<p><SPAN name="link2H_PREF" id="link2H_PREF"></SPAN></p>
<h2> PREFACE </h2>
<p>In the following pages I have confined myself in the main to those
problems of philosophy in regard to which I thought it 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.</p>
<p>I have derived valuable assistance from unpublished writings of G. E.
Moore and J. M. Keynes: from the former, as regards the relations of
sense-data to physical objects, and from the latter as regards probability
and induction. I have also profited greatly by the criticisms and
suggestions of Professor Gilbert Murray.</p>
<p>1912 <SPAN name="link2HCH0001" id="link2HCH0001"></SPAN></p>
<h2> CHAPTER I. APPEARANCE AND REALITY </h2>
<p>Is there any knowledge in the 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 realized the obstacles in the way of a straightforward and confident
answer, we shall be well launched on the study of philosophy—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 questions
puzzling, and after realizing all the vagueness and confusion that
underlie our ordinary ideas.</p>
<p>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 search for certainty, it is natural to begin with our
present experiences, and in some sense, no doubt, knowledge is to be
derived from them. 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 other normal person comes into my room, he
will see the same chairs and tables and books and papers as I see, and
that the table which I see is the same as the table which I feel pressing
against my arm. All this seems to be so evident as to be hardly worth
stating, except in answer to a man who doubts whether 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.</p>
<p>To make our difficulties plain, let us concentrate attention on the table.
To the eye 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 difficulty would arise; but as soon as we
try to be more precise our troubles begin. 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 parts look white
because of reflected light. I know that, if I move, the parts that reflect
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.</p>
<p>For most practical purposes these differences 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 sense says they
'really' have, and to learn the habit of seeing things as they appear.
Here we have already the beginning of one of the distinctions that cause
most trouble in philosophy—the distinction between 'appearance' and
'reality', between what things seem to be and what they are. The painter
wants to know what things seem to be, the practical man and the
philosopher want to know what they are; but the philosopher'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.</p>
<p>To return to the table. It is evident from what we have found, that there
is no colour which pre-eminently appears to be <i>the</i> colour of the
table, or even of any one particular part of the table—it appears to
be of different 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 artificial light, or to a colour-blind man, or to a man
wearing blue spectacles, while in the dark there will be no colour at all,
though to touch and hearing the table will be unchanged. This colour is
not something which is inherent in the table, but something depending upon
the table and the spectator and the way the light falls on the table.
When, in ordinary life, we speak of <i>the</i> colour 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 favouritism,
we are compelled to deny that, in itself, the table has any one particular
colour.</p>
<p>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 looked at it
through a microscope, we should see roughnesses and hills and valleys, and
all sorts of differences that are imperceptible to the naked eye. Which of
these is the 'real' table? We are naturally tempted to say that what we
see through the microscope is more real, but that in turn would be changed
by a still more powerful microscope. If, then, we cannot trust what we see
with the naked eye, why should we trust what we see through a microscope?
Thus, again, the confidence in our senses with which we began deserts us.</p>
<p>The shape of the table is no better. 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, from almost all points of view, as if it had two 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 construct the 'real' shape from the apparent
shape, and the 'real' shape is what interests us as practical men. But the
'real' shape is not what we see; it is something inferred from what we
see. And what we see is constantly changing in shape as we move about the
room; so that here again the senses seem not to give us the truth about
the table itself, but only about the appearance of the table.</p>
<p>Similar difficulties 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 sensation we obtain depends upon how hard we
press the table and also upon what part of the body we press with; thus
the various sensations due to various pressures or various parts of the
body cannot be supposed to reveal <i>directly</i> any definite property of
the table, but at most to be <i>signs</i> of some property which perhaps
<i>causes</i> all the sensations, 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.</p>
<p>Thus it becomes evident that the real table, if there is one, is not the
same as what we immediately experience by sight or touch or hearing. The
real table, if there is one, is not <i>immediately</i> known to us at all,
but must be an inference from what is immediately known. Hence, two very
difficult questions at once arise; namely, (1) Is there a real table at
all? (2) If so, what sort of object can it be?</p>
<p>It will help us in considering these questions to have a few simple terms
of which the meaning is definite and clear. Let us give the name of
'sense-data' to the things that are immediately 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. Thus, whenever we see a colour, we have a sensation
<i>of</i> the colour, but the colour itself is a sense-datum, not a
sensation. The colour is that <i>of</i> which we are immediately aware,
and the awareness itself is the sensation. It is plain that if we are to
know anything about the table, it must be by means of the sense-data—brown
colour, oblong shape, smoothness, etc.—which we associate with the
table; but, for the reasons which have been given, we cannot say that the
table is the sense-data, or even that the sense-data are directly
properties of the table. Thus a problem arises as to the relation of the
sense-data to the real table, supposing there is such a thing.</p>
<p>The real table, if it exists, we will call a 'physical object'. Thus we
have to consider the relation of sense-data to physical objects. The
collection of all physical objects is called 'matter'. Thus our two
questions may be re-stated as follows: (1) Is there any such thing as
matter? (2) If so, what is its nature?</p>
<p>The philosopher who first brought prominently forward the reasons for
regarding the immediate objects of our senses as not existing
independently of us was Bishop Berkeley (1685-1753). His <i>Three
Dialogues between Hylas and Philonous, in Opposition to Sceptics and
Atheists</i>, undertake to prove that there is no such thing as matter at
all, and that the world consists of nothing but minds and their ideas.
Hylas has hitherto believed in matter, but he is no match for Philonous,
who mercilessly drives him into 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 that the existence of matter is capable
of being denied without absurdity, and that if there are any things that
exist independently of us they cannot be the immediate objects of our
sensations.</p>
<p>There are two different questions involved when we ask whether matter
exists, and it is important to keep them clear. We commonly mean by
'matter' something which is opposed to 'mind', something which we think of
as occupying space and as radically incapable of any sort of thought or
consciousness. 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 <i>something</i> independent of us, but he does deny that
this something is non-mental, that it is neither mind nor ideas
entertained by some mind. He admits that there must be something which
continues to exist when we go out of the room or shut our eyes, and that
what we call seeing the table does really give us reason for believing in
something which persists even when we are not seeing it. But he thinks
that this something cannot be radically different in nature from what we
see, and cannot be independent of seeing altogether, though it must be
independent of <i>our</i> 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.</p>
<p>Other philosophers since Berkeley have also held that, although the table
does not depend for its existence upon being seen by me, it does depend
upon being seen (or otherwise apprehended in sensation) by <i>some</i>
mind—not necessarily the mind of God, but more often the whole
collective mind of the universe. This they hold, as Berkeley does, 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 idea in the mind of the person
thinking of it; therefore nothing can be thought of except ideas in minds;
therefore anything else is inconceivable, and what is inconceivable cannot
exist.'</p>
<p>Such an argument, in my opinion, is fallacious; 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 philosophers are called
'idealists'. When they come to explaining matter, they either say, like
Berkeley, that matter is really nothing but a collection of ideas, or they
say, like Leibniz (1646-1716), that what appears as matter is really a
collection of more or less rudimentary minds.</p>
<p>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? (2) If
so, what sort of object can it be? Now both Berkeley and Leibniz admit
that there is a real table, but Berkeley says it is certain ideas in the
mind of God, and Leibniz says it is a colony of souls. Thus both of them
answer our first question in the affirmative, and only diverge from the
views of ordinary mortals in their answer to our second question. In fact,
almost all philosophers seem to be agreed that there is a real table: they
almost all agree that, however much our sense-data—colour, shape,
smoothness, etc.—may depend upon us, yet their occurrence is a sign
of something existing independently of us, something differing, perhaps,
completely from our sense-data, and yet to be regarded as causing those
sense-data whenever we are in a suitable relation to the real table.</p>
<p>Now obviously this point in which the philosophers are agreed—the
view that there <i>is</i> 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 to the further question
as to the nature of the real table. Our next chapter, therefore, will be
concerned with the reasons for supposing that there is a real table at
all.</p>
<p>Before we go farther it will be well to consider for a moment what it is
that we have discovered so far. It has appeared that, if we take any
common object of the sort that is supposed to be known by the senses, what
the senses <i>immediately</i> tell us is not the truth about the object as
it is apart from us, but only the truth about certain sense-data which, so
far as we can see, depend upon the relations between us and the object.
Thus what we directly see 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 reality at
all? And if so, have we any means of finding out what it is like?</p>
<p>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 a problem
full of surprising possibilities. The 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.</p>
<p>Among these surprising possibilities, doubt suggests that perhaps there is
no table at all. Philosophy, if it cannot <i>answer</i> so many questions
as we could wish, has at least the power of <i>asking</i> 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.</p>
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