CHAPTER I

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THE PHILOSOPHY OF BIOLOGY

CAMBRIDGE UNIVERSITY PRESS

London: FETTER LANE, E.C.

C. F. CLAY, Manager

[Illustration]

Edinburgh: 100 PRINCES STREET

Berlin: A. ASHER AND CO.

Leipzig: F. A. BROCKHAUS

New York: G. P. PUTNAM’S SONS

Bombay and Calcutta: MACMILLAN AND CO., LTD.

Toronto: J. M. DENT & SONS, LTD.

Tokyo: THE MARUZEN-KABUSHIKI-KAISHA

_All rights reserved_

THE PHILOSOPHY

OF

BIOLOGY

BY

JAMES JOHNSTONE, D.Sc.

Cambridge:

at the University Press

1914

INTRODUCTION

It has been suggested that some reference, of an apologetic nature,

to the title of this book may be desirable, so I wish to point out

that it can really be justified. Science, says Driesch, is the

attempt to describe Givenness, and Philosophy is the attempt to

understand it. It is our task, as investigators of nature, to describe

what seems to us to happen there, and the knowledge that we so

attain--that is, our perceptions, thinned out, so to speak, modified

by our mental organisation, related to each other, classified and

remembered--constitutes our Givenness. This is only a description

of what seems to us to be nature. But few of us remain content with

it, and the impulse to go beyond our mere descriptions is at times

an irresistible one. Fettered by our habits of thought, and by the

limitations of sensation, we seem to look out into the dark and to see

only the shadows of things. Then we attempt to turn round in order that

we might discover what it is that casts the shadows, and what it is in

ourselves that gives shape to them. We seek for the Reality that we

feel is behind the shadows. That is Philosophy.

The Physics of a generation earlier than our own thought that it had

discovered Reality in its conception of an Universe consisting of

atoms and molecules in ceaseless motion. What it described were only

motions and transformations, but it understood these motions and

transformations as matter and energy. Yet more subtle minds than

the great physicists of the beginning of the nineteenth century had

already seen that sensation might mislead us. There was something

in us that continually changed--that was our consciousness, and it

was all that we knew. If external things did exist they existed only

because we thought them. But we ourselves exist, for we are not only

a stream of consciousness that continually changes, but there is in

us a personality, or identity, which has remained the same throughout

all the vicissitudes of our consciousness. If the things that exist

for us exist only because we think them, and if we also exist, then we

must exist in the thought of an Absolute Mind that thinks us. Physical

Science, studying only motions and transformations, understood that

there was something that moved and transformed--this was matter and

energy. Mental Science, studying only thought, understood that nature

was only the thought of an Universal Mind. Either conclusion was

equally valid Philosophy (or metaphysics), and neither could be proved

or disproved by the methods of Science. The speculative game is drawn,

said Huxley, let us get to practical work!

Both Physics and Biology did get to work, with the results that we

know. But Physics advanced far beyond the acquirement of the results

that stimulated Biology to formulate our present hypotheses of

evolution and heredity. As its knowledge accumulated, it began to doubt

whether matter and energy, atoms and molecules, mass and inertia--all

those things which it thought at first were so real--were anything else

after all than ways in which our mental organisation dealt with crude

sensations. They might, as Bergson said later on, be the moulds into

which we pour our perceptions. Physics set up a test of Reality, the

law of the conservation of matter and energy. There are existences

which may or may not persist. Visions and phantasms and dreams are

existences _while they last_. They are true for the mind in which

they occur. But they seem to arise out of nothing, and to disappear

into nothing, and physical Science cannot investigate them. They are

existences which are not conserved. On the other hand those images

which we call moving matter and transforming energy can be investigated

by the methods of physics. Molecules change, but something in them,

the atoms, remain constant. Energy becomes transformed, and it may

even seem to cease to exist, but if it disappears, then something is

changed so that the lost energy can be traced in the nature of the

change. Matter and energy are conserved and therefore they are the only

Realities. But the test is obviously one that has an _a priori_ basis,

and we may doubt whether it is a test of Reality.

Thus Physics constructed a dynamical Universe, that is, one which

consisted of atoms which attracted or repelled each other with forces

which were functions of the distances between them. Even now this

conception of a dynamical, Newtonian Universe is a useful one, though

we recognise that it is only symbolism. But it was not a conception

with which Physics could long remain content. How could atoms separated

from each other by empty space act on each other, that is, how could a

thing act where it was not? There must be something between the atoms.

The Universe could not be a discontinuous one, and so Physics invented

an Universe that was _full_. It was an immaterial, homogeneous,

imponderable, continuous Universe. That which existed behind the

appearances of atoms and molecules and energy was the ether of space.

It must be admitted that the conception appears to the layman to

involve only contradictions: heterogeneous, discontinuous, ponderable

atoms are only singularities in a homogeneous, continuous, imponderable

medium, or ether. Yet it is easy to see that this contradiction arises

in our mind only because we had previously thought of the Universe in

terms of matter and energy, and in spite of ourselves we attempt to

think of the new Reality in terms of the old one. In its attempt to

understand all its later results Physics had therefore to invent a new

Philosophy--that of the ether of space.

It is only in our own times that Biology has become sceptical and has

begun to doubt whether its earlier Philosophy is a sound one. That

which it describes--the object-matter of its Science--is not that which

Physics describes. There are two domains of Givenness, the organic

and the inorganic. Biology, leaning on Physics, studied motions and

transformations, just as Physics did, though the motions which it

studied were more complex and the transformations more mysterious. But

borrowing the methods of investigation of Physics it borrowed also

its Philosophy, and so it placed behind its Givenness the Reality

that Physics at first postulated and then abandoned. The organism was

therefore a material system actuated by energy. The notion, it should

be noted, is not a deduction from the results of Biology, but only from

its methods.

Did Physiology, that is, the Physiology of the Schools, ever really

investigate the organism? A muscle-nerve preparation, an excised kidney

through which blood is perfused, an exposed salivary gland which is

stimulated, even a frog deprived of its cerebral hemispheres--these

things are not organisms. They are not permanent centres of action,

autonomous physico-chemical constellations capable of independent

existence, and capable of indefinite growth by dissociation. They

are parts of the organism, which, having received the impulse of

life, an impulse which soon becomes exhausted, exhibit for a time

some of the phenomena of the organism. What Physiology did attain

in such investigations was an analytical description of some of the

activities of the organism. It did not describe life, but rather

the physico-chemical reactions in which life is manifested. The

description, it should be noted, is all-important for the human race

in its effort to acquire mastery over its environment; and there is

no other way in which it may be carried further but by the methods of

physical Science. Givenness is one, though we arbitrarily divide it

into the domains of the organic and the inorganic, and there can be

only one way of describing it. That is the mechanistic method.

Nevertheless all this is only a description, and our Philosophy

must be the attempt to understand our description. The mechanistic

biologist, in the attempt to identify his Philosophy with that of

a former generation of physicists, says that he is describing a

physico-chemical aggregate--an assemblage of molecules of a high degree

of complexity--actuated by energy, and undergoing transformations. But

our scepticism as to the validity of this conclusion is aroused by

reflecting on its origin. If it was borrowed from the Philosophy of a

past Physics, and if the more penetrating analysis of the Physics of

our own time has made a new Philosophy desirable, should not Biology

also revise its understanding of its descriptions? For Biology has

not stood still any more than Physics, and the Physiology of our own

day has become different from that of the times when the mechanistic

Philosophy of life took origin. The embryologists and the naturalists

of our own generation have studied the _whole_ organism in its normal

functioning and behaviour, and have obtained results which cannot

easily be understood as physico-chemical mechanism. Life is not the

activities of the organism, but the integration of the activities

of the organism, just as Reality for Physics is not the atoms and

molecules of gross matter, but the integration of these in the ether of

space.

This, then, is all that we mean by the philosophy of Biology--the

attempt to understand the descriptions of the Science in the light of

its later investigations. Philosophy, in the academic sense, we have

not considered in relation to the subject-matter of our science, though

there is much in the classic systems that is of absorbing interest,

even to the working investigator of the nineteenth century. The

biological education is not, however, such as to predispose one towards

these studies. The reader will recognise that the point of view, and

the methods of treatment, adopted in this book are those suggested by

Driesch and Bergson, even if no references are given. He may, perhaps,

appreciate this limitation; for, influenced by the modern scientific

training, he may be inclined to regard Philosophy as Mark Twain

regarded his Egyptian mummy: if he is to have a corpse it might as well

be a real fresh one.

J. J.

LIVERPOOL

_November 1913_

CONTENTS

CHAPTER I

PAGE

THE CONCEPTUAL WORLD 1

_Argument._--The conscious organism is one that acts. Its

consciousness of an external world is not simply the result of

the stimuli made by that world on its organs of sense, for it becomes

fully aware only of those stimuli which result in deliberated bodily

activity. This awareness of an outer world on which it acts is the

perception of the organism. Its consciousness is an intensive

multiplicity. This multiplicity is arbitrarily dissociated, for

convenience’ sake, by the mental organisation, which confers extension

and magnitude and succession on those aspects of consciousness

which it arbitrarily dissociates from each other. Our notion of

space is an intuitive one and depends on our modes of bodily

exertion. Our notions of motion and continuity are also intuitive

ones, and they cannot be represented intellectually, but we can

approximate to them by the methods of the infinitesimal calculus.

Mathematical time is only a series of standard events which punctuate

our duration. Duration is the accumulated existence and

experience of the organism. We cannot prove intellectually that

there is a world external to our consciousness, but that this world

exists is a conviction intuitively held.

CHAPTER II

THE ORGANISM AS A MECHANISM 49

_Argument._--If the organism is a physico-chemical mechanism its

activities must conform to the two principles of energetics: the law

of conservation of energy and matter, and the law of entropy-increase.

They conform strictly to the law of conservation.

The law of the degradation of energy is true of our experience

of inorganic nature, but we can show that it cannot be universally

true. Inorganic processes are irreversible ones, and they proceed

in one direction only, and in them energy is degraded. Organic

processes, that is, the processes carried on in the generalised

organism, are irreversible; or, at least, there is a tendency for

them to be carried on without necessary dissipation of energy.

CHAPTER III

THE ACTIVITIES OF THE ORGANISM 83

_Argument._--If the organism is investigated by the methods of

physical and chemical science, nothing but physico-chemical

activities can be discovered. This is necessarily the case, since

methods which yield physico-chemical results only are employed.

The physiologist makes an analysis of the activities of the organism,

and he reduces these activities to certain categories; although all

attempts completely to describe the functioning of the organism

solely in terms of physical and chemical reactions fail. In addition

to the reactions which make up the functioning of an organ or

organ-system, there is direction and co-ordination of these reactions.

The individual physico-chemical reactions which occur in the

functioning of the organism are integrated, and life is not merely

these reactions, but also their integration.

CHAPTER IV

THE VITAL IMPETUS 120

_Argument._--The notion of the organism as a physico-chemical

mechanism is a deduction from the methods of physiology, and

not from its results. The notion of vitalism is a natural or

intuitive one. The historic systems of vitalism assumed the

existence of a spiritual agency in the organism, or of a form of

energy which was peculiar to the activities of the organism.

Modern investigation lends no support to either belief. But the

study of the organism as a whole, that is, the study of developmental

processes, or that of the organism acting as a whole, afford a

logical disproof of pure mechanism. It shows that there cannot

be a functionality, in the mathematical sense, between the inorganic

agencies that affect the whole organism and the behaviour or

functioning of the whole organism. Mechanism is only suggested

in the study of isolated parts of the organism. We are compelled

toward the belief that there is an agency operative in the activities

of the organism which does not operate in purely inorganic becoming.

This is the Vital Impetus of Bergson, or the Entelechy of

Driesch.

CHAPTER V

THE INDIVIDUAL AND THE SPECIES 162

_Argument._--The concept of the organic individual is one which

is arbitrary, and is convenient only for purposes of description.

Life on the earth is integrally one. Personality is the intuition of

the conscious organism that it is a centre of action, and that all the

rest of the universe is relative to it. The individual organism,

regarded objectively, is an isolated, autonomous constellation,

capable of indefinite growth by dissociation, differentiation, and

re-integration. This growth is reproduction. The dissociated

part reproduces the form and manner of functioning of the individual

organism from which it has proceeded. The offspring varies

from the parent organism, but it resembles it much more than it

varies from it. There are therefore categories of organisms in

nature the individuals of which resemble each other more than they

resemble the individuals belonging to other categories: these are

the elementary species. Hypotheses of heredity are corpuscular

ones, and are based on the physical analogy of molecules and

atoms. The concept of the species is a logical one. The organism

is a phase in an evolutionary or a developmental flux, and the idea

of the species is attained by arresting this flux.

CHAPTER VI

TRANSFORMISM 208

_Argument._--A reasoned classification of organisms suggests that

a process of evolution has taken place. It suggests logical relation-

ships between organisms, while the results of embryology and

palæontology suggest chronological relationships. Yet this kinship

of organisms might only be a logical, and not a material

one. Evolution may have occurred somewhere, but it might be

argued that the ideas of species have generated each other in a

Creative Thought. But transformism may be produced experimentally,

and so science has adopted a mechanistic hypothesis of

the nature of the process. Transformism of species depends on

the occurrence of variations, but these arise spontaneously and

independently of each other, and they must be co-ordinated.

This co-ordination of variations cannot be the work of the environ

ment. Variations are cumulative, and they exhibit direction, and

this direction is either an accidental one, or it is the expression of

an impetus or directing agency in the varying organism itself.

The problem of the cause of variation is only a pseudo-problem.

CHAPTER VII

THE MEANING OF EVOLUTION 245

_Argument._--If we assume the existence of an evolutionary

process, the results of morphology, embryology, and palæontology

ought to enable us to trace the directions followed during this

process. But these results are still so uncertain that they indicate

only a few main lines of transformism. Phylogenetic trees are

largely conjectural in matters of detail. Evolution has resulted in

the establishment of several dominant groups of organisms--the

metatrophic bacteria, the chlorophyllian organisms, the arthropods,

and the vertebrates. Each of these groups displays certain

characters of morphology, energy-transformation, and behaviour;

and a certain combination of characters is concentrated in each of

the groups. But there is a community of character in all organisms

which have arisen during the evolutionary process. The transformation

of kinetic into potential energy is characteristic of the

chlorophyllian organisms. The utilisation of potential energy,

and its conversion into the kinetic energy of regulated bodily

activity, by means of a sensori-motor system, is characteristic of

the animal. The bacteria carry to the limit the energy-transformations

begun in the tissues of the plants and animals. Immobility

and unconsciousness characterise the plant, mobility and consciousness

the animal. Animals indicate two types of actions--intelligent

actions and instinctive actions. Instinctive activity

involves the habitual exercise of modes of action that have been

inherited. Intelligent activities involve the exercise of modes of

action that are not inherited, but which are acquired by the

animal during its own lifetime, and are the results of perceptions

which show the animal that its activity is relative to an outer

environment.

CHAPTER VIII

THE ORGANIC AND THE INORGANIC 289

_Argument._--A strictly mechanistic hypothesis of evolution

compels us to regard the organic world, and the inorganic environment

with which it interacts, as a physico-chemical system. All

the stages of an evolutionary process must therefore be equally

complex: they are simply phases, or rearrangements, of the

elements of a transforming system. The physics on which these

mechanistic hypotheses were based was that of a discontinuous,

granular, Newtonian universe, that is, one consisting of discrete

particles, or mass-points, attracting or repelling each other with

forces which are functions of the distances between them. It was

a spatially extended system of parts. Therefore at all stages in

an evolutionary process, or one of individual development, the

elements of the system constitute an extensive manifoldness, and

the obligation of mechanistic hypotheses of evolution and development

to accept this view has shaped modern theories of heredity.

Life is an intensive manifoldness, but in individual or racial evolu-

tion this intensive manifoldness becomes an extensive manifoldness.

Life is a bundle of tendencies which can co-exist, but which

cannot all be fully manifested, in the same material constellation,

therefore these tendencies become dissociated in the evolutionary

process. In this dissociation there is direction and co-ordination,

which are the Vital Impetus of Bergson, or the Entelechy of

Driesch.

Entelechy is an elemental agency in nature which we are

compelled to postulate because of the failure of mechanism. It is

not spirit, nor a form of energy, but the direction and co-ordination

of energies. There is a sign, or direction of inorganic happening

which absolutely characterises the processes which are capable of

analysis by physico-chemical methods of investigation, and the

result of this direction of inorganic happening is material inertia.

Yet this direction cannot be universal: it must be evaded somewhere

in the universe. It is evaded by the organism.

The problem of the nature of life is only a pseudo-problem.

APPENDIX

MATHEMATICAL AND PHYSICAL NOTIONS 342

Infinity and the notion of the limit. Functionality. Frequency

distributions and probability. Matter, force, mass, and inertia.

Energy-transformations. Isothermal and adiabetic transformations.

The Carnot engine and cycle. Entropy. Inert matter.

INDEX 377

THE PHILOSOPHY OF BIOLOGY

CHAPTER I

THE CONCEPTUAL WORLD

Let us suppose that we are walking along a street in a busy town;

that we are familiar with it, and all the things that are usually to

be seen in it, so that our attention is not likely to be arrested by

anything unusual; and let us further suppose that we are thinking

about something interesting but not intellectually difficult. In

these circumstances all the sights of the town, and all the turmoil

of the traffic fail to impress us, though we are, in a vague sort of

way, conscious of it all. Electric trams approach and recede with a

grinding noise; a taxicab passes and we hear the throb of the engine

and the hooting of the horn, and smell the burnt oil; a hansom comes

down the street and we hear the rhythmic tread of the horse’s feet and

the jingle of the bells; we pass a florist’s shop and become aware

of the colour of the flowers and of their odour; in a café a band

is playing “ragtime.” There are policemen, hawkers, idlers, ladies

with gaily coloured dresses and hats, newsboys, a crowd of people

of many characteristics. It is all a flux of experience of which we

are generally conscious without analysis or attention, and it is a

flux which is never for a moment quite the same, for everything in

it melts and flows into everything else. The noise of the tram-cars

is incessant, but now and then it becomes louder; the music of the

orchestra steals imperceptibly on our ears and as imperceptibly fades

away; the smell of the flowers lingers after we pass the shop, and we

do not notice just when we cease to be conscious of it; the rhythm of

the ragtime continues to irritate after we have ceased to hear the

band--all the sense-impressions that we receive melt and flow over

into each other and constitute our stream of consciousness, and this

changes from moment to moment without gap or discontinuity. It is not

a condition of “pure sensation,” but it is as nearly such as we can

experience in our adult intellectual life.

It is easy to discover that many things must have occurred in the

street which did not affect our full consciousness. We may learn

afterwards that we have passed several friends without recognising

them; we may read in the newspapers about things that happened that

we might have seen, but which we did not see; we may think we know

the street fairly well, but we find that we have difficulty in

recalling the names of three contiguous shops in it; if we happen to

see a photograph which was taken at the time we passed through the

street we are usually surprised to find that there were many things

there that we did not see. Why is it, then, that so much that might

have been perceived by us was not really perceived? We cannot doubt

that everything that came into the visual fields of our eyes must

have affected the terminations of the optic nerves in the retinas;

the complex disturbances of the air in the street must have set our

tympanic membranes in motion; and all the odoriferous particles inhaled

into our nostrils must have stimulated the olfactory mucous membranes.

In all these cases the stimulation of the receptor organs must have

initiated nervous impulses, and these must have been propagated along

the sensory nerves, and must have reached the brain, affecting masses

of nerve cells there. Nothing in physiology seems to indicate that we

can inhibit or repress the activity of the distance sense-receptors,

visual, auditory, and olfactory, with their central connections in

the brain; they must have functioned, and must have been physically

affected by the events that took place outside ourselves, and yet

we were unconscious, in the fullest sense of this term, of all this

activity. Why is it, then, that our perception was so much less

than the actual physical reception of external stimuli that we must

postulate as having occurred? Sherlock Holmes would have said that we

really saw and heard all these things although we did not observe them,

but the full explanation involves a much more careful consideration of

the phenomena of perception than this saying indicates.

There is, of course, no doubt that we did see and hear and smell

all the things that occurred in the street during our aimless

peregrination, that is, all the things which so happened that they

were capable of affecting our organs of sense. This is true if we

mean by seeing and hearing and smelling merely the stimulation of the

nerve-endings of the visual, auditory, and olfactory organs, and the

conduction into the brain of the nervous impulses so set up. But merely

to be stimulated is only a part of the full activity of the brain; the

stimulus transmitted from the receptor organs must result in some kind

of bodily activity if it is to affect our stream of consciousness.

Two main kinds of activity are induced by the stimulation of a

receptor organ and a central ganglion, (1) those which we call reflex

actions, and (2) those actions which we recognise as resulting from

deliberation. We must now consider what are the processes that are

involved in these kinds of neuro-muscular activity.

The term “reflex action” is one that denotes rather a scheme of

sensori-motor activity than anything that actually happens in the

animal body; it is a concept that is useful as a means of analysis of

complex phenomena. In a reflex three things happen, (1) the stimulation

of a receptor organ and of the nerve connecting this with the brain,

(2) the reflection, or shunting, of the nervous impulse so initiated

from the _terminus ad quem_ of the afferent or sensory nerve, to

the _terminus a quo_ of the efferent or motor nerve, and (3) the

stimulation of some effector organ, say a motor organ or muscle, by

the nervous impulse so set up. The simplest case, perhaps, of a reflex

is the rapid closure of the eyelids when something, say a few drops of

water, is flicked into the face. Stated in the way we have stated it

the simple reflex does not exist. In the first place, it is a concept

based on the structural analysis of the complex animal where the body

is differentiated to form tissues--receptor organs, nerves, muscles,

glands, and so on. But a protozoan animal, a _Paramœcium_ for instance,

responds to an external stimulus by some kind of bodily activity, and

yet it is a homogeneous, or nearly homogeneous, piece of protoplasm,

and this simple protoplasm acts at the same time as receptor organ,

conducting tissue or nerve, and effector organ. In the higher animal

certain parts of the integument are differentiated so as to form visual

organs, and the threshold of these for light stimuli is raised while it

is lowered for other kinds of physical stimuli. Similarly other parts

of the integument are modified for the reception of auditory stimuli,

becoming more susceptible for these but less susceptible for other

kinds of stimuli than the adjacent parts of the body. Within the body

itself certain tracts of protoplasm are differentiated so that they

can conduct molecular disturbances set up in the receptor organs in

the integument better than can the general protoplasm; these are the

nerves. Other parts are modified so that they can contract or secrete

the more easily; these are the muscles and glands. The conception

of a reflex action, as it is usually stated in books on physiology,

therefore includes this idea of the differentiation of the tissues, but

all the processes that are included in the typical reflex are processes

which can be carried on by undifferentiated protoplasm.

It is also a schematic description that assumes a simplicity that does

not really exist. As a rule a reflex is initiated by the stimulation

of more than one receptor organ, and the impulses initiated may thus

reach the central nervous system by more than one path. There is no

simple shunting of the afferent impulse from the cell in which it

terminates into another nerve, when it becomes an efferent impulse;

but, instead of this, the impulse may “zigzag” through a maze of paths

in the brain or spinal cord connecting together afferent and efferent

nerves and ganglia. Further, the final part of the reflex, the muscular

contraction, is far from being a simple thing, for usually a series

of muscles are stimulated to contract, each of them at the right time

and with the right amount of force, and every contraction of a muscle

is accompanied by the relaxation of the antagonistic muscle. There are

muscles which open the eyelids and others which close them, and the

cerebral impulse which causes the levators to contract at the same time

causes the depressors to relax.

It is quite necessary to remember that the simple reflex is really

a process of much complexity and may involve many other parts and

structures than those to which we immediately direct our attention. But

leaving aside these qualifications we may usefully consider the general

characters of the reflex, regarding it as a common, automatically

performed, restricted bodily action, involving receptor organ, central

nervous organ, and effector organ. There are certain kinds of external

stimuli that continually affect our organs of sense, and there are

certain kinds of muscular and glandular activity that occur “as a

matter of course,” when these stimuli fall on our organs of sense.

The emanation from onions or the vapour of ammonia causes our eyes to

water; the smell of savoury food causes a flow of saliva; and anything

that approaches the face very rapidly causes us to close the eyes.

Reflexes are, in a way, commonly occurring, purposeful and useful

actions, and their object is the maintenance of a normal condition of

bodily functioning.

We dare hardly say that the simple reflex is an unconsciously performed

action, although we are not conscious, in the fullest sense of the

term, of the reflexes that habitually take place in ourselves. But even

in the decapitated frog, which moves its limbs when a drop of acid is

placed on its back, something, it has been said, akin to consciousness

may flash out and light up the automatic activity of the spinal cord.

We must not think of consciousness as that state of acute mentality

which we experience in the performance of some difficult task, or in

some keenly appreciated pleasure, or in some condition of mental or

bodily distress; it is also that dimly felt condition of normality

that accompanies the satisfactory functioning of the parts of the

bodily organism. But this dim and obscure feeling of the awareness of

our actions is easily inhibited whenever what we call intellectual

activity proceeds.

Much of the stimulation of our receptor organs is of this generally

occurring nature, and we are not aware of it although the stimuli

received are such as to induce useful and purposeful bodily activity.

In walking along the street we automatically avoid the people, and the

other obstacles that we encounter, by means of regulated movements of

the body and limbs, but this is activity that has become so habitual

and easy that we are hardly aware of it, and not at all, perhaps,

of the physical stimuli which induce it. But not only do we receive

stimuli which are reflected into bodily actions without our being

keenly aware of this reception, but we also receive stimuli which do

not become reflected into bodily activity. It is, Bergson suggests, as

if we were to look out into the street through a sheet of glass held

perpendicularly to our line of sight; held in this way we see perfectly

all that happens in front of us, but when we incline the glass at a

certain angle it becomes a perfect reflector and throws back again the

rays of light that it receives. This is, of course, a physical analogy,

and no comparison of material things with psychical processes can go

very far, but in a way it is more than an analogy. In our indolent

absorbed state of mind we do not as a rule see the objects which we

are not compelled to avoid, and which do not, in any way, influence

our immediate condition of bodily activity. The optical images of all

these things are thrown upon our retinas and are, in some way, thrown

or projected upon the central ganglia, but there the series of events

comes to an end, for the images are not reflected out towards the

periphery of the body as muscular actions. We cannot doubt that this is

why we do not perceive all the stimulation of our organs of sense that

we are sure that take place. These stimuli pass through us, as it were,

unless they are reflected out again as actions. In this reflection, or

translation of neutral into muscular activity, perceptions arise.

But even then perception need not arise. It does not, as a rule,

accompany the automatically performed reflex action, because the latter

is the result of intra-cerebral activities that have become so habitual

that they proceed _without friction_. There are innumerable paths in

the brain along which impulses from the receptor organs may pass into

the motor ganglia, but in the habitually performed reflex actions these

paths have been worn smooth, so to speak. The images of objects which

are perceived over and over again by the receptor organs glide easily

through the brain and as easily translate themselves into muscular,

or some other kind of activity. The things that matter in the life of

an animal which lives “according to nature” are cyclically recurrent

events in which, after a time, there is nothing new. Most of them

proceed just as well in the animal deprived of its cerebral hemispheres

by operation as in the intact cerebrate animal. In the performance of

actions of this kind the organism becomes very much of an automaton.

Let something unusual happen in the street while we are walking

through it--a runaway horse, or the fall of an overhead “live”

wire, for instance, something that has seldom or never formed part

of our experience, and something that may have an immediate effect

on us as living organisms. Then perception arises at once because

the stimulation of our organs of sense presents us with something

which is unfamiliar, and yet not so unfamiliar that it does not

recall from memory, or from derived experience, reminiscences of

the images of somewhat similar things, and of the effects of these.

The train of events that now proceeds in our central nervous system

becomes radically different from that which proceeded in our former,

rather aimless, series of actions. The stimuli no longer pass easily

through the “lower” ganglia of the brain, but flash upwards into the

cortical regions, where they become confronted with the possibility of

innumerable alternative paths and connections with all the parts of

the body. They waver, so to speak, before adopting one or other, or

a combination of these paths; there is hesitation, deliberation, and

finally choice of a path, with the result that a series of muscular

organs become inervated and motor actions, of a type more or less

competent to the situation in which we find ourselves, are set up. In

this hesitation and deliberation perception arises. It is when the

animal may act in a certain way as the result of a stimulus which is

not a continually recurrent one, but at the same time may refrain from

acting, or may act in one of several different ways, that perception of

external things and their relations arises.

That is to say, we perceive and think because we act. We do not look

out on the environment in which we are placed in a speculative kind

of way, merely receiving the images of things, and classifying and

remembering them, while all the time we are passive in so far as our

bodily activities are concerned. If the results of modern physiology

teach us anything in an unequivocal way they teach us this--that the

organs of activity, muscles, glands, and so on, and the organs of sense

and communication, are integrally one series of parts, and that apart

from motor activity nervous activity is an aimless kind of thing. It

is because we act that we think and disentangle the images of things

presented to us by our organs of sense, and subject all that is in the

stream of consciousness to conceptual analysis.[1]

[1] All this is, of course, the argument of Bergson’s earlier books,

_Matière et Mémoire_ and _Données immédiates de la Conscience_.

That is to say, in thinking about the flux of consciousness we

decompose it into what we regard as its constituent parts, and we

confer upon these parts separate existence in space and time. But it

is clear that none of the things which we thus regard as the elements

of our consciousness has any real existence apart from the others. The

smell of the flowers and that of the burnt oil interpenetrate in our

consciousness of the stimulation of our olfactory organs just as do the

jingle of the cab bells, the music of the orchestra, and the throb of

the motor car in the impressions transmitted by our auditory organs.

It is difficult to see that all these things, with the multitude of

other things which we perceive, constitute a “multiplicity in unity,”

that is an assemblage of things which are separate things, but which do

not lie alongside each other in space and mutually exclude each other,

but which are all jammed into each other, so to speak. It is easy to

see that we are conscious of a heterogeneity, and whenever we think of

this multitude of things it seems natural that we should separate them

from each other. The stream of our consciousness is so complex that we

cannot attend to it all at once, not even to the few things that we

have picked out in our example. If we concentrate our attention on any

part, or rather aspect of it, all the rest ceases to exist, or rather

we agree to ignore it, and this very concentration of thought upon one

part of our experience isolates it from all the rest. To a certain

extent the analysis of the complex of sensation is the result of the

work of different receptor organs; certain fields of energy, which we

call light, radiation, etc., affect the nerve-endings in the retina;

chemically active particles in the atmosphere affect the nerve-endings

in the olfactory membranes; and rapidly repeated changes of pressure

in the atmosphere (sound vibrations) affect the auditory organs in the

internal ear, and so on. But this reception of different stimuli by

different receptor organs exists only in the higher animal; there are

no specialised sense organs in a _Paramœcium_, for instance, and the

whole periphery of the animal must receive all these different kinds

of external stimuli at once. The specialisation of its receptor organs

in the higher animal is rather the means whereby the organism becomes

more receptive of its environment, than the means whereby it analyses

that environment. This analysis is the work of the consciousness of the

animal.

[Illustration: FIG. 1.]

Suppose that we draw a curve _AB_ freehand with a single undivided

sweep of the pencil. By making a certain assumption--that the curve

which we drew was one that might be regarded as cyclical, that is,

might be repeated over and over again--we can subject it to harmonic

analysis. We can decompose it into a number of other curves (_CD_,

_EF_, etc.), each of which is a separate “wave” rising above and

falling below the axis _OX_ in a symmetrical manner. If we draw any

vertical line _MN_ cutting these curves, we shall find that the

distance between the axis _OX_ and the main curve _AB_ is always

equal to the algebraic sum of the distances between the axis and the

other curves. These latter we call the harmonic constituents of the

curve _AB_, supposing them to “add up” so as to form it. But _AB_

was something quite simple and elemental and its constituents cannot

be said to have existed in it when we drew it freehand; it was only

by an artifice of practical utility in mathematical computations

that we _constructed_ them. It may be, of course, that the harmonic

constituents of a curve had actual existence apart from the curve

itself, but, in the case that we take, they certainly had not. Now

we must think of our stream of consciousness in much the same way.

It is something immediately experienced and elementary; it is the

concomitant, if we choose so to regard it, of the external processes

that go on outside our bodies. We can investigate it by thinking about

it, and attending to one aspect of it after another, thus arbitrarily

detaching one “part” of it from all the rest, but immediately we

do this we rise above the flux of experience into the region of

intellectual concepts. We have converted a multiplicity of states of

consciousness, all of which co-exist along with each other, and in

each other, and which have no spatial existence, into a multiplicity

of states, visual, auditory, olfactory, etc., which have become

separated from each other and have therefore acquired extension. This

dissociation of the flux of experience is the process of conceptual

analysis carried out by thought.

If we dissociate the stream of consciousness in this way, breaking it

up into states which we choose to regard as separate from each other,

we shall see that of the elements which we thus isolate many are

like each other and can be associated. Obviously there is a greater

resemblance between different smells than between smells and sounds.

Different musical sounds are more like each other than are sounds, and

feelings of heat and cold. There is a greater likeness between the

states of consciousness which arise from the stimulation of the same

receptor organ, than between those that arise from the stimulation

of different receptors. Those differences of sensation accompanying

the stimulation of different sense organs we regard as different in

kind; there is absolutely no resemblance between a colour and a sound,

we say, however much the modern annotator of concert programmes may

suggest the analogy. But we say that there may be different degrees of

stimulation of the same sense organ, and that the sensations that we

thus receive are of the same kind though they differ in intensity. The

whistle of a railway engine becomes louder as the train approaches,

that is to say, more intense, and if we study the physical conditions

that are concomitant with the stimulation of our tympanic membranes

we shall see that waves of alternate rarefaction and compression are

set up in the atmosphere outside our ears. All the time that the train

approaches the frequency of these waves remains the same, that is, just

as many occur in a second when the train is distant as when it is near.

But the amplitude of the waves has been increasing, and the velocity

with which the molecules of air strike against the tympanic membranes

becomes greater the nearer is the source of sound. We can represent

this by means of a diagram which shows that the amplitude of the

waves--which represents the loudness of the sound--increases while the

frequency--which represents the pitch--remains the same. The amplitude

is represented by the straight vertical lines, 11, 22, 33, etc.,

which are of increasing magnitude. Thus we represent the physical

cause of the increasing loudness of the sound by space-magnitudes,

and then we transfer these magnitudes to the states of consciousness

concomitant with the vibrating molecules of air. Suppose that we knew

nothing at all about the cause of the differences of pitch of musical

sounds and that we listen to the notes of the octave, C, D, E,----C,

sounded by an organ; all that we should experience would be that the

sounds were different. If we were to sing the notes we might attain

the intuition that the notes G, A, B were “higher” than the notes C,

D, E, because a greater effort was required in order to produce these

sounds, but obviously this is a different thing from saying that the

notes themselves were “higher” or “lower.” But let us match the notes

by striking tuning-forks, and then having selected forks which give the

notes of the octave let us fix them so that they will make a tracing,

while still vibrating, on a revolving strip of paper. We shall then

find that the fork emitting the note C makes (say) 256 vibrations per

second, the fork D 9/8 256 vibrations, the fork E 5/4 256 vibrations,

and so on. Thus we associate the notes of the octave together and we

say that their quality was the same but that their pitch differed,

and since the pitch depends on the frequency of vibration of the

fork, or of the air in its vicinity, we say that pitch differences are

quantitative ones, and that the states of consciousness which accompany

these physical events are also quantitatively different.

[Illustration: FIG. 2.]

So also with colour. If we had no such apparatus as prisms or

diffraction gratings, which enable us to find what is the wave length

of light, should we have any idea of the spectral hues, red, yellow,

orange, green, etc., as differing from each other quantitatively? It is

certain that we should not. But observation and experiment have shown

that the nerve-endings of the optic nerve in the retina are stimulated

by vibrations of something which we agree to call the ether of space,

and that the frequency of vibration of light which we call red is

less than that which we call orange, while the frequency of vibration

of orange light is less again than that of blue light, and so on. To

our consciousness red, orange, yellow, and blue light are absolutely

different, but we disregard this intuition and we say that our

perceptions of light are similar in kind but differ, in some of them

are more intense than are some others. Again, have we any intuitive

knowledge of increasing temperature? If we dip our hands into ice-cold

water the sensation is one of pain, if the water has a temperature

of 5° C. it feels cold, if it is at 15° C. we have no particular

appreciation of temperature, if at 25° C. it feels very warm, if it

is at 60° it is very hot, and if it is at 90° we are probably scalded

and the feeling is again one of pain. If we place a thermometer in

the water we notice that each sensation in turn is associated with a

progressive lengthening of the mercury thread, and if we investigate

the physical condition of the water we find that at each stage the

velocity of movement of the molecules was greater than that at the

preceding stage. We say, then, that our different perceptions were

those of heat of different degrees of intensity, so transferring to

the perceptions themselves the notions of space-magnitudes acquired by

a study of the expansion of the mercury in the thermometer, or by the

adoption of the physical theory of the kinetic structure of the water.

Yet it is quite certain that what we experienced were quite different

things or conditions, cold, warmth, heat, and pain, and indeed, in this

series of perceptions different receptor organs are involved.

Suppose we listen to the note emitted by a syren which is sounding with

slowly increasing loudness but with a pitch which remains constant. We

do not notice at first that the sound is becoming louder, but after a

little time we do notice a difference. Let us call the amplitude of

vibration of the air when the syren first sounds _E_, and then, when we

notice a difference, let us call the amplitude Δ_E_ + _E_, Δ_E_ being

the increment of amplitude. Let us call our sensation when the syren

first sounds _S_, and our sensations when the sound has become louder

_S_ + Δ_S_, Δ_S_ being the “increment of sensation.” Then the relation

holds:--

Δ_E_/_E_ = constant.

That is to say, the louder is the sound the greater must be the

increase of loudness before we notice a difference. Let us assume now

that the successive sensations of loudness that we receive as the syren

blows louder and louder are, each of them, just the same amount louder

than the preceding sound; that is to say, let us assume that what we

experience are “minimal perceptible differences” of sensation--that

they are “elements of loudness”--thus we construct a series of sounds

each of which differs from that preceding it by an elemental increment

of loudness. Now things that cannot be further decomposed are

necessarily equal to each other; if, for instance, the atoms represent

the ultimate units into which we break up the matter called oxygen,

then these atoms are all equal to each other. Therefore the increments

of loudness are equal to each other.

[Illustration: FIG. 3.]

If we plot these equal increments of loudness as the dependent variable

_S_ in a graph, and the amplitude of the vibrations of the atmosphere

as the independent variable _E_, we can obtain the following curve.

If we investigate this we shall find that a certain relation exists

between the “values” of the sensation and the values of the stimuli

that correspond to them; a regular increase in the loudness of the

sensation corresponds to a regular increase in the logarithms of the

strength of the stimuli. Let S = the sensation, _E_ the stimulus, and

_C_ and _Q_ constants; then

_S_ = _C_ log(_E_/_Q_);

so that we seem to establish a mathematical relation between the

intensity of our sensations and the intensity of the stimuli that give

rise to those sensations, but this relation depends on the assumption

that what we call “minimal perceptible differences” of sensation are

numerical differences that are equal to each other, and this is, of

course, an assumption that cannot possibly be proved.

Thus we decompose our stream of consciousness into a series of

quantitatively different and qualitatively different things, upon

each of which we confer independent existence. We attribute to these

different aspects of our consciousness extension, but the extension is

due only to our analysis; for the qualities of pitch, loudness, colour,

odour, etc., which we disentangle from each other, did not exist apart

from each other, any more than do the sine and cosine curves into which

we decompose an arbitrarily drawn curved line. The multiplicity of

our consciousness is intensive, like the multiplicity that we see to

exist in the abstract number ten. This number stands for a group of

things, but its multiplicity is intensive and only exists because we

are able to subdivide anything in thought to an indefinite extent. Now,

so far we have only separated what we agree to regard as the elemental

parts of our general perception of the environment, but it is to be

noted that we have not given to these elements anything like spatial

extension.

We may, if we like, regard our intuition of space as that of an

indefinitely large, homogeneous, empty medium which surrounds us and

in which we may, in imagination, place things. So regarded it is

difficult to see in what way our notion of space differs from our idea

of “nothing,” a pseudo-idea incapable of analysis, except into the

idea of something which might be somewhere else. The more we think

about it the more we shall become convinced that space, that is the

“form” of space, represents our actual or potential modes of motion,

that is, our powers of exertional activity. Space, we say, has three

dimensions; in all our analysis of the universe, and of the activities

that we can perceive in it, this idea of movement in three dimensions,

forward and backward, up and down, and right and left, occurs; and

we have to recognise that in it there is something fundamental, as

fundamental as the intuitive knowledge that we possess of the direction

of right and left. It is because we can move in such a way that any

of our motions, no matter how complex, can be resolved into the

components of backward and forward, right and left, and up and down,

these directions all being at right angles to each other, that we speak

of our movements as three-dimensional ones. Our geometry is founded,

therefore, on concepts derived from our modes of activity; and there is

nothing in the universe, apart from our own activity, that makes this

the only geometry possible to us. Euclidean geometry does not depend

on the constitution of the external universe, but on the nature of the

organism itself.

There is a little Infusorian which lives, in its adult phase, on the

surface of the spherical ova of fishes. These ova float freely in

sea water, and the Infusorian crawls on their surfaces, moving about

by means of ciliary appendages. It does not swim about in the water,

but adheres closely to the surface of the ovum on which it lives. Let

us suppose that it is an intelligent animal and that it is able to

construct a geometry of its own; if so, this geometry would be very

different from our own.

It would be a two-dimensional geometry, for the animal can move

backward and forward, and right and left, but not up and down; it

is a stereotropic organism, as Jacques Loeb would say, that is, it

is _compelled_ by its organisation to apply its body closely to the

surface on which it lives. But its two-dimensional geometry would, on

this account, be different from ours. Our straight lines are really the

_directions_ in which we move from one point to another point in such

a way as to involve the least exertion; they are the shortest distances

between two points, and if we deviate from them we exert a greater

degree of activity than if we had moved along them. For us there is

only one straight line that can be drawn between two points, but this

is not necessarily true for our Infusorian, and its straight line need

not be the shortest distance between two points. It might be either the

longest or the shortest distance between the points, for the latter can

always be placed on a great circle passing through the two points and

the poles of the egg, and in moving from a point on which it is placed

the animal could reach the other point by moving in two directions,

just as we could go round the earth along the equator by moving to the

east or to the west. Therefore the straight line of the Infusorian

would be not only a scalar quantity but a vector quantity, that is,

it would represent, not only a quantity of energy, but a quantity of

energy that has direction. For us only one straight line can be drawn

between two given points, but this limitation would not exist in the

two-dimensional geometry of a curved surface. Suppose that the two

points are situated on a great circle and that they are exactly 180°

apart; then the Infusorian could move from one pole to another pole

along an infinite number of straight lines or meridians all of which

had a different direction, but all of which were of the same length;

that is to say, in this geometry an infinite number of straight lines

can be drawn between the same two points. Again, its triangles _might_

be different from ours; our triangles are figures formed by drawing

straight lines between three points, and on a plane surface the sum

of the angles of the triangle are together equal to two right angles,

though on a curved surface they may be greater or less than two right

angles. But our Infusorian could not imagine a triangle in which the

sum of the angles was not greater than two right angles, for all its

figures would be drawn on a convex surface.

Our three-dimensional geometry depends, therefore, on our modes of

activity and the concepts with which it operates; points, straight

lines, etc. are conceptual limits to those modes of activity. We can

imagine a straight line only as a direction along which we can move

without deviating to the right or the left, or up or down. But even

if we draw such a line on paper with a fine pencil the trace would

still have some width, and we can imagine ourselves small enough to be

able to deviate to the right or the left within the width of the line

drawn on the paper. We might make a very small mark on the paper, but

no matter how small this mark is it would still have some magnitude;

otherwise we should be unable to see it. If the straight line had

no width and the point no magnitude they would have no perceptual

existence. Our perceptual triangles are not figures, the angles of

which are necessarily equal to two right angles. If we drive three

walking sticks into a field and then measure the angles between them by

means of a sextant we shall find that the sum is _nearly_ 180°, but in

general not that amount. If we stick a darning needle into the heads

of each of the walking sticks and then remeasure the angles by means

of a theodolite we shall obtain values which are nearer to that of two

right angles, but we should not, except by “accident,” obtain exactly

this value. We do not, therefore, get the “theoretical” result, and we

say this is because of the errors of our methods of observation; but

why do we suppose that there is such a theoretical result from which

our observations deviate, if our observations themselves do not in

general give this ideal result? We might accumulate a great series

of measurements of the angles of our triangle, and we should then

find that these results would tend to group themselves symmetrically

round a certain value which would be 180°. Some of the results would

be considerably less than the ideal, and some of them would be

considerably more; but these relatively great deviations would be small

in number and most of the results would be a very little less than 180°

or a very little more, and there would be as many which would be a

little less as those that were a little more. We should have formed a

“frequency distribution”[2] with its “mode” at 180°.

[2] See appendix, p. 350.

But by “reasoning” about the “properties” of these lines and triangles

in plane two-dimensional space, we should arrive at the conclusion

that the angles of a triangle were equal to 180°, and neither more nor

less. We should then think of a straight line as still a _path_ along

which we move in imagination, and a path which still has some width.

But we imagine the width of the path to become less and less, so that,

even if we imagine ourselves to become thinner and thinner, we should

be unable to deviate either to the right or left in moving along the

path, because the thinner we make ourselves the thinner becomes also

the path. We imagine our intuition of a deviation to the right or left

becoming keener and keener, so that, no matter how small the deviation

we should still be able to appreciate it by the extra exertion which

it would involve. We think of a point as a little spot, and we think

of ourselves as being very small indeed, so that we can move about on

this spot. But we can reduce the area of the spot more and more, until

it becomes “infinitesimally” small; and at the same time we think of

ourselves as becoming smaller and smaller, so that we can still move

about on the spot. But we think of the area of the spot as becoming so

small that no matter how small we make ourselves we are unable to move

on it.

This means that we substitute conceptual lines and points and triangles

for the perceptual ones of our experience, and then we operate in

imagination with these concepts. That is to say, we carry our modes

of exertional activity to their _limits_,[3] in the way which we have

tried to indicate above--a process of thought which is the foundation

of the reasoning of the infinitesimal calculus.

[3] See appendix, p. 346.

What we call space, therefore, depends on our intuition of bodily

exertion. This intuition includes the knowledge that a certain change

has occurred as the consequence of the expenditure of a certain amount

of bodily energy, and that, as the result of this change, the relation

of the rest of the universe to our body has become different. We think

of our body as the origin, or centre, of a system of co-ordinates:--

[Illustration: FIG. 4.]

We imagine three lines at right angles to each other to extend

indefinitely out into space, and we think of ourselves as being

situated at the point of intersection of these three straight lines.

If anything moves in the universe outside ourselves we can resolve

this motion into three components, each of which is to be measured

along one of the axes of our system of co-ordinates. But any motion

whatever in the universe outside ourselves can be represented equally

well by supposing that the origin of the system of co-ordinates has

been changed; that is, by supposing that we have changed our position

relative to the rest of the universe. Therefore motion outside

ourselves is not to be distinguished from a contrary motion of our own

body--a statement of the “principle of relativity”--except that any

change outside ourselves may be distinguished from that compensatory

change in the position of our body which _appears_ to be the same

thing, by the absence of the intuition that we have expended a certain

quantity of energy in producing the change. Conscious motion of our own

body is something _absolute_; all other motion is relative.

So far we have been speaking of our crude bodily motion, but a very

little consideration will show that our knowledge of space attained

by scientific measurements depends just as much on our intuition of

our bodily activity, and its direction; the measurement of a stellar

parallax, or that of the meridian altitude of the sun, for instance,

by astronomical instruments, involves bodily exertion, though of a

refined kind. Three-dimensional space, that is _our_ space, therefore

represents the manner of our activity, just as convex two-dimensional

space represents the manner of the activity of the Infusorian, and

one-dimensional space would represent the manner of activity of an

animal which was compelled to live in a tube, the sides of which

it fitted closely, so that it could move only in one direction--up

and down. A parasite, living attached to some fixed object, and

the movements of which were represented only by the growth of its

tissues, could not form any idea of space; and the “higher” forms of

geometry, that is, space of four or more dimensions, present no clear

notion to our minds, even although we regard the operations included

in mathematics of this kind as pure symbolism, because we cannot

relate this imaginary space to any form of bodily exertion. Geometry,

then, represents the manner in which our bodily exertion cuts up the

homogeneous medium in which we live.

Motion, whether it be that of our own body in controlled muscular

activity, or that imaginary motion of the environment which we

call giddiness, or a sensibly perceived motion of some part of the

environment, that is, a motion which we can compensate by some actual

or imaginary change in the position of our own body produced by our

own exertion, is an intuitively felt change, and is incapable of

intellectual representation. It is not clearly conceived either in

ancient or in modern geometry. Euclidean geometry is, as we have

seen, based directly on our intuition of bodily exertion, but it is

essentially static in treatment. Let it be admitted that we can draw a

straight line of any length and in any direction, and so on; then we

regard these straight lines, etc., as motionless, abstract things, and

we proceed to discuss their relationships. Cartesian geometry, and the

methods of the infinitesimal calculus, do not treat of real motion, and

the concept, if it is introduced at all, is introduced illegitimately

and surreptitiously. Consider what we do when we “plot a curve.” Let

the latter be a parabola having the equation _y_ = 1/2 _x_. Now a

parabola is defined as “the locus of a point which _moves_, so that its

distance from a fixed point is in a constant relation to its distance

from a fixed straight line.” How do we construct such a curve?

[Illustration: FIG. 5.]

We proceed to fix the positions of a series of points in this way:

there are two straight lines, _OX_ and _OY_, at right angles to each

other, and we measure off certain steps along the line _OX_; these

steps are _OX_↓{0·5}, _OX_↓{1}, _OX_↓{1·5}, _OX_↓{2}, and so on, the

small numerals indicating the distance of each point (_OX_↓{0·5}, etc.)

from the origin _O_. We then draw lines perpendicular to the _X_-axis

through these points. We have now to calculate one-half of the square

of each of these lengths _OX_↓{0·5}, _OX_↓{1}, etc., and then we mark

off these calculated lengths along the perpendicular lines. The point

_A_, for instance, is 1/2(0·5)^2 from the point _X_↓{0·5}, _B_ is

1/2(1)^2 from _X_↓{1}, and so on. In this way we obtain a series of

points, _A_, _B_, _C_, _D_, _E_, etc., and these are points on the

locus of the “moving” point.

[Illustration: FIG. 6.]

There is nothing at all about motion here. All that we have done is

to measure lengths. We have made a kind of counterpoint, _X_-points

against _Y_-points, but we have not even made a curve. We connect the

points _A_, _B_, _C_, _D_, _E_, etc., by means of short, straight

lines, and then we may connect together these short lines, and, if we

plot a number of intermediate points between those that we have already

obtained and join these, the points may be so close together that they

may seem to be indistinguishable from a curve. Yet, no matter how

numerous they may be, they can never be connected together so as to

form a curve; we therefore draw a curved line freehand through them,

and at once, in so doing, we abandon our intellectual methods, for our

curve depends on our intuition of _continuously changing direction_.

But if we think about it we shall find that we can form no clear

intellectual notion of continuity and we can only measure the curvature

of a line _at a point in_ the line by drawing a tangent to the curve at

this point, and then by measuring the slope of the tangent. The curve

itself we obviously leave out of consideration.

We cannot conceive of the point moving along the locus _OD_. We can

think of it only as _at_ the places _O_, _A_, _B_, _C_, _D_, _E_, etc.,

but we must neglect the intervals _OA_, _AB_, _BC_, _CD_, _DE_, and so

on, or we can divide them into smaller intervals by supposing the point

to have occupied the positions _f_, _g_, _i_, _j_, between the points

_A_ and _B_, for instance. Yet, no matter how many these intervals

may be, we can only think of the point as being _at_ the places _O_,

_A_, _B_, _C_, _D_, _E_, or at _f_, _g_, _i_, _j_, and so on. We never

think of the intervals themselves, and, if all we think about is the

_position_ of the point, we do not really think of it as in motion at

all. We can _see_ it in motion, but we cannot form an intellectual

concept of its motion. It is not really necessary that we should in the

affairs of everyday life, but for the adequate treatment of problems

involving rates of change science had to wait for the invention of the

methods of the infinitesimal calculus before this disability of the

human mind could be circumvented.

But the moving point occupies _successively_ a number of different

positions in space. If it is a material point that we observe to move

from one place to another, we perceive that a certain interval of our

duration corresponds with the change of position of the point. Duration

was not used up in the occupancy of the different positions _O_, _A_,

_B_, _C_, _D_, _E_, and so on, nor in that of the occupancy of the

indefinitely numerous other positions in which we may place the moving

point, but in the intervals themselves. We have said “duration” and

not “time,” using Bergson’s term. By duration and time we understand

different things.

Time is, for us, only a series of standard events which punctuate, so

to speak, our experienced duration. The unit of time is the sidereal

day, that is, the interval of time between two successive transits

of a fixed star across the arbitrary meridian. But if we try to

conceptualise this interval we find that we can do so only by breaking

it up into smaller intervals, and this we do by using a pendulum of a

certain length which makes a certain number of swings (86,400) during

the interval between the two transits of the star. Thus we obtain a

smaller interval of duration and we call this a second of time. But for

many purposes this interval is too long, and we can again sub-divide

it by making use of a tuning-fork which makes, say, 1000 complete

vibrations in a second; in this way we obtain still smaller intervals

of duration--the sigmata of the physiologists. A sigma, therefore,

represents the interval between the beginning and end of one complete

vibration of a certain kind of tuning-fork; a second, that between the

beginning and end of one complete swing of a pendulum of a certain

length, placed at certain parts of the earth’s surface; and a day,

that between two successive transits of a fixed star across a selected

meridian, after all the necessary corrections have been made to the

observation. These actual occurrences, the positions of the prongs

of the tuning-fork, or those of the bob of the pendulum, or those of

the fixed star do not involve duration. We consider the meridian of

Greenwich as an imaginary line drawn across the celestial sphere, and

the star as a point of light, so that the actual transit is, in the

limit, an occurrence which occupies only an “infinitesimal” interval of

duration. So also with the pendulum and the tuning-fork; the positions

of these things do not “use up” time, and even if the intervals into

which we divide astronomical time are indefinitely numerous no real

quantity of duration is taken up by their occurrence. We know that the

interval between two successive transits of a fixed star are not really

constant, that is, the astronomical day is lengthening by an incredibly

small part of a second each year, but how do we know this? It is

not that we can _feel_ the increments of duration, but just that we

assume that Newton’s laws of motion are true; and hence that the tidal

friction due to the motions of the earth, sun, and moon must retard

the period of rotation of the earth so that the intervals between two

successive transits of a star must become greater.

Thus we do not conceptualise the actual intervals of duration of which

we are able to mark the end-points; they are lived by us, and they are

real absolute things independent of our wills. Suppose we come in from

a long walk, tired and thirsty, and ask the maid to get tea ready at

once. She puts the kettle on the gas stove and then sits down to read.

The water takes, say, five minutes to boil. What do we mean by this?

This is what we mean:--

{_The pendulum _and it has _The time

{ of the clock now swung_ _and now_ and so elapses_

Time { has already on

{ swung_

{ M times M + n times M + 2n times P swings

| | | |

{_The water in _it is now _and now_ _the kettle

{ the kettle at_ and so boils_

{ is at_ on

{ T° T° + t° T° + 2t° 100°

Tempera- { | | | |

ture {_The volume _it is now_ _and now_ It is

{ of mercury in | | and so |

{ the thermo- | | on |

{ meter is_ | | |

{ V V + v V + 2v W

What we call time here is only a series of simultaneously occurring

events. The standard events are the positions of the hands of the

clock on the clock face, that is, lengths of arc recording the number

of swings of the pendulum that have occurred since the beginning of

the operation of the boiling of the kettle. When this began, the hands

of the clock were at, say, 4.30, and the temperature of the water

was then, say, 17° C.; and, when it ended, the hands of the clock

were at 4.35 and the temperature of the water was 100° C. It is only

the simultaneities of these events that we have recorded and not the

interval of duration that they mark. It does not matter how many times

we might have looked at the hands of the clock and the thermometer, we

should still have observed only simultaneities.

But we had to _wait_ for the kettle to boil, and the temperature 100°

was attained _after_ the temperature 90°, and so on. What does this

mean? While we were waiting, the water seemed to take an intolerably

long time to boil. But the maid was reading one of Mr Charles Garvice’s

novels, and “before she knew where she was” the kettle boiled over.

There was a certain interval of duration experienced by her, and

another, but different, interval of duration experienced by us. In each

case there was a stream of consciousness. We felt fatigue, thirst, a

lack of satisfaction, wandering attention, and irritation--all that

was our duration. But the maid was identifying herself with Lady Mary,

who had sprained an ankle and was being helped along by the new, young

gamekeeper, and that was her duration.

There need not be any succession of events in the conceptual

representation of a physical process. There is, for instance, no

succession in such a conception as is represented by the following

diagram--a conception well worth analysis:--

[Illustration: FIG. 7.]

The figure represents a tracing made by a muscle-nerve preparation.

A living muscle taken from an animal has been attached to a light

lever, the end of which makes a scratch on a piece of smoked paper.

The paper is fastened on a revolving cylinder and so long as the

muscle is motionless the end of the lever marks a horizontal line on

the paper. But if the muscle is stimulated so that it contracts and

then relaxes again the lever is pulled up and is then lowered, and so

its point makes a curve on the paper. The nerve going to the muscle

can be stimulated electrically and the moment of the stimulation can

be recorded by another lever, which makes a mark on the paper below

the trace made by the lever which is attached to the muscle. Two

such shocks have been applied to the nerve and they have elicited

two contractions of the muscle and these two contractions have fused

together.

In the actual experiment the operators could _see_ that the muscle

moved, and they could _feel_ that a certain interval of their own

duration coincided with the interval between the first and second

depressions of the key that made the electric shocks. But the extent

of motion of the muscle was too small, and the depressions of the key

succeeded each other too rapidly to be easily observed, and therefore

all these events were made to record themselves on the myogram. The

series of little notches at the base of the figure represent the

movements of the time-lever, that is, they are scratches made on

the paper by a little lever which moves up and down at a rate fixed

beforehand. Now when this time lever had made ten notches on the paper

the first shock was applied to the nerve, and at the eleventh the

muscle began to contract. At the seventeenth notch the second shock

was applied and the muscle continued to contract. At the twenty-fifth

notch the muscle ceased to contract and began to relax, and at the

forty-second notch the muscle had ceased to contract. Everything now

becomes clear and easy to represent mentally; the time-lever makes 100

notches on the paper in a second, so that there was an interval of

0.07 seconds between the two stimuli, and these two stimuli produced a

compound contraction of the muscle lasting for 0.1 second. This is what

the experimenters might have perceived, had human unaided senses been

sufficiently acute. But they are not, and so the crude perception of

the results of the experiment is replaced by a conception of the train

of events involved in the operation. Duration and succession disappear

and the myogram represents only a series of simultaneous events of

this nature; the first stimulus occurs simultaneously with the tenth

movement of the time-lever; the second stimulus with the seventeenth,

and so on. In seeing the experiment the operators had to _wait_ for one

phase to be completed before they could observe another one, but in

reasoning about it all the phases are spread out and are present in the

conception at once. The duration was in the operators but not in the

experiment: it was experienced, but it disappears when the results of

the experiment are conceptualised.

A succession of events is in ourselves and not in the events observed.

If a point is said to move along the locus _OD_ through the positions

_A_, _B_, _C_, it is we that have the feeling of succession, and

the whole trajectory, or locus, or path of the point corresponds

with a portion of our duration. The operation of boiling the kettle

corresponds with a portion of our duration, which in its turn

corresponds with that part of our duration which was marked by the

positions of the hands of the clock. Thus we perceive a simultaneity

in these two trains of events, and this enables us to assign a

certain period of astronomical time to the operation of raising the

temperature of the water, in the conditions of the experiment, from

17° C. to 100° C. But there is nothing absolute in this interval

of astronomical time: what is absolute is that certain successions

of events always correspond with other successions of events. A

certain number of swings of a seconds-pendulum always corresponds

with a certain rise in temperature of a definite mass of water which

is in thermal contact with an indefinitely large reservoir of heat

at a certain temperature, and, no matter how often we repeat this

experience, the same simultaneity is always to be observed. Thus what

the physicist considers is not intervals of his own duration but series

of correspondences--that is, correspondences of certain standard events

with the events which he is studying.

In reality time, in the sense of the astronomer’s time, does not enter

into the methods of the mathematical physicist. Let us suppose that he

is investigating the change that occurs in a material system between

the two moments of time _t_↓{1} and _t_↓{2}, these moments being

separated from each other by a period of duration that we can feel. Let

the system be, say, the earth and moon; the first body being supposed

to be motionless, and the second being supposed to have a certain

tangential velocity of movement. If the interval _t_↓{1} to _t_↓{2}

is really an interval of astronomical time, the problem, what is the

difference of position of the moon owing to the gravitation of the

earth, is incapable of solution, and even if we reduce the interval of

time indefinitely while still supposing that it is a finite interval,

the mathematical difficulty remains. We then replace the finite

interval _t_↓{1} to _t_↓{2} by the differential _dt_, which means

that the two phases of the system, motionless earth and moving moon

at the time _t_↓{1}, and motionless earth and moving moon at the time

_t_↓{2}, are separated by an interval of time _dt_, which is smaller

than any finite interval that we can conceive. We must then integrate

the differential of the position difference so as to obtain the real

difference in the condition of the system after the finite interval

of time _t_↓{1} to _t_↓{2} has elapsed. Thus mathematics, incapable

of dealing with real intervals of time, _evades_ this difficulty by

considering tendencies, not real occurrences.

Things that happen in a part of inorganic nature arbitrarily detached

from the rest, and investigated by the methods of mathematical physics,

do not endure. Let us suppose that we take some silver and add nitric

acid to it: the metal dissolves. We can then add hydrochloric acid

to the solution and precipitate the metal in the form of chloride;

and we can then fuse this chloride with carbonate of soda, or some

other substance, and so obtain the metal again. If we work carefully

enough we can repeat this series of operations again and again and the

original portion of silver will remain unchanged both in nature and

in mass. All the chemical reactions into which it has entered have

not affected it in any way; that is to say, these reactions have not

endured.

If we inject a serum, containing a toxin, into the blood stream of

a susceptible animal, certain things happen. The animal will become

ill, but, provided that the amount of serum which has been injected

was not too great, it will recover. If the toxin be again injected

a reaction occurs, but the animal does not become so ill as on the

first occasion, and after a number of injections the dose administered

may be so great as to kill a susceptible animal but may yet produce

no effect on the animal which is the subject of the process of

immunisation: immunity has been conferred on it. Now can we compare the

two operations, that of the solution and precipitation of the metal

and that of the immunisation of the animal? We can to some extent, but

the analogy soon fails, and indeed we should not attempt to formulate

a theory of immunity on a physico-chemical basis if we did not start

with the assumption that the series of operations was one in which

only physico-chemical reactions were involved, that is to say, there

is nothing in the phenomena of immunisation that suggests that what

occurs in the animal body is similar to what we can cause to occur in

inorganic materials outside the tissues of the living organism. We

start with the assumption that the administration of the toxin causes

the formation of an antitoxin in very much the same sort of way as

the administration of hydrochloric acid to a solution of nitrate of

silver causes the formation of chloride of silver. This antitoxin

then neutralises the dose of toxin which may be administered after

the process of immunisation has been effected, very much in the same

sort of way as a certain amount of some acid can be neutralised by an

equivalent amount of some base with which the acid can combine. If

the reader will analyse any of the theories of immunisation current

at the present day he will find that these are the physical ideas

that are involved in it.[4] But physiological science has the much

more formidable task of explaining the persistence of the immunity.

The animal rendered immune to the toxins produced by certain species

of bacteria may remain so for many years, that is, for a very long

time after the antitoxins originally produced by the reaction of the

tissues to the toxins first administered have disappeared. We must

imagine, therefore, that the anti-substances produced originally

by the reaction of the toxin are produced again and again by the

tissues of the susceptible animal, for the latter may resist repeated

infections, that is, repeated doses of toxin, without illness. But

then the tissues of the animal body are transitory substances and they

do not persist unchanged. Muscles, glands, connective tissues, even

nerve-fibres and nerve-cells undergo metabolism, and the chemical

substances of which they are composed break down into the excretory

products, pass out into the blood stream, and are eliminated from

the body; while at the same time these tissues are continually being

renewed from the nutritive substances in the blood and lymph. It is the

_organisation_ of the tissues--their form and modes of reaction--that

endure, but the material substances of which they are composed are

in a state of continual flux. Yet the organisation of these tissues

does not persist unchanged, for it is continually _responding_ to new

conditions experienced by it. The reactions that occur when a toxin

is administered to a susceptible animal affect the organisation of

its tissues in such a way that the latter acquire the capability of

producing antitoxins which may--if we like to say so--neutralise the

toxins that enter into them when they become infected. The reaction

endures. But this is a different thing from saying that the process is

a physico-chemical one alone.

[4] Except that, of course, the reactions that are supposed to occur

are very complex ones.

This is what we must understand by the duration of the organism.

Everything that it experiences for the first time persists in its

organisation. It acquires the ability of responding to some stimulus

by a definite, purposeful reaction, the effect of which is to aid

it in its struggle for existence; and this reaction, once carried

out, becomes a “motor habit” or the basis of a reflex, or in some

other way, as in the process of immunisation, remains a part of the

modes of functioning of the animal. In our behaviour certain cerebral

nerve tracts become laid down and continue to exist throughout life,

modifying all our future experience. Our past experience accumulates.

There must be direct continuity in our flux of consciousness, for

no perception seems ever to fade absolutely from memory. This

continual addition of perceptions to those that already exist makes

our consciousness ever become more complex, so that a perception

experienced for the first time is never quite the same when it is again

experienced. The first time that we go up and down in an elevator,

or sit on a “joy-wheel,” or ascend in a balloon or an aeroplane, or

become intoxicated, constitutes an unique event in our lives, and we

experience a “new sensation.” What the blasé man of the world complains

of is this accumulation, or rather persistence, of his experiences. A

repetition of the same stimulus never again begets the same perception.

The first hearing of a modern drawing-room song may be enjoyable, but

the next time we hear it we are not interested, and by-and-bye it

becomes very tiresome. The first hearing of a great symphony usually

perplexes us, and we are perhaps repelled by unusual harmonies, or

progressions, or strange modulations, but subsequent hearings afford

increasing pleasure. We say that there was “so much in it” that we

did not understand it, yet precisely the same series of external

stimuli affected our auditory membranes on each occasion, and the same

molecular disturbances were transmitted along our afferent nerves

to the central nervous system, where the same physical effects must

have been produced. The difference in all these cases between the

repetitions of the same stimuli was that the later ones became added

to the earlier ones, so that the state of consciousness produced by,

or which was concomitant with, these external stimuli was a different

state in each case.

This is the duration of the intelligently acting animal: it is not

merely memory, but memory and the accumulation of all its past modes

of responding to changes in its environment, whether these modes of

response were conscious ones (as in the case of an intelligently

performed or “learned” action), or unconscious ones (as, for instance,

in the case of the acquirement of immunity by an animal which had

become able to resist disease). It is not merely the experience of

the individual organism, but also all the experience of those things

which were done or experienced by the ancestry of the organism, and

which were transmitted by heredity to the progeny. Motor habits are

formed, so that much the same series of muscular actions are carried

out when a stimulus formerly experienced is again experienced. Pure

memory remains, so that the images of past things and actions somehow

persist in our consciousness. Physical analogy suggests that these

images are inscribed on the substance of the brain or are stored away

in some manner; but, apart from the incredible difficulty of imagining

a mechanism competent for this purpose, it is obvious that we thus

apply to the investigation of our consciousness (which is an intensive

multiplicity), the concept of extension which can only apply in all

its strictness to the things outside ourselves on which we are able

to act. All these motor habits, functional reactions, and memory

images are our duration or accumulated experience. The motor habits

and those functional habitual reactions of other parts of the body

than the sensori-motor system are the basis of our actions, but the

memory images are, so to speak, pressed back into that part of our

organisation which does not emerge into consciousness. Only so much

of them as bear on the situation in which we, for the moment, find

ourselves and which may therefore influence our actions, flash out

into consciousness. As “dreamers” we indulge ourselves in the luxury

of becoming conscious of these memory images, but as “men of action”

we sternly repress them, or so much of them as do not assist us in the

actions that we are performing. Yet it is in the experience of each of

us that, in spite of this continual inhibition, parts of our memories

slip through the barriers of utility and surreptitiously remind us of

all that we have been and thought.

* * * * *

Thus we simplify the stream of our consciousness. That of which we

are conscious at any time is never more than a part of our crude

sensation: we never perceive more than a small part of all that our

organs of sense transmit to our central nervous system. But even these

chosen perceptions of the external world are so rich, so chaotic and

confused, that we are unable to attend to them all at once and we

therefore “skeletonise” the contents of our consciousness. We think

about it a bit at a time. It is an unitary thing, unable to be broken

up, but we look at it from a great number of different points of view,

so to speak; and then, fixing our attention on some aspect of it, we

agree to ignore all the rest. We thus detach parts of it from the rest

and, having thus arbitrarily decomposed it, we call these separate

aspects the elements of our perceptions, and confer upon them separate

existence in space and time. We remember and classify things and

group together all those that seem to resemble each other. We form

genera, agreeing to ignore all but the most general characteristics of

the things which we try to conceptualise. We do not think separately

about all the dogs or horses or fishes that we have ever seen, but we

group all these animals into species, and it is usually the species

that we think about when the idea of a dog or a horse or a herring

emerges into our consciousness. When we think about a tramcar we do

not think about all the separate vehicles that we have seen, nor

about their colours, nor the advertisements on the boards outside,

nor the people hanging on to the straps inside. Just so much of the

experience of what is relevant to the purpose of our thought enters

into our idea of the tramcar: it is a conceptual vehicle that we

think about. Such is the nature of the concepts that form the basis

of our reasoning: they are generalised aspects of our experience of

nature, usually poorer in content than were the actually perceived

things, except when it is necessary that some individual thing seen

or otherwise experienced should be investigated or reasoned about.

All our descriptions of nature are conceptual schemes. The world of

perception, says William James, is too rich to be attended to all at

once, but in conceptualising it we spread it out and make it thinner,

and we mark out boundaries and division lines in it that do not really

exist. It is this generalised nature that is the subject matter of

our reasoning of pure science; and it is these concepts that form the

matter of all our descriptions. We do not describe nature “as we see

it,” it is our conceptions that we write about. Genera and species

and varieties do not really exist in the animate world: all these are

logical categories generated by our thought, concepts that facilitate

our descriptions. When an anatomist gives an account of the structure

of an animal he does not say what it looks like, nor as a rule does

he content himself by making a photograph of his dissections. For him

the animal is a complex of muscles, skeleton, nerves, glands, and so

on, and in his drawings all these things are given an individuality

that they do not really possess. In the living creature there were no

such sharply-distinguished organs as a good drawing represents: all

are bound together and are continuous. But for practical convenience

in description--that is, in the long run, that we may act upon these

things, we isolate from each other aspects that are in reality one

unitary whole.

* * * * *

The universe, that is, all that is given to us, presents itself

as immediately perceived phenomena which are then conceptually

transformed. It is an aggregate of things--gross matter, particles,

molecules, atoms, and electrons. These things have separate existence

and shape, so that each of them lies outside all other things--we apply

to them the category of extension. They possess properties--that is,

they are hard, or heavy, or hot, or cold, or they are coloured, or they

smell, and so on--we thus apply to them the category of inherence. They

are not things that are immutable, for they change in place, or are

transformed in other ways, that is, they are acted upon by energies.

But beneath the properties of the things, or the transformations that

they undergo, we imagine something that has properties and which

transforms: it is not convenient that we speak solely of attributes or

transformations as entities in themselves, for we think of things as

having properties and being subject to transformations. Thus we apply

the category of substance.

Has this universe that we construct from the data of sensation

objective reality? We are led quite naturally by our study of

physiology to the notion of idealism. We see that our perception

of things, that is, our knowledge of the universe, depends on the

integrity of functioning of certain bodily structures, and upon the

condition that in men in general this integrity of functioning is

normal, that is, common to the great majority of mankind.

To say that a thing exists is to say that it is perceived in some way;

that immediately or remotely it affects our state of consciousness.

To say that the star Sirius exists is to say that the stimulation

of the retina by a minute spot of light transmits certain molecular

disturbances along the optic nerve, and that other molecular

disturbances are set up in the tissues of the central nervous system.

Even if we do not see those dark stars that we know to exist, there are

still evidences of their being that in some way affect the instruments

of the astronomer and lead to their being perceived. Even if we do

not actually see the emanations from a radio-active substance, we can

cause these emanations to produce changes in something that we can

see. We speak of the star as a minute spot of coloured light. But if

we are short-sighted the spot becomes a little flare, and if we are

colour-blind the hue of the star is different from what it is to normal

persons. If we put a drop of atropine into one eye and then close the

other, objects appear to lose their distinctness, but if we close

this eye and then open the other, the original sharpness of vision

returns. When we are bilious, wisps and spots may appear on a sheet

of white paper that at other times was blank. If we take an overdose

of quinine, rustlings and singing noises become apparent even in

conditions that ought to preclude all sensation of sound. If we have

a bad cold, we do not smell substances which at other times strongly

affect our olfactory membranes. When we become intoxicated, a host of

aberrations of sense displace our normal perceptions of things.

Our perception of the universe, therefore, depends on the normal

functioning of our organs of sense, that is, such modes of functioning

as we can describe and communicate to others, and which are thus

common to the majority of other men and women. These perceptions

resulting from the normal functioning of the organs of sense constitute

givenness, and we enlarge, or conceptualise this givenness and call it

the subject matter of science. But what is this reality that we say

is external to us? It is, we see, our inner consciousness. If we walk

along a road in the dark we can feel what is the nature of the path on

which we tread, whether stones or gravel, or sand or grass. But this

feeling is obviously not in the soles of our boots, and neither is it

in the skin of the feet, for we should feel nothing if the afferent

nerves in the legs were severed. Is it then in the brain? It would

appear to be there, but it disappears if certain tracts in the brain

are injured.

All that we can say is that the appearance of reality of things outside

ourselves is only the ever-changing condition of our consciousness.

This is all that we immediately know, and if we say that there is an

universe external to ourselves we thus project outside our own minds

what is in them; and we construct an environment which may or may not

exist, but which we have no right to say does exist. A philosophy based

on the science of the organism would appear to be restricted to this

idealistic view of the universe. When we come across it for the first

time when we are young it appeals to us with all the force of exact

reasoning, and yet it has all the charm of paradox. There is no part

of our intuitive knowledge which appears to us to be more certain than

this distinction between ourselves and an outer environment: we know

that our conscious Ego is something different from our body--and we

know that outside our body there is something else. Yet the idealistic

view so appeals to the intellect that we cannot think speculatively

about it without, at times, almost convincing ourselves of the

unreality and shadowiness of all that at other times seems most real

and tangible; and we indulge in these speculations all the more readily

because we know that whenever we begin to _act_, the intuitively

felt body and outer world will return to us with all their original

conviction of reality.

Some such system of idealism must generally characterise a system of

philosophy founded on pure reasoning. We cannot but feel that the

universe that we construct is one that depends on our perceptions: it

is our perceptions. The essence of a thing is that it is perceived. If

there were no mind to perceive it, would it exist? The universe is our

thought, and we, that is our thought, exist only in the Thought of an

absolute Mind which we call God. Such is the metaphysics to which the

study of sensation led Berkeley.

The metaphysics of science has taken another turn. It is true

that men and women see something outside themselves which differs

slightly in different individuals--these differences are due to what

we call the “personal equation.” The image of the universe seen by

some individuals may differ profoundly from the image seen by some

others, or most others; but a well-marked gap separates these slight

individual deviations in the images seen by normal individuals from

the large deviations seen by those whose perceptions are what we call

pathological ones. The normal universe common to the majority of

men and women is an aggregate of molecules in motion. But this is a

conclusion with which modern physics has been unable to remain content,

for molecules must be able to act on each other across empty space, and

this is inconceivable. The universe therefore consists of a homogeneous

immaterial medium, the ether of space, and this is the true _substantia

physica_. Molecules and radiation are conditions of the ether, and for

the physicist it is the only reality. The “materialism” of our own

time is therefore the belief in the existence, unconditioned by time

or anything else, of the ether, or physical continuum; a homogeneous

medium, of which matter and energy, and the consciousness of the

organism, are only states or conditions.

The materialism of the twentieth century, like the idealism of

Berkeley, thus finds that there is something outside our own

consciousness that possesses absolute existence. To the materialist it

is the ether of space, and to Berkeley it is the existence of absolute

Mind. But if our desire to avoid metaphysics is a genuine one, we

must reject the notion of the universal ether no less than we must

reject the notion of an absolute Mind, and we must rest content with

pure phenomenalism. For each of us there can be no existence except

that which is perceived or conceptualised. There is nothing but our

own consciousness; there cannot even be an Ego which perceives; there

is only perception. We never do really believe this in spite of our

professions of reason. We find on strict self-analysis that we believe

that there is an Ego that perceives and that there are other Egos

that perceive, and that the universe which our Ego perceives is also

the same universe that other Egos perceive. If we did not believe that

there were other men and women that perceived--other consciousnesses

like our own, all that part of our own behaviour that we call morality

would be meaningless. In a philosophy of pure idealism other men and

women are only phenomena; only bodies moving in nature. Why, then,

should these elements of our consciousness influence the rest of our

consciousness as if they were men and women like ourselves. All this

amounts to saying that while our speculative thought suggests to us

that all that exists is our stream of consciousness, our actions must

convince us that there are other thinking individuals like ourselves.[5]

[5] The reader may recognise in this argument that of Driesch’s _Three

Windows into the Absolute_.

Even if we do surrender ourselves to phenomenalism and try to believe

that all that exists is our own consciousness, the fact of our duration

would suggest to us that this present consciousness is not all. Our

reality is not only that which is present in our minds now, but all

that was ever present in our mind. All that we have ever thought and

done persists and forms our conscious and unconscious experience. This

past of ours is something that is ever being added to, or becoming

incorporated with, our present state of consciousness; and if it is

something other than that which we now perceive and conceptualise, it

is something that has an existence of its own.

We must believe that there is something that we perceive, and not

that we merely perceive. For the phases of our immediate givenness,

that is, those things which were present in our minds from moment to

moment of the past were connected together and had direction, and this

direction was something that could not be influenced by our will, and

may even have been contrary to our will. Something that is very hot

always cools, a wheel that is revolving of itself always comes to a

stop, a pendulum ceases to swing, a stone that is rolling down a hill

continues to roll. Let us look back at a fire that was going out: it

is now nearly dead; let us start a pendulum to swing and then go away:

when we come back the pendulum is still swinging but the amplitude

of its vibrations is now less than it was; let us look away from the

stone that was falling: when we look again it is still falling but it

is not where it was. In all our givenness, in all the phenomena that

we perceive, there is something that is determined and unequivocal,

something that goes its own way apart from our consciousness of it.

Above all, we have the conviction of absoluteness in our sense of

personal identity. We, that is our Ego, are something that endures, and

we can trace no beginning to our identity, and we have no intuition

that it will cease to exist. Our Ego is now the same Ego that it was

in the past, and round it something has accumulated--the memories of

our former perceptions, and the habits that these have engendered. Did

our Ego create this from itself? Was it not rather a centre of action

which, residing in an existence other than itself--the absolute which

we call the universe--modified that existence and continually acquired

new relationships to it?