather with whole systems to which the particulars
belong and of which they are signs. What we see makes us say
"Hullo, there's Jones," and the fact that what we see is a sign
of Jones (which is the case because it is one of the particulars
that make up Jones) is more interesting to us than the actual
particular itself. Hence we give the name "Jones" to the whole
set of particulars, but do not trouble to give separate names to
the separate particulars that make up the set.

Passing on from proper names, we come next to general names, such
as "man," "cat," "triangle." A word such as "man" means a whole
class of such collections of particulars as have proper names.
The several members of the class are assembled together in virtue
of some similarity or common property. All men resemble each
other in certain important respects; hence we want a word which
shall be equally applicable to all of them. We only give proper
names to the individuals of a species when they differ inter se
in practically important respects. In other cases we do not do
this. A poker, for instance, is just a poker; we do not call one
"John" and another "Peter."

There is a large class of words, such as "eating," "walking,"
"speaking," which mean a set of similar occurrences. Two
instances of walking have the same name because they resemble
each other, whereas two instances of Jones have the same name
because they are causally connected. In practice, however, it is
difficult to make any precise distinction between a word such as
"walking" and a general name such as "man." One instance of
walking cannot be concentrated into an instant: it is a process
in time, in which there is a causal connection between the
earlier and later parts, as between the earlier and later parts
of Jones. Thus an instance of walking differs from an instance of
man solely by the fact that it has a shorter life. There is a
notion that an instance of walking, as compared with Jones, is
unsubstantial, but this seems to be a mistake. We think that
Jones walks, and that there could not be any walking unless there
were somebody like Jones to perform the walking. But it is
equally true that there could be no Jones unless there were
something like walking for him to do. The notion that actions are
performed by an agent is liable to the same kind of criticism as
the notion that thinking needs a subject or ego, which we
rejected in Lecture I. To say that it is Jones who is walking is
merely to say that the walking in question is part of the whole
series of occurrences which is Jones. There is no LOGICAL
impossibility in walking occurring as an isolated phenomenon, not
forming part of any such series as we call a "person."

We may therefore class with "eating," "walking," "speaking" words
such as "rain," "sunrise," "lightning," which do not denote what
would commonly be called actions. These words illustrate,
incidentally, how little we can trust to the grammatical
distinction of parts of speech, since the substantive "rain" and
the verb "to rain" denote precisely the same class of
meteorological occurrences. The distinction between the class of
objects denoted by such a word and the class of objects denoted
by a general name such as "man," "vegetable," or "planet," is
that the sort of object which is an instance of (say) "lightning"
is much simpler than (say) an individual man. (I am speaking of
lightning as a sensible phenomenon, not as it is described in
physics.) The distinction is one of degree, not of kind. But
there is, from the point of view of ordinary thought, a great
difference between a process which, like a flash of lightning,
can be wholly comprised within one specious present and a process
which, like the life of a man, has to be pieced together by
observation and memory and the apprehension of causal
connections. We may say broadly, therefore, that a word of the
kind we have been discussing denotes a set of similar
occurrences, each (as a rule) much more brief and less complex
than a person or thing. Words themselves, as we have seen, are
sets of similar occurrences of this kind. Thus there is more
logical affinity between a word and what it means in the case of
words of our present sort than in any other case.

There is no very great difference between such words as we have
just been considering and words denoting qualities, such as
"white" or "round." The chief difference is that words of this
latter sort do not denote processes, however brief, but static
features of the world. Snow falls, and is white; the falling is a
process, the whiteness is not. Whether there is a universal,
called "whiteness," or whether white things are to be defined as
those having a certain kind of similarity to a standard thing,
say freshly fallen snow, is a question which need not concern us,
and which I believe to be strictly insoluble. For our purposes,
we may take the word "white" as denoting a certain set of similar
particulars or collections of particulars, the similarity being
in respect of a static quality, not of a process.

From the logical point of view, a very important class of words
are those that express relations, such as "in," "above,"
"before," "greater," and so on. The meaning of one of these words
differs very fundamentally from the meaning of one of any of our
previous classes, being more abstract and logically simpler than
any of them. If our business were logic, we should have to spend
much time on these words. But as it is psychology that concerns
us, we will merely note their special character and pass on,
since the logical classification of words is not our main

We will consider next the question what is implied by saying that
a person "understands" a word, in the sense in which one
understands a word in one's own language, but not in a language
of which one is ignorant. We may say that a person understands a
word when (a) suitable circumstances make him use it, (b) the
hearing of it causes suitable behaviour in him. We may call these
two active and passive understanding respectively. Dogs often
have passive understanding of some words, but not active
understanding, since they cannot use words.

It is not necessary, in order that a man should "understand" a
word, that he should "know what it means," in the sense of being
able to say "this word means so-and-so." Understanding words does
not consist in knowing their dictionary definitions, or in being
able to specify the objects to which they are appropriate. Such
understanding as this may belong to lexicographers and students,
but not to ordinary mortals in ordinary life. Understanding
language is more like understanding cricket*: it is a matter of
habits, acquired in oneself and rightly presumed in others. To
say that a word has a meaning is not to say that those who use
the word correctly have ever thought out what the meaning is: the
use of the word comes first, and the meaning is to be distilled
out of it by observation and analysis. Moreover, the meaning of a
word is not absolutely definite: there is always a greater or
less degree of vagueness. The meaning is an area, like a target:
it may have a bull's eye, but the outlying parts of the target
are still more or less within the meaning, in a gradually
diminishing degree as we travel further from the bull's eye. As
language grows more precise, there is less and less of the target
outside the bull's eye, and the bull's eye itself grows smaller
and smaller; but the bull's eye never shrinks to a point, and
there is always a doubtful region, however small, surrounding

* This point of view, extended to the analysis of "thought" is
urged with great force by J. B. Watson, both in his "Behavior,"
and in "Psychology from the Standpoint of a Behaviorist"
(Lippincott. 1919), chap. ix.

** On the understanding of words, a very admirable little book is
Ribot's "Evolution of General Ideas," Open Court Co., 1899. Ribot
says (p. 131): "We learn to understand a concept as we learn to
walk, dance, fence or play a musical instrument: it is a habit,
i.e. an organized memory. General terms cover an organized,
latent knowledge which is the hidden capital without which we
should be in a state of bankruptcy, manipulating false money or
paper of no value. General ideas are habits in the intellectual

A word is used "correctly" when the average hearer will be
affected by it in the way intended. This is a psychological, not
a literary, definition of "correctness." The literary definition
would substitute, for the average hearer, a person of high
education living a long time ago; the purpose of this definition
is to make it difficult to speak or write correctly.

The relation of a word to its meaning is of the nature of a
causal law governing our use of the word and our actions when we
hear it used. There is no more reason why a person who uses a
word correctly should be able to tell what it means than there is
why a planet which is moving correctly should know Kepler's laws.

To illustrate what is meant by "understanding" words and
sentences, let us take instances of various situations.

Suppose you are walking in London with an absent-minded friend,
and while crossing a street you say, "Look out, there's a motor
coming." He will glance round and jump aside without the need of
any "mental" intermediary. There need be no "ideas," but only a
stiffening of the muscles, followed quickly by action. He
"understands" the words, because he does the right thing. Such
"understanding" may be taken to belong to the nerves and brain,
being habits which they have acquired while the language was
being learnt. Thus understanding in this sense may be reduced to
mere physiological causal laws.

If you say the same thing to a Frenchman with a slight knowledge
of English he will go through some inner speech which may be
represented by "Que dit-il? Ah, oui, une automobile!" After this,
the rest follows as with the Englishman. Watson would contend
that the inner speech must be incipiently pronounced; we should
argue that it MIGHT be merely imaged. But this point is not
important in the present connection.

If you say the same thing to a child who does not yet know the
word "motor," but does know the other words you are using, you
produce a feeling of anxiety and doubt you will have to point and
say, "There, that's a motor." After that the child will roughly
understand the word "motor," though he may include trains and
steam-rollers If this is the first time the child has heard the
word "motor," he may for a long time continue to recall this
scene when he hears the word.

So far we have found four ways of understanding words:

(1) On suitable occasions you use the word properly.

(2) When you hear it you act appropriately.

(3) You associate the word with another word (say in a different
language) which has the appropriate effect on behaviour.

(4) When the word is being first learnt, you may associate it
with an object, which is what it "means," or a representative of
various objects that it "means."

In the fourth case, the word acquires, through association, some
of the same causal efficacy as the object. The word "motor" can
make you leap aside, just as the motor can, but it cannot break
your bones. The effects which a word can share with its object
are those which proceed according to laws other than the general
laws of physics, i.e. those which, according to our terminology,
involve vital movements as opposed to merely mechanical
movements. The effects of a word that we understand are always
mnemic phenomena in the sense explained in Lecture IV, in so far
as they are identical with, or similar to, the effects which the
object itself might have.

So far, all the uses of words that we have considered can be
accounted for on the lines of behaviourism.

But so far we have only considered what may be called the
"demonstrative" use of language, to point out some feature in the
present environment. This is only one of the ways in which
language may be used. There are also its narrative and
imaginative uses, as in history and novels. Let us take as an
instance the telling of some remembered event.

We spoke a moment ago of a child who hears the word "motor" for
the first time when crossing a street along which a motor-car is
approaching. On a later occasion, we will suppose, the child
remembers the incident and relates it to someone else. In this
case, both the active and passive understanding of words is
different from what it is when words are used demonstratively.
The child is not seeing a motor, but only remembering one; the
hearer does not look round in expectation of seeing a motor
coming, but "understands" that a motor came at some earlier time.
The whole of this occurrence is much more difficult to account
for on behaviourist lines. It is clear that, in so far as the
child is genuinely remembering, he has a picture of the past
occurrence, and his words are chosen so as to describe the
picture; and in so far as the hearer is genuinely apprehending
what is said, the hearer is acquiring a picture more or less like
that of the child. It is true that this process may be telescoped
through the operation of the word-habit. The child may not
genuinely remember the incident, but only have the habit of the
appropriate words, as in the case of a poem which we know by
heart, though we cannot remember learning it. And the hearer also
may only pay attention to the words, and not call up any
corresponding picture. But it is, nevertheless, the possibility
of a memory-image in the child and an imagination-image in the
hearer that makes the essence of the narrative "meaning" of the
words. In so far as this is absent, the words are mere counters,
capable of meaning, but not at the moment possessing it.

Yet this might perhaps be regarded as something of an
overstatement. The words alone, without the use of images, may
cause appropriate emotions and appropriate behaviour. The words
have been used in an environment which produced certain
emotions;. by a telescoped process, the words alone are now
capable of producing similar emotions. On these lines it might be
sought to show that images are unnecessary. I do not believe,
however, that we could account on these lines for the entirely
different response produced by a narrative and by a description
of present facts. Images, as contrasted with sensations, are the
response expected during a narrative; it is understood that
present action is not called for. Thus it seems that we must
maintain our distinction words used demonstratively describe and
are intended to lead to sensations, while the same words used in
narrative describe and are only intended to lead to images.

We have thus, in addition to our four previous ways in which
words can mean, two new ways, namely the way of memory and the
way of imagination. That is to say:

(5) Words may be used to describe or recall a memory-image: to
describe it when it already exists, or to recall it when the
words exist as a habit and are known to be descriptive of some
past experience.

(6) Words may be used to describe or create an imagination-image:
to describe it, for example, in the case of a poet or novelist,
or to create it in the ordinary case for giving
information-though, in the latter case, it is intended that the
imagination-image, when created, shall be accompanied by belief
that something of the sort occurred.

These two ways of using words, including their occurrence in
inner speech, may be spoken of together as the use of words in
"thinking." If we are right, the use of words in thinking
depends, at least in its origin, upon images, and cannot be fully
dealt with on behaviourist lines. And this is really the most
essential function of words, namely that, originally through
their connection with images, they bring us into touch with what
is remote in time or space. When they operate without the medium
of images, this seems to be a telescoped process. Thus the
problem of the meaning of words is brought into connection with
the problem of the meaning of images.

To understand the function that words perform in what is called
"thinking," we must understand both the causes and the effects of
their occurrence. The causes of the occurrence of words require
somewhat different treatment according as the object designated
by the word is sensibly present or absent. When the object is
present, it may itself be taken as the cause of the word, through
association. But when it is absent there is more difficulty in
obtaining a behaviourist theory of the occurrence of the word.
The language-habit consists not merely in the use of words
demonstratively, but also in their use to express narrative or
desire. Professor Watson, in his account of the acquisition of
the language-habit, pays very little attention to the use of
words in narrative and desire. He says ("Behavior," pp. 329-330):

"The stimulus (object) to which the child often responds, a box,
e.g. by movements such as opening and closing and putting objects
into it, may serve to illustrate our argument. The nurse,
observing that the child reacts with his hands, feet, etc., to
the box, begins to say 'box' when the child is handed the box,
'open box' when the child opens it, 'close box' when he closes
it, and 'put doll in box ' when that act is executed. This is
repeated over and over again. In the process of time it comes
about that without any other stimulus than that of the box which
originally called out the bodily habits, he begins to say 'box'
when he sees it, 'open box' when he opens it, etc. The visible
box now becomes a stimulus capable of releasing either the bodily
habits or the word-habit, i.e. development has brought about two
things : (1) a series of functional connections among arcs which
run from visual receptor to muscles of throat, and (2) a series
of already earlier connected arcs which run from the same
receptor to the bodily muscles.... The object meets the child's
vision. He runs to it and tries to reach it and says 'box.'...
Finally the word is uttered without the movement of going towards
the box being executed.... Habits are formed of going to the box
when the arms are full of toys. The child has been taught to
deposit them there. When his arms are laden with toys and no box
is there, the word-habit arises and he calls 'box'; it is handed
to him, and he opens it and deposits the toys therein. This
roughly marks what we would call the genesis of a true
language-habit."(pp. 329-330).*

* Just the same account of language is given in Professor
Watson's more recent book (reference above).

We need not linger over what is said in the above passage as to
the use of the word "box" in the presence of the box. But as to
its use in the absence of the box, there is only one brief
sentence, namely: "When his arms are laden with toys and no box
is there, the word-habit arises and he calls 'box.' " This is
inadequate as it stands, since the habit has been to use the word
when the box is present, and we have to explain its extension to
cases in which the box is absent.

Having admitted images, we may say that the word "box," in the
absence of the box, is caused by an image of the box. This may or
may not be true--in fact, it is true in some cases but not in
others. Even, however, if it were true in all cases, it would
only slightly shift our problem: we should now have to ask what
causes an image of the box to arise. We might be inclined to say
that desire for the box is the cause. But when this view is
investigated, it is found that it compels us to suppose that the
box can be desired without the child's having either an image of
the box or the word "box." This will require a theory of desire
which may be, and I think is, in the main true, but which removes
desire from among things that actually occur, and makes it merely
a convenient fiction, like force in mechanics.* With such a view,
desire is no longer a true cause, but merely a short way of
describing certain processes.

* See Lecture III, above.

In order to explain the occurrence of either the word or the
image in the absence of the box, we have to assume that there is
something, either in the environment or in our own sensations,
which has frequently occurred at about the same time as the word
"box." One of the laws which distinguish psychology (or
nerve-physiology?) from physics is the law that, when two things
have frequently existed in close temporal contiguity, either
comes in time to cause the other.* This is the basis both of
habit and of association. Thus, in our case, the arms full of
toys have frequently been followed quickly by the box, and the
box in turn by the word "box." The box itself is subject to
physical laws, and does not tend to be caused by the arms full of
toys, however often it may in the past have followed them--always
provided that, in the case in question, its physical position is
such that voluntary movements cannot lead to it. But the word
"box" and the image of the box are subject to the law of habit;
hence it is possible for either to be caused by the arms full of
toys. And we may lay it down generally that, whenever we use a
word, either aloud or in inner speech, there is some sensation or
image (either of which may be itself a word) which has frequently
occurred at about the same time as the word, and now, through
habit, causes the word. It follows that the law of habit is
adequate to account for the use of words in the absence of their
objects; moreover, it would be adequate even without introducing
images. Although, therefore, images seem undeniable, we cannot
derive an additional argument in their favour from the use of
words, which could, theoretically, be explained without
introducing images.

 *For a more exact statement of this law, with the limitations
suggested by experiment, see A. Wohlgemuth, "On Memory and the
Direction of Associations," "British Journal of Psychology," vol.
v, part iv (March, 1913).

When we understand a word, there is a reciprocal association
between it and the images of what it "means." Images may cause us
to use words which mean them, and these words, heard or read, may
in turn cause the appropriate images. Thus speech is a means of
producing in our hearers the images which are in us. Also, by a
telescoped process, words come in time to produce directly the
effects which would have been produced by the images with which
they were associated. The general law of telescoped processes is
that, if A causes B and B causes C, it will happen in time that A
will cause C directly, without the intermediary of B. This is a
characteristic of psychological and neural causation. In virtue
of this law, the effects of images upon our actions come to be
produced by words, even when the words do not call up appropriate
images. The more familiar we are with words, the more our
"thinking" goes on in words instead of images. We may, for
example, be able to describe a person's appearance correctly
without having at any time had any image of him, provided, when
we saw him, we thought of words which fitted him; the words alone
may remain with us as a habit, and enable us to speak as if we
could recall a visual image of the man. In this and other ways
the understanding of a word often comes to be quite free from
imagery; but in first learning the use of language it would seem
that imagery always plays a very important part.

Images as well as words may be said to have "meaning"; indeed,
the meaning of images seems more primitive than the meaning of
words. What we call (say) an image of St. Paul's may be said to
"mean" St. Paul's. But it is not at all easy to say exactly what
constitutes the meaning of an image. A memory-image of a
particular occurrence, when accompanied by a memory-belief, may
be said to mean the occurrence of which it is an image. But most
actual images do not have this degree of definiteness. If we call
up an image of a dog, we are very likely to have a vague image,
which is not representative of some one special dog, but of dogs
in general. When we call up an image of a friend's face, we are
not likely to reproduce the expression he had on some one
particular occasion, but rather a compromise expression derived
from many occasions. And there is hardly any limit to the
vagueness of which images are capable. In such cases, the meaning
of the image, if defined by relation to the prototype, is vague:
there is not one definite prototype, but a number, none of which
is copied exactly.*

* Cf. Semon, Mnemische Empfindungen, chap. xvi, especially pp.

There is, however, another way of approaching the meaning of
images, namely through their causal efficacy. What is called an
image "of" some definite object, say St. Paul's, has some of the
effects which the object would have. This applies especially to
the effects that depend upon association. The emotional effects,
also, are often similar: images may stimulate desire almost as
strongly as do the objects they represent. And conversely desire
may cause images*: a hungry man will have images of food, and so
on. In all these ways the causal laws concerning images are
connected with the causal laws concerning the objects which the
images "mean." An image may thus come to fulfil the function of a
general idea. The vague image of a dog, which we spoke of a
moment ago, will have effects which are only connected with dogs
in general, not the more special effects which would be produced
by some dogs but not by others. Berkeley and Hume, in their
attack on general ideas, do not allow for the vagueness of
images: they assume that every image has the definiteness that a
physical object would have This is not the case, and a vague
image may well have a meaning which is general.

* This phrase is in need of interpretation, as appears from the
analysis of desire. But the reader can easily supply the
interpretation for himself.

In order to define the "meaning" of an image, we have to take
account both of its resemblance to one or more prototypes, and of
its causal efficacy. If there were such a thing as a pure
imagination-image, without any prototype whatever, it would be
destitute of meaning. But according to Hume's principle, the
simple elements in an image, at least, are derived from
prototypes-except possibly in very rare exceptional cases. Often,
in such instances as our image of a friend's face or of a
nondescript dog, an image is not derived from one prototype, but
from many; when this happens, the image is vague, and blurs the
features in which the various prototypes differ. To arrive at the
meaning of the image in such a case, we observe that there are
certain respects, notably associations, in which the effects of
images resemble those of their prototypes. If we find, in a given
case, that our vague image, say, of a nondescript dog, has those
associative effects which all dogs would have, but not those
belonging to any special dog or kind of dog, we may say that our
image means "dog" in general. If it has all the associations
appropriate to spaniels but no others, we shall say it means
"spaniel"; while if it has all the associations appropriate to
one particular dog, it will mean that dog, however vague it may
be as a picture. The meaning of an image, according to this
analysis, is constituted by a combination of likeness and
associations. It is not a sharp or definite conception, and in
many cases it will be impossible to decide with any certainty
what an image means. I think this lies in the nature of things,
and not in defective analysis.

We may give somewhat more precision to the above account of the
meaning of images, and extend it to meaning in general. We find
sometimes that, IN MNEMIC CAUSATION, an image or word, as
stimulus, has the same effect (or very nearly the same effect) as
would belong to some object, say, a certain dog. In that case we
say that the image or word means that object. In other cases the
mnemic effects are not all those of one object, but only those
shared by objects of a certain kind, e.g. by all dogs. In this
case the meaning of the image or word is general: it means the
whole kind. Generality and particularity are a matter of degree.
If two particulars differ sufficiently little, their mnemic
effects will be the same; therefore no image or word can mean the
one as opposed to the other; this sets a bound to the
particularity of meaning. On the other hand, the mnemic effects
of a number of sufficiently dissimilar objects will have nothing
discoverable in common; hence a word which aims at complete
generality, such as "entity" for example, will have to be devoid
of mnemic effects, and therefore of meaning. In practice, this is
not the case: such words have VERBAL associations, the learning
of which constitutes the study of metaphysics.

The meaning of a word, unlike that of an image, is wholly
constituted by mnemic causal laws, and not in any degree by
likeness (except in exceptional cases). The word "dog" bears no
resemblance to a dog, but its effects, like those of an image of
a dog, resemble the effects of an actual dog in certain respects.
It is much easier to say definitely what a word means than what
an image means, since words, however they originated, have been
framed in later times for the purpose of having meaning, and men
have been engaged for ages in giving increased precision to the
meanings of words. But although it is easier to say what a word
means than what an image means, the relation which constitutes
meaning is much the same in both cases. A word, like an image,
has the same associations as its meaning has. In addition to
other associations, it is associated with images of its meaning,
so that the word tends to call up the image and the image tends
to call up the word., But this association is not essential to
the intelligent use of words. If a word has the right
associations with other objects, we shall be able to use it
correctly, and understand its use by others, even if it evokes no
image. The theoretical understanding of words involves only the
power of associating them correctly with other words; the
practical understanding involves associations with other bodily

The use of words is, of course, primarily social, for the purpose
of suggesting to others ideas which we entertain or at least wish
them to entertain. But the aspect of words that specially
concerns us is their power of promoting our own thought. Almost
all higher intellectual activity is a matter of words, to the
nearly total exclusion of everything else. The advantages of
words for purposes of thought are so great that I should never
end if I were to enumerate them. But a few of them deserve to be

In the first place, there is no difficulty in producing a word,
whereas an image cannot always be brought into existence at will,
and when it comes it often contains much irrelevant detail. In
the second place, much of our thinking is concerned with abstract
matters which do not readily lend themselves to imagery, and are
apt to be falsely conceived if we insist upon finding images that
may be supposed to represent them. The word is always concrete
and sensible, however abstract its meaning may be, and thus by
the help of words we are able to dwell on abstractions in a way
which would otherwise be impossible. In the third place, two
instances of the same word are so similar that neither has
associations not capable of being shared by the other. Two
instances of the word "dog" are much more alike than (say) a pug
and a great dane; hence the word "dog" makes it much easier to
think about dogs in general. When a number of objects have a
common property which is important but not obvious, the invention
of a name for the common property helps us to remember it and to
think of the whole set of objects that possess it. But it is
unnecessary to prolong the catalogue of the uses of language in

At the same time, it is possible to conduct rudimentary thought
by means of images, and it is important, sometimes, to check
purely verbal thought by reference to what it means. In
philosophy especially the tyranny of traditional words is
dangerous, and we have to be on our guard against assuming that
grammar is the key to metaphysics, or that the structure of a
sentence corresponds at all accurately with the structure of the
fact that it asserts. Sayce maintained that all European
philosophy since Aristotle has been dominated by the fact that
the philosophers spoke Indo-European languages, and therefore
supposed the world, like the sentences they were used to,
necessarily divisible into subjects and predicates. When we come
to the consideration of truth and falsehood, we shall see how
necessary it is to avoid assuming too close a parallelism between
facts and the sentences which assert them. Against such errors,
the only safeguard is to be able, once in a way, to discard words
for a moment and contemplate facts more directly through images.
Most serious advances in philosophic thought result from some
such comparatively direct contemplation of facts. But the outcome
has to be expressed in words if it is to be communicable. Those
who have a relatively direct vision of facts are often incapable
of translating their vision into words, while those who possess
the words have usually lost the vision. It is partly for this
reason that the highest philosophical capacity is so rare: it
requires a combination of vision with abstract words which is
hard to achieve, and too quickly lost in the few who have for a
moment achieved it.

download audio

It is said to be one of the merits of the human mind that it is
capable of framing abstract ideas, and of conducting
nonsensational thought. In this it is supposed to differ from the
mind of animals. From Plato onward the "idea" has played a great
part in the systems of idealizing philosophers. The "idea" has
been, in their hands, always something noble and abstract, the
apprehension and use of which by man confers upon him a quite
special dignity.

The thing we have to consider to-day is this: seeing that there
certainly are words of which the meaning is abstract, and seeing
that we can use these words intelligently, what must be assumed
or inferred, or what can be discovered by observation, in the way
of mental content to account for the intelligent use of abstract

Taken as a problem in logic, the answer is, of course, that
absolutely nothing in the way of abstract mental content is
inferable from the mere fact that we can use intelligently words
of which the meaning is abstract. It is clear that a sufficiently
ingenious person could manufacture a machine moved by olfactory
stimuli which, whenever a dog appeared in its neighbourhood,
would say, "There is a dog," and when a cat appeared would throw
stones at it. The act of saying "There is a dog," and the act of
throwing stones, would in such a case be equally mechanical.
Correct speech does not of itself afford any better evidence of
mental content than the performance of any other set of
biologically useful movements, such as those of flight or combat.
All that is inferable from language is that two instances of a
universal, even when they differ very greatly, may cause the
utterance of two instances of the same word which only differ
very slightly. As we saw in the preceding lecture, the word "dog"
is useful, partly, because two instances of this word are much
more similar than (say) a pug and a great dane. The use of words
is thus a method of substituting for two particulars which differ
widely, in spite of being instances of the same universal, two
other particulars which differ very little, and which are also
instances of a universal, namely the name of the previous
universal. Thus, so far as logic is concerned, we are entirely
free to adopt any theory as to general ideas which empirical
observation may recommend.

Berkeley and Hume made a vigorous onslaught on "abstract ideas."
They meant by an idea approximately what we should call an image.
Locke having maintained that he could form an idea of triangle in
general, without deciding what sort of triangle it was to be,
Berkeley contended that this was impossible. He says:

"Whether others,have this wonderful faculty of abstracting their
ideas, they best can tell: for myself, I dare be confident I have
it not. I find, indeed, I have indeed a faculty of imagining, or
representing to myself, the ideas of those particular things I
have perceived, and of variously compounding and dividing them. I
can imagine a man with two heads, or the upper parts of a man
joined to the body of a horse. I can consider the hand, the eye,
the nose, each by itself abstracted or separated from the rest of
the body. But, then, whatever hand or eye I imagine, it must have
some particular shape and colour. Likewise the idea of a man that
I frame to myself must be either of a white, or a black, or a
tawny, a straight, or a crooked, a tall, or a low, or a
middle-sized man. I cannot by any effort of thought conceive the
abstract idea above described. And it is equally impossible for
me to form the abstract idea of motion distinct from the body
moving, and which is neither swift nor slow, curvilinear nor
rectilinear; and the like may be said of all other abstract
general ideas whatsoever. To be plain, I own myself able to
abstract in one sense, as when I consider some particular parts
of qualities separated from others, with which, though they are
united in some object, yet it is possible they may really exist
without them. But I deny that I can abstract from one another, or
conceive separately, those qualities which it is impossible
should exist so separated; or that I can frame a general notion,
by abstracting from particulars in the manner aforesaid--which
last are the two proper acceptations of ABSTRACTION. And there is
ground to think most men will acknowledge themselves to be in my
case. The generality of men which are simple and illiterate never
pretend to ABSTRACT NOTIONS. It is said they are difficult and
not to be attained without pains and study; we may therefore
reasonably conclude that, if such there be, they are confined
only to the learned.

"I proceed to examine what can be alleged in defence of the
doctrine of abstraction, and try if I can discover what it is
that inclines the men of speculation to embrace an opinion so
remote from common sense as that seems to be. There has been a
late excellent and deservedly esteemed philosopher who, no doubt,
has given it very much countenance, by seeming to think the
having abstract general ideas is what puts the widest difference
in point of understanding betwixt man and beast. 'The having of
general ideas,' saith he, 'is that which puts a perfect
distinction betwixt man and brutes, and is an excellency which
the faculties of brutes do by no means attain unto. For, it is
evident we observe no footsteps in them of making use of general
signs for universal ideas; from which we have reason to imagine
that they have not the faculty of abstracting, or making general
ideas, since they have no use of words or any other general
signs.' And a little after: 'Therefore, I think, we may suppose
that it is in this that the species of brutes are discriminated
from men, and it is that proper difference wherein they are
wholly separated, and which at last widens to so wide a distance.
For, if they have any ideas at all, and are not bare machines (as
some would have them), we cannot deny them to have some reason.
It seems as evident to me that they do, some of them, in certain
instances reason as that they have sense; but it is only in
particular ideas, just as they receive them from their senses.
They are the best of them tied up within those narrow bounds, and
have not (as I think) the faculty to enlarge them by any kind of
abstraction.* ("Essay on Human Understanding," Bk. II, chap. xi,
paragraphs 10 and 11.) I readily agree with this learned author,
that the faculties of brutes can by no means attain to
abstraction. But, then, if this be made the distinguishing
property of that sort of animals, I fear a great many of those
that pass for men must be reckoned into their number. The reason
that is here assigned why we have no grounds to think brutes have
abstract general ideas is, that we observe in them no use of
words or any other general signs; which is built on this
supposition-that the making use of words implies the having
general ideas. From which it follows that men who use language
are able to abstract or generalize their ideas. That this is the
sense and arguing of the author will further appear by his
answering the question he in another place puts: 'Since all
things that exist are only particulars, how come we by general
terms?' His answer is: 'Words become general by being made the
signs of general ideas.' ("Essay on Human Understanding," Bk.
III, chap. III, paragraph 6.) But it seems that a word becomes
general by being made the sign, not of an abstract general idea,
but of several particular ideas, any one of which it
indifferently suggests to the mind. For example, when it is said
'the change of motion is proportional to the impressed force,' or
that 'whatever has extension is divisible,' these propositions
are to be understood of motion and extension in general; and
nevertheless it will not follow that they suggest to my thoughts
an idea of motion without a body moved, or any determinate
direction and velocity, or that I must conceive an abstract
general idea of extension, which is neither line, surface, nor
solid, neither great nor small, black, white, nor red, nor of any
other determinate colour. It is only implied that whatever
particular motion I consider, whether it be swift or slow,
perpendicular, horizontal, or oblique, or in whatever object, the
axiom concerning it holds equally true. As does the other of
every particular extension, it matters not whether line, surface,
or solid, whether of this or that magnitude or figure.

"By observing how ideas become general, we may the better judge
how words are made so. And here it is to be noted that I do not
deny absolutely there are general ideas, but only that there are
any ABSTRACT general ideas; for, in the passages we have quoted
wherein there is mention of general ideas, it is always supposed
that they are formed by abstraction, after the manner set forth
in sections 8 and 9. Now, if we will annex a meaning to our
words, and speak only of what we can conceive, I believe we shall
acknowledge that an idea which, considered in itself, is
particular, becomes general by being made to represent or stand
for all other particular ideas of the same sort. To make this
plain by an example, suppose a geometrician is demonstrating the
method of cutting a line in two equal parts. He draws, for
instance, a black line of an inch in length: this, which in
itself is a particular line, is nevertheless with regard to its
signification general, since, as it is there used, it represents
all particular lines whatsoever; so that what is demonstrated of
it is demonstrated of all lines, or, in other words, of a line in
general. And, as THAT PARTICULAR LINE becomes general by being
made a sign, so the NAME 'line,' which taken absolutely is
particular, by being a sign is made general. And as the former
owes its generality not to its being the sign of an abstract or
general line, but of all particular right lines that may possibly
exist, so the latter must be thought to derive its generality
from the same cause, namely, the various particular lines which
it indifferently denotes." *

* Introduction to "A Treatise concerning the Principles of Human
Knowledge," paragraphs 10, 11, and 12.

Berkeley's view in the above passage, which is essentially the
same as Hume's, does not wholly agree with modern psychology,
although it comes nearer to agreement than does the view of those
who believe that there are in the mind single contents which can
be called abstract ideas. The way in which Berkeley's view is
inadequate is chiefly in the fact that images are as a rule not
of one definite prototype, but of a number of related similar
prototypes. On this subject Semon has written well. In "Die
Mneme," pp. 217 ff., discussing the effect of repeated similar
stimuli in producing and modifying our images, he says: "We
choose a case of mnemic excitement whose existence we can
perceive for ourselves by introspection, and seek to ekphore the
bodily picture of our nearest relation in his absence, and have
thus a pure mnemic excitement before us. At first it may seem to
us that a determinate quite concrete picture becomes manifest in
us, but just when we are concerned with a person with whom we are
in constant contact, we shall find that the ekphored picture has
something so to speak generalized. It is something like those
American photographs which seek to display what is general about
a type by combining a great number of photographs of different
heads over each other on one plate. In our opinion, the
generalizations happen by the homophonic working of different
pictures of the same face which we have come across in the most
different conditions and situations, once pale, once reddened,
once cheerful, once earnest, once in this light, and once in
that. As soon as we do not let the whole series of repetitions
resound in us uniformly, but give our attention to one particular
moment out of the many... this particular mnemic stimulus at once
overbalances its simultaneously roused predecessors and
successors, and we perceive the face in question with concrete
definiteness in that particular situation." A little later he
says: "The result is--at least in man, but probably also in the
higher animals--the development of a sort of PHYSIOLOGICAL
abstraction. Mnemic homophony gives us, without the addition of
other processes of thought, a picture of our friend X which is in
a certain sense abstract, not the concrete in any one situation,
but X cut loose from any particular point of time. If the circle
of ekphored engrams is drawn even more widely, abstract pictures
of a higher order appear: for instance, a white man or a negro.
In my opinion, the first form of abstract concepts in general is
based upon such abstract pictures. The physiological abstraction
which takes place in the above described manner is a predecessor
of purely logical abstraction. It is by no means a monopoly of
the human race, but shows itself in various ways also among the
more highly organized animals." The same subject is treated in
more detail in Chapter xvi of "Die mnemischen Empfindungen," but
what is said there adds nothing vital to what is contained in the
above quotations.

It is necessary, however, to distinguish between the vague and
the general. So long as we are content with Semon's composite
image, we MAY get no farther than the vague. The question whether
this image takes us to the general or not depends, I think, upon
the question whether, in addition to the generalized image, we
have also particular images of some of the instances out of which
it is compounded. Suppose, for example, that on a number of
occasions you had seen one negro, and that you did not know
whether this one was the same or different on the different
occasions. Suppose that in the end you had an abstract
memory-image of the different appearances presented by the negro
on different occasions, but no memory-image of any one of the
single appearances. In that case your image would be vague. If,
on the other hand, you have, in addition to the generalized
image, particular images of the several appearances, sufficiently
clear to be recognized as different, and as instances of the
generalized picture, you will then not feel the generalized
picture to be adequate to any one particular appearance, and you
will be able to make it function as a general idea rather than a
vague idea. If this view is correct, no new general content needs
to be added to the generalized image. What needs to be added is
particular images compared and contrasted with the generalized
image. So far as I can judge by introspection, this does occur in
practice. Take for example Semon's instance of a friend's face.
Unless we make some special effort of recollection, the face is
likely to come before us with an average expression, very blurred
and vague, but we can at will recall how our friend looked on
some special occasion when he was pleased or angry or unhappy,
and this enables us to realize the generalized character of the
vague image.

There is, however, another way of distinguishing between the
vague, the particular and the general, and this is not by their
content, but by the reaction which they produce. A word, for
example, may be said to be vague when it is applicable to a
number of different individuals, but to each as individuals; the
name Smith, for example, is vague: it is always meant to apply to
one man, but there are many men to each of whom it applies.* The
word "man," on the other hand, is general. We say, "This is
Smith," but we do not say "This is man," but "This is a man."
Thus we may say that a word embodies a vague idea when its
effects are appropriate to an individual, but are the same for
various similar individuals, while a word embodies a general idea
when its effects are different from those appropriate to
individuals. In what this difference consists it is, however, not
easy to say. I am inclined to think that it consists merely in
the knowledge that no one individual is represented, so that what
distinguishes a general idea from a vague idea is merely the
presence of a certain accompanying belief. If this view is
correct, a general idea differs from a vague one in a way
analogous to that in which a memory-image differs from an
imagination-image. There also we found that the difference
consists merely of the fact that a memory-image is accompanied by
a belief, in this case as to the past.

* "Smith" would only be a quite satisfactory representation of
vague words if we failed to discriminate between different people
called Smith.

It should also be said that our images even of quite particular
occurrences have always a greater or a less degree of vagueness.
That is to say, the occurrence might have varied within certain
limits without causing our image to vary recognizably. To arrive
at the general it is necessary that we should be able to contrast
it with a number of relatively precise images or words for
particular occurrences; so long as all our images and words are
vague, we cannot arrive at the contrast by which the general is
defined. This is the justification for the view which I quoted on
p. 184 from Ribot (op. cit., p. 32), viz. that intelligence
progresses from the indefinite to the definite, and that the
vague appears earlier than either the particular or the general.

I think the view which I have been advocating, to the effect that
a general idea is distinguished from a vague one by the presence
of a judgment, is also that intended by Ribot when he says (op.
cit., p. 92): "The generic image is never, the concept is always,
a judgment. We know that for logicians (formerly at any rate) the
concept is the simple and primitive element; next comes the
judgment, uniting two or several concepts; then ratiocination,
combining two or several judgments. For the psychologists, on the
contrary, affirmation is the fundamental act; the concept is the
result of judgment (explicit or implicit), of similarities with
exclusion of differences."

A great deal of work professing to be experimental has been done
in recent years on the psychology of thought. A good summary of
such work up to the year agog is contained in Titchener's
"Lectures on the Experimental Psychology of the Thought
Processes" (1909). Three articles in the "Archiv fur die gesammte
Psychologie" by Watt,* Messer** and Buhler*** contain a great
deal of the material amassed by the methods which Titchener calls

* Henry J. Watt, "Experimentelle Beitrage zu einer Theorie des
Denkens," vol. iv (1905) pp. 289-436.

** August Messer, "Experimentell-psychologische Untersuchu gen
uber das Denken," vol. iii (1906), pp. 1-224.

*** Karl Buhler, "Uber Gedanken," vol. ix (1907), pp. 297-365.

For my part I am unable to attach as much importance to this work
as many psychologists do. The method employed appears to me
hardly to fulfil the conditions of scientific experiment. Broadly
speaking, what is done is, that a set of questions are asked of
various people, their answers are recorded, and likewise their
own accounts, based upon introspection, of the processes of
thought which led them to give those answers. Much too much
reliance seems to me to be placed upon the correctness of their
introspection. On introspection as a method I have spoken earlier
(Lecture VI). I am not prepared, like Professor Watson, to reject
it wholly, but I do consider that it is exceedingly fallible and
quite peculiarly liable to falsification in accordance with
preconceived theory. It is like depending upon the report of a
shortsighted person as to whom he sees coming along the road at a
moment when he is firmly convinced that Jones is sure to come. If
everybody were shortsighted and obsessed with beliefs as to what
was going to be visible, we might have to make the best of such
testimony, but we should need to correct its errors by taking
care to collect the simultaneous evidence of people with the most
divergent expectations. There is no evidence that this was done
in the experiments in question, nor indeed that the influence of
theory in falsifying the introspection was at all adequately
recognized. I feel convinced that if Professor Watson had been
one of the subjects of the questionnaires, he would have given
answers totally different from those recorded in the articles in
question. Titchener quotes an opinion of Wundt on these
investigations, which appears to me thoroughly justified. "These
experiments," he says, "are not experiments at all in the sense
of a scientific methodology; they are counterfeit experiments,
that seem methodical simply because they are ordinarily performed
in a psychological laboratory, and involve the co-operation of
two persons, who purport to be experimenter and observer. In
reality, they are as unmethodical as possible; they possess none
of the special features by which we distinguish the
introspections of experimental psychology from the casual
introspections of everyday life."* Titchener, of course, dissents
from this opinion, but I cannot see that his reasons for dissent
are adequate. My doubts are only increased by the fact that
Buhler at any rate used trained psychologists as his subjects. A
trained psychologist is, of course, supposed to have acquired the
habit of observation, but he is at least equally likely to have
acquired a habit of seeing what his theories require. We may take
Buhler's "Uber Gedanken" to illustrate the kind of results
arrived at by such methods. Buhler says (p. 303): "We ask
ourselves the general question: 'WHAT DO WE EXPERIENCE WHEN WE
THINK?' Then we do not at all attempt a preliminary determination
of the concept 'thought,' but choose for analysis only such
processes as everyone would describe as processes of thought."
The most important thing in thinking, he says, is "awareness
that..." (Bewusstheit dass), which he calls a thought. It is, he
says, thoughts in this sense that are essential to thinking.
Thinking, he maintains, does not need language or sensuous
presentations. "I assert rather that in principle every object
can be thought (meant) distinctly, without any help from sensuous
presentation (Anschauungshilfen). Every individual shade of blue
colour on the picture that hangs in my room I can think with
complete distinctness unsensuously (unanschaulich), provided it
is possible that the object should be given to me in another
manner than by the help of sensations. How that is possible we
shall see later." What he calls a thought (Gedanke) cannot be
reduced, according to him, to other psychic occurrences. He
maintains that thoughts consist for the most part of known rules
(p. 342). It is clearly essential to the interest of this theory
that the thought or rule alluded to by Buhler should not need to
be expressed in words, for if it is expressed in words it is
immediately capable of being dealt with on the lines with which
the behaviourists have familiarized us. It is clear also that the
supposed absence of words rests solely upon the introspective
testimony of the persons experimented upon. I cannot think that
there is sufficient certainty of their reliability in this
negative observation to make us accept a difficult and
revolutionary view of thought, merely because they have failed to
observe the presence of words or their equivalent in their
thinking. I think it far more likely, especially in view of the
fact that the persons concerned were highly educated, that we are
concerned with telescoped processes, in which habit has caused a
great many intermediate terms to be elided or to be passed over
so quickly as to escape observation.

* Titchener, op. cit., p. 79.

I am inclined to think that similar remarks apply to the general
idea of "imageless thinking," concerning which there has been
much controversy. The advocates of imageless thinking are not
contending merely that there can be thinking which is purely
verbal; they are contending that there can be thinking which
proceeds neither in words nor in images. My own feeling is that
they have rashly assumed the presence of thinking in cases where
habit has rendered thinking unnecessary. When Thorndike
experimented with animals in cages, he found that the
associations established were between a sensory stimulus and a
bodily movement (not the idea of it), without the need of
supposing any non-physiological intermediary (op. cit., p. 100
ff.). The same thing, it seems to me, applies to ourselves. A
certain sensory situation produces in us a certain bodily
movement. Sometimes this movement consists in uttering words.
Prejudice leads us to suppose that between the sensory stimulus
and the utterance of the words a process of thought must have
intervened, but there seems no good reason for such a
supposition. Any habitual action, such as eating or dressing, may
be performed on the appropriate occasion, without any need of
thought, and the same seems to be true of a painfully large
proportion of our talk. What applies to uttered speech applies of
course equally to the internal speech which is not uttered. I
remain, therefore, entirely unconvinced that there is any such
phenomenon as thinking which consists neither of images nor of
words, or that "ideas" have to be added to sensations and images
as part of the material out of which mental phenomena are built.

The question of the nature of our consciousness of the universal
is much affected by our view as to the general nature of the
relation of consciousness to its object. If we adopt the view of
Brentano, according to which all mental content has essential
reference to an object, it is then natural to suppose that there
is some peculiar kind of mental content of which the object is a
universal, as oppose to a particular. According to this view, a
particular cat can be PERceived or imagined, while the universal
"cat" is CONceived. But this whole manner of viewing our dealings
with universals has to be abandoned when the relation of a mental
occurrence to its "object" is regarded as merely indirect and
causal, which is the view that we have adopted. The mental
content is, of course, always particular, and the question as to
what it "means" (in case it means anything) is one which cannot
be settled by merely examining the intrinsic character of the
mental content, but only by knowing its causal connections in the
case of the person concerned. To say that a certain thought
"means" a universal as opposed to either a vague or a particular,
is to say something exceedingly complex. A horse will behave in a
certain manner whenever he smells a bear, even if the smell is
derived from a bearskin. That is to say, any environment
containing an instance of the universal "smell of a bear"
produces closely similar behaviour in the horse, but we do not
say that the horse is conscious of this universal. There is
equally little reason to regard a man as conscious of the same
universal, because under the same circumstances he can react by
saying, "I smell a bear." This reaction, like that of the horse,
is merely closely similar on different occasions where the
environment affords instances of the same universal. Words of
which the logical meaning is universal can therefore be employed
correctly, without anything that could be called consciousness of
universals. Such consciousness in the only sense in which it can
be said to exist is a matter of reflective judgment consisting in
the observation of similarities and differences. A universal
never appears before the mind as a single object in the sort of
way in which something perceived appears. I THINK a logical
argument could be produced to show that universals are part of
the structure of the world, but they are an inferred part, not a
part of our data. What exists in us consists of various factors,
some open to external observation, others only visible to
introspection. The factors open to external observation are
primarily habits, having the peculiarity that very similar
reactions are produced by stimuli which are in many respects very
different from each other. Of this the reaction of the horse to
the smell of the bear is an instance, and so is the reaction of
the man who says "bear" under the same circumstances. The verbal
reaction is, of course, the most important from the point of view
of what may be called knowledge of universals. A man who can
always use the word "dog" when he sees a dog may be said, in a
certain sense, to know the meaning of the word "dog," and IN THAT
SENSE to have knowledge of the universal "dog." But there is, of
course, a further stage reached by the logician in which he not
merely reacts with the word "dog," but sets to work to discover
what it is in the environment that causes in him this almost
identical reaction on different occasions. This further stage
consists in knowledge of similarities and differences:
similarities which are necessary to the applicability of the word
"dog," and differences which are compatible with it. Our
knowledge of these similarities and differences is never
exhaustive, and therefore our knowledge of the meaning of a
universal is never complete.

In addition to external observable habits (including the habit of
words), there is also the generic image produced by the
superposition, or, in Semon's phrase, homophony, of a number of
similar perceptions. This image is vague so long as the
multiplicity of its prototypes is not recognized, but becomes
universal when it exists alongside of the more specific images of
its instances, and is knowingly contrasted with them. In this
case we find again, as we found when we were discussing words in
general in the preceding lecture, that images are not logically
necessary in order to account for observable behaviour, i.e. in
this case intelligent speech. Intelligent speech could exist as a
motor habit, without any accompaniment of images, and this
conclusion applies to words of which the meaning is universal,
just as much as to words of which the meaning is relatively
particular. If this conclusion is valid, it follows that
behaviourist psychology, which eschews introspective data, is
capable of being an independent science, and of accounting for
all that part of the behaviour of other people which is commonly
regarded as evidence that they think. It must be admitted that
this conclusion considerably weakens the reliance which can be
placed upon introspective data. They must be accepted simply on
account of the fact that we seem to perceive them, not on account
of their supposed necessity for explaining the data of external

This, at any rate, is the conclusion to which. we are forced, so
long as, with the behaviourists, we accept common-sense views of
the physical world. But if, as I have urged, the physical world
itself, as known, is infected through and through with
subjectivity, if, as the theory of relativity suggests, the
physical universe contains the diversity of points of view which
we have been accustomed to regard as distinctively psychological,
then we are brought back by this different road to the necessity
for trusting observations which are in an important sense
private. And it is the privacy of introspective data which causes
much of the behaviourists' objection to them.

This is an example of the difficulty of constructing an adequate
philosophy of any one science without taking account of other
sciences. The behaviourist philosophy of psychology, though in
many respects admirable from the point of view of method, appears
to me to fail in the last analysis because it is based upon an
inadequate philosophy of physics. In spite, therefore, of the
fact that the evidence for images, whether generic or particular,
is merely introspective, I cannot admit that images should be
rejected, or that we should minimize their function in our
knowledge of what is remote in time or space.

download audio

Belief, which is our subject to-day, is the central problem in
the analysis of mind. Believing seems the most "mental" thing we
do, the thing most remote from what is done by mere matter. The
whole intellectual life consists of beliefs, and of the passage
from one belief to another by what is called "reasoning." Beliefs
give knowledge and error; they are the vehicles of truth and
falsehood. Psychology, theory of knowledge and metaphysics
revolve about belief, and on the view we take of belief our
philosophical outlook largely depends.

Before embarking upon the detailed analysis of belief, we shall
do well to note certain requisites which any theory must fulfil.

(1) Just as words are characterized by meaning, so beliefs are
characterized by truth or falsehood. And just as meaning consists
in relation to the object meant, so truth and falsehood consist
in relation to something that lies outside the belief. You may
believe that such-and-such a horse will win the Derby. The time
comes, and your horse wins or does not win; according to the
outcome, your belief was true or false. You may believe that six
times nine is fifty-six; in this case also there is a fact which
makes your belief false. You may believe that America was
discovered in 1492, or that it was discovered in 1066. In the one
case your belief is true, in the other false; in either case its
truth or falsehood depends upon the actions of Columbus, not upon
anything present or under your control. What makes a belief true
or false I call a "fact." The particular fact that makes a given
belief true or false I call its "objective,"* and the relation of
the belief to its objective I call the "reference" or the
"objective reference" of the belief. Thus, if I believe that
Columbus crossed the Atlantic in 1492, the "objective" of my
belief is Columbus's actual voyage, and the "reference" of my
belief is the relation between my belief and the voyage--that
relation, namely, in virtue of which the voyage makes my belief
true (or, in another case, false). "Reference" of beliefs differs
from "meaning" of words in various ways, but especially in the
fact that it is of two kinds, "true" reference and "false"
reference. The truth or falsehood of a belief does not depend
upon anything intrinsic to the belief, but upon the nature of its
relation to its objective. The intrinsic nature of belief can be
treated without reference to what makes it true or false. In the
remainder of the present lecture I shall ignore truth and
falsehood, which will be the subject of Lecture XIII. It is the
intrinsic nature of belief that will concern us to-day.

* This terminology is suggested by Meinong, but is not exactly
the same as his.

(2) We must distinguish between believing and what is believed. I
may believe that Columbus crossed the Atlantic, that all Cretans
are liars, that two and two are four, or that nine times six is
fifty-six; in all these cases the believing is just the same, and
only the contents believed are different. I may remember my
breakfast this morning, my lecture last week, or my first sight
of New York. In all these cases the feeling of memory-belief is
just the same, and only what is remembered differs. Exactly
similar remarks apply to expectations. Bare assent, memory and
expectation are forms of belief; all three are different from
what is believed, and each has a constant character which is
independent of what is believed.

In Lecture I we criticized the analysis of a presentation into
act, content and object. But our analysis of belief contains
three very similar elements, namely the believing, what is
believed and the objective. The objections to the act (in the
case of presentations) are not valid against the believing in the
case of beliefs, because the believing is an actual experienced
feeling, not something postulated, like the act. But it is
necessary first to complete our preliminary requisites, and then
to examine the content of a belief. After that, we shall be in a
position to return to the question as to what constitutes

(3) What is believed, and the believing, must both consist of
present occurrences in the believer, no matter what may be the
objective of the belief. Suppose I believe, for example, "that
Caesar crossed the Rubicon." The objective of my belief is an
event which happened long ago, which I never saw and do not
remember. This event itself is not in my mind when I believe that
it happened. It is not correct to say that I am believing the
actual event; what I am believing is something now in my mind,
something related to the event (in a way which we shall
investigate in Lecture XIII), but obviously not to be confounded
with the event, since the event is not occurring now but the
believing is. What a man is believing at a given moment is wholly
determinate if we know the contents of his mind at that moment;
but Caesar's crossing of the Rubicon was an historical physical
event, which is distinct from the present contents of every
present mind. What is believed, however true it may be, is not
the actual fact that makes the belief true, but a present event
related to the fact. This present event, which is what is
believed, I shall call the "content" of the belief. We have
already had occasion to notice the distinction between content
and objective in the case of memory-beliefs, where the content is
"this occurred" and the objective is the past event.

(4) Between content and objective there is sometimes a very wide
gulf, for example in the case of "Caesar crossed the Rubicon."
This gulf may, when it is first perceived, give us a feeling that
we cannot really " know " anything about the outer world. All we
can "know," it may be said, is what is now in our thoughts. If
Caesar and the Rubicon cannot be bodily in our thoughts, it might
seem as though we must remain cut off from knowledge of them. I
shall not now deal at length with this feeling, since it is
necessary first to define "knowing," which cannot be done yet.
But I will say, as a preliminary answer, that the feeling assumes
an ideal of knowing which I believe to be quite mistaken. ~ it
assumes, if it is thought out, something like the mystic unity of
knower and known. These two are often said to be combined into a
unity by the fact of cognition; hence when this unity is plainly
absent, it may seem as if there were no genuine cognition. For my
part, I think such theories and feelings wholly mistaken: I
believe knowing to be a very external and complicated relation,
incapable of exact definition, dependent upon causal laws, and
involving no more unity than there is between a signpost and the
town to which it points. I shall return to this question on a
later occasion; for the moment these provisional remarks must

(5) The objective reference of a belief is connected with the
fact that all or some of the constituents of its content have
meaning. If I say "Caesar conquered Gaul," a person who knows the
meaning of the three words composing my statement knows as much
as can be known about the nature of the objective which would
make my statement true. It is clear that the objective reference
of a belief is, in general, in some way derivative from the
meanings of the words or images that occur in its content. There
are, however, certain complications which must be borne in mind.
In the first place, it might be contended that a memory-image
acquires meaning only through the memory-belief, which would
seem, at least in the case of memory, to make belief more
primitive than the meaning of images. In the second place, it is
a very singular thing that meaning, which is single, should
generate objective reference, which is dual, namely true and
false. This is one of the facts which any theory of belief must
explain if it is to be satisfactory.

It is now time to leave these preliminary requisites, and attempt
the analysis of the contents of beliefs.

The first thing to notice about what is believed, i.e. about the
content of a belief, is that it is always complex: We believe
that a certain thing has a certain property, or a certain
relation to something else, or that it occurred or will occur (in
the sense discussed at the end of Lecture IX); or we may believe
that all the members of a certain class have a certain property,
or that a certain property sometimes occurs among the members of
a class; or we may believe that if one thing happens, another
will happen (for example, "if it rains I shall bring my
umbrella"), or we may believe that something does not happen, or
did not or will not happen (for example, "it won't rain"); or
that one of two things must happen (for example, "either you
withdraw your accusation, or I shall bring a libel action"). The
catalogue of the sorts of things we may believe is infinite, but
all of them are complex.

Language sometimes conceals the complexity of a belief. We say
that a person believes in God, and it might seem as if God formed
the whole content of the belief. But what is really believed is
that God exists, which is very far from being simple. Similarly,
when a person has a memory-image with a memory-belief, the belief
is "this occurred," in the sense explained in Lecture IX; and
"this occurred" is not simple. In like manner all cases where the
content of a belief seems simple at first sight will be found, on
examination, to confirm the view that the content is always

The content of a belief involves not merely a plurality of
constituents, but definite relations between them; it is not
determinate when its constituents alone are given. For example,
"Plato preceded Aristotle" and "Aristotle preceded Plato" are
both contents which may be believed, but, although they consist
of exactly the same constituents, they are different, and even

The content of a belief may consist of words only, or of images
only, or of a mixture of the two, or of either or both together
with one or more sensations. It must contain at least one
constituent which is a word or an image, and it may or may not
contain one or more sensations as constituents. Some examples
will make these various possibilities clear.

We may take first recognition, in either of the forms "this is of
such-and-such a kind" or "this has occurred before." In either
case, present sensation is a constituent. For example, you hear a
noise, and you say to yourself "tram." Here the noise and the
word "tram" are both constituents of your belief; there is also a
relation between them, expressed by "is" in the proposition "that
is a tram." As soon as your act of recognition is completed by
the occurrence of the word "tram," your actions are affected: you
hurry if you want the tram, or cease to hurry if you want a bus.
In this case the content of your belief is a sensation (the
noise) and a word ("tram") related in a way which may be called

The same noise may bring into your mind the visual image of a
tram, instead of the word "tram." In this case your belief
consists of a sensation and an image suitable related. Beliefs of
this class are what are called "judgments of perception." As we
saw in Lecture VIII, the images associated with a sensation often
come with such spontaneity and force that the unsophisticated do
not distinguish them from the sensation; it is only the
psychologist or the skilled observer who is aware of the large
mnemic element that is added to sensation to make perception. It
may be objected that what is added consists merely of images
without belief. This is no doubt sometimes the case, but is
certainly sometimes not the case. That belief always occurs in
perception as opposed to sensation it is not necessary for us to
maintain; it is enough for our purposes to note that it sometimes
occurs, and that when it does, the content of our belief consists
of a sensation and an image suitably related.

In a PURE memory-belief only images occur. But a mixture of words
and images is very common in memory. You have an image of the
past occurrence, and you say to yourself: "Yes, that's how it
was." Here the image and the words together make up the content
of the belief. And when the remembering of an incident has become
a habit, it may be purely verbal, and the memory-belief may
consist of words alone.

The more complicated forms of belief tend to consist only of
words. Often images of various kinds accompany them, but they are
apt to be irrelevant, and to form no part of what is actually
believed. For example, in thinking of the Solar System, you are
likely to have vague images of pictures you have seen of the
earth surrounded by clouds, Saturn and his rings, the sun during
an eclipse, and so on; but none of these form part of your belief
that the planets revolve round the sun in elliptical orbits. The
only images that form an actual part of such beliefs are, as a
rule, images of words. And images of words, for the reasons
considered in Lecture VIII, cannot be distinguished with any
certainty from sensations, when, as is often, if not usually, the
case, they are kinaesthetic images of pronouncing the words.

It is impossible for a belief to consist of sensations alone,
except when, as in the case of words, the sensations have
associations which make them signs possessed of meaning. The
reason is that objective reference is of the essence of belief,
and objective reference is derived from meaning. When I speak of
a belief consisting partly of sensations and partly of words, I
do not mean to deny that the words, when they are not mere
images, are sensational, but that they occur as signs, not (so to
speak) in their own right. To revert to the noise of the tram,
when you hear it and say "tram," the noise and the word are both
sensations (if you actually pronounce the word), but the noise is
part of the fact which makes your belief true, whereas the word
is not part of this fact. It is the MEANING of the word "tram,"
not the actual word, that forms part of the fact which is the
objective of your belief. Thus the word occurs in the belief as a
symbol, in virtue of its meaning, whereas the noise enters into
both the belief and its objective. It is this that distinguishes
the occurrence of words as symbols from the occurrence of
sensations in their own right: the objective contains the
sensations that occur in their own right, but contains only the
meanings of the words that occur as symbols.

For the sake of simplicity, we may ignore the cases in which
sensations in their own right form part of the content of a
belief, and confine ourselves to images and words. We may also
omit the cases in which both images and words occur in the
content of a belief. Thus we become confined to two cases: (a)
when the content consists wholly of images, (b) when it consists
wholly of words. The case of mixed images and words has no
special importance, and its omission will do no harm.

Let us take in illustration a case of memory. Suppose you are
thinking of some familiar room. You may call up an image of it,
and in your image the window may be to the left of the door.
Without any intrusion of words, you may believe in the
correctness of your image. You then have a belief, consisting
wholly of images, which becomes, when put into words, "the window
is to the left of the door." You may yourself use these words and
proceed to believe them. You thus pass from an image-content to
the corresponding word-content. The content is different in the
two cases, but its objective reference is the same. This shows
the relation of image-beliefs to word-beliefs in a very simple
case. In more elaborate cases the relation becomes much less

It may be said that even in this very simple case the objective
reference of the word-content is not quite the same as that of
the image-content, that images have a wealth of concrete features
which are lost when words are substituted, that the window in the
image is not a mere window in the abstract, but a window of a
certain shape and size, not merely to the left of the door, but a
certain distance to the left, and so on. In reply, it may be
admitted at once that there is, as a rule, a certain amount of
truth in the objection. But two points may be urged to minimize
its force. First, images do not, as a rule, have that wealth of
concrete detail that would make it IMPOSSIBLE to express them
fully in words. They are vague and fragmentary: a finite number
of words, though perhaps a large number, would exhaust at least
their SIGNIFICANT features. For--and this is our second
point--images enter into the content of a belief through the fact
that they are capable of meaning, and their meaning does not, as
a rule, have as much complexity as they have: some of their
characteristics are usually devoid of meaning. Thus it may well
be possible to extract in words all that has meaning in an
image-content; in that case the word-content and the
image-content will have exactly the same objective reference.

The content of a belief, when expressed in words, is the same
thing (or very nearly the same thing) as what in logic is called
a "proposition." A proposition is a series of words (or sometimes
a single word) expressing the kind of thing that can be asserted
or denied. "That all men are mortal," "that Columbus discovered
America," "that Charles I died in his bed," "that all
philosophers are wise," are propositions. Not any series of words
is a proposition, but only such series of words as have
"meaning," or, in our phraseology, "objective reference." Given
the meanings of separate words, and the rules of syntax, the
meaning of a proposition is determinate. This is the reason why
we can understand a sentence we never heard before. You probably
never heard before the proposition "that the inhabitants of the
Andaman Islands habitually eat stewed hippopotamus for dinner,"
but there is no difficulty in understanding the proposition. The
question of the relation between the meaning of a sentence and
the meanings of the separate words is difficult, and I shall not
pursue it now; I brought it up solely as being illustrative of
the nature of propositions.

We may extend the term "proposition" so as to cover the
image-contents of beliefs consisting of images. Thus, in the case
of remembering a room in which the window is to the left of the
door, when we believe the image-content the proposition will
consist of the image of the window on the left together with the
image of the door on the right. We will distinguish propositions
of this kind as "image-propositions" and propositions in words as
"word-propositions." We may identify propositions in general with
the contents of actual and possible beliefs, and we may say that
it is propositions that are true or false. In logic we are
concerned with propositions rather than beliefs, since logic is
not interested in what people do in fact believe, but only in the
conditions which determine the truth or falsehood of possible
beliefs. Whenever possible, except when actual beliefs are in
question, it is generally a simplification to deal with

It would seem that image-propositions are more primitive than
word-propositions, and may well ante-date language. There is no
reason why memory-images, accompanied by that very simple
belief-feeling which we decided to be the essence of memory,
should not have occurred before language arose; indeed, it would
be rash to assert positively that memory of this sort does not
occur among the higher animals. Our more elementary beliefs,
notably those that are added to sensation to make perception,
often remain at the level of images. For example, most of the
visual objects in our neighbourhood rouse tactile images: we have
a different feeling in looking at a sofa from what we have in
looking at a block of marble, and the difference consists chiefly
in different stimulation of our tactile imagination. It may be
said that the tactile images are merely present, without any
accompanying belief; but I think this view, though sometimes
correct, derives its plausibility as a general proposition from
our thinking of explicit conscious belief only. Most of our
beliefs, like most of our wishes, are "unconscious," in the sense
that we have never told ourselves that we have them. Such beliefs
display themselves when the expectations that they arouse fail in
any way. For example, if someone puts tea (without milk) into a
glass, and you drink it under the impression that it is going to
be beer; or if you walk on what appears to be a tiled floor, and
it turns out to be a soft carpet made to look like tiles. The
shock of surprise on an occasion of this kind makes us aware of
the expectations that habitually enter into our perceptions; and
such expectations must be classed as beliefs, in spite of the
fact that we do not normally take note of them or put them into
words. I remember once watching a cock pigeon running over and
over again to the edge of a looking-glass to try to wreak
vengeance on the particularly obnoxious bird whom he expected to
find there, judging by what he saw in the glass. He must have
experienced each time the sort of surprise on finding nothing,
which is calculated to lead in time to the adoption of Berkeley's
theory that objects of sense are only in the mind. His
expectation, though not expressed in words, deserved, I think, to
be called a belief.

I come now to the question what constitutes believing, as opposed
to the content believed.

To begin with, there are various different attitudes that may be
taken towards the same content. Let us suppose, for the sake of
argument, that you have a visual image of your breakfast-table.
You may expect it while you are dressing in the morning; remember
it as you go to your work; feel doubt as to its correctness when
questioned as to your powers of visualizing; merely entertain the
image, without connecting it with anything external, when you are
going to sleep; desire it if you are hungry, or feel aversion for
it if you are ill. Suppose, for the sake of definiteness, that
the content is "an egg for breakfast." Then you have the
following attitudes "I expect there will be an egg for
breakfast"; "I remember there was an egg for breakfast"; "Was
there an egg for breakfast?" "An egg for breakfast: well, what of
it?" "I hope there will be an egg for breakfast"; "I am afraid
there will be an egg for breakfast and it is sure to be bad." I
do not suggest that this is a list of all possible attitudes on
the subject; I say only that they are different attitudes, all
concerned with the one content "an egg for breakfast."

These attitudes are not all equally ultimate. Those that involve
desire and aversion have occupied us in Lecture III. For the
present, we are only concerned with such as are cognitive. In
speaking of memory, we distinguished three kinds of belief
directed towards the same content, namely memory, expectation and
bare assent without any time-determination in the belief-feeling.
But before developing this view, we must examine two other
theories which might be held concerning belief, and which, in
some ways, would be more in harmony with a behaviourist outlook
than the theory I wish to advocate.

(1) The first theory to be examined is the view that the
differentia of belief consists in its causal efficacy I do not
wish to make any author responsible for this theory: I wish
merely to develop it hypothetically so that we may judge of its

We defined the meaning of an image or word by causal efficacy,
namely by associations: an image or word acquires meaning, we
said, through having the same associations as what it means.

We propose hypothetically to define "belief" by a different kind
of causal efficacy, namely efficacy in causing voluntary
movements. (Voluntary movements are defined as those vital
movements which are distinguished from reflex movements as
involving the higher nervous centres. I do not like to
distinguish them by means of such notions as "consciousness" or
"will," because I do not think these notions, in any definable
sense, are always applicable. Moreover, the purpose of the theory
we are examining is to be, as far as possible, physiological and
behaviourist, and this purpose is not achieved if we introduce
such a conception as "consciousness" or "will." Nevertheless, it
is necessary for our purpose to find some way of distinguishing
between voluntary and reflex movements, since the results would
be too paradoxical, if we were to say that reflex movements also
involve beliefs.) According to this definition, a content is said
to be "believed" when it causes us to move. The images aroused
are the same if you say to me, "Suppose there were an escaped
tiger coming along the street," and if you say to me, "There is
an escaped tiger coming along the street." But my actions will be
very different in the two cases: in the first, I shall remain
calm; in the second, it is possible that I may not. It is
suggested, by the theory we are considering, that this difference
of effects constitutes what is meant by saying that in the second
case I believe the proposition suggested, while in the first case
I do not. According to this view, images or words are "believed"
when they cause bodily movements.

I do not think this theory is adequate, but I think it is
suggestive of truth, and not so easily refutable as it might
appear to be at first sight.

It might be objected to the theory that many things which we
certainly believe do not call for any bodily movements. I believe
that Great Britain is an island, that whales are mammals, that
Charles I was executed, and so on; and at first sight it seems
obvious that such beliefs, as a rule, do not call for any action
on my part. But when we investigate the matter more closely, it
becomes more doubtful. To begin with, we must distinguish belief
as a mere DISPOSITION from actual active belief. We speak as if
we always believed that Charles I was executed, but that only
means that we are always ready to believe it when the subject
comes up. The phenomenon we are concerned to analyse is the
active belief, not the permanent disposition. Now, what are the
occasions when, we actively believe that Charles I was executed?
Primarily: examinations, when we perform the bodily movement of
writing it down; conversation, when we assert it to display our
historical erudition; and political discourses, when we are
engaged in showing what Soviet government leads to. In all these
cases bodily movements (writing or speaking) result from our

But there remains the belief which merely occurs in "thinking."
One may set to work to recall some piece of history one has been
reading, and what one recalls is believed, although it probably
does not cause any bodily movement whatever. It is true that what
we believe always MAY influence action. Suppose I am invited to
become King of Georgia: I find the prospect attractive, and go to
Cook's to buy a third-class ticket to my new realm. At the last
moment I remember Charles I and all the other monarchs who have
come to a bad end; I change my mind, and walk out without
completing the transaction. But such incidents are rare, and
cannot constitute the whole of my belief that Charles I was
executed. The conclusion seems to be that, although a belief
always MAY influence action if it becomes relevant to a practical
issue, it often exists actively (not as a mere disposition)
without producing any voluntary movement whatever. If this is
true, we cannot define belief by the effect on voluntary

There is another, more theoretical, ground for rejecting the view
we are examining. It is clear that a proposition can be either
believed or merely considered, and that the content is the same
in both cases. We can expect an egg for breakfast, or merely
entertain the supposition that there may be an egg for breakfast.
A moment ago I considered the possibility of being invited to
become King of Georgia, but I do not believe that this will
happen. Now, it seems clear that, since believing and considering
have different effects if one produces bodily movements while the
other does not, there must be some intrinsic difference between
believing and considering*; for if they were precisely similar,
their effects also would be precisely similar. We have seen that
the difference between believing a given proposition and merely
considering it does not lie in the content; therefore there must
be, in one case or in both, something additional to the content
which distinguishes the occurrence of a belief from the
occurrence of a mere consideration of the same content. So far as
the theoretical argument goes, this additional element may exist
only in belief, or only in consideration, or there may be one
sort of additional element in the case of belief, and another in
the case of consideration. This brings us to the second view
which we have to examine.

* Cf. Brentano, "Psychologie vom empirischen Standpunkte," p. 268
(criticizing Bain, "The Emotions and the Will").

(1) The theory which we have now to consider regards belief as
belonging to every idea which is entertained, except in so far as
some positive counteracting force interferes. In this view belief
is not a positive phenomenon, though doubt and disbelief are so.
What we call belief, according to this hypothesis, involves only
the appropriate content, which will have the effects
characteristic of belief unless something else operating
simultaneously inhibits them. James (Psychology, vol. ii, p. 288)
quotes with approval, though inaccurately, a passage from Spinoza
embodying this view:

"Let us conceive a boy imagining to himself a horse, and taking
note of nothing else. As this imagination involves the existence
EXISTENCE [James's italics], he will necessarily contemplate the
horse as present, nor will he be able to doubt of its existence,
however little certain of it he may be. I deny that a man in so
far as he imagines [percipit] affirms nothing. For what is it to
imagine a winged horse but to affirm that the horse [that horse,
namely] has wings? For if the mind had nothing before it but the
winged horse, it would contemplate the same as present, would
have no cause to doubt of its existence, nor any power of
dissenting from its existence, unless the imagination of the
winged horse were joined to an idea which contradicted [tollit]
its existence" ("Ethics," vol. ii, p. 49, Scholium).

To this doctrine James entirely assents, adding in italics:


If this view is correct, it follows (though James does not draw
the inference) that there is no need of any specific feeling
called "belief," and that the mere existence of images yields all
that is required. The state of mind in which we merely consider a
proposition, without believing or disbelieving it, will then
appear as a sophisticated product, the result of some rival force
adding to the image-proposition a positive feeling which may be
called suspense or non-belief--a feeling which may be compared to
that of a man about to run a race waiting for the signal. Such a
man, though not moving, is in a very different condition from
that of a man quietly at rest And so the man who is considering a
proposition without believing it will be in a state of tension,
restraining the natural tendency to act upon the proposition
which he would display if nothing interfered. In this view belief
primarily consists merely in the existence of the appropriate
images without any counteracting forces.

There is a great deal to be said in favour of this view, and I
have some hesitation in regarding it as inadequate. It fits
admirably with the phenomena of dreams and hallucinatory images,
and it is recommended by the way in which it accords with mental
development. Doubt, suspense of judgment and disbelief all seem
later and more complex than a wholly unreflecting assent. Belief
as a positive phenomenon, if it exists, may be regarded, in this
view, as a product of doubt, a decision after debate, an
acceptance, not merely of THIS, but of THIS-RATHER-THAN-THAT. It
is not difficult to suppose that a dog has images (possible
olfactory) of his absent master, or of the rabbit that he dreams
of hunting. But it is very difficult to suppose that he can
entertain mere imagination-images to which no assent is given.

I think it must be conceded that a mere image, without the
addition of any positive feeling that could be called "belief,"
is apt to have a certain dynamic power, and in this sense an
uncombated image has the force of a belief. But although this may
be true, it accounts only for some of the simplest phenomena in
the region of belief. It will not, for example, explain memory.
Nor can it explain beliefs which do not issue in any proximate
action, such as those of mathematics. I conclude, therefore, that
there must be belief-feelings of the same order as those of doubt
or disbelief, although phenomena closely analogous to those of
belief can be produced by mere uncontradicted images.

(3) I come now to the view of belief which I wish to advocate. It
seems to me that there are at least three kinds of belief, namely
memory, expectation and bare assent. Each of these I regard as
constituted by a certain feeling or complex of sensations,
attached to the content believed. We may illustrate by an
example. Suppose I am believing, by means of images, not words,
that it will rain. We have here two interrelated elements, namely
the content and the expectation. The content consists of images
of (say) the visual appearance of rain, the feeling of wetness,
the patter of drops, interrelated, roughly, as the sensations
would be if it were raining. Thus the content is a complex fact
composed of images. Exactly the same content may enter into the
memory "it was raining" or the assent "rain occurs." The
difference of these cases from each other and from expectation
does not lie in the content. The difference lies in the nature of
the belief-feeling. I, personally, do not profess to be able to
analyse the sensations constituting respectively memory,
expectation and assent; but I am not prepared to say that they
cannot be analysed. There may be other belief-feelings, for
example in disjunction and implication; also a disbelief-feeling.

It is not enough that the content and the belief-feeling should
coexist: it is necessary that there should be a specific relation
between them, of the sort expressed by saying that the content is
what is believed. If this were not obvious, it could be made
plain by an argument. If the mere co-existence of the content and
the belief-feeling sufficed, whenever we were having (say) a
memory-feeling we should be remembering any proposition which
came into our minds at the same time. But this is not the case,
since we may simultaneously remember one proposition and merely
consider another.

We may sum up our analysis, in the case of bare assent to a
proposition not expressed in words, as follows: (a) We have a
proposition, consisting of interrelated images, and possibly
partly of sensations; (b) we have the feeling of assent, which is
presumably a complex sensation demanding analysis; (c) we have a
relation, actually subsisting, between the assent and the
proposition, such as is expressed by saying that the proposition
in question is what is assented to. For other forms of
belief-feeling or of content, we have only to make the necessary
substitutions in this analysis.

If we are right in our analysis of belief, the use of words in
expressing beliefs is apt to be misleading. There is no way of
distinguishing, in words, between a memory and an assent to a
proposition about the past: "I ate my breakfast" and "Caesar
conquered Gaul" have the same verbal form, though (assuming that
I remember my breakfast) they express occurrences which are
psychologically very different. In the one case, what happens is
that I remember the content "eating my breakfast"; in the other
case, I assent to the content "Caesar's conquest of Gaul
occurred." In the latter case, but not in the former, the
pastness is part of the content believed. Exactly similar remarks
apply to the difference between expectation, such as we have when
waiting for the thunder after a flash of lightning, and assent to
a proposition about the future, such as we have in all the usual
cases of inferential knowledge as to what will occur. I think
this difficulty in the verbal expression of the temporal aspects
of beliefs is one among the causes which have hampered philosophy
in the consideration of time.

The view of belief which I have been advocating contains little
that is novel except the distinction of kinds of belief-feeling~
such as memory and expectation. Thus James says: "Everyone knows
the difference between imagining a thing and believing in its
existence, between supposing a proposition and acquiescing in its
ELSE" ("Psychology," vol. ii, p. 283. James's italics). He
proceeds to point out that drunkenness, and, still more, nitrous-
oxide intoxication, will heighten the sense of belief: in the
latter case, he says, a man's very soul may sweat with
conviction, and he be all the time utterly unable to say what he
is convinced of. It would seem that, in such cases, the feeling
of belief exists unattached, without its usual relation to a
content believed, just as the feeling of familiarity may
sometimes occur without being related to any definite familiar
object. The feeling of belief, when it occurs in this separated
heightened form, generally leads us to look for a content to
which to attach it. Much of what passes for revelation or mystic
insight probably comes in this way: the belief-feeling, in
abnormal strength, attaches itself, more or less accidentally, to
some content which we happen to think of at the appropriate
moment. But this is only a speculation, upon which I do not wish
to lay too much stress.

download audio

The definition of truth and falsehood, which is our topic to-day,
lies strictly outside our general subject, namely the analysis of
mind. From the psychological standpoint, there may be different
kinds of belief, and different degrees of certainty, but there
cannot be any purely psychological means of distinguishing
between true and false beliefs. A belief is rendered true or
false by relation to a fact, which may lie outside the experience
of the person entertaining the belief. Truth and falsehood,
except in the case of beliefs about our own minds, depend upon
the relations of mental occurrences to outside things, and thus
take us beyond the analysis of mental occurrences as they are in
themselves. Nevertheless, we can hardly avoid the consideration
of truth and falsehood. We wish to believe that our beliefs,
sometimes at least, yield KNOWLEDGE, and a belief does not yield
knowledge unless it is true. The question whether our minds are
instruments of knowledge, and, if so, in what sense, is so vital
that any suggested analysis of mind must be examined in relation
to this question. To ignore this question would be like
describing a chronometer without regard to its accuracy as a
time-keeper, or a thermometer without mentioning the fact that it
measures temperature.

Many difficult questions arise in connection with knowledge. It
is difficult to define knowledge, difficult to decide whether we
have any knowledge, and difficult, even if it is conceded that we
sometimes have knowledge to discover whether we can ever know
that we have knowledge in this or that particular case. I shall
divide the discussion into four parts:

I. We may regard knowledge, from a behaviourist standpoint, as
exhibited in a certain kind of response to the environment. This
response must have some characteristics which it shares with
those of scientific instruments, but must also have others that
are peculiar to knowledge. We shall find that this point of view
is important, but not exhaustive of the nature of knowledge.

II. We may hold that the beliefs that constitute knowledge are
distinguished from such as are erroneous or uncertain by
properties which are intrinsic either to single beliefs or to
systems of beliefs, being in either case discoverable without
reference to outside fact. Views of this kind have been widely
held among philosophers, but we shall find no reason to accept

III. We believe that some beliefs are true, and some false. This
raises the problem of VERIFIABILITY: are there any circumstances
which can justifiably give us an unusual degree of certainty that
such and such a belief is true? It is obvious that there are
circumstances which in fact cause a certainty of this sort, and
we wish to learn what we can from examining these circumstances.

IV. Finally, there is the formal problem of defining truth and
falsehood, and deriving the objective reference of a proposition
from the meanings of its component words.

We will consider these four problems in succession.

I. We may regard a human being as an instrument, which makes
various responses to various stimuli. If we observe these
responses from outside, we shall regard them as showing knowledge
when they display two characteristics, ACCURACY and
APPROPRIATENESS. These two are quite distinct, and even sometimes
incompatible. If I am being pursued by a tiger, accuracy is
furthered by turning round to look at him, but appropriateness by
running away without making any search for further knowledge of
the beast. I shall return to the question of appropriateness
later; for the present it is accuracy that I wish to consider.

When we are viewing a man from the outside, it is not his
beliefs, but his bodily movements, that we can observe. His
knowledge must be inferred from his bodily movements, and
especially from what he says and writes. For the present we may
ignore beliefs, and regard a man's knowledge as actually
consisting in what he says and does. That is to say, we will
construct, as far as possible, a purely behaviouristic account of
truth and falsehood.

If you ask a boy "What is twice two?" and the boy says "four,"
you take that as prima facie evidence that the boy knows what
twice two is. But if you go on to ask what is twice three, twice
four, twice five, and so on, and the boy always answers "four,"
you come to the conclusion that he knows nothing about it.
Exactly similar remarks apply to scientific instruments. I know a
certain weather-cock which has the pessimistic habit of always
pointing to the north-east. If you were to see it first on a cold
March day, you would think it an excellent weather-cock; but with
the first warm day of spring your confidence would be shaken. The
boy and the weather-cock have the same defect: they do not vary
their response when the stimulus is varied. A good instrument, or
a person with much knowledge, will give different responses to
stimuli which differ in relevant ways. This is the first point in
defining accuracy of response.

We will now assume another boy, who also, when you first question
him, asserts that twice two is four. But with this boy, instead
of asking him different questions, you make a practice of asking
him the same question every day at breakfast. You find that he
says five, or six, or seven, or any other number at random, and
you conclude that he also does not know what twice two is, though
by good luck he answered right the first time. This boy is like a
weather-cock which, instead of being stuck fast, is always going
round and round, changing without any change of wind. This boy
and weather-cock have the opposite defect to that of the previous
pair: they give different responses to stimuli which do not
differ in any relevant way.

In connection with vagueness in memory, we already had occasion
to consider the definition of accuracy. Omitting some of the
niceties of our previous discussion, we may say that an
instrument is ACCURATE when it avoids the defects of the two boys
and weather-cocks, that is to say, when--

(a) It gives different responses to stimuli which differ in
relevant ways;

(b) It gives the same response to stimuli which do not differ in
relevant ways.

What are relevant ways depends upon the nature and purpose of the
instrument. In the case of a weather-cock, the direction of the
wind is relevant, but not its strength; in the case of the boy,
the meaning of the words of your question is relevant, but not
the loudness of your voice, or whether you are his father or his
schoolmaster If, however, you were a boy of his own age, that
would be relevant, and the appropriate response would be

It is clear that knowledge is displayed by accuracy of response
to certain kinds of stimuli, e.g. examinations. Can we say,
conversely, that it consists wholly of such accuracy of response?
I do not think we can; but we can go a certain distance in this
direction. For this purpose we must define more carefully the
kind of accuracy and the kind of response that may be expected
where there is knowledge.

From our present point of view, it is difficult to exclude
perception from knowledge; at any rate, knowledge is displayed by
actions based upon perception. A bird flying among trees avoids
bumping into their branches; its avoidance is a response to
visual sensations. This response has the characteristic of
accuracy, in the main, and leads us to say that the bird "knows,"
by sight, what objects are in its neighbourhood. For a
behaviourist, this must certainly count as knowledge, however it
may be viewed by analytic psychology. In this case, what is
known, roughly, is the stimulus; but in more advanced knowledge
the stimulus and what is known become different. For example, you
look in your calendar and find that Easter will be early next
year. Here the stimulus is the calendar, whereas the response
concerns the future. Even this can be paralleled among
instruments: the behaviour of the barometer has a present
stimulus but foretells the future, so that the barometer might be
said, in a sense, to know the future. However that may be, the
point I am emphasizing as regards knowledge is that what is known
may be quite different from the stimulus, and no part of the
cause of the knowledge-response. It is only in sense-knowledge
that the stimulus and what is known are, with qualifications,
identifiable. In knowledge of the future, it is obvious that they
are totally distinct, since otherwise the response would precede
the stimulus. In abstract knowledge also they are distinct, since
abstract facts have no date. In knowledge of the past there are
complications, which we must briefly examine.

Every form of memory will be, from our present point of view, in
one sense a delayed response. But this phrase does not quite
clearly express what is meant. If you light a fuse and connect it
with a heap of dynamite, the explosion of the dynamite may be
spoken of, in a sense, as a delayed response to your lighting of
the fuse. But that only means that it is a somewhat late portion
of a continuous process of which the earlier parts have less
emotional interest. This is not the case with habit. A display of
habit has two sorts of causes: (a) the past occurrences which
generated the habit, (b) the present occurrence which brings it
into play. When you drop a weight on your toe, and say what you
do say, the habit has been caused by imitation of your
undesirable associates, whereas it is brought into play by the
dropping of the weight. The great bulk of our knowledge is a
habit in this sense: whenever I am asked when I was born, I reply
correctly by mere habit. It would hardly be correct to say that
getting born was the stimulus, and that my reply is a delayed
response But in cases of memory this way of speaking would have
an element of truth. In an habitual memory, the event remembered
was clearly an essential part of the stimulus to the formation of
the habit. The present stimulus which brings the habit into play
produces a different response from that which it would produce if
the habit did not exist. Therefore the habit enters into the
causation of the response, and so do, at one remove, the causes
of the habit. It follows that an event remembered is an essential
part of the causes of our remembering.

In spite, however, of the fact that what is known is SOMETIMES an
indispensable part of the cause of the knowledge, this
circumstance is, I think, irrelevant to the general question with
which we are concerned, namely What sort of response to what sort
of stimulus can be regarded as displaying knowledge? There is one
characteristic which the response must have, namely, it must
consist of voluntary movements. The need of this characteristic
is connected with the characteristic of APPROPRIATENESS, which I
do not wish to consider as yet. For the present I wish only to
obtain a clearer idea of the sort of ACCURACY that a
knowledge-response must have. It is clear from many instances
that accuracy, in other cases, may be purely mechanical. The most
complete form of accuracy consists in giving correct answers to
questions, an achievement in which calculating machines far
surpass human beings. In asking a question of a calculating
machine, you must use its language: you must not address it in
English, any more than you would address an Englishman in
Chinese. But if you address it in the language it understands. it
will tell you what is 34521 times 19987, without a moment's
hesitation or a hint of inaccuracy. We do not say the machine
KNOWS the answer, because it has no purpose of its own in giving
the answer: it does not wish to impress you with its cleverness,
or feel proud of being such a good machine. But as far as mere
accuracy goes, the machine leaves nothing to be desired.

Accuracy of response is a perfectly clear notion in the case of
answers to questions, but in other cases it is much more obscure.
We may say generally that an object whether animate or inanimate,
is "sensitive" to a certain feature of the environment if it
behaves differently according to the presence or absence of that
feature. Thus iron is sensitive to anything magnetic. But
sensitiveness does not constitute knowledge, and knowledge of a
fact which is not sensible is not sensitiveness to that fact, as
we have seen in distinguishing the fact known from the stimulus.
As soon as we pass beyond the simple case of question and answer,
the definition of knowledge by means of behaviour demands the
consideration of purpose. A carrier pigeon flies home, and so we
say it "knows" the way. But if it merely flew to some place at
random, we should not say that it "knew" the way to that place,
any more than a stone rolling down hill knows the way to the

On the features which distinguish knowledge from accuracy of
response in general, not much can be said from a behaviourist
point of view without referring to purpose. But the necessity of
SOMETHING besides accuracy of response may be brought out by the
following consideration: Suppose two persons, of whom one
believed whatever the other disbelieved, and disbelieved whatever
the other believed. So far as accuracy and sensitiveness of
response alone are concerned, there would be nothing to choose
between these two persons. A thermometer which went down for warm
weather and up for cold might be just as accurate as the usual
kind; and a person who always believes falsely is just as
sensitive an instrument as a person who always believes truly.
The observable and practical difference between them would be
that the one who always believed falsely would quickly come to a
bad end. This illustrates once more that accuracy of response to
stimulus does not alone show knowledge, but must be reinforced by
appropriateness, i.e. suitability for realizing one's purpose.
This applies even in the apparently simple case of answering
questions: if the purpose of the answers is to deceive, their
falsehood, not their truth, will be evidence of knowledge. The
proportion of the combination of appropriateness with accuracy in
the definition of knowledge is difficult; it seems that both
enter in, but that appropriateness is only required as regards
the general type of response, not as regards each individual

II. I have so far assumed as unquestionable the view that the
truth or falsehood of a belief consists in a relation to a
certain fact, namely the objective of the belief. This view has,
however, been often questioned. Philosophers have sought some
intrinsic criterion by which true and false beliefs could be
distinguished.* I am afraid their chief reason for this search
has been the wish to feel more certainty than seems otherwise
possible as to what is true and what is false. If we could
discover the truth of a belief by examining its intrinsic
characteristics, or those of some collection of beliefs of which
it forms part, the pursuit of truth, it is thought, would be a
less arduous business than it otherwise appears to be. But the
attempts which have been made in this direction are not
encouraging. I will take two criteria which have been suggested,
namely, (1) self-evidence, (2) mutual coherence. If we can show
that these are inadequate, we may feel fairly certain that no
intrinsic criterion hitherto suggested will suffice to
distinguish true from false beliefs.

* The view that such a criterion exists is generally held by
those whose views are in any degree derived from Hegel. It may be
illustrated by the following passage from Lossky, "The Intuitive
Basis of Knowledge" (Macmillan, 1919), p. 268: "Strictly
speaking, a false judgment is not a judgment at all. The
predicate does not follow from the subject S alone, but from the
subject plus a certain addition C, WHICH IN NO SENSE BELONGS TO
THE CONTENT OF THE JUDGMENT. What takes place may be a process of
association of ideas, of imagining, or the like, but is not a
process of judging. An experienced psychologist will be able by
careful observation to detect that in this process there is
wanting just the specific element of the objective dependence of
the predicate upon the subject which is characteristic of a
judgment. It must be admitted, however, that an exceptional power
of observation is needed in order to distinguish, by means of
introspection, mere combination of ideas from judgments."

(1) Self-evidence.--Some of our beliefs seem to be peculiarly
indubitable. One might instance the belief that two and two are
four, that two things cannot be in the same place at the same
time, nor one thing in two places, or that a particular buttercup
that we are seeing is yellow. The suggestion we are to examine is
that such: beliefs have some recognizable quality which secures
their truth, and the truth of whatever is deduced from them
according to self-evident principles of inference. This theory is
set forth, for example, by Meinong in his book, "Ueber die
Erfahrungsgrundlagen unseres Wissens."

If this theory is to be logically tenable, self-evidence must not
consist merely in the fact that we believe a proposition. We
believe that our beliefs are sometimes erroneous, and we wish to
be able to select a certain class of beliefs which are never
erroneous. If we are to do this, it must be by some mark which
belongs only to certain beliefs, not to all; and among those to
which it belongs there must be none that are mutually
inconsistent. If, for example, two propositions p and q were
self-evident, and it were also self-evident that p and q could
not both be true, that would condemn self-evidence as a guarantee
of truth. Again, self-evidence must not be the same thing as the
absence of doubt or the presence of complete certainty. If we are
completely certain of a proposition, we do not seek a ground to
support our belief. If self-evidence is alleged as a ground of
belief, that implies that doubt has crept in, and that our
self-evident proposition has not wholly resisted the assaults of
scepticism. To say that any given person believes some things so
firmly that he cannot be made to doubt them is no doubt true.
Such beliefs he will be willing to use as premisses in reasoning,
and to him personally they will seem to have as much evidence as
any belief can need. But among the propositions which one man
finds indubitable there will be some that another man finds it
quite possible to doubt. It used to seem self-evident that there
could not be men at the Antipodes, because they would fall off,
or at best grow giddy from standing on their heads. But New
Zealanders find the falsehood of this proposition self-evident.
Therefore, if self-evidence is a guarantee of truth, our
ancestors must have been mistaken in thinking their beliefs about
the Antipodes self-evident. Meinong meets this difficulty by
saying that some beliefs are falsely thought to be self-evident,
but in the case of others it is self-evident that they are
self-evident, and these are wholly reliable. Even this, however,
does not remove the practical risk of error, since we may
mistakenly believe it self-evident that a certain belief is
self-evident. To remove all risk of error, we shall need an
endless series of more and more complicated self-evident beliefs,
which cannot possibly be realized in practice. It would seem,
therefore, that self-evidence is useless as a practical criterion
for insuring truth.

The same result follows from examining instances. If we take the
four instances mentioned at the beginning of this discussion, we
shall find that three of them are logical, while the fourth is a
judgment of perception. The proposition that two and two are four
follows by purely logical deduction from definitions: that means
that its truth results, not from the properties of objects, but
from the meanings of symbols. Now symbols, in mathematics, mean
what we choose; thus the feeling of self-evidence, in this case,
seems explicable by the fact that the whole matter is within our
control. I do not wish to assert that this is the whole truth
about mathematical propositions, for the question is complicated,
and I do not know what the whole truth is. But I do wish to
suggest that the feeling of self-evidence in mathematical
propositions has to do with the fact that they are concerned with
the meanings of symbols, not with properties of the world such as
external observation might reveal.

Similar considerations apply to the impossibility of a thing
being in two places at once, or of two things being in one place
at the same time. These impossibilities result logically, if I am
not mistaken, from the definitions of one thing and one place.
That is to say, they are not laws of physics, but only part of
the intellectual apparatus which we have manufactured for
manipulating physics. Their self-evidence, if this is so, lies
merely in the fact that they represent our decision as to the use
of words, not a property of physical objects.

Judgments of perception, such as "this buttercup is yellow," are
in a quite different position from judgments of logic, and their
self-evidence must have a different explanation. In order to
arrive at the nucleus of such a judgment, we will eliminate, as
far as possible, the use of words which take us beyond the
present fact, such as "buttercup" and "yellow." The simplest kind
of judgment underlying the perception that a buttercup is yellow
would seem to be the perception of similarity in two colours seen
simultaneously. Suppose we are seeing two buttercups, and we
perceive that their colours are similar. This similarity is a
physical fact, not a matter of symbols or words; and it certainly
seems to be indubitable in a way that many judgments are not.

The first thing to observe, in regard to such judgments, is that
as they stand they are vague. The word "similar" is a vague word,
since there are degrees of similarity, and no one can say where
similarity ends and dissimilarity begins. It is unlikely that our
two buttercups have EXACTLY the same colour, and if we judged
that they had we should have passed altogether outside the region
of self-evidence. To make our proposition more precise, let us
suppose that we are also seeing a red rose at the same time. Then
we may judge that the colours of the buttercups are more similar
to each other than to the colour of the rose. This judgment seems
more complicated, but has certainly gained in precision. Even
now, however, it falls short of complete precision, since
similarity is not prima facie measurable, and it would require
much discussion to decide what we mean by greater or less
similarity. To this process of the pursuit of precision there is
strictly no limit.

The next thing to observe (although I do not personally doubt
that most of our judgments of perception are true) is that it is
very difficult to define any class of such judgments which can be
known, by its intrinsic quality, to be always exempt from error.
Most of our judgments of perception involve correlations, as when
we judge that a certain noise is that of a passing cart. Such
judgments are all obviously liable to error, since there is no
correlation of which we have a right to be certain that it is
invariable. Other judgments of perception are derived from
recognition, as when we say "this is a buttercup," or even merely
"this is yellow." All such judgments entail some risk of error,
though sometimes perhaps a very small one; some flowers that look
like buttercups are marigolds, and colours that some would call
yellow others might call orange. Our subjective certainty is
usually a result of habit, and may lead us astray in
circumstances which are unusual in ways of which we are unaware.

For such reasons, no form of self-evidence seems to afford an
absolute criterion of truth. Nevertheless, it is perhaps true
that judgments having a high degree of subjective certainty are
more apt to be true than other judgments. But if this be the
case, it is a result to be demonstrated, not a premiss from which
to start in defining truth and falsehood. As an initial
guarantee, therefore, neither self-evidence nor subjective
certainty can be accepted as adequate.

(2) Coherence.--Coherence as the definition of truth is advocated
by idealists, particularly by those who in the main follow Hegel.
It is set forth ably in Mr. Joachim's book, "The Nature of Truth"
(Oxford, 1906). According to this view, any set of propositions
other than the whole of truth can be condemned on purely logical
grounds, as internally inconsistent; a single proposition, if it
is what we should ordinarily call false, contradicts itself
irremediably, while if it is what we should ordinarily call true,
it has implications which compel us to admit other propositions,
which in turn lead to others, and so on, until we find ourselves
committed to the whole of truth. One might illustrate by a very
simple example: if I say "so-and-so is a married man," that is
not a self-subsistent proposition. We cannot logically conceive
of a universe in which this proposition constituted the whole of
truth. There must be also someone who is a married woman, and who
is married to the particular man in question. The view we are
considering regards everything that can be said about any one
object as relative in the same sort of way as "so-and-so is a
married man." But everything, according to this view, is
relative, not to one or two other things, but to all other
things, so that from one bit of truth the whole can be inferred.

The fundamental objection to this view is logical, and consists
in a criticism of its doctrine as to relations. I shall omit this
line of argument, which I have developed elsewhere.* For the
moment I will content myself with saying that the powers of logic
seem to me very much less than this theory supposes. If it were
taken seriously, its advocates ought to profess that any one
truth is logically inferable from any other, and that, for
example, the fact that Caesar conquered Gaul, if adequately
considered, would enable us to discover what the weather will be
to-morrow. No such claim is put forward in practice, and the
necessity of empirical observation is not denied; but according
to the theory it ought to be.

* In the article on "The Monistic Theory of Truth" in
"Philosophical Essays" (Longmans, 1910), reprinted from the
"Proceedings of the Aristotelian Society," 1906-7.

Another objection is that no endeavour is made to show that we
cannot form a consistent whole composed partly or wholly of false
propositions, as in a novel. Leibniz's conception of many
possible worlds seems to accord much better with modern logic and
with the practical empiricism which is now universal. The attempt
to deduce the world by pure thought is attractive, and in former
times was largely supposed capable of success. But nowadays most
men admit that beliefs must be tested by observation, and not
merely by the fact that they harmonize with other beliefs. A
consistent fair-ytale is a different thing from truth, however
elaborate it may be. But to pursue this topic would lead us into
difficult technicalities; I shall therefore assume, without
further argument, that coherence is not sufficient as a
definition of truth.

III. Many difficult problems arise as regards the verifiability
of beliefs. We believe various things, and while we believe them
we think we know them. But it sometimes turns out that we were
mistaken, or at any rate we come to think we were. We must be
mistaken either in our previous opinion or in our subsequent
recantation; therefore our beliefs are not all correct, and there
are cases of belief which are not cases of knowledge. The
question of verifiability is in essence this: can we discover any
set of beliefs which are never mistaken or any test which, when
applicable, will always enable us to discriminate between true
and false beliefs? Put thus broadly and abstractly, the answer
must be negative. There is no way hitherto discovered of wholly
eliminating the risk of error, and no infallible criterion. If we
believe we have found a criterion, this belief itself may be
mistaken; we should be begging the question if we tried to test
the criterion by applying the criterion to itself.

But although the notion of an absolute criterion is chimerical,
there may be relative criteria, which increase the probability of
truth. Common sense and science hold that there are. Let us see
what they have to say.

One of the plainest cases of verification, perhaps ultimately the
only case, consists in the happening of something expected. You
go to the station believing that there will be a train at a
certain time; you find the train, you get into it, and it starts
at the expected time This constitutes verification, and is a
perfectly definite experience. It is, in a sense, the converse of
memory instead of having first sensations and then images
accompanied by belief, we have first images accompanied by belief
and then sensations. Apart from differences as to the time-order
and the accompanying feelings, the relation between image and
sensation is closely similar in the two cases of memory and
expectation; it is a relation of similarity, with difference as
to causal efficacy--broadly, the image has the psychological but
not the physical effects that the sensation would have. When an
image accompanied by an expectation-belief is thus succeeded by a
sensation which is the "meaning" of the image, we say that the
expectation-belief has been verified. The experience of
verification in this sense is exceedingly familiar; it happens
every time that accustomed activities have results that are not
surprising, in eating and walking and talking and all our daily

But although the experience in question is common, it is not
wholly easy to give a theoretical account of it. How do we know
that the sensation resembles the previous image? Does the image
persist in presence of the sensation, so that we can compare the
two? And even if SOME image does persist, how do we know that it
is the previous image unchanged? It does not seem as if this line
of inquiry offered much hope of a successful issue. It is better,
I think, to take a more external and causal view of the relation
of expectation to expected occurrence. If the occurrence, when it
comes, gives us the feeling of expectedness, and if the
expectation, beforehand, enabled us to act in a way which proves
appropriate to the occurrence, that must be held to constitute
the maximum of verification. We have first an expectation, then a
sensation with the feeling of expectedness related to memory of
the expectation. This whole experience, when it occurs, may be
defined as verification, and as constituting the truth of the
expectation. Appropriate action, during the period of
expectation, may be regarded as additional verification, but is
not essential. The whole process may be illustrated by looking up
a familiar quotation, finding it in the expected words, and in
the expected part of the book. In this case we can strengthen the
verification by writing down beforehand the words which we expect
to find.

I think all verification is ultimately of the above sort. We
verify a scientific hypothesis indirectly, by deducing
consequences as to the future, which subsequent experience
confirms. If somebody were to doubt whether Caesar had crossed
the Rubicon, verification could only be obtained from the future.
We could proceed to display manuscripts to our historical
sceptic, in which it was said that Caesar had behaved in this
way. We could advance arguments, verifiable by future experience,
to prove the antiquity of the manuscript from its texture,
colour, etc. We could find inscriptions agreeing with the
historian on other points, and tending to show his general
accuracy. The causal laws which our arguments would assume could
be verified by the future occurrence of events inferred by means
of them. The existence and persistence of causal laws, it is
true, must be regarded as a fortunate accident, and how long it
will continue we cannot tell. Meanwhile verification remains
often practically possible. And since it is sometimes possible,
we can gradually discover what kinds of beliefs tend to be
verified by experience, and what kinds tend to be falsified; to
the former kinds we give an increased degree of assent, to the
latter kinds a diminished degree. The process is not absolute or
infallible, but it has been found capable of sifting beliefs and
building up science. It affords no theoretical refutation of the
sceptic, whose position must remain logically unassailable; but
if complete scepticism is rejected, it gives the practical method
by which the system of our beliefs grows gradually towards the
unattainable ideal of impeccable knowledge.

IV. I come now to the purely formal definition of the truth or
falsehood of a belief. For this definition it is necessary first
of all to consider the derivation of the objective reference of a
proposition from the meanings of its component words or images.

Just as a word has meaning, so a proposition has an objective
reference. The objective reference of a proposition is a function
(in the mathematical sense) of the meanings of its component
words. But the objective reference differs from the meaning of a
word through the duality of truth and falsehood. You may believe
the proposition "to-day is Tuesday" both when, in fact, to-day is
Tuesday, and when to-day is not Tuesday. If to-day is not
Tuesday, this fact is the objective of your belief that to-day is
Tuesday. But obviously the relation of your belief to the fact is
different in this case from what it is in the case when to-day is
Tuesday. We may say, metaphorically, that when to-day is Tuesday,
your belief that it is Tuesday points TOWARDS the fact, whereas
when to-day is not Tuesday your belief points AWAY FROM the fact.
Thus the objective reference of a belief is not determined by the
fact alone, but by the direction of the belief towards or away
from the fact.* If, on a Tuesday, one man believes that it is
Tuesday while another believes that it is not Tuesday, their
beliefs have the same objective, namely the fact that it is
Tuesday but the true belief points towards the fact while the
false one points away from it. Thus, in order to define the
reference of a proposition we have to take account not only of
the objective, but also of the direction of pointing, towards the
objective in the case of a true proposition and away from it in
the case of a false one.

* I owe this way of looking at the matter to my friend Ludwig

This mode of stating the nature of the objective reference of a
proposition is necessitated by the circumstance that there are
true and false propositions, but not true and false facts. If
to-day is Tuesday, there is not a false objective "to-day is not
Tuesday," which could be the objective of the false belief
"to-day is not Tuesday." This is the reason why two beliefs which
are each other's contradictories have the same objective. There
is, however, a practical inconvenience, namely that we cannot
determine the objective reference of a proposition, according to
this definition, unless we know whether the proposition is true
or false. To avoid this inconvenience, it is better to adopt a
slightly different phraseology, and say: The "meaning" of the
proposition "to-day is Tuesday" consists in pointing to the fact
"to-day is Tuesday" if that is a fact, or away from the fact
"to-day is not Tuesday" if that is a fact. The "meaning" of the
proposition "to-day is not Tuesday" will be exactly the opposite.
By this hypothetical form we are able to speak of the meaning of
a proposition without knowing whether it is true or false.
According to this definition, we know the meaning of a
proposition when we know what would make it true and what would
make it false, even if we do not know whether it is in fact true
or false.

The meaning of a proposition is derivative from the meanings of
its constituent words. Propositions occur in pairs, distinguished
(in simple cases) by the absence or presence of the word "not."
Two such propositions have the same objective, but opposite
meanings: when one is true, the other is false, and when one is
false, the other is true.

The purely formal definition of truth and falsehood offers little
difficulty. What is required is a formal expression of the fact
that a proposition is true when it points towards its objective,
and false when it points away from it, In very simple cases we
can give a very simple account of this: we can say that true
propositions actually resemble their objectives in a way in which
false propositions do not. But for this purpose it is necessary
to revert to image-propositions instead of word-propositions. Let
us take again the illustration of a memory-image of a familiar
room, and let us suppose that in the image the window is to the
left of the door. If in fact the window is to the left of the
door, there is a correspondence between the image and the
objective; there is the same relation between the window and the
door as between the images of them. The image-memory consists of
the image of the window to the left of the image of the door.
When this is true, the very same relation relates the terms of
the objective (namely the window and the door) as relates the
images which mean them. In this case the correspondence which
constitutes truth is very simple.

In the case we have just been considering the objective consists
of two parts with a certain relation (that of left-to-right), and
the proposition consists of images of these parts with the very
same relation. The same proposition, if it were false, would have
a less simple formal relation to its objective. If the
image-proposition consists of an image of the window to the left
of an image of the door, while in fact the window is not to the
left of the door, the proposition does not result from the
objective by the mere substitution of images for their
prototypes. Thus in this unusually simple case we can say that a
true proposition "corresponds" to its objective in a formal sense
in which a false proposition does not. Perhaps it may be possible
to modify this notion of formal correspondence in such a way as
to be more widely applicable, but if so, the modifications
required will be by no means slight. The reasons for this must
now be considered.

To begin with, the simple type of correspondence we have been
exhibiting can hardly occur when words are substituted for
images, because, in word-propositions, relations are usually
expressed by words, which are not themselves relations. Take such
a proposition as "Socrates precedes Plato." Here the word
"precedes" is just as solid as the words "Socrates" and "Plato";
it MEANS a relation, but is not a relation. Thus the objective
which makes our proposition true consists of TWO terms with a
relation between them, whereas our proposition consists of THREE
terms with a relation of order between them. Of course, it would
be perfectly possible, theoretically, to indicate a few chosen
relations, not by words, but by relations between the other
words. "Socrates-Plato" might be used to mean "Socrates precedes
Plato"; "PlaSocrates-to" might be used to mean "Plato was born
before Socrates and died after him"; and so on. But the
possibilities of such a method would be very limited. For aught I
know, there may be languages that use it, but they are not among
the languages with which I am acquainted. And in any case, in
view of the multiplicity of relations that we wish to express, no
language could advance far without words for relations. But as
soon as we have words for relations, word-propositions have
necessarily more terms than the facts to which they refer, and
cannot therefore correspond so simply with their objectives as
some image-propositions can.

The consideration of negative propositions and negative facts
introduces further complications. An image-proposition is
necessarily positive: we can image the window to the left of the
door, or to the right of the door, but we can form no image of
the bare negative "the window not to the left of the door." We
can DISBELIEVE the image-proposition expressed by "the window to
the left of the door," and our disbelief will be true if the
window is not to the left of the door. But we can form no image
of the fact that the window is not to the left of the door.
Attempts have often been made to deny such negative facts, but,
for reasons which I have given elsewhere,* I believe these
attempts to be mistaken, and I shall assume that there are
negative facts.

* "Monist," January, 1919, p. 42 ff.

Word-propositions, like image-propositions, are always positive
facts. The fact that Socrates precedes Plato is symbolized in
English by the fact that the word "precedes" occurs between the
words "Socrates" and "Plato." But we cannot symbolize the fact
that Plato does not precede Socrates by not putting the word
"precedes" between "Plato" and "Socrates." A negative fact is not
sensible, and language, being intended for communication, has to
be sensible. Therefore we symbolize the fact that Plato does not
precede Socrates by putting the words "does not precede" between
"Plato" and "Socrates." We thus obtain a series of words which is
just as positive a fact as the series "Socrates precedes Plato."
The propositions asserting negative facts are themselves positive
facts; they are merely different positive facts from those
asserting positive facts.

We have thus, as regards the opposition of positive and negative,
three different sorts of duality, according as we are dealing
with facts, image-propositions, or word-propositions. We have,

(1) Positive and negative facts;

(2) Image-propositions, which may be believed or disbelieved, but
do not allow any duality of content corresponding to positive and
negative facts;

(3) Word-propositions, which are always positive facts, but are
of two kinds: one verified by a positive objective, the other by
a negative objective.

Owing to these complications, the simplest type of correspondence
is impossible when either negative facts or negative propositions
are involved.

Even when we confine ourselves to relations between two terms
which are both imaged, it may be impossible to form an
image-proposition in which the relation of the terms is
represented by the same relation of the images. Suppose we say
"Caesar was 2,000 years before Foch," we express a certain
temporal relation between Caesar and Foch; but we cannot allow
2,000 years to elapse between our image of Caesar and our image
of Foch. This is perhaps not a fair example, since "2,000 years
before" is not a direct relation. But take a case where the
relation is direct, say, "the sun is brighter than the moon." We
can form visual images of sunshine and moonshine, and it may
happen that our image of the sunshine is the brighter of the two,
but this is by no means either necessary or sufficient. The act
of comparison, implied in our judgment, is something more than
the mere coexistence of two images, one of which is in fact
brighter than the other. It would take us too far from our main
topic if we were to go into the question what actually occurs
when we make this judgment. Enough has been said to show that the
correspondence between the belief and its objective is more
complicated in this case than in that of the window to the left
of the door, and this was all that had to be proved.

In spite of these complications, the general nature of the formal
correspondence which makes truth is clear from our instances. In
the case of the simpler kind of propositions, namely those that I
call "atomic" propositions, where there is only one word
expressing a relation, the objective which would verify our
proposition, assuming that the word "not" is absent, is obtained
by replacing each word by what it means, the word meaning a
relation being replaced by this relation among the meanings of
the other words. For example, if the proposition is "Socrates
precedes Plato," the objective which verifies it results from
replacing the word "Socrates" by Socrates, the word "Plato" by
Plato, and the word "precedes" by the relation of preceding
between Socrates and Plato. If the result of this process is a
fact, the proposition is true; if not, it is false. When our
proposition is "Socrates does not precede Plato," the conditions
of truth and falsehood are exactly reversed. More complicated
propositions can be dealt with on the same lines. In fact, the
purely formal question, which has occupied us in this last
section, offers no very formidable difficulties.

I do not believe that the above formal theory is untrue, but I do
believe that it is inadequate. It does not, for example, throw
any light upon our preference for true beliefs rather than false
ones. This preference is only explicable by taking account of the
causal efficacy of beliefs, and of the greater appropriateness of
the responses resulting from true beliefs. But appropriateness
depends upon purpose, and purpose thus becomes a vital part of
theory of knowledge.

download audio

On the two subjects of the present lecture I have nothing
original to say, and I am treating them only in order to complete
the discussion of my main thesis, namely that all psychic
phenomena are built up out of sensations and images alone.

Emotions are traditionally regarded by psychologists as a
separate class of mental occurrences: I am, of course, not
concerned to deny the obvious fact that they have characteristics
which make a special investigation of them necessary. What I am
concerned with is the analysis of emotions. It is clear that an
emotion is essentially complex, and we have to inquire whether it
ever contains any non-physiological material not reducible to
sensations and images and their relations.

Although what specially concerns us is the analysis of emotions,
we shall find that the more important topic is the physiological
causation of emotions. This is a subject upon which much valuable
and exceedingly interesting work has been done, whereas the bare
analysis of emotions has proved somewhat barren. In view of the
fact that we have defined perceptions, sensations, and images by
their physiological causation, it is evident that our problem of
the analysis of the emotions is bound up with the problem of
their physiological causation.

Modern views on the causation of emotions begin with what is
called the James-Lange theory. James states this view in the
following terms ("Psychology," vol. ii, p. 449):

"Our natural way of thinking about these coarser emotions, grief,
fear, rage, love, is that the mental perception of some fact
excites the mental affection called the emotion, and that this
latter state of mind gives rise to the bodily expression. My
theory, on the contrary, is that THE BODILY CHANGES FOLLOW
(James's italics). Common sense says: we lose our fortune, are
sorry and weep; we meet a bear, are frightened and run; we are
insulted by a rival, are angry and strike. The hypothesis here to
be defended says that this order of sequence is incorrect, that
the one mental state is not immediately induced by the other,
that the bodily manifestations must first be interposed between,
and that the more rational statement is that we feel sorry
because we cry, angry because we strike, afraid because we
tremble, and not that we cry, strike, or tremble, because we are
sorry, angry, or fearful, as the case may be. Without the bodily
states following on the perception, the latter would be purely
cognitive in form, pale, colourless, destitute of emotional

Round this hypothesis a very voluminous literature has grown up.
The history of its victory over earlier criticism, and its
difficulties with the modern experimental work of Sherrington and
Cannon, is well told by James R. Angell in an article called "A
Reconsideration of James's Theory of Emotion in the Light of
Recent Criticisms."* In this article Angell defends James's
theory and to me--though I speak with diffidence on a question as
to which I have little competence--it appears that his defence is
on the whole successful.

* "Psychological Review," 1916.

Sherrington, by experiments on dogs, showed that many of the
usual marks of emotion were present in their behaviour even when,
by severing the spinal cord in the lower cervical region, the
viscera were cut off from all communication with the brain,
except that existing through certain cranial nerves. He mentions
the various signs which "contributed to indicate the existence of
an emotion as lively as the animal had ever shown us before the
spinal operation had been made."* He infers that the
physiological condition of the viscera cannot be the cause of the
emotion displayed under such circumstances, and concludes: "We
are forced back toward the likelihood that the visceral
expression of emotion is SECONDARY to the cerebral action
occurring with the psychical state.... We may with James accept
visceral and organic sensations and the memories and associations
of them as contributory to primitive emotion, but we must regard
them as re-enforcing rather than as initiating the psychosis."*

* Quoted by Angell, loc. cit.

Angell suggests that the display of emotion in such cases may be
due to past experience, generating habits which would require
only the stimulation of cerebral reflex arcs. Rage and some forms
of fear, however, may, he thinks, gain expression without the
brain. Rage and fear have been especially studied by Cannon,
whose work is of the greatest importance. His results are given
in  his book, "Bodily Changes in Pain, Hunger, Fear and Rage" (D.
Appleton and Co., 1916).

The most interesting part of Cannon's book consists in the
investigation of the effects produced by secretion of adrenin.
Adrenin is a substance secreted into the blood by the adrenal
glands. These are among the ductless glands, the functions of
which, both in physiology and in connection with the emotions,
have only come to be known during recent years. Cannon found that
pain, fear and rage occurred in circumstances which affected the
supply of adrenin, and that an artificial injection of adrenin
could, for example, produce all the symptoms of fear. He studied
the effects of adrenin on various parts of the body; he found
that it causes the pupils to dilate, hairs to stand erect, blood
vessels to be constricted, and so on. These effects were still
produced if the parts in question were removed from the body and
kept alive artificially.*

* Cannon's work is not unconnected with that of Mosso, who
maintains, as the result of much experimental work, that "the
seat of the emotions lies in the sympathetic nervous system." An
account of the work of both these men will be found in Goddard's
"Psychology of the Normal and Sub-normal" (Kegan Paul, 1919),
chap. vii and Appendix.

Cannon's chief argument against James is, if I understand him
rightly, that similar affections of the viscera may accompany
dissimilar emotions, especially fear and rage. Various different
emotions make us cry, and therefore it cannot be true to say, as
James does, that we "feel sorry because we cry," since sometimes
we cry when we feel glad. This argument, however, is by no means
conclusive against James, because it cannot be shown that there
are no visceral differences for different emotions, and indeed it
is unlikely that this is the case.

As Angell says (loc. cit.): "Fear and joy may both cause cardiac
palpitation, but in one case we find high tonus of the skeletal
muscles, in the other case relaxation and the general sense of

Angell's conclusion, after discussing the experiments of
Sherrington and Cannon, is: "I would therefore submit that, so
far as concerns the critical suggestions by these two
psychologists, James's essential contentions are not materially
affected." If it were necessary for me to take sides on this
question, I should agree with this conclusion; but I think my
thesis as to the analysis of emotion can be maintained without
coming to. a probably premature conclusion upon the doubtful
parts of the physiological problem.

According to our definitions, if James is right, an emotion may
be regarded as involving a confused perception of the viscera
concerned in its causation, while if Cannon and Sherrington are
right, an emotion involves a confused perception of its external
stimulus. This follows from what was said in Lecture VII. We
there defined a perception as an appearance, however irregular,
of one or more objects external to the brain. And in order to be
an appearance of one or more objects, it is only necessary that
the occurrence in question should be connected with them by a
continuous chain, and should vary when they are varied
sufficiently. Thus the question whether a mental occurrence can
be called a perception turns upon the question whether anything
can be inferred from it as to its causes outside the brain: if
such inference is possible, the occurrence in question will come
within our definition of a perception. And in that case,
according to the definition in Lecture VIII, its non-mnemic
elements will be sensations. Accordingly, whether emotions are
caused by changes in the viscera or by sensible objects, they
contain elements which are sensations according to our

An emotion in its entirety is, of course, something much more
complex than a perception. An emotion is essentially a process,
and it will be only what one may call a cross-section of the
emotion that will be a perception, of a bodily condition
according to James, or (in certain cases) of an external object
according to his opponents. An emotion in its entirety contains
dynamic elements, such as motor impulses, desires, pleasures and
pains. Desires and pleasures and pains, according to the theory
adopted in Lecture III, are characteristics of processes, not
separate ingredients. An emotion--rage, for example--will be a
certain kind of process, consisting of perceptions and (in
general) bodily movements. The desires and pleasures and pains
involved are properties of this process, not separate items in
the stuff of which the emotion is composed. The dynamic elements
in an emotion, if we are right in our analysis, contain, from our
point of view, no ingredients beyond those contained in the
processes considered in Lecture III. The ingredients of an
emotion are only sensations and images and bodily movements
succeeding each other according to a certain pattern. With this
conclusion we may leave the emotions and pass to the
consideration of the will.

The first thing to be defined when we are dealing with Will is a
VOLUNTARY MOVEMENT. We have already defined vital movements, and
we have maintained that, from a behaviourist standpoint, it is
impossible to distinguish which among such movements are reflex
and which voluntary. Nevertheless, there certainly is a
distinction. When we decide in the morning that it is time to get
up, our consequent movement is voluntary. The beating of the
heart, on the other hand, is involuntary: we can neither cause it
nor prevent it by any decision of our own, except indirectly, as
e.g. by drugs. Breathing is intermediate between the two: we
normally breathe without the help of the will, but we can alter
or stop our breathing if we choose.

James ("Psychology," chap. xxvi) maintains that the only
distinctive characteristic of a voluntary act is that it involves
an idea of the movement to be performed, made up of memory-images
of the kinaesthetic sensations which we had when the same
movement occurred on some former occasion. He points out that, on
this view, no movement can be made voluntarily unless it has
previously occurred involuntarily.*

* "Psychology," Vol. ii, pp. 492-3.

I see no reason to doubt the correctness of this view. We shall
say, then, that movements which are accompanied by kinaesthetic
sensations tend to be caused by the images of those sensations,
and when so caused are called VOLUNTARY.

Volition, in the emphatic sense, involves something more than
voluntary movement. The sort of case I am thinking of is decision
after deliberation. Voluntary movements are a part of this, but
not the whole. There is, in addition to them, a judgment: "This
is what I shall do"; there is also a sensation of tension during
doubt, followed by a different sensation at the moment of
deciding. I see no reason whatever to suppose that there is any
specifically new ingredient; sensations and images, with their
relations and causal laws, yield all that seems to be wanted for
the analysis of the will, together with the fact that
kinaesthetic images tend to cause the movements with which they
are connected. Conflict of desires is of course essential in the
causation of the emphatic kind of will: there will be for a time
kinaesthetic images of incompatible movements, followed by the
exclusive image of the movement which is said to be willed. Thus
will seems to add no new irreducible ingredient to the analysis
of the mind.

download audio

At the end of our journey it is time to return to the question
from which we set out, namely: What is it that characterizes mind
as opposed to matter? Or, to state the same question in other
terms: How is psychology to be distinguished from physics? The
answer provisionally suggested at the outset of our inquiry was
that psychology and physics are distinguished by the nature of
their causal laws, not by their subject matter. At the same time
we held that there is a certain subject matter, namely images, to
which only psychological causal laws are applicable; this subject
matter, therefore, we assigned exclusively to psychology. But we
found no way of defining images except through their causation;
in their intrinsic character they appeared to have no universal
mark by which they could be distinguished from sensations.

In this last lecture I propose to pass in review various
suggested methods of distinguishing mind from matter. I shall
then briefly sketch the nature of that fundamental science which
I believe to be the true metaphysic, in which mind and matter
alike are seen to be constructed out of a neutral stuff, whose
causal laws have no such duality as that of psychology, but form
the basis upon which both physics and psychology are built.

In search for the definition of "mental phenomena," let us begin
with "consciousness," which is often thought to be the essence of
mind. In the first lecture I gave various arguments against the
view that consciousness is fundamental, but I did not attempt to
say what consciousness is. We must find a definition of it, if we
are to feel secure in deciding that it is not fundamental. It is
for the sake of the proof that it is not fundamental that we must
now endeavour to decide what it is.

"Consciousness," by those who regard it as fundamental, is taken
to be a character diffused throughout our mental life, distinct
from sensations and images, memories, beliefs and desires, but
present in all of them.* Dr. Henry Head, in an article which I
quoted in Lecture III, distinguishing sensations from purely
physiological occurrences, says: "Sensation, in the strict sense
of the term, demands the existence of consciousness." This
statement, at first sight, is one to which we feel inclined to
assent, but I believe we are mistaken if we do so. Sensation is
the sort of thing of which we MAY be conscious, but not a thing
of which we MUST be conscious. We have been led, in the course of
our inquiry, to admit unconscious beliefs and unconscious
desires. There is, so far as I can see, no class of mental or
other occurrences of which we are always conscious whenever they

* Cf. Lecture VI.

The first thing to notice is that consciousness must be of
something. In view of this, I should define "consciousness" in
terms of that relation of an image of a word to an object which
we defined, in Lecture XI, as "meaning." When a sensation is
followed by an image which is a "copy" of it, I think it may be
said that the existence of the image constitutes consciousness of
the sensation, provided it is accompanied by that sort of belief
which, when we reflect upon it, makes us feel that the image is a
"sign" of something other than itself. This is the sort of belief
which, in the case of memory, we expressed in the words "this
occurred"; or which, in the case of a judgment of perception,
makes us believe in qualities correlated with present sensations,
as e.g., tactile and visual qualities are correlated. The
addition of some element of belief seems required, since mere
imagination does not involve consciousness of anything, and there
can be no consciousness which is not of something. If images
alone constituted consciousness of their prototypes, such
imagination-images as in fact have prototypes would involve
consciousness of them; since this is not the case, an element of
belief must be added to the images in defining consciousness. The
belief must be of that sort that constitutes objective reference,
past or present. An image, together with a belief of this sort
concerning it, constitutes, according to our definition,
consciousness of the prototype of the image.

But when we pass from consciousness of sensations to
consciousness of objects of perception, certain further points
arise which demand an addition to our definition. A judgment of
perception, we may say, consists of a core of sensation, together
with associated images, with belief in the present existence of
an object to which sensation and images are referred in a way
which is difficult to analyse. Perhaps we might say that the
belief is not fundamentally in any PRESENT existence, but is of
the nature of an expectation: for example. when we see an object,
we expect certain sensations to result if we proceed to touch it.
Perception, then, will consist of a present sensation together
with expectations of future sensations. (This, of course, is a
reflective analysis, not an account of the way perception appears
to unchecked introspection.) But all such expectations are liable
to be erroneous, since they are based upon correlations which are
usual but not invariable. Any such correlation may mislead us in
a particular case, for example, if we try to touch a reflection
in a looking-glass under the impression that it is "real." Since
memory is fallible, a similar difficulty arises as regards
consciousness of past objects. It would seem odd to say that we
can be "conscious" of a thing which does not or did not exist.
The only way to avoid this awkwardness is to add to our
definition the proviso that the beliefs involved in consciousness
must be TRUE.

In the second place, the question arises as to whether we can be
conscious of images. If we apply our definition to this case, it
seems to demand images of images. In order, for example, to be
conscious of an image of a cat, we shall require, according to
the letter of the definition, an image which is a copy of our
image of the cat, and has this image for its prototype. Now, it
hardly seems probable, as a matter of observation, that there are
images of images, as opposed to images of sensations. We may meet
this difficulty in two ways, either by boldly denying
consciousness of images, or by finding a sense in which, by means
of a different accompanying belief, an image, instead of meaning
its prototype, can mean another image of the same prototype.

The first alternative, which denies consciousness of images, has
already been discussed when we were dealing with Introspection in
Lecture VI. We then decided that there must be, in some sense,
consciousness of images. We are therefore left with the second
suggested way of dealing with knowledge of images. According to
this second hypothesis, there may be two images of the same
prototype, such that one of them means the other, instead of
meaning the prototype. It will be remembered that we defined
meaning by association a word or image means an object, we said,
when it has the same associations as the object. But this
definition must not be interpreted too absolutely: a word or
image will not have ALL the same associations as the object which
it means. The word "cat" may be associated with the word "mat,"
but it would not happen except by accident that a cat would be
associated with a mat. And in like manner an image may have
certain associations which its prototype will not have, e.g. an
association with the word "image." When these associations are
active, an image means an image, instead of meaning its
prototype. If I have had images of a given prototype many times,
I can mean one of these, as opposed to the rest, by recollecting
the time and place or any other distinctive association of that
one occasion. This happens, for example, when a place recalls to
us some thought we previously had in that place, so that we
remember a thought as opposed to the occurrence to which it
referred. Thus we may say that we think of an image A when we
have a similar image B associated with recollections of
circumstances connected with A, but not with its prototype or
with other images of the same prototype. In this way we become
aware of images without the need of any new store of mental
contents, merely by the help of new associations. This theory, so
far as I can see, solves the problems of introspective knowledge,
without requiring heroic measures such as those proposed by
Knight Dunlap, whose views we discussed in Lecture VI.

According to what we have been saying, sensation itself is not an
instance of consciousness, though the immediate memory by which
it is apt to be succeeded is so. A sensation which is remembered
becomes an object of consciousness as soon as it begins to be
remembered, which will normally be almost immediately after its
occurrence (if at all); but while it exists it is not an object
of consciousness. If, however, it is part of a perception, say of
some familiar person, we may say that the person perceived is an
object of consciousness. For in this case the sensation is a SIGN
of the perceived object in much the same way in which a
memory-image is a sign of a remembered object. The essential
practical function of "consciousness" and "thought" is that they
enable us to act with reference to what is distant in time or
space, even though it is not at present stimulating our senses.
This reference to absent objects is possible through association
and habit. Actual sensations, in themselves, are not cases of
consciousness, because they do not bring in this reference to
what is absent. But their connection with consciousness is very
close, both through immediate memory, and through the
correlations which turn sensations into perceptions.

Enough has, I hope, been said to show that consciousness is far
too complex and accidental to be taken as the fundamental
characteristic of mind. We have seen that belief and images both
enter into it. Belief itself, as we saw in an earlier lecture, is
complex. Therefore, if any definition of mind is suggested by our
analysis of consciousness, images are what would naturally
suggest themselves. But since we found that images can only be
defined causally, we cannot deal with this suggestion, except in
connection with the difference between physical and psychological
causal laws.

I come next to those characteristics of mental phenomena which
arise out of mnemic causation. The possibility of action with
reference to what is not sensibly present is one of the things
that might be held to characterize mind. Let us take first a very
elementary example. Suppose you are in a familiar room at night,
and suddenly the light goes out. You will be able to find your
way to the door without much difficulty by means of the picture
of the room which you have in your mind. In this case visual
images serve, somewhat imperfectly it is true, the purpose which
visual sensations would otherwise serve. The stimulus to the
production of visual images is the desire to get out of the room,
which, according to what we found in Lecture III, consists
essentially of present sensations and motor impulses caused by
them. Again, words heard or read enable you to act with reference
to the matters about which they give information; here, again, a
present sensible stimulus, in virtue of habits formed in the
past, enables you to act in a manner appropriate to an object
which is not sensibly present. The whole essence of the practical
efficiency of "thought" consists in sensitiveness to signs: the
sensible presence of A, which is a sign of the present or future
existence of B, enables us to act in a manner appropriate to B.
Of this, words are the supreme example, since their effects as
signs are prodigious, while their intrinsic interest as sensible
occurrences on their own account is usually very slight. The
operation of signs may or may not be accompanied by
consciousness. If a sensible stimulus A calls up an image of B,
and we then act with reference to B, we have what may be called
consciousness of B. But habit may enable us to act in a manner
appropriate to B as soon as A appears, without ever having an
image of B. In that case, although A operates as a sign, it
operates without the help of consciousness. Broadly speaking, a
very familiar sign tends to operate directly in this manner, and
the intervention of consciousness marks an imperfectly
established habit.

The power of acquiring experience, which characterizes men and
animals, is an example of the general law that, in mnemic
causation, the causal unit is not one event at one time, but two
or more events at two or more times.& A burnt child fears the
fire, that is to say, the neighbourhood of fire has a different
effect upon a child which has had the sensations of burning than
upon one which has not. More correctly, the observed effect, when
a child which has been burnt is put near a fire, has for its
cause, not merely the neighbourhood of the fire, but this
together with the previous burning. The general formula, when an
animal has acquired experience through some event A, is that,
when B occurs at some future time, the animal to which A has
happened acts differently from an animal which A has not
happened. Thus A and B together, not either separately, must be
regarded as the cause of the animal's behaviour, unless we take
account of the effect which A has had in altering the animal's
nervous tissue, which is a matter not patent to external
observation except under very special circumstances. With this
possibility, we are brought back to causal laws,and to the
suggestion that many things which seem essentially mental are
really neural. Perhaps it is the nerves that acquire experience
rather than the mind. If so, the possibility of acquiring
experience cannot be used to define mind.*

* Cf. Lecture IV.

Very similar considerations apply to memory, if taken as the
essence of mind. A recollection is aroused by something which is
happening now, but is different from the effect which the present
occurrence would have produced if the recollected event had not
occurred. This may be accounted for by the physical effect of the
past event on the brain, making it a different instrument from
that which would have resulted from a different experience. The
causal peculiarities of memory may, therefore, have a
physiological explanation. With every special class of mental
phenomena this possibility meets us afresh. If psychology is to
be a separate science at all, we must seek a wider ground for its
separateness than any that we have been considering hitherto.

We have found that "consciousness" is too narrow to characterize
mental phenomena, and that mnemic causation is too wide. I come
now to a characteristic which, though difficult to define, comes
much nearer to what we require, namely subjectivity.

Subjectivity, as a characteristic of mental phenomena, was
considered in Lecture VII, in connection with the definition of
perception. We there decided that those particulars which
constitute the physical world can be collected into sets in two
ways, one of which makes a bundle of all those particulars that
are appearances of a given thing from different places, while the
other makes a bundle of all those particulars which are
appearances of different things from a given place. A bundle of
this latter sort, at a given time, is called a "perspective";
taken throughout a period of time, it is called a "biography."
Subjectivity is the characteristic of perspectives and
biographies, the characteristic of giving the view of the world
from a certain place. We saw in Lecture VII that this
characteristic involves none of the other characteristics that
are commonly associated with mental phenomena, such as
consciousness, experience and memory. We found in fact that it is
exhibited by a photographic plate, and, strictly speaking, by any
particular taken in conjunction with those which have the same
"passive" place in the sense defined in Lecture VII. The
particulars forming one perspective are connected together
primarily by simultaneity; those forming one biography, primarily
by the existence of direct time-relations between them. To these
are to be added relations derivable from the laws of perspective.
In all this we are clearly not in the region of psychology, as
commonly understood; yet we are also hardly in the region of
physics. And the definition of perspectives and biographies,
though it does not yet yield anything that would be commonly
called "mental," is presupposed in mental phenomena, for example
in mnemic causation: the causal unit in mnemic causation, which
gives rise to Semon's engram, is the whole of one perspective--
not of any perspective, but of a perspective in a place where
there is nervous tissue, or at any rate living tissue of some
sort. Perception also, as we saw, can only be defined in terms of
perspectives. Thus the conception of subjectivity, i.e. of the
"passive" place of a particular, though not alone sufficient to
define mind, is clearly an essential element in the definition.

I have maintained throughout these lectures that the data of
psychology do not differ in, their intrinsic character from the
data of physics. I have maintained that sensations are data for
psychology and physics equally, while images, which may be in
some sense exclusively psychological data, can only be
distinguished from sensations by their correlations, not by what
they are in themselves. It is now necessary, however, to examine
the notion of a "datum," and to obtain, if possible, a definition
of this notion.

The notion of "data" is familiar throughout science, and is
usually treated by men of science as though it were perfectly
clear. Psychologists, on the other hand, find great difficulty in
the conception. "Data" are naturally defined in terms of theory
of knowledge: they are those propositions of which the truth is
known without demonstration, so that they may be used as
premisses in proving other propositions. Further, when a
proposition which is a datum asserts the existence of something,
we say that the something is a datum, as well as the proposition
asserting its existence. Thus those objects of whose existence we
become certain through perception are said to be data.

There is some difficulty in connecting this epistemological
definition of "data" with our psychological analysis of
knowledge; but until such a connection has been effected, we have
no right to use the conception "data."

It is clear, in the first place, that there can be no datum apart
from a belief. A sensation which merely comes and goes is not a
datum; it only becomes a datum when it is remembered. Similarly,
in perception, we do not have a datum unless we have a JUDGMENT
of perception. In the sense in which objects (as opposed to
propositions) are data, it would seem natural to say that those
objects of which we are conscious are data. But consciousness, as
we have seen, is a complex notion, involving beliefs, as well as
mnemic phenomena such as are required for perception and memory.
It follows that no datum is theoretically indubitable, since no
belief is infallible; it follows also that every datum has a
greater or less degree of vagueness, since there is always some
vagueness in memory and the meaning of images.

Data are not those things of which our consciousness is earliest
in time. At every period of life, after we have become capable of
thought, some of our beliefs are obtained by inference, while
others are not. A belief may pass from either of these classes
into the other, and may therefore become, or cease to be, a
belief giving a datum. When, in what follows, I speak of data, I
do not mean the things of which we feel sure before scientific
study begins, but the things which, when a science is well
advanced, appear as affording grounds for other parts of the
science, without themselves being believed on any ground except
observation. I assume, that is to say, a trained observer, with
an analytic attention, knowing the sort of thing to look for, and
the sort of thing that will be important. What he observes is, at
the stage of science which he has reached, a datum for his
science. It is just as sophisticated and elaborate as the
theories which he bases upon it, since only trained habits and
much practice enable a man to make the kind of observation that
will be scientifically illuminating. Nevertheless, when once it
has been observed, belief in it is not based on inference and
reasoning, but merely upon its having been seen. In this way its
logical status differs from that of the theories which are proved
by its means.

In any science other than psychology the datum is primarily a
perception, in which only the sensational core is ultimately and
theoretically a datum, though some such accretions as turn the
sensation into a perception are practically unavoidable. But if
we postulate an ideal observer, he will be able to isolate the
sensation, and treat this alone as datum. There is, therefore, an
important sense in which we may say that, if we analyse as much
as we ought, our data, outside psychology, consist of sensations,
which include within themselves certain spatial and temporal

Applying this remark to physiology, we see that the nerves and
brain as physical objects are not truly data; they are to be
replaced, in the ideal structure of science, by the sensations
through which the physiologist is said to perceive them. The
passage from these sensations to nerves and brain as physical
objects belongs really to the initial stage in the theory of
physics, and ought to be placed in the reasoned part, not in the
part supposed to be observed. To say we see the nerves is like
saying we hear the nightingale; both are convenient but
inaccurate expressions. We hear a sound which we believe to be
causally connected with the nightingale, and we see a sight which
we believe to be causally connected with a nerve. But in each
case it is only the sensation that ought, in strictness, to be
called a datum. Now, sensations are certainly among the data of
psychology. Therefore all the data of the physical sciences are
also psychological data. It remains to inquire whether all the
data of psychology are also data of physical science, and
especially of physiology.

If we have been right in our analysis of mind, the ultimate data
of psychology are only sensations and images and their relations.
Beliefs, desires, volitions, and so on, appeared to us to be
complex phenomena consisting of sensations and images variously
interrelated. Thus (apart from certain relations) the occurrences
which seem most distinctively mental, and furthest removed from
physics, are, like physical objects, constructed or inferred, not
part of the original stock of data in the perfected science. From
both ends, therefore, the difference between physical and
psychological data is diminished. Is there ultimately no
difference, or do images remain as irreducibly and exclusively
psychological? In view of the causal definition of the difference
between images and sensations, this brings us to a new question,
namely: Are the causal laws of psychology different from those of
any other science, or are they really physiological?

Certain ambiguities must be removed before this question can be
adequately discussed.

First, there is the distinction between rough approximate laws
and such as appear to be precise and general. I shall return to
the former presently; it is the latter that I wish to discuss

Matter, as defined at the end of Lecture V, is a logical fiction,
invented because it gives a convenient way of stating causal
laws. Except in cases of perfect regularity in appearances (of
which we can have no experience), the actual appearances of a
piece of matter are not members of that ideal system of regular
appearances which is defined as being the matter in question. But
the matter is. after all, inferred from its appearances, which
are used to VERIFY physical laws. Thus, in so far as physics is
an empirical and verifiable science, it must assume or prove that
the inference from appearances to matter is, in general,
legitimate, and it must be able to tell us, more or less, what
appearances to expect. It is through this question of
verifiability and empirical applicability to experience that we
are led to a theory of matter such as I advocate. From the
consideration of this question it results that physics, in so far
as it is an empirical science, not a logical phantasy, is
concerned with particulars of just the same sort as those which
psychology considers under the name of sensations. The causal
laws of physics, so interpreted, differ from those of psychology
only by the fact that they connect a particular with other
appearances in the same piece of matter, rather than with other
appearances in the same perspective. That is to say, they group
together particulars having the same "active" place, while
psychology groups together those having the same "passive" place.
Some particulars, such as images, have no "active" place, and
therefore belong exclusively to psychology.

We can now understand the distinction between physics and
psychology. The nerves and brain are matter: our visual
sensations when we look at them may be, and I think are, members
of the system constituting irregular appearances of this matter,
but are not the whole of the system. Psychology is concerned,
inter alia, with our sensations when we see a piece of matter, as
opposed to the matter which we see. Assuming, as we must, that
our sensations have physical causes, their causal laws are
nevertheless radically different from the laws of physics, since
the consideration of a single sensation requires the breaking up
of the group of which it is a member. When a sensation is used to
verify physics, it is used merely as a sign of a certain material
phenomenon, i.e. of a group of particulars of which it is a
member. But when it is studied by psychology, it is taken away
from that group and put into quite a different context, where it
causes images or voluntary movements. It is primarily this
different grouping that is characteristic of psychology as
opposed to all the physical sciences, including physiology; a
secondary difference is that images, which belong to psychology,
are not easily to be included among the aspects which constitute
a physical thing or piece of matter.

There remains, however, an important question, namely: Are mental
events causally dependent upon physical events in a sense in
which the converse dependence does not hold? Before we can
discuss the answer to this question, we must first be clear as to
what our question means.

When, given A, it is possible to infer B, but given B, it is not
possible to infer A, we say that B is dependent upon A in a sense
in which A is not dependent upon B. Stated in logical terms, this
amounts to saying that, when we know a many-one relation of A to
B, B is dependent upon A in respect of this relation. If the
relation is a causal law, we say that B is causally dependent
upon A. The illustration that chiefly concerns us is the system
of appearances of a physical object. We can, broadly speaking,
infer distant appearances from near ones, but not vice versa. All
men look alike when they are a mile away, hence when we see a man
a mile off we cannot tell what he will look like when he is only
a yard away. But when we see him a yard away, we can tell what he
will look like a mile away. Thus the nearer view gives us more
valuable information, and the distant view is causally dependent
upon it in a sense in which it is not causally dependent upon the
distant view.

It is this greater causal potency of the near appearance that
leads physics to state its causal laws in terms of that system of
regular appearances to which the nearest appearances increasingly
approximate, and that makes it value information derived from the
microscope or telescope. It is clear that our sensations,
considered as irregular appearances of physical objects, share
the causal dependence belonging to comparatively distant
appearances; therefore in our sensational life we are in causal
dependence upon physical laws.

This, however, is not the most important or interesting part of
our question. It is the causation of images that is the vital
problem. We have seen that they are subject to mnenic causation,
and that mnenic causation may be reducible to ordinary physical
causation in nervous tissue. This is the question upon which our
attitude must turn towards what may be called materialism. One
sense of materialism is the view that all mental phenomena are
causally dependent upon physical phenomena in the above-defined
sense of causal dependence. Whether this is the case or not, I do
not profess to know. The question seems to me the same as the
question whether mnemic causation is ultimate, which we
considered without deciding in Lecture IV. But I think the bulk
of the evidence points to the materialistic answer as the more

In considering the causal laws of psychology, the distinction
between rough generalizations and exact laws is important. There
are many rough generalizations in psychology, not only of the
sort by which we govern our ordinary behaviour to each other, but
also of a more nearly scientific kind. Habit and association
belong among such laws. I will give an illustration of the kind
of law that can be obtained. Suppose a person has frequently
experienced A and B in close temporal contiguity, an association
will be established, so that A, or an image of A, tends to cause
an image of B. The question arises: will the association work in
either direction, or only from the one which has occurred earlier
to the one which has occurred later? In an article by Mr.
Wohlgemuth, called "The Direction of Associations" ("British
Journal of Psychology," vol. v, part iv, March, 1913), it is
claimed to be proved by experiment that, in so far as motor
memory (i.e. memory of movements) is concerned, association works
only from earlier to later, while in visual and auditory memory
this is not the case, but the later of two neighbouring
experiences may recall the earlier as well as the earlier the
later. It is suggested that motor memory is physiological, while
visual and auditory memory are more truly psychological. But that
is not the point which concerns us in the illustration. The point
which concerns us is that a law of association, established by
purely psychological observation, is a purely psychological law,
and may serve as a sample of what is possible in the way of
discovering such laws. It is, however, still no more than a rough
generalization, a statistical average. It cannot tell us what
will result from a given cause on a given occasion. It is a law
of tendency, not a precise and invariable law such as those of
physics aim at being.

If we wish to pass from the law of habit, stated as a tendency or
average, to something more precise and invariable, we seem driven
to the nervous system. We can more or less guess how an
occurrence produces a change in the brain, and how its repetition
gradually produces something analogous to the channel of a river,
along which currents flow more easily than in neighbouring paths.
We can perceive that in this way, if we had more knowledge, the
tendency to habit through repetition might be replaced by a
precise account of the effect of each occurrence in bringing
about a modification of the sort from which habit would
ultimately result. It is such considerations that make students
of psychophysiology materialistic in their methods, whatever they
may be in their metaphysics. There are, of course, exceptions,
such as Professor J. S. Haldane,* who maintains that it is
theoretically impossible to obtain physiological explanations of
psychical phenomena, or physical explanations of physiological
phenomena. But I think the bulk of expert opinion, in practice,
is on the other side.

*See his book, "The New Physiology and Other Addresses" (Charles
Griffin & Co., 1919).

The question whether it is possible to obtain precise causal laws
in which the causes are psychological, not material, is one of
detailed investigation. I have done what I could to make clear
the nature of the question, but I do not believe that it is
possible as yet to answer it with any confidence. It seems to be
by no means an insoluble question, and we may hope that science
will be able to produce sufficient grounds for regarding one
answer as much more probable than the other. But for the moment I
do not see how we can come to a decision.

I think, however, on grounds of the theory of matter explained in
Lectures V and VII, that an ultimate scientific account of what
goes on in the world, if it were ascertainable, would resemble
psychology rather than physics in what we found to be the
decisive difference between them. I think, that is to say, that
such an account would not be content to speak, even formally, as
though matter, which is a logical fiction, were the ultimate
reality. I think that, if our scientific knowledge were adequate
to the task, which it neither is nor is likely to become, it
would exhibit the laws of correlation of the particulars
constituting a momentary condition of a material unit, and would
state the causal laws* of the world in terms of these
particulars, not in terms of matter. Causal laws so stated would,
I believe, be applicable to psychology and physics equally; the
science in which they were stated would succeed in achieving what
metaphysics has vainly attempted, namely a unified account of
what really happens, wholly true even if not the whole of truth,
and free from all convenient fictions or unwarrantable
assumptions of metaphysical entities. A causal law applicable to
particulars would count as a law of physics if it could be stated
in terms of those fictitious systems of regular appearances which
are matter; if this were not the case, it would count as a law of
psychology if one of the particulars were a sensation or an
image, i.e. were subject to mnemic causation. I believe that the
realization of the complexity of a material unit, and its
analysis into constituents analogous to sensations, is of the
utmost importance to philosophy, and vital for any understanding
of the relations between mind and matter, between our perceptions
and the world which they perceive. It is in this direction, I am
convinced, that we must look for the solution of many ancient

* In a perfected science, causal laws will take the form of
differential equations--or of finite-difference equations, if the
theory of quanta should prove correct.

It is probable that the whole science of mental occurrences,
especially where its initial definitions are concerned, could be
simplified by the development of the fundamental unifying science
in which the causal laws of particulars are sought, rather than
the causal laws of those systems of particulars that constitute
the material units of physics. This fundamental science would
cause physics to become derivative, in the sort of way in which
theories of the constitution of the atom make chemistry
derivative from physics; it would also cause psychology to appear
less singular and isolated among sciences. If we are right in
this, it is a wrong philosophy of matter which has caused many of
the difficulties in the philosophy of mind--difficulties which a
right philosophy of matter would cause to disappear.

The conclusions at which we have arrived may be summed up as

I. Physics and psychology are not distinguished by their
material. Mind and matter alike are logical constructions; the
particulars out of which they are constructed, or from which they
are inferred, have various relations, some of which are studied
by physics, others by psychology. Broadly speaking, physics group
particulars by their active places, psychology by their passive

II. The two most essential characteristics of the causal laws
which would naturally be called psychological are SUBJECTIVITY
and MNEMIC CAUSATION; these are not unconnected, since the causal
unit in mnemic causation is the group of particulars having a
given passive place at a given time, and it is by this manner of
grouping that subjectivity is defined.

III. Habit, memory and thought are all developments of mnemic
causation. It is probable, though not certain, that mnemic
causation is derivative from ordinary physical causation in
nervous (and other) tissue.

IV. Consciousness is a complex and far from universal
characteristic of mental phenomena.

V. Mind is a matter of degree, chiefly exemplified in number and
complexity of habits.

VI. All our data, both in physics and psychology, are subject to
psychological causal laws; but physical causal laws, at least in
traditional physics, can only be stated in terms of matter, which
is both inferred and constructed, never a datum. In this respect
psychology is nearer to what actually exists.