Muirhead Library of Philosophy



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




Preface



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

concerned.



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.




Contents


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 Phenomena

Lecture I.
Recent Criticisms of "Consciousness"



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

(psycho-analysis).



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

themselves."



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

valid.



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

it.



* 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:

"EXPERIENCE, I BELIEVE, HAS NO SUCH INNER DUPLICITY; AND THE

SEPARATION OF IT INTO CONSCIOUSNESS AND CONTENT COMES, NOT BY WAY

OF SUBTRACTION, BUT BY WAY OF ADDITION"(p. 9).



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

thought.



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

continues:



"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

INTO FREUD'S REALM OF THE UNCONSCIOUS. It may be inferred from

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.

Lecture II
Instinct and Habit



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

continuity.



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,

12):



"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

movements?



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

remainder.



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

experience.



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

CIRCUMSTANCES DO NOT APPARENTLY MAKE ANY DIFFERENCE TO THE LARVA,

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

Bergson.



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

behaviour.

Lecture III
Desire and Feeling



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

mover.



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

"censor."



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

poem:



     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

desire.

Lecture IV
 Influence on Past History on Present Occurrences in Living Organisms



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.



(d) NON-SENSATIONAL ELEMENTS IN PERCEPTION.--When we perceive any

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

reactions.



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:



IF A COMPLEX STIMULUS A HAS CAUSED A COMPLEX REACTION B IN AN

ORGANISM, THE OCCURRENCE OF A PART OF A ON A FUTURE OCCASION

TENDS TO CAUSE THE WHOLE REACTION B.



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

causation.



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

physics.



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

rationality.



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.

Lecture V
Psychological and Physical Causal Laws



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

effect.



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

observed.



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

principles:



(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

distinguish--



(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

perception.



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

mind.



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

stage.



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

concerned.

Lecture VI
Introspection



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

disappears.



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

awareness.



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.



(1) PUBLICITY OR PRIVACY OF WHAT IS OBSERVED. Confining

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.



(2) DOES EVERYTHING OBSERVABLE OBEY THE LAWS OF PHYSICS? We come

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.).





(3) CAN WE OBSERVE ANYTHING INTRINSICALLY DIFFERENT FROM

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"

perception.



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.