lOME UNIVERSITY LIBRARY OF MODERN KNOWLEDGE

No. 35

™^"»s». xivv

Editors:

HERBERT FISHER, M.A., F.B.A. Prof. GILBERT MURRAY, Litt.D,,

LL.D., F.B.A. Prof. J. ARTHUR THOMSON, M.A. Prof. WiLLIAM T. BREWSTER, M.A.

THE HOME UlTIVEESITY LIBKAEY

OF MODEEIST KITOWLEDGE

i6mo cloth, so cents net, by mail 56 cents

PHILOSOPHY AND RELIGIONi

Just Published PROBLEMS OF PHILOSOPHY . By Bebtrand RussEii;

BUDDHISM By Mrs. Rhys Davids

ENGLISH SECTS By W. B. Selbib

THE MAKING OF THE NEW

TESTAMENT . By B. W. Bacon

ETHICS By G. E. Mooke

MISSIONS By Mrs. Creighton

Future Issues

THE OLD TESTAMENT .... By George Moore BETWEEN THE OLD AND NEW

TESTAMENTS By R. H. Charles

COMPARATIVE RELIGION . . By J. Estlin CARPENTSa A HISTORY OF FREEDOM OF

THOUGHT . . . . . . . >: .. . By J. B. Buby

THE PROBLEMS OF PHILOSOPHY

I

BY

BERTRAND RUSSELL

M.A.. v.R.S,

LECTURER AND LATE Fi:LLOW OF TRINITY COLLEGE CAMBRIDGE

•C^

NEW YORK HENRY HOLT AND COMPANY

LONDON WTLLIAMS AND NORGATE

PREFACE

In the following pages, I have confined myself in the main to those problems of philosophy in regard to which it seemed to me possible to say something positive and-^ constructive, since merely negative criticism seemed out of place. For this reason, theory of knowledge occupies a larger space than metaphysics in the present volume, and some topics much discussed by philosophers are treated very briefly, if at all.

I have derived valuable assistance from unpublished writings of Mr. G. E. Moore and •'' Mr. J. M. Keynes : from the former, as re- gards the relations of sense-data to physical objects, and from the latter as regards prob- ability and induction. I have also profited greatly by the criticisms and suggestions of Professor Gilbert Murray.

CONTENTS

^Kii 1

piaig I APPEARANCE AND REALITY , . 9

II THE EXISTENCE OF MATTER , . 26 ni THE NATURE OF MATTER ... 42 ^ IV IDEALISM 68

V KNOWLEDGE BY ACQUAINTANCE AND

KNOWLEDGE BY DESCRIPTION . . 72

VI ON INDUCTION ..... 93

VII ON OUR KNOWLEDGE OF GENERAL

PRINCIPLES . . . . . 109

VIII HOW A PRIORI KNOWLEDGE IS POSSIBLE 127

IX THE WORLD OF UNI VERS ALS . .142

X ON OUR KNOWLEDGE OF UNIVERSALS . 168

XI ON INTUITIVE KNOWLEDGE . . .174

vii

viii CONTENTS

OHAPTBB PA.QH

XII TRUTH AND FALSEHOOD . . .186

XIII KNOWLEDGE, ERROR, AND PROBABLE

OPINION 204

XIV THE LIMITS OF PHILOSOPHICAL KNOW-

LEDGE 220

XV THE VALUE OF PHILOSOPHY . . 237

BIBLIOGRAPHICAL NOTE . . . 251

INDEX 253

THE PROBLEMS OF PHILOSOPHY

CHAPTER I

APPEARANCE AND REALITY

IsJhei:gjany_knowledge inthe world which . . is so certain that no reasonable man could^ doubt it ? This question, which at first sight might not seem difficult, is really one of the most difficult that can be asked. When we have realised the obstacles in the way of a straightforward and confident answer, we shall be well launched on the study of philo- sophy— for philosophy is merely the attempt to answer such ultimate questions, not carelessly and dogmatically, as we do in ordinary life and even in the sciences, but critically, after exploring all that makes such 9

10 THE PROBLEMS OF PHILOSOPHY

questions puzzling, and after realisiiig all the vagueness and confusion that underlie our ordinary ideas.

In daily life, we assume as certain many things which, on a closer scrutiny, are found to be so full of apparent contradictions that only a great amount of thought enables us to know what it is that we really may believe.

In the seari^h ^^^ ^^^^^^r^^YilJJ:J^J]!^!^Iirf^^ ^^ I^Arfjn ^^ifV^ r>nr preseij^t cxperiences^ ond In gr>r^P ^"^rii^ea T^^ dftliht, knowlpdgp is t,^ be jdexivfid^-frflaaajliem. But any statement as to what it is that our immediate experiences make us know is very likely to be wrong. It seems to me that I am now sitting in a chair, at a table of a certain shape, on which I see sheets of paper with writing or print. By turning my head I see out of the window buildings and clouds and the sun. I believe that the sun is about ninety-three million miles from the earth ; that it is a hot globe many times bigger than the earth ; that, owing to the earth's rotation, it rises every morning, and will continue to do so for an indefinite time in the future. I believe that,^ if any

APPEARANCE AND REALITY H

other normal person comes into my ropm, he "^ IfviJl see the same chairs and tables and books "^^ and papers as I see, and that the table which

Ksee is the same as the table which I feel iressing against my arm. All this seems to e so evident as to be hardly worth stating, xcept in answer to a man who doubts v/hether I know anything. Yet all this may be reasonably doubted, and all of it requires much careful discussion before we can be sure that we have stated it in a form that is wholly true.

t To make our difficulties plain, let us con- centrate attention on the table. To the eye p it is oblong, brown and shiny, to the touch it is smooth and cool and hard ; when I tap it, it gives out a wooden sound. Any one else who sees and feels and hears the table will agree with this description, so that it might seem as if no difficjiltj^ would arise ; but as_sogn^s we^try to be more precise our troujblesJaegin. Although I believe that the table is " really " of the same colour all over, the parts that reflect the light look much brighter than the other parts, and some

12 THE PROBLEMS OF PHILOSOPHY

parts look white because of reflected light. I know that, if I move, the parts that re-* fleet the light will be different, so that the apparent distribution of colours on the table will change. It follows that if several people are looking at the table at the same moment, no two of them will see exactly the same distribution of colours, because no two can see it from exactly the same point of view, and any change in the point of view makes some change in the way the light is reflected.

For most_BTaciiiial..purpGses these differ- ences are unimportant, but to the painter they are all-important : the painter has to unlearn the habit of thinking that things seem to have the colour which common se^nse says they "reajly" have, and to learn the habit of seeing things as they appear^ Here we have already the beginning csf one of the distinctions that cause most trouble in philosophy — the . -Ji.llinctjon Jbetween ,. .'lap- pearance '^ and " reality," between^whaT things seem to be aiid what they are. The pamter wailtS^to know what fliings**seem to

]

APPEARANCE AND REALITY 13

be, the practical man and the philosopher want to know whftt theyf'are;^'but the philo- sopher's wish to know this is stronger than the practical man's, and is more troubled by- knowledge as to the difficulties of answering the question.

To return to the table. It is evident from what we have found, that there is no colour which pre-eminently appears to be the colour of the table, or even of any one particular part of the table — it appears to be of different

j colours from different points of view, and there is no reason for regarding some of these as more really its colour than others. And we know that even from a given point of view the colour will seem different by

' -Q^tificial light, or to a colour-blind man, or to a man wearing blue spectacles, wMle in the dark there will be no colour at all, though to touch and hearing the table will be un- changed. Thus colour is nLQJLSjamething which isinherenLofi^the table, but something de- pending upon the tafile and the spectator and the way the light falls on the table. When, in ordmury lifej wej£eak of the colour

14 THE PROBLEMS OF PHILOSOPHY

of the table, we only mean the sort of colour which it will seem to have to a normal spectator from an ordinary point of view under usual conditions of light. But the other colours which appear under other conditions have just as good a right to be considered real ; and therefore, to avoid i favouritism, we are compelled to deny that, in itself, the table has any one particular ' ' colour.

-The^same thing applies to the-^texture.

With the naked eye one can see the grain,

but otherwise the table looks smooth and

even. If we look at it through a microscope,

we should see roughnesses and hills and

valleys, and all sorts of differences that are

I imperceptible to the naked eye. Which of

\\ these is the " reay table ? We are~imtua.

\\ rally tempted to say that what we see

l\ through the microscope is more real, but

\ihat in turn would Jtne^-i^h^^ still

mtH*e- powerf ul__mi(grDscope. '^"^J^'^iien^" we

'--'''cannoFjrust what we see v^Mti the naked

'< — ^it^a- wiiy should we trust what we see

^through a microscope ? Thus, again, the

APPEARANCE AND REALITY 15

confidence in our senses with which we be- gan deserts us.

The .g^gge cj theJ^ablei^jaaJ^ter^^We are all in the habit of judging as to the " real " shapes of things, and we do this so unreflectingly that we come to think we actually see the real shapes. But, in fact, as we all have to learn if we try to draw, a given thing looks different in shape from every different point of view. If our table is *' really '- rectangular, it will look^lrom" almost alLpLOiiiis^f" view,"" as if 'ilrliaa- f wo acute angles and two obtuse angles. If opposite sides are parallel, they will look as if they converged to a point away from the spectator ; if they are of equal length,, .they will look as if the nearer side were longer. All these things are not commonly noticed in looking at a table^ because experience has taught us to jsonstruct the "real" shape fcom the anpn rpnt. gh n pf>. and the *' real " shape < is what interests us as practical men. But tteJ.l?^L'' ^tep?_ js not what \ye see ; it is \ something. J|if erred from what ^we^ see. And s wharwe see is constantly changing in shape

/

;>

^

16 THE PROBLEMS OF PHILOSOPHY

as we move about the room ; so that here again the s^ses seem not to give us the truth about the tabla . itself ,but_ Quly , ^bout-ihe _jappearance of the table.

SirniTaF"difficultres arise when we consider the sense of touch. It is true that the table always gives us a ^sensation of hardness, and we feel that it resists pressure. But the isensation we obtain depends upon how har^ we press the table and also upon what partj of the body we press with ; thus the various^ ' sensations due to various pressures or variolas parts of the body cannot be supposed to- re veal directly any definite property of the ^ table, but at most to be si^ns of sornje^ property which perhaps causes'^all the s^i:^ sations, but is not actually apparent in any/ of them. And the same applies still more obviously to the sounds which can be elicited by rapping the table. *

/ TJfeus it becomes evident that thejreal table, J ^f fh^e is one, is not the same as what we imiae'diate^y e^^enence^ by sight or touch or hearing. The real table, if there is one, is \ V ijtot immediately known to us at all, but must

\-

APPEARANCE AND REALITY 17

be an inference from what is immediately \ known, llenee, two v-ery difficult questions atlSnce aif?se> jiamely , |j.\lg there a real table > I at all ? f t^^ so, what sort of object can it 1

It will help us in considering these questions to have a few^simple terms of which the j\ meaning is definite and clear. Let us give \ Uhe name of " sense.-^g-tg, " to the things tha,fc. j ,] arft^ nngj^ediately known in sensation: such things as colours, sounds, smells, hardnesses, roughnesses, and so on. We shall give the name " sensation " to the experience of ? being immediately aware of these things, i Thus, whenever we see a colour, we have a | sensation of the colour, but the colour itself l is a sense-datum, not a sensation. The colour is that of which we are immediately aware, and the awareness itself is the sensation. It is plainJJaat tf we-are^to know anything abQut_t^he table, it^piust be by means of the sense-data— brawn.,., colour, oblong shape, smoothness;" ^Tc.—wEich we assocfate -oyith the- table j~ but for-the Teasonirwhich, have jcn given, wecannot say that the table is the*

18 THE PROBLEMS OF PHILOSOPHY

sense-data, or even that the sense-data are directly properties ^ of the table. Thus ai^ problem arists as to the relation of the sense- -data to the real table, supposing .there is such «, thing. -

,./ThfiL;reiil table, jLifc. exists, we will call a

! "physical object." Thus we have to consider

the relation pi sense-data to physical objects.

The collection of all physical objects is called

. "matte;'." Thus our two questions may

I i "^'be re-stated as follows : (1) Is there any

^1 J f such thing as matter ? (2) If so, what is its

"^^4 nature ?

, ,^,/ The philosopher who first brought pro-

minently forward the reasStts foj*. regarding

T^^fiie immediate_oBjeTt^^ senses as not

\ existing in3ependently of us was Bishop

^Berkeley (1685-1753). His Three Dialogues

"between Tlylas and Philonous, in Opposition.

to Sceptics and Atheists, undertake to prove

t^hat there is no such, thing as matter. at all.

and that the world consists of nothing but

nunds.ajxd. their idej3.s. Hylas has hitherto

believed in matter, but he is no match for

Philonous, who mercilessly drives him into

H

i| APPEARANCE AND REALITY 19

contradictions and paradoxes, and makes his own denial of matter seem, in the end, as if it were almost common sense. The arguments employed are of very different value: some are important and sound, others are confused or quibbling. But

Berkeley retains the merit of having shown i

II -— — .,.1, ,^,, ^ f

4iat Jthe existence dt'matter'ls^ enable of .' being denied" without absurdity, and^that if

^liefe are any things that exist independcni&y" ; T ' of^usjbhey cannot be the immediate objecta// ^ "^

of our sensations.- "^- ---. \ t «

There are two different questions involved when we ask whether matter exists, and it is important to keep them clear. W,acommonly mean by " matter '' something which "'is"" opposed:^ T6"*^*lnind," something which we tlunk-ef-as ucuupying space and as radically

,jnc^able-©l-anyS5rl 61 thought or conscious-] ness^.^-it is chiefly in this sense that Berkeley \ denies matter ; that is to say, he does not • deny that the sense-data which we commonly take as signs of the existence of the table are really signs of the existence of something inde- pendent of us, but he does deny that this some-

i

20 THE PROBLEMS OF PHILOSOPHY

thing isCnon-mental,- thatdt.isLJaeither mind, nor ideas entertained by some mind. Hel admits that there must be something which continues to exist when we go out of the roomj or shut our eyes, and that what we calj seeing the table does really give us reason for believing in something which persists even when we are not seeing it. But hfe thinks that this something cannot be radi- cally different in nature from what we see, and cannot be independent of seeing altogether, though it must be independent of our seeing. He is thus led to regard the *' real " table as an idea in the mind of God. Such an idea has the required permanence and independence of ourselves, without being — as matter would otherwise be — something quite unknowable, in the sense that we can only infer it, and can never be directly and immediately aware of it.

Otfeer-pMosepligrs since Berkeley have also held that, although the t^^^a.do^s ,not depend for its existence upon being seen by me,'"'Tr";3Sprndepeiid upon bmng 'seen (or otherwise apprehended in sensation) hy some

APPEARANCE AND REALITY 21

mind — not necessarily the mind of God, but mSre often the whole collective mind of jthe imiverse. This they hold, as Berkeley

7tees~ chiefly because they think there can be nothing real — or at any rate nothing known to be real — except minds and their thoughts and feelings. We might state the argument by which they support their view in some such way as this : " Whatever can be thought of is an ~iHea Tn the

XTmird~^©f'-4h©-^rson thinking of it. ; tberef ore

— »o%h«ig^cah be thought of except ideas in minds ; therefore anything else is incon-

^j^pivabl^ -«ft4'-*wli:;i ^ is^ ineoncei vable cannot exist."

Sucli^ 311 argument, in my opinion, is iallaciqus ; and of course those who advance it do not put it so shortly or so crudely. But whether valid or not, the argument has been very widely advanced in one form or another ; and very many philosophers, perhaps a majority, have held that there is nothing real except minds and their ideas. Such philo- sophers are called *' idealists." When they me lo explaining matter, they either say.

22 THE PROBLEMS OF PHILOSOPH^

like Berkeley, that matter is really nothing^ but a collection of ideas, or they say, like, III Leibniz (1646-1716), that what appear^ a^ 11 matter is really a collection of more or less rudimentary minds.

But these philosophers, though they deny matter as opposed to mind, nevertheless, in another sense, admit matter. It will be remembered that we asked two questions ; namely, (1) Is there a real table at all ? (2KIf so, what sort of object can it be ? NdV both Berkeley, and Leibniz admit that th^i'e^ is SL real table, but Berkeley says it is certain ideas in the mind of God, and Leibniz sSjS^ it is a colony of souls. Thus both of theiriK answer our first question in the affirmgtfive, and only diverge from the views' of ordi- nary mortals in their answer to our second question. In fact, almost all philosophers, seem to be agreed IHaOHere is^aTeal'taBTe :;| th^^almost--€tlP^ree~*fliat, howevei' much OUT sense-data — colour, shape, sm^)othness.. etc.!.— mayldepend upori""us, yet their oc-- currence is a sign of something existing independently of u^, something diilernr

]:ARANGE ANirWALITY 1 2fe

APPEARANCE

perhaps, completely from our sense-data, and-~yet.jto be regarded as causing those sense-data whenever we are in a suitable relation to the feal table.

Now obviously this point in which the philosophers are agreed — the view that there is a real table, whatever its nature may be — is vitally important, and it will be worth while to consider what reasons there are for accepting this view before we go on tothe / f urtfier-questioR- asrt?cHJT'G^Tra:fiire of the real/ / table. Our next chapter, therefore, will bc» concerned with the reasons for supposing/ that there is a real table at all. :> \ \ ,

Before we go farther it will be well to consider for a moment wkat it is that we have discovered so far. .lit has appeared that, if we take any common object of the sort that is supposed to be known by the senses, what the senses immediately tell us ; is not the truth about t^e.^bject as it is apart from us, but only jhg truth about certain sense-data which, so far as "Vife can see, degend upon the relations betweenjiis ^ and the object. Thus wh^^t we directly see

f 'mi ^'Mr^^ -' ''

24 THE PROBLEMS OF PHILOSOPHY

I and feel is merely " appearance," which we

^believe to be a sign of some "reality"

behind. But if the reality is not what

appears, have we any means of knowing

whether there is any I'ealrtlT'at^air? And if

sonSave we any means of finding out what it is like ?

Such questions are bewildering, and it is difficult to know that even the strangest hypotheses may not be true. Thus our familiar table, which has roused but the slightest thoughts in us hitherto, has become ^ problem full of surprising possibilities, ^he one thing we know about it is that it is not what it seems. Beyond this modest result, so far, we have the most complete liberty of conjecture. Leibniz tells us.. it is a community of souls ; Berkeley tells us it is an idea in the mind of God ; sober science, scarcely less wonderful, tells us it is a vast collection of electric charges in violent motion.

Among these surprising possibilities, doubt suggests that perhaps there is no table at all. Philosophy, if it cannot answer so many

APPEARANCE AND REALITY 25

questions as we could wish, has at least the power of ashing questions which increase the interest of the world, and show the strangeness and wonder lying just below the surface even in the commonest things of daily life.

CHAPTER II

THE EXISTENCE OF MATTER

^ In this chapter we have to ask ourselves whether, in any sense at all, there is such a thing as matter. Is there a table which has a certain intrinsic nature, and continues to exist when -I am^jxpt Jooking, or is the table merely a product of my imagination,„^dream- table in a very prolonged dream ? Tfiis question is of the greatest importance. For if wejcannot be sure^of the independent existence of objects, we cannot be^STi?e-^ the independent existence of other-people's bodies, and therefore still less of other people's minds, since we have no grounds for be- lieving iii their minds except such as are derived from observing their bodies. Thus if" we' cannot be sure" of "^ the independent exlstehce ol o'bjects^'^we^'^ali- be left alone

26

THE EXISTENCE OF MATTER 27

irtf ji, desert — it may be that the whole -, outer world is^nJothing 6 It K dream, and that we aTon£exi^. p?his is an uncomfort- able possibility ; "buf 'although it cannot be strictly proved to be false, t lere is not the slightest reason to suppose that it is true. In this chapter we have to see why this is* ihe case.

Before we embark upon doubtful matters, let us try to find some more or less fixed point from which to start. Although we are doubting ±he .physical jexi^tence of the taJ5e, w^^acg,^ not doubting the existence of the*^0 sens£tdaia^hichjriade usthijik-thei^'^ a I tabl^ ; -JQ^ are miL doubting Ihat^ .„3?x:hije y^'Q'^^ look, a certain colbxir andTsEape^ppear to j

us,^>»4- while we-^3Pe5>s^,au£££^^i^ sensation' of- hardness is experienGed»-43iy *nsl ATT^This, which is psychological, we are not calling in question. In fact, whatever else may be doufet f ul J sQoia..at least pj.. „ou.F mimediate experi£jiC£S.^eni absolutely certain.

Descartes (15?fB^BKDXthe founder of modern philosophy, invented a method which may still be used with profit — the method of

28 THE PROBLEMS OF PHILOSOPHY

sy^tema^ie^ -doubt. He determined that he would believe nothing which he did not see quite clearl^and distinctly to be true. What- ever he could bring himself to doubt, he would doubt, until he saw reason for not doubting it. By applying this method he gradually became convinced that the only existence of which he could be quite certain was his own. He imagined a deceitful demon, who pre- sented unreal things to his senses in a perpetual phantasmagoria ; it might be very improbable that such a demon existed, but still it was possible, and therefore doubt concerning things perceived by the senses ^ was possible. ^1

But doubt concerning his own existence was not^^p.^sible, for if he did not exist, no d^on could deceive him. If he doubted, 'he-irmsfexist ; if he had any experiences wliateveJvJie must exist. Thus his own ex- * ist^rrrce -was—an absolute certainty to him. " I think, therefore I am," he said {Cogito, ergo sum) ; and on the basis of this certainty he set to work to build up again the world of knowledge which his doubt had laid in

THE EXISTENCE OF MATTER 29

ruins. By inventing the method of doubt, and by" i^hO'Wlng Ih^lL scri»i«ftti3z:e tfajljijgs^ oxdl'^'^

•.,it[e_jnost certain, Descartes performed a great service to philosophy, and one which makes him still useful to all students of the subject.

But some care is n^^ifed-in, using Des- cartes' argument. Hi /think, therefore fl am" says rather moiiQlhani^ strictly cer

^ain. It might segjxu-as though 3££_^were

quite s,urec-of^=1Seingthe"~'saTn«-'persQn to-day ~ as we were yesterday, aetd-this is iiU"^"dt>ubF true in some sense. But the real Self is as hard to arrive, at as the real table^ and de«s not" seem to have that absolute, con- vincing certaiuty that belongs to particular experiences. When I look at my table and - see a certain brown colour, what is quite cer- tain at once js^ not "/ am. seeing a „bxQ3Kn.. colour," but^railieiv-" cl brown «QlQiUMLg.Jbeing seen." This of^^^co^rsc-^^^v^lvcs-- something (or somebody) which (or wha)-S€es the brown colour ; Jhi^t ^^- dops ript of jtsgljMnvolve that iitJfe'or less permanent person whom we" tall " I^i -So^ 3ai^^^ftS~immediat(r certainty goes,^

\

■-^e"

1

I

so THE PROBLEMS OF PHILOSOPHY I

^|it might be that the something whicli'

11 sees the brown colour is quite momentarwi and not the same as the something whichS *

' has some different experience the next J moment.

t Thus it is our jQarticialjgyL. JJioughJt^„ and feelings thatjbave^linaitive certainty. And this applies to dreams and hallucinations as well as to normal perceptions : when we dream or see a ghost, we certainly do have the sensations we think we have, but for various reasons it is held that no physical object corresponds to these sensations. Thus the certainty of our knowledge of our own exjperiences does not h^ve. to be^ limited in any way to allow for exceptional cases. Here, therefore, we have, for what it is worth, a solid basis from which to begin our pursuit of knowledge.

'^f , The problem we have to consider is this : 'Granted that we are certain of our own sense- ^ata, have^we any reason for regarding the.ni |as signs of the existence cf something else, » which we can call the physic^ object ? Whei we have enumerated all the sensations wnici

THE EXISTENCE OF MATTER 31

we should naturally regard as connected with the table, have we said all there is to say- about the table, or is there still something else — something not a sensation, something which persists when we go out of the room ? Common sense unhesitatingly answers that there is. What can be bought and sold and pushed about and have a cloth laid on it, and so on, cannot be a mere collection of sense- data. If the cloth completely hides the f table, we shall derive no sense-data froni the table, and therefore, if the table werCj . merely sense-data, it would have ceased to^ exist, and the cloth would be suspended in empty air, resting, by a miracle, in the place where the table formerly was. This seems plainly absurd ; but whoever wishes to be- come a philosopher must learn not to be frightened by absurdities. \

One great reas„Qii..why4tisiettThat we must secure'^'a^'^i^wiaj^object in additioTx..to the / sense- data, is that w^j^^nt^fee-'^sa^Tiir-ekiect' for different people. When ten peopje jare^' stt-tiftg- TomiT3-''u^-3inner^aS[e,^ir^"^s^^ - pfg-—- — posterous to mamtam that they""aje*T*0t _

'XV*

S2 THE PROBLEMS OF PHILOSOPHY

'^ — S££iiigJJiajsaifte--tabi^Trl5th; the same knives and f 6rks^-a»d -sfioDJOS^and glasses. But the sense-data are private to each separate person ; what* is immediately present to the sight of one is not immediately present to the j sight of another : they all see things from ■ slightly different points of view, and therefore j see them slightly differently. Thus, i:l^here- [ r^rp to be pnhlir n^^i^^f^l ^hjrrtSj whi^h ^nu bff in-eeme-sense known to many different people, there must be something over and abpve the

""jrlyaie^ and particular sense«data_which ap- pear to various people. What reason, then, Hiave we for belieTing that there are such — public Tieutral objects ? ^*-^The IBrst answer that naturally occurs to

^ one is that, although different people may see the table slightly differently, still they all see more or less similar things when they look at the table, and the variations in what they see follow the l^ws of perspective and reflection of light, so that it is easy to arrive at a permanent object underlying all the dif- ferent people's sense-data. I bought my table \ from the former occupant of my room ; I

THE EXISTENCE OF MATTER 33

could not buy his sense-data, which died""^ when he went away, but I could and did buy the confident expectation of more or less similar sense -data. Thus it is the fact that different people have similar sense-data, and /' that one person in a given place at different y times has similar sense-data, which makes / us suppose that over and above the sense- x data there is a permanent public object wliich underlies or causes the sense-data of various

Jeople and various times. Now -m-ft^^-laiL^s the above considerations epend upon supposin^jyiiaLjtJi£re^jare„ o^ people besi<^£ja-JW«pscivi^, " 1^ que^Sn nt issue.. — Q%her "people are repre-'"'^ sented to me by certain sense-data, such as the sight of them or the sound of their voices, and if I had no reason to believe that there were physical objects independtinl uf J^py sens^jzdatayl^'dhfmM-h^^v^lSaTegigon to believe th£it other j)eople exist except as part of^my- dream. Thug, when we are trying to show that there must be objects independent of our own sense-data, we cannot appeal to the testimony of other people, since this testimony itself

34 THE PROBLEMS OF PHILOSOPHY

consists of sense-data, and does not reveal other people's experiences unless our own sense-data are signs of things existing inde- pendently of us. We must therefore, if possible, find, in our own purely private experiences, characteristics which show, or tend to show, that there are in the world

j^ things other than ourselves and our private

* experiences.

t^ •jhrrmc acnGfeiLjnustbe admittedtlia£>-we can never prove thje existence of ffii^gsnotljer thaa^iEfttrseUsefi — ajid gwj '''!e^^<'Ti^rif*ps . No logical absurdity results from the hypothesis that the world consists of myself and my thoughts and feelings and sensations, and that everything else is mere fancy. In dreams a very complicated world may seem to be present, and yet on waking we find it was a delusion ; that is to say, we find that the sense-data in the dream do not appear to have corresponded with such physical object i as we should naturally infer from our sense- data. (It is true that, when the ph;TsicaI world is assumed, it is possible to find ph; sical causes for the sense-data in dreams : a door

THE EXISTENCE OF MATTER 35

banging, for instance, may cause us to dream of a naval engagement. But although, in this case, there is a physical cause for the sense-data, there is not a physical object corresponding to the seiise-dat.i in the^way in which an actual n.aval battle wonlc^ corre- spond.) There is no logical impossibility ^ti the supposition that the whole of life di^mIIli3L--^bich we ourscr/es create aii tb(^ objects that come before us* J^But cJb^nugh this is not logically impossible, there is ii.) reason whatever to suppose that it is true ; and it is, in fact, a less simple hypothesis, jti^^ viewed a^ /v, means of accounting for the''v* facts of our own life, than the common-sense hypothesis that there really are objects inde- pendent of us, whose action on us causes our sensations.

The way in which simplicity comes in from *^ supposing that there really are physical objects is easily seen. If the cat appears at one moment in one part of the room, and at another in another part, it is natural to suppose thai: it has moved from the one to the other, passing over a series of intermediate

36 THE PROBLEMS OF PHILOSOPHY

positions. But if it is merely a set of sense- data, it cannot have ever been in any place where I did not see it ; thus we shall have to suppose that it did not exist at all while I was not looking, but suddenly sprang into being in a new place. Jf the cat exists whether I see it or not, we can understand from our own experience how it gets hungry between one meal and the next ; but if it does not exist when I am not seeing it, it seems odd that appetite should grow during / non-existence as fast as during existence. And if the cat consists only of sgnse^-datarilr^

.OMXk- csLTt- be ar-sgfise^^tum- to mr.^ Thus the behaviour of the sense -data which repre- sent the cat to me, though it seems quite natural when regarded as an expression of hunger, becomes utterly inexplicable when regarded as mere movements and changes of patches of colour, which are as incapable of hunger as a triangle is of playing foot- ball.

But the difficulty in the case of the cat is nothing compared to the difficulty in the case

THE EXISTENCE OF MATTER 37

of human beings. JVVhen human beings speak — that is, v/hen we ^^'^^^^^^^^^'*TiTi nnrnt^s ^ryS>h_^^ ^we associate with ideas, and simultaneously see certain motions of lips and ex^ressions-tjf" face— ;itisji£e*ydtfficult to suppose that what we hear is not the expression of a thought, as we- knQ3£IIE"wQuld.-b^ emitted th^ '

ime sounds. Of course similar things happen dreams, where we are mistaken as to the dstence of other people. But dreams are Lore or less suggested by what we call waking v^, [e, and are capable of being more or less '^^J accounted for on scientific principles if we assume that there really is a physical V world. Thus every pf inTCtpie of --simplieity J^^^^^^ urges us to acTopt the natural view, that 'X, there really are objects-~-t>ttec_Jhan our selves and our sense -^ata^ -which hav?^ri' existence not dependent^U^o^ our perceiving them, -'""'

IQf course it is not by argument that we originally come by our belief in an independent external world. We find this belief ready in ourselves as soon as we begin to reflect : it is what may be called an instinctive belief <^

38 THE PROBLEMS OF PHILOSOPHY

We should never have been led to question this belief but for the fact that, at any rate in the case of sight, ife/seems as if the sense- datum itself were instinctively believed to be the independent object, whereas argument shows that the object cannot be identical with the sense-datum. This ^isco very, how- ever— which is not at all paradoxical in the case of taste and smell and sound, and only slightly so in the case of touch — leaves un- r diminished our instinctive belief that there art objects corresponding to our sense-data. Since this belief does not lead to any diffi- culties, but on the contrary tends to simplify and systematise our account of our experi- ences, there seems no good reason for rejecting it. We may therefore admit — though with a sK^^ht doubt derived from dreams — that the external Avorld does really exist, and is not wholly dependent for its existence up_QQ^ur continuing to perceive it.

The argument which has led us to this con- clusion is doubtless less strong than we could wish, but it is typical of many philor:ophicaI argum^ents, and it is therefore worth while to

THE EXISTENCE OF MATTER 39

consider briefly its general character and validity. AIL Jinp\v:Jedge,_ we find, must be built up upon our instinctive beliefs, and if these are rejected, nothing is left. But among our instinctive beliefs some are much stronger than others, while many have, by habit and association, become entangled with other beliefs, not really instinctive, but falsely supposed to be part cjf what is believed instinctively.

Philosophy should show us the hierarchy of our instinctive beliefs, beginning with those we hold most strongly, and presenting each as much isolated and as free from irrele- vant additions as possible. It should take care to show that, in the form in which they are finally set forth, our, in§jtinctive beliefs do not clash, but form a harmonious system. ^ V There can never be any reason for rejecting one instinctive belief except that it clashes with others ; thus, if they are found to har- monise, the whole system becomes worthy of acceptance.

It is of course 'possible. \hsX all or any of our beliefs may be mistaken, and therefore all

40 THE PROBLEMS OF PHILOSOPHY

ought to be held with at least some slight element of doubt. But we cannot have reason to reject a belief except on the ground of some other belief. Hence, by organising our instinctive beliefs and their consequences, by considering which among them it is most possible, if necessary, to modify or abandon, we can arrive, on the basis of accepting as our sole data what we instinctively believe, at an or- derly systematic organisation of our know- ledge, in which, though the possibility of error remains, its likelihood is diminished by the interrelation of the parts and by the critical scrutiny which has preceded acquiescence.

This function, at least, philosophy can per- form. INJost philosophers, rightly or wrongly, believe that philosophy can do much more than this — that it can give us knowledge, not otherwise attainable, concerning the universe as a whole, and concerning the nature of ultimate reality. Whether this be the case or not, the more modest function we have spoken of can certainly be performed by

THE EXISTENCE OF MATTER 41

philosophy, and certainly suffices, for those who have once begun to doubt the adequacy of common sense, to justify the arduous and difficult labours that philosophical problems involve.

CHAPTER III

THE NATURE OF MATTER

/ In the preceding chapter we agreed, though without being able to find demonstra- tive reasons, that it is rational to believe that our sense-data — for example, those which we regard as associated with my table — are really signg of the existence of something" independent of us and our perceptions. That is to say, over and above the sensations of colour, hardness, noise, and so on, which make up the appearance of the table to me, I assume that there is something else, of which these things are appearances. The colour ceases to exist if I shut my eyes, the sensation of hardness ceases to exist if I remove my arm from contact with the table, the sound ceases to exist if I cease to rap the -table with my knuckles,

42

THE NATURE OF MATTER 43

But I do not believe that when all these things cease the table ceases. On the contrary, I believe that . jt is Jbecause the table exists continuously that all jQiese sense-data will reappear when I open ^my eyes, replace my arm, and begin again to rap with my knuckles. The question'^ we have to consider in this chapter is: What is the nature of this real table, ,^/ which persists independently of my per- ception of it ?

To this question physical science gives an answer, somewhat incomplete it is true, and in part still very hypothetical, but yet deserving of respect so far as it goes. Physical science, ^ more or less unconsciouslv, has drifted into the viejwjhyat jail natural phenomena ought to be reduced to motipjis. Light and heat and sound are all due to wave-motions, which travel from the body emitting them to the person who sees light or feels heat or hears sound. That which has the wave-motion is either aether or " gross matter," but in either ca se is what the philosopher would call matter. The only properties which science assigns to

M THE PROBLEMS OF PHILOSOPHll

at are position in spacCj and the power oi motion according to the laws of motion.] Science does not deny that it may have othei properties ; but if so, such other properties! are not useful to the man of science, and in| no way assist him in explaining the pheno- mena.

It is sometimes said that " light is a form'

^f wave-motion," but this is misleading, for

the light which we immediately see, which -we know directly by means of our senses, IS not a form of wave-motion, but some- thing quite different — something which we all know if