PREFACE
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.
I have derived valuable assistance from unpublished writings of G. E. Moore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.
1912
CHAPTER I. APPEARANCE AND REALITY
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.
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.
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.
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.
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
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 the 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.
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.
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.
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 directly any definite property of the table, but at
most to be signs of some property which perhaps causes 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.
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 immediately 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?
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 of the colour, but the
colour itself 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
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.
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?
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 Three Dialogues between Hylas and
Philonous, in Opposition to Sceptics and Atheists, 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.
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 something 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 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.
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 some 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.'
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.
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.
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 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.
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
immediately 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?
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.
Among these surprising possibilities, doubt suggests that perhaps there is no
table at all. Philosophy, if it cannot answer so many questions as we
could wish, has at least the power of asking 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 not looking, or is the table merely a
product of my imagination, a dream-table in a very prolonged dream? This
question is of the greatest importance. For if we cannot be sure of the
independent existence of objects, we cannot be sure of the independent existence
of other people's bodies, and therefore still less of other people's minds,
since we have no grounds for believing in their minds except such as are derived
from observing their bodies. Thus if we cannot be sure of the independent
existence of objects, we shall be left alone in a desert—it may be that the
whole outer world is nothing but a dream, and that we alone exist. This is an
uncomfortable possibility; but although it cannot be strictly proved to be
false, there is not the slightest reason to suppose that it is true. In this
chapter we have to see why this is the 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 the physical existence
of the table, we are not doubting the existence of the sense-data which made us
think there was a table; we are not doubting that, while we look, a certain
colour and shape appear to us, and while we press, a certain sensation of
hardness is experienced by us. All this, which is psychological, we are not
calling in question. In fact, whatever else may be doubtful, some at least of
our immediate experiences seem absolutely certain.
Descartes (1596-1650), the founder of modern philosophy, invented a method
which may still be used with profit—the method of systematic doubt. He
determined that he would believe nothing which he did not see quite clearly and
distinctly to be true. Whatever 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 presented 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.
But doubt concerning his own existence was not possible, for if he did not
exist, no demon could deceive him. If he doubted, he must exist; if he had any
experiences whatever, he must exist. Thus his own existence 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 ruins. By inventing the method of doubt,
and by showing that subjective things are the most 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 needed in using Descartes' argument. 'I think, therefore I
am' says rather more than is strictly certain. It might seem as though we were
quite sure of being the same person to-day as we were yesterday, and this is no
doubt true in some sense. But the real Self is as hard to arrive at as the real
table, and does not seem to have that absolute, convincing certainty that
belongs to particular experiences. When I look at my table and see a certain
brown colour, what is quite certain at once is not 'I am seeing a brown
colour', but rather, 'a brown colour is being seen'. This of course involves
something (or somebody) which (or who) sees the brown colour; but it does not of
itself involve that more or less permanent person whom we call 'I'. So far as
immediate certainty goes, it might be that the something which sees the brown
colour is quite momentary, and not the same as the something which has some
different experience the next moment.
Thus it is our particular thoughts and feelings that have primitive
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
experiences does not have 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.
The problem we have to consider is this: Granted that we are certain of our
own sense-data, have we any reason for regarding them as signs of the existence
of something else, which we can call the physical object? When we have
enumerated all the sense-data which 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 sense-datum, 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
table, we shall derive no sense-data from the table, and therefore, if the table
were 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 become a
philosopher must learn not to be frightened by absurdities.
One great reason why it is felt that we must secure a physical object in
addition to the sense-data, is that we want the same object for different
people. When ten people are sitting round a dinner-table, it seems preposterous
to maintain that they are not seeing the same tablecloth, the same knives and
forks and spoons 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 sight of another: they all see things from slightly different
points of view, and therefore see them slightly differently. Thus, if there are
to be public neutral objects, which can be in some sense known to many different
people, there must be something over and above the private and particular
sense-data which appear to various people. What reason, then, have we for
believing that there are such public neutral objects?
The first 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 laws of perspective and reflection of light, so that it is easy to
arrive at a permanent object underlying all the different people's sense-data. I
bought my table from the former occupant of my room; I 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 times has similar sense-data, which makes us suppose that over and
above the sense-data there is a permanent public object which underlies or
causes the sense-data of various people at various times.
Now in so far as the above considerations depend upon supposing that there
are other people besides ourselves, they beg the very question at issue. Other
people are represented 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 independent of my sense-data, I should have no reason to
believe that other people exist except as part of my dream. Thus, 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
consists of sense-data, and does not reveal other people's experiences unless
our own sense-data are signs of things existing independently 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 things
other than ourselves and our private experiences.
In one sense it must be admitted that we can never prove the existence of
things other than ourselves and our experiences. 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 objects as we should naturally
infer from our sense-data. (It is true that, when the physical world is assumed,
it is possible to find physical causes for the sense-data in dreams: a door
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 sense-data in the way in which an
actual naval battle would correspond.) There is no logical impossibility in the
supposition that the whole of life is a dream, in which we ourselves create all
the objects that come before us. But although this is not logically impossible,
there is no reason whatever to suppose that it is true; and it is, in fact, a
less simple hypothesis, viewed as a means of accounting for the facts of our own
life, than the common-sense hypothesis that there really are objects independent
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 that it has
moved from the one to the other, passing over a series of intermediate
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. If 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
sense-data, it cannot be hungry, since no hunger but my own can be a sense-datum
to me. Thus the behaviour of the sense-data which represent 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 football.
But the difficulty in the case of the cat is nothing compared to the
difficulty in the case of human beings. When human beings speak—that is, when we
hear certain noises which we associate with ideas, and simultaneously see
certain motions of lips and expressions of face—it is very difficult to suppose
that what we hear is not the expression of a thought, as we know it would be if
we emitted the same sounds. Of course similar things happen in dreams, where we
are mistaken as to the existence of other people. But dreams are more or less
suggested by what we call waking life, and are capable of being more or less
accounted for on scientific principles if we assume that there really is a
physical world. Thus every principle of simplicity urges us to adopt the natural
view, that there really are objects other than ourselves and our sense-data
which have an existence not dependent upon our perceiving them.
Of 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. We
should never have been led to question this belief but for the fact that, at any
rate in the case of sight, it 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 discovery,
however—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 undiminished our
instinctive belief that there are objects corresponding to our
sense-data. Since this belief does not lead to any difficulties, but on the
contrary tends to simplify and systematize our account of our experiences, there
seems no good reason for rejecting it. We may therefore admit—though with a
slight doubt derived from dreams—that the external world does really exist, and
is not wholly dependent for its existence upon our continuing to perceive it.
The argument which has led us to this conclusion is doubtless less strong
than we could wish, but it is typical of many philosophical arguments, and it is
therefore worth while to consider briefly its general character and validity.
All knowledge, 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 of 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 irrelevant additions as possible. It should take care to show that, in
the form in which they are finally set forth, our instinctive beliefs do not
clash, but form a harmonious system. There can never be any reason for rejecting
one instinctive belief except that it clashes with others; thus, if they are
found to harmonize, the whole system becomes worthy of acceptance.
It is of course possible that all or any of our beliefs may be
mistaken, and therefore all 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 organizing our instinctive beliefs and
their consequences, by considering which among them 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 orderly systematic organization
of our knowledge, 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 perform. Most 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 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
demonstrative reasons, that it is rational to believe that our sense-data—for
example, those which we regard as associated with my table—are really signs 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. But I do not believe that when all these things cease the
table ceases. On the contrary, I believe that it is because the table exists
continuously that all these 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 perception 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 unconsciously, has drifted into the
view that all natural phenomena ought to be reduced to motions. 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 case is what the
philosopher would call matter. The only properties which science assigns to it
are position in space, and the power of motion according to the laws of motion.
Science does not deny that it may have other properties; but if so, such
other properties are not useful to the man of science, and in no way assist him
in explaining the phenomena.
It is sometimes said that 'light is a form of 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 something quite
different—something which we all know if we are not blind, though we cannot
describe it so as to convey our knowledge to a man who is blind. A wave-motion,
on the contrary, could quite well be described to a blind man, since he can
acquire a knowledge of space by the sense of touch; and he can experience a
wave-motion by a sea voyage almost as well as we can. But this, which a blind
man can understand, is not what we mean by light: we mean by light
just that which a blind man can never understand, and which we can never
describe to him.
Now this something, which all of us who are not blind know, is not, according
to science, really to be found in the outer world: it is something caused by the
action of certain waves upon the eyes and nerves and brain of the person who
sees the light. When it is said that light is waves, what is really meant
is that waves are the physical cause of our sensations of light. But light
itself, the thing which seeing people experience and blind people do not, is not
supposed by science to form any part of the world that is independent of us and
our senses. And very similar remarks would apply to other kinds of sensations.
It is not only colours and sounds and so on that are absent from the
scientific world of matter, but also space as we get it through sight or
touch. It is essential to science that its matter should be in a space,
but the space in which it is cannot be exactly the space we see or feel. To
begin with, space as we see it is not the same as space as we get it by the
sense of touch; it is only by experience in infancy that we learn how to touch
things we see, or how to get a sight of things which we feel touching us. But
the space of science is neutral as between touch and sight; thus it cannot be
either the space of touch or the space of sight.
Again, different people see the same object as of different shapes, according
to their point of view. A circular coin, for example, though we should always
judge it to be circular, will look oval unless we are straight in
front of it. When we judge that it is circular, we are judging that it
has a real shape which is not its apparent shape, but belongs to it
intrinsically apart from its appearance. But this real shape, which is what
concerns science, must be in a real space, not the same as anybody's apparent
space. The real space is public, the apparent space is private to the
percipient. In different people's private spaces the same object seems to
have different shapes; thus the real space, in which it has its real shape, must
be different from the private spaces. The space of science, therefore, though
connected with the spaces we see and feel, is not identical with them, and
the manner of its connexion requires investigation.
We agreed provisionally that physical objects cannot be quite like our
sense-data, but may be regarded as causing our sensations. These physical
objects are in the space of science, which we may call 'physical' space. It is
important to notice that, if our sensations are to be caused by physical
objects, there must be a physical space containing these objects and our
sense-organs and nerves and brain. We get a sensation of touch from an object
when we are in contact with it; that is to say, when some part of our body
occupies a place in physical space quite close to the space occupied by the
object. We see an object (roughly speaking) when no opaque body is between the
object and our eyes in physical space. Similarly, we only hear or smell or taste
an object when we are sufficiently near to it, or when it touches the tongue, or
has some suitable position in physical space relatively to our body. We cannot
begin to state what different sensations we shall derive from a given object
under different circumstances unless we regard the object and our body as both
in one physical space, for it is mainly the relative positions of the object and
our body that determine what sensations we shall derive from the object.
Now our sense-data are situated in our private spaces, either the space of
sight or the space of touch or such vaguer spaces as other senses may give us.
If, as science and common sense assume, there is one public all-embracing
physical space in which physical objects are, the relative positions of physical
objects in physical space must more or less correspond to the relative positions
of sense-data in our private spaces. There is no difficulty in supposing this to
be the case. If we see on a road one house nearer to us than another, our other
senses will bear out the view that it is nearer; for example, it will be reached
sooner if we walk along the road. Other people will agree that the house which
looks nearer to us is nearer; the ordnance map will take the same view; and thus
everything points to a spatial relation between the houses corresponding to the
relation between the sense-data which we see when we look at the houses. Thus we
may assume that there is a physical space in which physical objects have spatial
relations corresponding to those which the corresponding sense-data have in our
private spaces. It is this physical space which is dealt with in geometry and
assumed in physics and astronomy.
Assuming that there is physical space, and that it does thus correspond to
private spaces, what can we know about it? We can know only what is
required in order to secure the correspondence. That is to say, we can know
nothing of what it is like in itself, but we can know the sort of arrangement of
physical objects which results from their spatial relations. We can know, for
example, that the earth and moon and sun are in one straight line during an
eclipse, though we cannot know what a physical straight line is in itself, as we
know the look of a straight line in our visual space. Thus we come to know much
more about the relations of distances in physical space than about the
distances themselves; we may know that one distance is greater than another, or
that it is along the same straight line as the other, but we cannot have that
immediate acquaintance with physical distances that we have with distances in
our private spaces, or with colours or sounds or other sense-data. We can know
all those things about physical space which a man born blind might know through
other people about the space of sight; but the kind of things which a man born
blind could never know about the space of sight we also cannot know about
physical space. We can know the properties of the relations required to preserve
the correspondence with sense-data, but we cannot know the nature of the terms
between which the relations hold.
With regard to time, our feeling of duration or of the lapse of time
is notoriously an unsafe guide as to the time that has elapsed by the clock.
Times when we are bored or suffering pain pass slowly, times when we are
agreeably occupied pass quickly, and times when we are sleeping pass almost as
if they did not exist. Thus, in so far as time is constituted by duration, there
is the same necessity for distinguishing a public and a private time as there
was in the case of space. But in so far as time consists in an order of
before and after, there is no need to make such a distinction; the time-order
which events seem to have is, so far as we can see, the same as the time-order
which they do have. At any rate no reason can be given for supposing that the
two orders are not the same. The same is usually true of space: if a regiment of
men are marching along a road, the shape of the regiment will look different
from different points of view, but the men will appear arranged in the same
order from all points of view. Hence we regard the order as true also in
physical space, whereas the shape is only supposed to correspond to the physical
space so far as is required for the preservation of the order.
In saying that the time-order which events seem to have is the same as the
time-order which they really have, it is necessary to guard against a possible
misunderstanding. It must not be supposed that the various states of different
physical objects have the same time-order as the sense-data which constitute the
perceptions of those objects. Considered as physical objects, the thunder and
lightning are simultaneous; that is to say, the lightning is simultaneous with
the disturbance of the air in the place where the disturbance begins, namely,
where the lightning is. But the sense-datum which we call hearing the thunder
does not take place until the disturbance of the air has travelled as far as to
where we are. Similarly, it takes about eight minutes for the sun's light to
reach us; thus, when we see the sun we are seeing the sun of eight minutes ago.
So far as our sense-data afford evidence as to the physical sun they afford
evidence as to the physical sun of eight minutes ago; if the physical sun had
ceased to exist within the last eight minutes, that would make no difference to
the sense-data which we call 'seeing the sun'. This affords a fresh illustration
of the necessity of distinguishing between sense-data and physical objects.
What we have found as regards space is much the same as what we find in
relation to the correspondence of the sense-data with their physical
counterparts. If one object looks blue and another red, we may reasonably
presume that there is some corresponding difference between the physical
objects; if two objects both look blue, we may presume a corresponding
similarity. But we cannot hope to be acquainted directly with the quality in the
physical object which makes it look blue or red. Science tells us that this
quality is a certain sort of wave-motion, and this sounds familiar, because we
think of wave-motions in the space we see. But the wave-motions must really be
in physical space, with which we have no direct acquaintance; thus the real
wave-motions have not that familiarity which we might have supposed them to
have. And what holds for colours is closely similar to what holds for other
sense-data. Thus we find that, although the relations of physical objects
have all sorts of knowable properties, derived from their correspondence with
the relations of sense-data, the physical objects themselves remain unknown in
their intrinsic nature, so far at least as can be discovered by means of the
senses. The question remains whether there is any other method of discovering
the intrinsic nature of physical objects.
The most natural, though not ultimately the most defensible, hypothesis to
adopt in the first instance, at any rate as regards visual sense-data, would be
that, though physical objects cannot, for the reasons we have been considering,
be exactly like sense-data, yet they may be more or less like. According
to this view, physical objects will, for example, really have colours, and we
might, by good luck, see an object as of the colour it really is. The colour
which an object seems to have at any given moment will in general be very
similar, though not quite the same, from many different points of view; we might
thus suppose the 'real' colour to be a sort of medium colour, intermediate
between the various shades which appear from the different points of view.
Such a theory is perhaps not capable of being definitely refuted, but it can
be shown to be groundless. To begin with, it is plain that the colour we see
depends only upon the nature of the light-waves that strike the eye, and is
therefore modified by the medium intervening between us and the object, as well
as by the manner in which light is reflected from the object in the direction of
the eye. The intervening air alters colours unless it is perfectly clear, and
any strong reflection will alter them completely. Thus the colour we see is a
result of the ray as it reaches the eye, and not simply a property of the object
from which the ray comes. Hence, also, provided certain waves reach the eye, we
shall see a certain colour, whether the object from which the waves start has
any colour or not. Thus it is quite gratuitous to suppose that physical objects
have colours, and therefore there is no justification for making such a
supposition. Exactly similar arguments will apply to other sense-data.
It remains to ask whether there are any general philosophical arguments
enabling us to say that, if matter is real, it must be of such and such a
nature. As explained above, very many philosophers, perhaps most, have held that
whatever is real must be in some sense mental, or at any rate that whatever we
can know anything about must be in some sense mental. Such philosophers are
called 'idealists'. Idealists tell us that what appears as matter is really
something mental; namely, either (as Leibniz held) more or less rudimentary
minds, or (as Berkeley contended) ideas in the minds which, as we should
commonly say, 'perceive' the matter. Thus idealists deny the existence of matter
as something intrinsically different from mind, though they do not deny that our
sense-data are signs of something which exists independently of our private
sensations. In the following chapter we shall consider briefly the reasons—in my
opinion fallacious—which idealists advance in favour of their theory.
CHAPTER IV. IDEALISM
The word 'idealism' is used by different philosophers in somewhat different
senses. We shall understand by it the doctrine that whatever exists, or at any
rate whatever can be known to exist, must be in some sense mental. This
doctrine, which is very widely held among philosophers, has several forms, and
is advocated on several different grounds. The doctrine is so widely held, and
so interesting in itself, that even the briefest survey of philosophy must give
some account of it.
Those who are unaccustomed to philosophical speculation may be inclined to
dismiss such a doctrine as obviously absurd. There is no doubt that common sense
regards tables and chairs and the sun and moon and material objects generally as
something radically different from minds and the contents of minds, and as
having an existence which might continue if minds ceased. We think of matter as
having existed long before there were any minds, and it is hard to think of it
as a mere product of mental activity. But whether true or false, idealism is not
to be dismissed as obviously absurd.
We have seen that, even if physical objects do have an independent existence,
they must differ very widely from sense-data, and can only have a
correspondence with sense-data, in the same sort of way in which a catalogue
has a correspondence with the things catalogued. Hence common sense leaves us
completely in the dark as to the true intrinsic nature of physical objects, and
if there were good reason to regard them as mental, we could not legitimately
reject this opinion merely because it strikes us as strange. The truth about
physical objects must be strange. It may be unattainable, but if any
philosopher believes that he has attained it, the fact that what he offers as
the truth is strange ought not to be made a ground of objection to his opinion.
The grounds on which idealism is advocated are generally grounds derived from
the theory of knowledge, that is to say, from a discussion of the conditions
which things must satisfy in order that we may be able to know them. The first
serious attempt to establish idealism on such grounds was that of Bishop
Berkeley. He proved first, by arguments which were largely valid, that our
sense-data cannot be supposed to have an existence independent of us, but must
be, in part at least, 'in' the mind, in the sense that their existence would not
continue if there were no seeing or hearing or touching or smelling or tasting.
So far, his contention was almost certainly valid, even if some of his arguments
were not so. But he went on to argue that sense-data were the only things of
whose existence our perceptions could assure us; and that to be known is to be
'in' a mind, and therefore to be mental. Hence he concluded that nothing can
ever be known except what is in some mind, and that whatever is known without
being in my mind must be in some other mind.
In order to understand his argument, it is necessary to understand his use of
the word 'idea'. He gives the name 'idea' to anything which is immediately
known, as, for example, sense-data are known. Thus a particular colour which we
see is an idea; so is a voice which we hear, and so on. But the term is not
wholly confined to sense-data. There will also be things remembered or imagined,
for with such things also we have immediate acquaintance at the moment of
remembering or imagining. All such immediate data he calls 'ideas'.
He then proceeds to consider common objects, such as a tree, for instance. He
shows that all we know immediately when we 'perceive' the tree consists of ideas
in his sense of the word, and he argues that there is not the slightest ground
for supposing that there is anything real about the tree except what is
perceived. Its being, he says, consists in being perceived: in the Latin of the
schoolmen its 'esse' is 'percipi'. He fully admits that the tree
must continue to exist even when we shut our eyes or when no human being is near
it. But this continued existence, he says, is due to the fact that God continues
to perceive it; the 'real' tree, which corresponds to what we called the
physical object, consists of ideas in the mind of God, ideas more or less like
those we have when we see the tree, but differing in the fact that they are
permanent in God's mind so long as the tree continues to exist. All our
perceptions, according to him, consist in a partial participation in God's
perceptions, and it is because of this participation that different people see
more or less the same tree. Thus apart from minds and their ideas there is
nothing in the world, nor is it possible that anything else should ever be
known, since whatever is known is necessarily an idea.
There are in this argument a good many fallacies which have been important in
the history of philosophy, and which it will be as well to bring to light. In
the first place, there is a confusion engendered by the use of the word 'idea'.
We think of an idea as essentially something in somebody's mind, and thus when
we are told that a tree consists entirely of ideas, it is natural to suppose
that, if so, the tree must be entirely in minds. But the notion of being 'in'
the mind is ambiguous. We speak of bearing a person in mind, not meaning that
the person is in our minds, but that a thought of him is in our minds. When a
man says that some business he had to arrange went clean out of his mind, he
does not mean to imply that the business itself was ever in his mind, but only
that a thought of the business was formerly in his mind, but afterwards ceased
to be in his mind. And so when Berkeley says that the tree must be in our minds
if we can know it, all that he really has a right to say is that a thought of
the tree must be in our minds. To argue that the tree itself must be in our
minds is like arguing that a person whom we bear in mind is himself in our
minds. This confusion may seem too gross to have been really committed by any
competent philosopher, but various attendant circumstances rendered it possible.
In order to see how it was possible, we must go more deeply into the question as
to the nature of ideas.
Before taking up the general question of the nature of ideas, we must
disentangle two entirely separate questions which arise concerning sense-data
and physical objects. We saw that, for various reasons of detail, Berkeley was
right in treating the sense-data which constitute our perception of the tree as
more or less subjective, in the sense that they depend upon us as much as upon
the tree, and would not exist if the tree were not being perceived. But this is
an entirely different point from the one by which Berkeley seeks to prove that
whatever can be immediately known must be in a mind. For this purpose arguments
of detail as to the dependence of sense-data upon us are useless. It is
necessary to prove, generally, that by being known, things are shown to be
mental. This is what Berkeley believes himself to have done. It is this
question, and not our previous question as to the difference between sense-data
and the physical object, that must now concern us.
Taking the word 'idea' in Berkeley's sense, there are two quite distinct
things to be considered whenever an idea is before the mind. There is on the one
hand the thing of which we are aware—say the colour of my table—and on the other
hand the actual awareness itself, the mental act of apprehending the thing. The
mental act is undoubtedly mental, but is there any reason to suppose that the
thing apprehended is in any sense mental? Our previous arguments concerning the
colour did not prove it to be mental; they only proved that its existence
depends upon the relation of our sense organs to the physical object—in our
case, the table. That is to say, they proved that a certain colour will exist,
in a certain light, if a normal eye is placed at a certain point relatively to
the table. They did not prove that the colour is in the mind of the percipient.
Berkeley's view, that obviously the colour must be in the mind, seems to
depend for its plausibility upon confusing the thing apprehended with the act of
apprehension. Either of these might be called an 'idea'; probably either would
have been called an idea by Berkeley. The act is undoubtedly in the mind; hence,
when we are thinking of the act, we readily assent to the view that ideas must
be in the mind. Then, forgetting that this was only true when ideas were taken
as acts of apprehension, we transfer the proposition that 'ideas are in the
mind' to ideas in the other sense, i.e. to the things apprehended by our acts of
apprehension. Thus, by an unconscious equivocation, we arrive at the conclusion
that whatever we can apprehend must be in our minds. This seems to be the true
analysis of Berkeley's argument, and the ultimate fallacy upon which it rests.
This question of the distinction between act and object in our apprehending
of things is vitally important, since our whole power of acquiring knowledge is
bound up with it. The faculty of being acquainted with things other than itself
is the main characteristic of a mind. Acquaintance with objects essentially
consists in a relation between the mind and something other than the mind; it is
this that constitutes the mind's power of knowing things. If we say that the
things known must be in the mind, we are either unduly limiting the mind's power
of knowing, or we are uttering a mere tautology. We are uttering a mere
tautology if we mean by 'in the mind' the same as by 'before the
mind', i.e. if we mean merely being apprehended by the mind. But if we mean
this, we shall have to admit that what, in this sense, is in the mind,
may nevertheless be not mental. Thus when we realize the nature of knowledge,
Berkeley's argument is seen to be wrong in substance as well as in form, and his
grounds for supposing that 'ideas'—i.e. the objects apprehended—must be mental,
are found to have no validity whatever. Hence his grounds in favour of idealism
may be dismissed. It remains to see whether there are any other grounds.
It is often said, as though it were a self-evident truism, that we cannot
know that anything exists which we do not know. It is inferred that whatever can
in any way be relevant to our experience must be at least capable of being known
by us; whence it follows that if matter were essentially something with which we
could not become acquainted, matter would be something which we could not know
to exist, and which could have for us no importance whatever. It is generally
also implied, for reasons which remain obscure, that what can have no importance
for us cannot be real, and that therefore matter, if it is not composed of minds
or of mental ideas, is impossible and a mere chimaera.
To go into this argument fully at our present stage would be impossible,
since it raises points requiring a considerable preliminary discussion; but
certain reasons for rejecting the argument may be noticed at once. To begin at
the end: there is no reason why what cannot have any practical importance
for us should not be real. It is true that, if theoretical importance is
included, everything real is of some importance to us, since, as persons
desirous of knowing the truth about the universe, we have some interest in
everything that the universe contains. But if this sort of interest is included,
it is not the case that matter has no importance for us, provided it exists even
if we cannot know that it exists. We can, obviously, suspect that it may exist,
and wonder whether it does; hence it is connected with our desire for knowledge,
and has the importance of either satisfying or thwarting this desire.
Again, it is by no means a truism, and is in fact false, that we cannot know
that anything exists which we do not know. The word 'know' is here used in two
different senses. (1) In its first use it is applicable to the sort of knowledge
which is opposed to error, the sense in which what we know is true, the
sense which applies to our beliefs and convictions, i.e. to what are called
judgements. In this sense of the word we know that something is the
case. This sort of knowledge may be described as knowledge of truths. (2)
In the second use of the word 'know' above, the word applies to our knowledge of
things, which we may call acquaintance. This is the sense in which
we know sense-data. (The distinction involved is roughly that between savoir
and connaître in French, or between wissen and kennen in
German.)
Thus the statement which seemed like a truism becomes, when re-stated, the
following: 'We can never truly judge that something with which we are not
acquainted exists.' This is by no means a truism, but on the contrary a palpable
falsehood. I have not the honour to be acquainted with the Emperor of China, but
I truly judge that he exists. It may be said, of course, that I judge this
because of other people's acquaintance with him. This, however, would be an
irrelevant retort, since, if the principle were true, I could not know that any
one else is acquainted with him. But further: there is no reason why I should
not know of the existence of something with which nobody is acquainted. This
point is important, and demands elucidation.
If I am acquainted with a thing which exists, my acquaintance gives me the
knowledge that it exists. But it is not true that, conversely, whenever I can
know that a thing of a certain sort exists, I or some one else must be
acquainted with the thing. What happens, in cases where I have true judgement
without acquaintance, is that the thing is known to me by description,
and that, in virtue of some general principle, the existence of a thing
answering to this description can be inferred from the existence of something
with which I am acquainted. In order to understand this point fully, it will be
well first to deal with the difference between knowledge by acquaintance and
knowledge by description, and then to consider what knowledge of general
principles, if any, has the same kind of certainty as our knowledge of the
existence of our own experiences. These subjects will be dealt with in the
following chapters.
CHAPTER V. KNOWLEDGE BY ACQUAINTANCE AND KNOWLEDGE BY DESCRIPTION
In the preceding chapter we saw that there are two sorts of knowledge:
knowledge of things, and knowledge of truths. In this chapter we shall be
concerned exclusively with knowledge of things, of which in turn we shall have
to distinguish two kinds. Knowledge of things, when it is of the kind we call
knowledge by acquaintance, is essentially simpler than any knowledge of
truths, and logically independent of knowledge of truths, though it would be
rash to assume that human beings ever, in fact, have acquaintance with things
without at the same time knowing some truth about them. Knowledge of things by
description, on the contrary, always involves, as we shall find in the
course of the present chapter, some knowledge of truths as its source and
ground. But first of all we must make clear what we mean by 'acquaintance' and
what we mean by 'description'.
We shall say that we have acquaintance with anything of which we are
directly aware, without the intermediary of any process of inference or any
knowledge of truths. Thus in the presence of my table I am acquainted with the
sense-data that make up the appearance of my table—its colour, shape, hardness,
smoothness, etc.; all these are things of which I am immediately conscious when
I am seeing and touching my table. The particular shade of colour that I am
seeing may have many things said about it—I may say that it is brown, that it is
rather dark, and so on. But such statements, though they make me know truths
about the colour, do not make me know the colour itself any better than I did
before so far as concerns knowledge of the colour itself, as opposed to
knowledge of truths about it, I know the colour perfectly and completely when I
see it, and no further knowledge of it itself is even theoretically possible.
Thus the sense-data which make up the appearance of my table are things with
which I have acquaintance, things immediately known to me just as they are.
My knowledge of the table as a physical object, on the contrary, is not
direct knowledge. Such as it is, it is obtained through acquaintance with the
sense-data that make up the appearance of the table. We have seen that it is
possible, without absurdity, to doubt whether there is a table at all, whereas
it is not possible to doubt the sense-data. My knowledge of the table is of the
kind which we shall call 'knowledge by description'. The table is 'the physical
object which causes such-and-such sense-data'. This describes the table by means
of the sense-data. In order to know anything at all about the table, we must
know truths connecting it with things with which we have acquaintance: we must
know that 'such-and-such sense-data are caused by a physical object'. There is
no state of mind in which we are directly aware of the table; all our knowledge
of the table is really knowledge of truths, and the actual thing which is the
table is not, strictly speaking, known to us at all. We know a description, and
we know that there is just one object to which this description applies, though
the object itself is not directly known to us. In such a case, we say that our
knowledge of the object is knowledge by description.
All our knowledge, both knowledge of things and knowledge of truths, rests
upon acquaintance as its foundation. It is therefore important to consider what
kinds of things there are with which we have acquaintance.
Sense-data, as we have already seen, are among the things with which we are
acquainted; in fact, they supply the most obvious and striking example of
knowledge by acquaintance. But if they were the sole example, our knowledge
would be very much more restricted than it is. We should only know what is now
present to our senses: we could not know anything about the past—not even that
there was a past—nor could we know any truths about our sense-data, for all
knowledge of truths, as we shall show, demands acquaintance with things which
are of an essentially different character from sense-data, the things which are
sometimes called 'abstract ideas', but which we shall call 'universals'. We have
therefore to consider acquaintance with other things besides sense-data if we
are to obtain any tolerably adequate analysis of our knowledge.
The first extension beyond sense-data to be considered is acquaintance by
memory. It is obvious that we often remember what we have seen or heard or
had otherwise present to our senses, and that in such cases we are still
immediately aware of what we remember, in spite of the fact that it appears as
past and not as present. This immediate knowledge by memory is the source of all
our knowledge concerning the past: without it, there could be no knowledge of
the past by inference, since we should never know that there was anything past
to be inferred.
The next extension to be considered is acquaintance by introspection.
We are not only aware of things, but we are often aware of being aware of them.
When I see the sun, I am often aware of my seeing the sun; thus 'my seeing the
sun' is an object with which I have acquaintance. When I desire food, I may be
aware of my desire for food; thus 'my desiring food' is an object with which I
am acquainted. Similarly we may be aware of our feeling pleasure or pain, and
generally of the events which happen in our minds. This kind of acquaintance,
which may be called self-consciousness, is the source of all our knowledge of
mental things. It is obvious that it is only what goes on in our own minds that
can be thus known immediately. What goes on in the minds of others is known to
us through our perception of their bodies, that is, through the sense-data in us
which are associated with their bodies. But for our acquaintance with the
contents of our own minds, we should be unable to imagine the minds of others,
and therefore we could never arrive at the knowledge that they have minds. It
seems natural to suppose that self-consciousness is one of the things that
distinguish men from animals: animals, we may suppose, though they have
acquaintance with sense-data, never become aware of this acquaintance. I do not
mean that they doubt whether they exist, but that they have never become
conscious of the fact that they have sensations and feelings, nor therefore of
the fact that they, the subjects of their sensations and feelings, exist.
We have spoken of acquaintance with the contents of our minds as self-consciousness,
but it is not, of course, consciousness of our self: it is consciousness
of particular thoughts and feelings. The question whether we are also acquainted
with our bare selves, as opposed to particular thoughts and feelings, is a very
difficult one, upon which it would be rash to speak positively. When we try to
look into ourselves we always seem to come upon some particular thought or
feeling, and not upon the 'I' which has the thought or feeling. Nevertheless
there are some reasons for thinking that we are acquainted with the 'I', though
the acquaintance is hard to disentangle from other things. To make clear what
sort of reason there is, let us consider for a moment what our acquaintance with
particular thoughts really involves.
When I am acquainted with 'my seeing the sun', it seems plain that I am
acquainted with two different things in relation to each other. On the one hand
there is the sense-datum which represents the sun to me, on the other hand there
is that which sees this sense-datum. All acquaintance, such as my acquaintance
with the sense-datum which represents the sun, seems obviously a relation
between the person acquainted and the object with which the person is
acquainted. When a case of acquaintance is one with which I can be acquainted
(as I am acquainted with my acquaintance with the sense-datum representing the
sun), it is plain that the person acquainted is myself. Thus, when I am
acquainted with my seeing the sun, the whole fact with which I am acquainted is
'Self-acquainted-with-sense-datum'.
Further, we know the truth 'I am acquainted with this sense-datum'. It is
hard to see how we could know this truth, or even understand what is meant by
it, unless we were acquainted with something which we call 'I'. It does not seem
necessary to suppose that we are acquainted with a more or less permanent
person, the same to-day as yesterday, but it does seem as though we must be
acquainted with that thing, whatever its nature, which sees the sun and has
acquaintance with sense-data. Thus, in some sense it would seem we must be
acquainted with our Selves as opposed to our particular experiences. But the
question is difficult, and complicated arguments can be adduced on either side.
Hence, although acquaintance with ourselves seems probably to occur, it
is not wise to assert that it undoubtedly does occur.
We may therefore sum up as follows what has been said concerning acquaintance
with things that exist. We have acquaintance in sensation with the data of the
outer senses, and in introspection with the data of what may be called the inner
sense—thoughts, feelings, desires, etc.; we have acquaintance in memory with
things which have been data either of the outer senses or of the inner sense.
Further, it is probable, though not certain, that we have acquaintance with
Self, as that which is aware of things or has desires towards things.
In addition to our acquaintance with particular existing things, we also have
acquaintance with what we shall call universals, that is to say, general
ideas, such as whiteness, diversity, brotherhood, and so
on. Every complete sentence must contain at least one word which stands for a
universal, since all verbs have a meaning which is universal. We shall return to
universals later on, in Chapter IX; for the present, it is only necessary to
guard against the supposition that whatever we can be acquainted with must be
something particular and existent. Awareness of universals is called
conceiving, and a universal of which we are aware is called a concept.
It will be seen that among the objects with which we are acquainted are not
included physical objects (as opposed to sense-data), nor other people's minds.
These things are known to us by what I call 'knowledge by description', which we
must now consider.
By a 'description' I mean any phrase of the form 'a so-and-so' or 'the
so-and-so'. A phrase of the form 'a so-and-so' I shall call an 'ambiguous'
description; a phrase of the form 'the so-and-so' (in the singular) I shall call
a 'definite' description. Thus 'a man' is an ambiguous description, and 'the man
with the iron mask' is a definite description. There are various problems
connected with ambiguous descriptions, but I pass them by, since they do not
directly concern the matter we are discussing, which is the nature of our
knowledge concerning objects in cases where we know that there is an object
answering to a definite description, though we are not acquainted with any such
object. This is a matter which is concerned exclusively with definite
descriptions. I shall therefore, in the sequel, speak simply of 'descriptions'
when I mean 'definite descriptions'. Thus a description will mean any phrase of
the form 'the so-and-so' in the singular.
We shall say that an object is 'known by description' when we know that it is
'the so-and-so', i.e. when we know that there is one object, and no more, having
a certain property; and it will generally be implied that we do not have
knowledge of the same object by acquaintance. We know that the man with the iron
mask existed, and many propositions are known about him; but we do not know who
he was. We know that the candidate who gets the most votes will be elected, and
in this case we are very likely also acquainted (in the only sense in which one
can be acquainted with some one else) with the man who is, in fact, the
candidate who will get most votes; but we do not know which of the candidates he
is, i.e. we do not know any proposition of the form 'A is the candidate who will
get most votes' where A is one of the candidates by name. We shall say that we
have 'merely descriptive knowledge' of the so-and-so when, although we know that
the so-and-so exists, and although we may possibly be acquainted with the object
which is, in fact, the so-and-so, yet we do not know any proposition 'a
is the so-and-so', where a is something with which we are acquainted.
When we say 'the so-and-so exists', we mean that there is just one object
which is the so-and-so. The proposition 'a is the so-and-so' means that
a has the property so-and-so, and nothing else has. 'Mr. A. is the
Unionist candidate for this constituency' means 'Mr. A. is a Unionist candidate
for this constituency, and no one else is'. 'The Unionist candidate for this
constituency exists' means 'some one is a Unionist candidate for this
constituency, and no one else is'. Thus, when we are acquainted with an object
which is the so-and-so, we know that the so-and-so exists; but we may know that
the so-and-so exists when we are not acquainted with any object which we know to
be the so-and-so, and even when we are not acquainted with any object which, in
fact, is the so-and-so.
Common words, even proper names, are usually really descriptions. That is to
say, the thought in the mind of a person using a proper name correctly can
generally only be expressed explicitly if we replace the proper name by a
description. Moreover, the description required to express the thought will vary
for different people, or for the same person at different times. The only thing
constant (so long as the name is rightly used) is the object to which the name
applies. But so long as this remains constant, the particular description
involved usually makes no difference to the truth or falsehood of the
proposition in which the name appears.
Let us take some illustrations. Suppose some statement made about Bismarck.
Assuming that there is such a thing as direct acquaintance with oneself,
Bismarck himself might have used his name directly to designate the particular
person with whom he was acquainted. In this case, if he made a judgement about
himself, he himself might be a constituent of the judgement. Here the proper
name has the direct use which it always wishes to have, as simply standing for a
certain object, and not for a description of the object. But if a person who
knew Bismarck made a judgement about him, the case is different. What this
person was acquainted with were certain sense-data which he connected (rightly,
we will suppose) with Bismarck's body. His body, as a physical object, and still
more his mind, were only known as the body and the mind connected with these
sense-data. That is, they were known by description. It is, of course, very much
a matter af chance which characteristics of a man's appearance will come into a
friend's mind when he thinks of him; thus the description actually in the
friend's mind is accidental. The essential point is that he knows that the
various descriptions all apply to the same entity, in spite of not being
acquainted with the entity in question.
When we, who did not know Bismarck, make a judgement about him, the
description in our minds will probably be some more or less vague mass of
historical knowledge—far more, in most cases, than is required to identify him.
But, for the sake of illustration, let us assume that we think of him as 'the
first Chancellor of the German Empire'. Here all the words are abstract except
'German'. The word 'German' will, again, have different meanings for different
people. To some it will recall travels in Germany, to some the look of Germany
on the map, and so on. But if we are to obtain a description which we know to be
applicable, we shall be compelled, at some point, to bring in a reference to a
particular with which we are acquainted. Such reference is involved in any
mention of past, present, and future (as opposed to definite dates), or of here
and there, or of what others have told us. Thus it would seem that, in some way
or other, a description known to be applicable to a particular must involve some
reference to a particular with which we are acquainted, if our knowledge about
the thing described is not to be merely what follows logically from the
description. For example, 'the most long-lived of men' is a description
involving only universals, which must apply to some man, but we can make no
judgements concerning this man which involve knowledge about him beyond what the
description gives. If, however, we say, 'The first Chancellor of the German
Empire was an astute diplomatist', we can only be assured of the truth of our
judgement in virtue of something with which we are acquainted—usually a
testimony heard or read. Apart from the information we convey to others, apart
from the fact about the actual Bismarck, which gives importance to our
judgement, the thought we really have contains the one or more particulars
involved, and otherwise consists wholly of concepts.
All names of places—London, England, Europe, the Earth, the Solar
System—similarly involve, when used, descriptions which start from some one or
more particulars with which we are acquainted. I suspect that even the Universe,
as considered by metaphysics, involves such a connexion with particulars. In
logic, on the contrary, where we are concerned not merely with what does exist,
but with whatever might or could exist or be, no reference to actual particulars
is involved.
It would seem that, when we make a statement about something only known by
description, we often intend to make our statement, not in the form
involving the description, but about the actual thing described. That is to say,
when we say anything about Bismarck, we should like, if we could, to make the
judgement which Bismarck alone can make, namely, the judgement of which he
himself is a constituent. In this we are necessarily defeated, since the actual
Bismarck is unknown to us. But we know that there is an object B, called
Bismarck, and that B was an astute diplomatist. We can thus describe the
proposition we should like to affirm, namely, 'B was an astute diplomatist',
where B is the object which was Bismarck. If we are describing Bismarck as 'the
first Chancellor of the German Empire', the proposition we should like to affirm
may be described as 'the proposition asserting, concerning the actual object
which was the first Chancellor of the German Empire, that this object was an
astute diplomatist'. What enables us to communicate in spite of the varying
descriptions we employ is that we know there is a true proposition concerning
the actual Bismarck, and that however we may vary the description (so long as
the description is correct) the proposition described is still the same. This
proposition, which is described and is known to be true, is what interests us;
but we are not acquainted with the proposition itself, and do not know it,
though we know it is true.
It will be seen that there are various stages in the removal from
acquaintance with particulars: there is Bismarck to people who knew him;
Bismarck to those who only know of him through history; the man with the iron
mask; the longest-lived of men. These are progressively further removed from
acquaintance with particulars; the first comes as near to acquaintance as is
possible in regard to another person; in the second, we shall still be said to
know 'who Bismarck was'; in the third, we do not know who was the man with the
iron mask, though we can know many propositions about him which are not
logically deducible from the fact that he wore an iron mask; in the fourth,
finally, we know nothing beyond what is logically deducible from the definition
of the man. There is a similar hierarchy in the region of universals. Many
universals, like many particulars, are only known to us by description. But
here, as in the case of particulars, knowledge concerning what is known by
description is ultimately reducible to knowledge concerning what is known by
acquaintance.
The fundamental principle in the analysis of propositions containing
descriptions is this: Every proposition which we can understand must be
composed wholly of constituents with which we are acquainted.
We shall not at this stage attempt to answer all the objections which may be
urged against this fundamental principle. For the present, we shall merely point
out that, in some way or other, it must be possible to meet these objections,
for it is scarcely conceivable that we can make a judgement or entertain a
supposition without knowing what it is that we are judging or supposing about.
We must attach some meaning to the words we use, if we are to speak
significantly and not utter mere noise; and the meaning we attach to our words
must be something with which we are acquainted. Thus when, for example, we make
a statement about Julius Caesar, it is plain that Julius Caesar himself is not
before our minds, since we are not acquainted with him. We have in mind some
description of Julius Caesar: 'the man who was assassinated on the Ides of
March', 'the founder of the Roman Empire', or, perhaps, merely 'the man whose
name was Julius Caesar'. (In this last description, Julius Caesar
is a noise or shape with which we are acquainted.) Thus our statement does not
mean quite what it seems to mean, but means something involving, instead of
Julius Caesar, some description of him which is composed wholly of particulars
and universals with which we are acquainted.
The chief importance of knowledge by description is that it enables us to
pass beyond the limits of our private experience. In spite of the fact that we
can only know truths which are wholly composed of terms which we have
experienced in acquaintance, we can yet have knowledge by description of things
which we have never experienced. In view of the very narrow range of our
immediate experience, this result is vital, and until it is understood, much of
our knowledge must remain mysterious and therefore doubtful.
CHAPTER VI. ON INDUCTION
In almost all our previous discussions we have been concerned in the attempt
to get clear as to our data in the way of knowledge of existence. What things
are there in the universe whose existence is known to us owing to our being
acquainted with them? So far, our answer has been that we are acquainted with
our sense-data, and, probably, with ourselves. These we know to exist. And past
sense-data which are remembered are known to have existed in the past. This
knowledge supplies our data.
But if we are to be able to draw inferences from these data—if we are to know
of the existence of matter, of other people, of the past before our individual
memory begins, or of the future, we must know general principles of some kind by
means of which such inferences can be drawn. It must be known to us that the
existence of some one sort of thing, A, is a sign of the existence of some other
sort of thing, B, either at the same time as A or at some earlier or later time,
as, for example, thunder is a sign of the earlier existence of lightning. If
this were not known to us, we could never extend our knowledge beyond the sphere
of our private experience; and this sphere, as we have seen, is exceedingly
limited. The question we have now to consider is whether such an extension is
possible, and if so, how it is effected.
Let us take as an illustration a matter about which none of us, in fact, feel
the slightest doubt. We are all convinced that the sun will rise to-morrow. Why?
Is this belief a mere blind outcome of past experience, or can it be justified
as a reasonable belief? It is not easy to find a test by which to judge whether
a belief of this kind is reasonable or not, but we can at least ascertain what
sort of general beliefs would suffice, if true, to justify the judgement that
the sun will rise to-morrow, and the many other similar judgements upon which
our actions are based.
It is obvious that if we are asked why we believe that the sun will rise
to-morrow, we shall naturally answer 'Because it always has risen every day'. We
have a firm belief that it will rise in the future, because it has risen in the
past. If we are challenged as to why we believe that it will continue to rise as
heretofore, we may appeal to the laws of motion: the earth, we shall say, is a
freely rotating body, and such bodies do not cease to rotate unless something
interferes from outside, and there is nothing outside to interfere with the
earth between now and to-morrow. Of course it might be doubted whether we are
quite certain that there is nothing outside to interfere, but this is not the
interesting doubt. The interesting doubt is as to whether the laws of motion
will remain in operation until to-morrow. If this doubt is raised, we find
ourselves in the same position as when the doubt about the sunrise was first
raised.
The only reason for believing that the laws of motion will remain in
operation is that they have operated hitherto, so far as our knowledge of the
past enables us to judge. It is true that we have a greater body of evidence
from the past in favour of the laws of motion than we have in favour of the
sunrise, because the sunrise is merely a particular case of fulfilment of the
laws of motion, and there are countless other particular cases. But the real
question is: Do any number of cases of a law being fulfilled in the past
afford evidence that it will be fulfilled in the future? If not, it becomes
plain that we have no ground whatever for expecting the sun to rise to-morrow,
or for expecting the bread we shall eat at our next meal not to poison us, or
for any of the other scarcely conscious expectations that control our daily
lives. It is to be observed that all such expectations are only probable;
thus we have not to seek for a proof that they must be fulfilled, but
only for some reason in favour of the view that they are likely to be
fulfilled.
Now in dealing with this question we must, to begin with, make an important
distinction, without which we should soon become involved in hopeless
confusions. Experience has shown us that, hitherto, the frequent repetition of
some uniform succession or coexistence has been a cause of our expecting
the same succession or coexistence on the next occasion. Food that has a certain
appearance generally has a certain taste, and it is a severe shock to our
expectations when the familiar appearance is found to be associated with an
unusual taste. Things which we see become associated, by habit, with certain
tactile sensations which we expect if we touch them; one of the horrors of a
ghost (in many ghost-stories) is that it fails to give us any sensations of
touch. Uneducated people who go abroad for the first time are so surprised as to
be incredulous when they find their native language not understood.
And this kind of association is not confined to men; in animals also it is
very strong. A horse which has been often driven along a certain road resists
the attempt to drive him in a different direction. Domestic animals expect food
when they see the person who usually feeds them. We know that all these rather
crude expectations of uniformity are liable to be misleading. The man who has
fed the chicken every day throughout its life at last wrings its neck instead,
showing that more refined views as to the uniformity of nature would have been
useful to the chicken.
But in spite of the misleadingness of such expectations, they nevertheless
exist. The mere fact that something has happened a certain number of times
causes animals and men to expect that it will happen again. Thus our instincts
certainly cause us to believe that the sun will rise to-morrow, but we may be in
no better a position than the chicken which unexpectedly has its neck wrung. We
have therefore to distinguish the fact that past uniformities cause
expectations as to the future, from the question whether there is any reasonable
ground for giving weight to such expectations after the question of their
validity has been raised.
The problem we have to discuss is whether there is any reason for believing
in what is called 'the uniformity of nature'. The belief in the uniformity of
nature is the belief that everything that has happened or will happen is an
instance of some general law to which there are no exceptions. The crude
expectations which we have been considering are all subject to exceptions, and
therefore liable to disappoint those who entertain them. But science habitually
assumes, at least as a working hypothesis, that general rules which have
exceptions can be replaced by general rules which have no exceptions.
'Unsupported bodies in air fall' is a general rule to which balloons and
aeroplanes are exceptions. But the laws of motion and the law of gravitation,
which account for the fact that most bodies fall, also account for the fact that
balloons and aeroplanes can rise; thus the laws of motion and the law of
gravitation are not subject to these exceptions.
The belief that the sun will rise to-morrow might be falsified if the earth
came suddenly into contact with a large body which destroyed its rotation; but
the laws of motion and the law of gravitation would not be infringed by such an
event. The business of science is to find uniformities, such as the laws of
motion and the law of gravitation, to which, so far as our experience extends,
there are no exceptions. In this search science has been remarkably successful,
and it may be conceded that such uniformities have held hitherto. This brings us
back to the question: Have we any reason, assuming that they have always held in
the past, to suppose that they will hold in the future?
It has been argued that we have reason to know that the future will resemble
the past, because what was the future has constantly become the past, and has
always been found to resemble the past, so that we really have experience of the
future, namely of times which were formerly future, which we may call past
futures. But such an argument really begs the very question at issue. We have
experience of past futures, but not of future futures, and the question is: Will
future futures resemble past futures? This question is not to be answered by an
argument which starts from past futures alone. We have therefore still to seek
for some principle which shall enable us to know that the future will follow the
same laws as the past.
The reference to the future in this question is not essential. The same
question arises when we apply the laws that work in our experience to past
things of which we have no experience—as, for example, in geology, or in
theories as to the origin of the Solar System. The question we really have to
ask is: 'When two things have been found to be often associated, and no instance
is known of the one occurring without the other, does the occurrence of one of
the two, in a fresh instance, give any good ground for expecting the other?' On
our answer to this question must depend the validity of the whole of our
expectations as to the future, the whole of the results obtained by induction,
and in fact practically all the beliefs upon which our daily life is based.
It must be conceded, to begin with, that the fact that two things have been
found often together and never apart does not, by itself, suffice to prove
demonstratively that they will be found together in the next case we examine.
The most we can hope is that the oftener things are found together, the more
probable it becomes that they will be found together another time, and that, if
they have been found together often enough, the probability will amount
almost to certainty. It can never quite reach certainty, because we know
that in spite of frequent repetitions there sometimes is a failure at the last,
as in the case of the chicken whose neck is wrung. Thus probability is all we
ought to seek.
It might be urged, as against the view we are advocating, that we know all
natural phenomena to be subject to the reign of law, and that sometimes, on the
basis of observation, we can see that only one law can possibly fit the facts of
the case. Now to this view there are two answers. The first is that, even if
some law which has no exceptions applies to our case, we can never, in
practice, be sure that we have discovered that law and not one to which there
are exceptions. The second is that the reign of law would seem to be itself only
probable, and that our belief that it will hold in the future, or in unexamined
cases in the past, is itself based upon the very principle we are examining.
The principle we are examining may be called the principle of induction,
and its two parts may be stated as follows:
(a) When a thing of a certain sort A has been found to be associated with a
thing of a certain other sort B, and has never been found dissociated from a
thing of the sort B, the greater the number of cases in which A and B have been
associated, the greater is the probability that they will be associated in a
fresh case in which one of them is known to be present;
(b) Under the same circumstances, a sufficient number of cases of association
will make the probability of a fresh association nearly a certainty, and will
make it approach certainty without limit.
As just stated, the principle applies only to the verification of our
expectation in a single fresh instance. But we want also to know that there is a
probability in favour of the general law that things of the sort A are always
associated with things of the sort B, provided a sufficient number of cases of
association are known, and no cases of failure of association are known. The
probability of the general law is obviously less than the probability of the
particular case, since if the general law is true, the particular case must also
be true, whereas the particular case may be true without the general law being
true. Nevertheless the probability of the general law is increased by
repetitions, just as the probability of the particular case is. We may therefore
repeat the two parts of our principle as regards the general law, thus:
(a) The greater the number of cases in which a thing of the sort A has been
found associated with a thing of the sort B, the more probable it is (if no
cases of failure of association are known) that A is always associated with B;
b) Under the same circumstances, a sufficient number of cases of the
association of A with B will make it nearly certain that A is always associated
with B, and will make this general law approach certainty without limit.
It should be noted that probability is always relative to certain data. In
our case, the data are merely the known cases of coexistence of A and B. There
may be other data, which might be taken into account, which would gravely
alter the probability. For example, a man who had seen a great many white swans
might argue, by our principle, that on the data it was probable that all
swans were white, and this might be a perfectly sound argument. The argument is
not disproved ny the fact that some swans are black, because a thing may very
well happen in spite of the fact that some data render it improbable. In the
case of the swans, a man might know that colour is a very variable
characteristic in many species of animals, and that, therefore, an induction as
to colour is peculiarly liable to error. But this knowledge would be a fresh
datum, by no means proving that the probability relatively to our previous data
had been wrongly estimated. The fact, therefore, that things often fail to
fulfil our expectations is no evidence that our expectations will not
probably be fulfilled in a given case or a given class of cases. Thus our
inductive principle is at any rate not capable of being disproved by an
appeal to experience.
The inductive principle, however, is equally incapable of being proved
by an appeal to experience. Experience might conceivably confirm the inductive
principle as regards the cases that have been already examined; but as regards
unexamined cases, it is the inductive principle alone that can justify any
inference from what has been examined to what has not been examined. All
arguments which, on the basis of experience, argue as to the future or the
unexperienced parts of the past or present, assume the inductive principle;
hence we can never use experience to prove the inductive principle without
begging the question. Thus we must either accept the inductive principle on the
ground of its intrinsic evidence, or forgo all justification of our expectations
about the future. If the principle is unsound, we have no reason to expect the
sun to rise to-morrow, to expect bread to be more nourishing than a stone, or to
expect that if we throw ourselves off the roof we shall fall. When we see what
looks like our best friend approaching us, we shall have no reason to suppose
that his body is not inhabited by the mind of our worst enemy or of some total
stranger. All our conduct is based upon associations which have worked in the
past, and which we therefore regard as likely to work in the future; and this
likelihood is dependent for its validity upon the inductive principle.
The general principles of science, such as the belief in the reign of law,
and the belief that every event must have a cause, are as completely dependent
upon the inductive principle as are the beliefs of daily life All such general
principles are believed because mankind have found innumerable instances of
their truth and no instances of their falsehood. But this affords no evidence
for their truth in the future, unless the inductive principle is assumed.
Thus all knowledge which, on a basis of experience tells us something about
what is not experienced, is based upon a belief which experience can neither
confirm nor confute, yet which, at least in its more concrete applications,
appears to be as firmly rooted in us as many of the facts of experience. The
existence and justification of such beliefs—for the inductive principle, as we
shall see, is not the only example—raises some of the most difficult and most
debated problems of philosophy. We will, in the next chapter, consider briefly
what may be said to account for such knowledge, and what is its scope and its
degree of certainty.
CHAPTER VII. ON OUR KNOWLEDGE OF GENERAL PRINCIPLES
We saw in the preceding chapter that the principle of induction, while
necessary to the validity of all arguments based on experience, is itself not
capable of being proved by experience, and yet is unhesitatingly believed by
every one, at least in all its concrete applications. In these characteristics
the principle of induction does not stand alone. There are a number of other
principles which cannot be proved or disproved by experience, but are used in
arguments which start from what is experienced.
Some of these principles have even greater evidence than the principle of
induction, and the knowledge of them has the same degree of certainty as the
knowledge of the existence of sense-data. They constitute the means of drawing
inferences from what is given in sensation; and if what we infer is to be true,
it is just as necessary that our principles of inference should be true as it is
that our data should be true. The principles of inference are apt to be
overlooked because of their very obviousness—the assumption involved is assented
to without our realizing that it is an assumption. But it is very important to
realize the use of principles of inference, if a correct theory of knowledge is
to be obtained; for our knowledge of them raises interesting and difficult
questions.
In all our knowledge of general principles, what actually happens is that
first of all we realize some particular application of the principle, and then
we realize that the particularity is irrelevant, and that there is a generality
which may equally truly be affirmed. This is of course familiar in such matters
as teaching arithmetic: 'two and two are four' is first learnt in the case of
some particular pair of couples, and then in some other particular case, and so
on, until at last it becomes possible to see that it is true of any pair of
couples. The same thing happens with logical principles. Suppose two men are
discussing what day of the month it is. One of them says, 'At least you will
admit that if yesterday was the 15th to-day must be the 16th.' 'Yes',
says the other, 'I admit that.' 'And you know', the first continues, 'that
yesterday was the 15th, because you dined with Jones, and your diary will tell
you that was on the 15th.' 'Yes', says the second; 'therefore to-day is
the 16th.'
Now such an argument is not hard to follow; and if it is granted that its
premisses are true in fact, no one will deny that the conclusion must also be
true. But it depends for its truth upon an instance of a general logical
principle. The logical principle is as follows: 'Suppose it known that if
this is true, then that is true. Suppose it also known that this is true,
then it follows that that is true.' When it is the case that if this is true,
that is true, we shall say that this 'implies' that, and that that 'follows
from' this. Thus our principle states that if this implies that, and this is
true, then that is true. In other words, 'anything implied by a true proposition
is true', or 'whatever follows from a true proposition is true'.
This principle is really involved—at least, concrete instances of it are
involved—in all demonstrations. Whenever one thing which we believe is used to
prove something else, which we consequently believe, this principle is relevant.
If any one asks: 'Why should I accept the results of valid arguments based on
true premisses?' we can only answer by appealing to our principle. In fact, the
truth of the principle is impossible to doubt, and its obviousness is so great
that at first sight it seems almost trivial. Such principles, however, are not
trivial to the philosopher, for they show that we may have indubitable knowledge
which is in no way derived from objects of sense.
The above principle is merely one of a certain number of self-evident logical
principles. Some at least of these principles must be granted before any
argument or proof becomes possible. When some of them have been granted, others
can be proved, though these others, so long as they are simple, are just as
obvious as the principles taken for granted. For no very good reason, three of
these principles have been singled out by tradition under the name of 'Laws of
Thought'.
They are as follows:
(1) The law of identity: 'Whatever is, is.'
(2) The law of contradiction: 'Nothing can both be and not be.'
(3) The law of excluded middle: 'Everything must either be or not be.'
These three laws are samples of self-evident logical principles, but are not
really more fundamental or more self-evident than various other similar
principles: for instance, the one we considered just now, which states that what
follows from a true premiss is true. The name 'laws of thought' is also
misleading, for what is important is not the fact that we think in accordance
with these laws, but the fact that things behave in accordance with them; in
other words, the fact that when we think in accordance with them we think
truly. But this is a large question, to which we must return at a later
stage.
In addition to the logical principles which enable us to prove from a given
premiss that something is certainly true, there are other logical
principles which enable us to prove, from a given premiss, that there is a
greater or less probability that something is true. An example of such
principles—perhaps the most important example is the inductive principle, which
we considered in the preceding chapter.
One of the great historic controversies in philosophy is the controversy
between the two schools called respectively 'empiricists' and 'rationalists'.
The empiricists—who are best represented by the British philosophers, Locke,
Berkeley, and Hume—maintained that all our knowledge is derived from experience;
the rationalists—who are represented by the Continental philosophers of the
seventeenth century, especially Descartes and Leibniz—maintained that, in
addition to what we know by experience, there are certain 'innate ideas' and
'innate principles', which we know independently of experience. It has now
become possible to decide with some confidence as to the truth or falsehood of
these opposing schools. It must be admitted, for the reasons already stated,
that logical principles are known to us, and cannot be themselves proved by
experience, since all proof presupposes them. In this, therefore, which was the
most important point of the controversy, the rationalists were in the right.
On the other hand, even that part of our knowledge which is logically
independent of experience (in the sense that experience cannot prove it) is yet
elicited and caused by experience. It is on occasion of particular experiences
that we become aware of the general laws which their connexions exemplify. It
would certainly be absurd to suppose that there are innate principles in the
sense that babies are born with a knowledge of everything which men know and
which cannot be deduced from what is experienced. For this reason, the word
'innate' would not now be employed to describe our knowledge of logical
principles. The phrase 'a priori' is less objectionable, and is more
usual in modern writers. Thus, while admitting that all knowledge is elicited
and caused by experience, we shall nevertheless hold that some knowledge is a
priori, in the sense that the experience which makes us think of it does not
suffice to prove it, but merely so directs our attention that we see its truth
without requiring any proof from experience.
There is another point of great importance, in which the empiricists were in
the right as against the rationalists. Nothing can be known to exist
except by the help of experience. That is to say, if we wish to prove that
something of which we have no direct experience exists, we must have among our
premisses the existence of one or more things of which we have direct
experience. Our belief that the Emperor of China exists, for example, rests upon
testimony, and testimony consists, in the last analysis, of sense-data seen or
heard in reading or being spoken to. Rationalists believed that, from general
consideration as to what must be, they could deduce the existence of this or
that in the actual world. In this belief they seem to have been mistaken. All
the knowledge that we can acquire a priori concerning existence seems to
be hypothetical: it tells us that if one thing exists, another must exist, or,
more generally, that if one proposition is true, another must be true. This is
exemplified by the principles we have already dealt with, such as 'if
this is true, and this implies that, then that is true', or 'if this and
that have been repeatedly found connected, they will probably be connected in
the next instance in which one of them is found'. Thus the scope and power of
a priori principles is strictly limited. All knowledge that something exists
must be in part dependent on experience. When anything is known immediately, its
existence is known by experience alone; when anything is proved to exist,
without being known immediately, both experience and a priori principles
must be required in the proof. Knowledge is called empirical when it
rests wholly or partly upon experience. Thus all knowledge which asserts
existence is empirical, and the only a priori knowledge concerning
existence is hypothetical, giving connexions among things that exist or may
exist, but not giving actual existence.
A priori knowledge is not all of the logical kind we have been
hitherto considering. Perhaps the most important example of non-logical a
priori knowledge is knowledge as to ethical value. I am not speaking of
judgements as to what is useful or as to what is virtuous, for such judgements
do require empirical premisses; I am speaking of judgements as to the intrinsic
desirability of things. If something is useful, it must be useful because it
secures some end; the end must, if we have gone far enough, be valuable on its
own account, and not merely because it is useful for some further end. Thus all
judgements as to what is useful depend upon judgements as to what has value on
its own account.
We judge, for example, that happiness is more desirable than misery,
knowledge than ignorance, goodwill than hatred, and so on. Such judgements must,
in part at least, be immediate and a priori. Like our previous a
priori judgements, they may be elicited by experience, and indeed they must
be; for it seems not possible to judge whether anything is intrinsically
valuable unless we have experienced something of the same kind. But it is fairly
obvious that they cannot be proved by experience; for the fact that a thing
exists or does not exist cannot prove either that it is good that it should
exist or that it is bad. The pursuit of this subject belongs to ethics, where
the impossibility of deducing what ought to be from what is has to be
established. In the present connexion, it is only important to realize that
knowledge as to what is intrinsically of value is a priori in the same
sense in which logic is a priori, namely in the sense that the truth of
such knowledge can be neither proved nor disproved by experience.
All pure mathematics is a priori, like logic. This was strenuously
denied by the empirical philosophers, who maintained that experience was as much
the source of our knowledge of arithmetic as of our knowledge of geography. They
maintained that by the repeated experience of seeing two things and two other
things, and finding that altogether they made four things, we were led by
induction to the conclusion that two things and two other things would always
make four things altogether. If, however, this were the source of our knowledge
that two and two are four, we should proceed differently, in persuading
ourselves of its truth, from the way in which we do actually proceed. In fact, a
certain number of instances are needed to make us think of two abstractly,
rather than of two coins or two books or two people, or two of any other
specified kind. But as soon as we are able to divest our thoughts of irrelevant
particularity, we become able to see the general principle that two and two are
four; any one instance is seen to be typical, and the examination of
other instances becomes unnecessary.(1)
(1) Cf. A. N. Whitehead, Introduction to Mathematics (Home University
Library).
The same thing is exemplified in geometry. If we want to prove some property
of all triangles, we draw some one triangle and reason about it; but we
can avoid making use of any property which it does not share with all other
triangles, and thus, from our particular case, we obtain a general result. We do
not, in fact, feel our certainty that two and two are four increased by fresh
instances, because, as soon as we have seen the truth of this proposition, our
certainty becomes so great as to be incapable of growing greater. Moreover, we
feel some quality of necessity about the proposition 'two and two are four',
which is absent from even the best attested empirical generalizations. Such
generalizations always remain mere facts: we feel that there might be a world in
which they were false, though in the actual world they happen to be true. In any
possible world, on the contrary, we feel that two and two would be four: this is
not a mere fact, but a necessity to which everything actual and possible must
conform.
The case may be made clearer by considering a genuinely-empirical
generalization, such as 'All men are mortal.' It is plain that we believe this
proposition, in the first place, because there is no known instance of men
living beyond a certain age, and in the second place because there seem to be
physiological grounds for thinking that an organism such as a man's body must
sooner or later wear out. Neglecting the second ground, and considering merely
our experience of men's mortality, it is plain that we should not be content
with one quite clearly understood instance of a man dying, whereas, in the case
of 'two and two are four', one instance does suffice, when carefully considered,
to persuade us that the same must happen in any other instance. Also we can be
forced to admit, on reflection, that there may be some doubt, however slight, as
to whether all men are mortal. This may be made plain by the attempt to
imagine two different worlds, in one of which there are men who are not mortal,
while in the other two and two make five. When Swift invites us to consider the
race of Struldbugs who never die, we are able to acquiesce in imagination. But a
world where two and two make five seems quite on a different level. We feel that
such a world, if there were one, would upset the whole fabric of our knowledge
and reduce us to utter doubt.
The fact is that, in simple mathematical judgements such as 'two and two are
four', and also in many judgements of logic, we can know the general proposition
without inferring it from instances, although some instance is usually necessary
to make clear to us what the general proposition means. This is why there is
real utility in the process of deduction, which goes from the general to
the general, or from the general to the particular, as well as in the process of
induction, which goes from the particular to the particular, or from the
particular to the general. It is an old debate among philosophers whether
deduction ever gives new knowledge. We can now see that in certain cases,
at least, it does do so. If we already know that two and two always make four,
and we know that Brown and Jones are two, and so are Robinson and Smith, we can
deduce that Brown and Jones and Robinson and Smith are four. This is new
knowledge, not contained in our premisses, because the general proposition, 'two
and two are four', never told us there were such people as Brown and Jones and
Robinson and Smith, and the particular premisses do not tell us that there were
four of them, whereas the particular proposition deduced does tell us both these
things.
But the newness of the knowledge is much less certain if we take the stock
instance of deduction that is always given in books on logic, namely, 'All men
are mortal; Socrates is a man, therefore Socrates is mortal.' In this case, what
we really know beyond reasonable doubt is that certain men, A, B, C, were
mortal, since, in fact, they have died. If Socrates is one of these men, it is
foolish to go the roundabout way through 'all men are mortal' to arrive at the
conclusion that probably Socrates is mortal. If Socrates is not one of
the men on whom our induction is based, we shall still do better to argue
straight from our A, B, C, to Socrates, than to go round by the general
proposition, 'all men are mortal'. For the probability that Socrates is mortal
is greater, on our data, than the probability that all men are mortal. (This is
obvious, because if all men are mortal, so is Socrates; but if Socrates is
mortal, it does not follow that all men are mortal.) Hence we shall reach the
conclusion that Socrates is mortal with a greater approach to certainty if we
make our argument purely inductive than if we go by way of 'all men are mortal'
and then use deduction.
This illustrates the difference between general propositions known a
priori such as 'two and two are four', and empirical generalizations such as
'all men are mortal'. In regard to the former, deduction is the right mode of
argument, whereas in regard to the latter, induction is always theoretically
preferable, and warrants a greater confidence in the truth of our conclusion,
because all empirical generalizations are more uncertain than the instances of
them.
We have now seen that there are propositions known a priori, and that
among them are the propositions of logic and pure mathematics, as well as the
fundamental propositions of ethics. The question which must next occupy us is
this: How is it possible that there should be such knowledge? And more
particularly, how can there be knowledge of general propositions in cases where
we have not examined all the instances, and indeed never can examine them all,
because their number is infinite? These questions, which were first brought
prominently forward by the German philosopher Kant (1724-1804), are very
difficult, and historically very important.
CHAPTER VIII. HOW A PRIORI KNOWLEDGE IS POSSIBLE
Immanuel Kant is generally regarded as the greatest of the modern
philosophers. Though he lived through the Seven Years War and the French
Revolution, he never interrupted his teaching of philosophy at Königsberg in
East Prussia. His most distinctive contribution was the invention of what he
called the 'critical' philosophy, which, assuming as a datum that there is
knowledge of various kinds, inquired how such knowledge comes to be possible,
and deduced, from the answer to this inquiry, many metaphysical results as to
the nature of the world. Whether these results were valid may well be doubted.
But Kant undoubtedly deserves credit for two things: first, for having perceived
that we have a priori knowledge which is not purely 'analytic', i.e. such
that the opposite would be self-contradictory, and secondly, for having made
evident the philosophical importance of the theory of knowledge.
Before the time of Kant, it was generally held that whatever knowledge was
a priori must be 'analytic'. What this word means will be best illustrated
by examples. If I say, 'A bald man is a man', 'A plane figure is a figure', 'A
bad poet is a poet', I make a purely analytic judgement: the subject spoken
about is given as having at least two properties, of which one is singled out to
be asserted of it. Such propositions as the above are trivial, and would never
be enunciated in real life except by an orator preparing the way for a piece of
sophistry. They are called 'analytic' because the predicate is obtained by
merely analysing the subject. Before the time of Kant it was thought that all
judgements of which we could be certain a priori were of this kind: that
in all of them there was a predicate which was only part of the subject of which
it was asserted. If this were so, we should be involved in a definite
contradiction if we attempted to deny anything that could be known a priori.
'A bald man is not bald' would assert and deny baldness of the same man, and
would therefore contradict itself. Thus according to the philosophers before
Kant, the law of contradiction, which asserts that nothing can at the same time
have and not have a certain property, sufficed to establish the truth of all
a priori knowledge.
Hume (1711-76), who preceded Kant, accepting the usual view as to what makes
knowledge a priori, discovered that, in many cases which had previously
been supposed analytic, and notably in the case of cause and effect, the
connexion was really synthetic. Before Hume, rationalists at least had supposed
that the effect could be logically deduced from the cause, if only we had
sufficient knowledge. Hume argued—correctly, as would now be generally
admitted—that this could not be done. Hence he inferred the far more doubtful
proposition that nothing could be known a priori about the connexion of
cause and effect. Kant, who had been educated in the rationalist tradition, was
much perturbed by Hume's scepticism, and endeavoured to find an answer to it. He
perceived that not only the connexion of cause and effect, but all the
propositions of arithmetic and geometry, are 'synthetic', i.e. not analytic: in
all these propositions, no analysis of the subject will reveal the predicate.
His stock instance was the proposition 7 + 5 = 12. He pointed out, quite truly,
that 7 and 5 have to be put together to give 12: the idea of 12 is not contained
in them, nor even in the idea of adding them together. Thus he was led to the
conclusion that all pure mathematics, though a priori, is synthetic; and
this conclusion raised a new problem of which he endeavoured to find the
solution.
The question which Kant put at the beginning of his philosophy, namely 'How
is pure mathematics possible?' is an interesting and difficult one, to which
every philosophy which is not purely sceptical must find some answer. The answer
of the pure empiricists, that our mathematical knowledge is derived by induction
from particular instances, we have already seen to be inadequate, for two
reasons: first, that the validity of the inductive principle itself cannot be
proved by induction; secondly, that the general propositions of mathematics,
such as 'two and two always make four', can obviously be known with certainty by
consideration of a single instance, and gain nothing by enumeration of other
cases in which they have been found to be true. Thus our knowledge of the
general propositions of mathematics (and the same applies to logic) must be
accounted for otherwise than our (merely probable) knowledge of empirical
generalizations such as 'all men are mortal'.
The problem arises through the fact that such knowledge is general, whereas
all experience is particular. It seems strange that we should apparently be able
to know some truths in advance about particular things of which we have as yet
no experience; but it cannot easily be doubted that logic and arithmetic will
apply to such things. We do not know who will be the inhabitants of London a
hundred years hence; but we know that any two of them and any other two of them
will make four of them. This apparent power of anticipating facts about things
of which we have no experience is certainly surprising. Kant's solution of the
problem, though not valid in my opinion, is interesting. It is, however, very
difficult, and is differently understood by different philosophers. We can,
therefore, only give the merest outline of it, and even that will be thought
misleading by many exponents of Kant's system.
What Kant maintained was that in all our experience there are two elements to
be distinguished, the one due to the object (i.e. to what we have called the
'physical object'), the other due to our own nature. We saw, in discussing
matter and sense-data, that the physical object is different from the associated
sense-data, and that the sense-data are to be regarded as resulting from an
interaction between the physical object and ourselves. So far, we are in
agreement with Kant. But what is distinctive of Kant is the way in which he
apportions the shares of ourselves and the physical object respectively. He
considers that the crude material given in sensation—the colour, hardness,
etc.—is due to the object, and that what we supply is the arrangement in space
and time, and all the relations between sense-data which result from comparison
or from considering one as the cause of the other or in any other way. His chief
reason in favour of this view is that we seem to have a priori knowledge
as to space and time and causality and comparison, but not as to the actual
crude material of sensation. We can be sure, he says, that anything we shall
ever experience must show the characteristics affirmed of it in our a priori
knowledge, because these characteristics are due to our own nature, and
therefore nothing can ever come into our experience without acquiring these
characteristics.
The physical object, which he calls the 'thing in itself',(1) he regards as
essentially unknowable; what can be known is the object as we have it in
experience, which he calls the 'phenomenon'. The phenomenon, being a joint
product of us and the thing in itself, is sure to have those characteristics
which are due to us, and is therefore sure to conform to our a priori
knowledge. Hence this knowledge, though true of all actual and possible
experience, must not be supposed to apply outside experience. Thus in spite of
the existence of a priori knowledge, we cannot know anything about the
thing in itself or about what is not an actual or possible object of experience.
In this way he tries to reconcile and harmonize the contentions of the
rationalists with the arguments of the empiricists.
(1) Kant's 'thing in itself' is identical in definition with the
physical object, namely, it is the cause of sensations. In the properties
deduced from the definition it is not identical, since Kant held (in spite of
some inconsistency as regards cause) that we can know that none of the
categories are applicable to the 'thing in itself'.
Apart from minor grounds on which Kant's philosophy may be criticized, there
is one main objection which seems fatal to any attempt to deal with the problem
of a priori knowledge by his method. The thing to be accounted for is our
certainty that the facts must always conform to logic and arithmetic. To say
that logic and arithmetic are contributed by us does not account for this. Our
nature is as much a fact of the existing world as anything, and there can be no
certainty that it will remain constant. It might happen, if Kant is right, that
to-morrow our nature would so change as to make two and two become five. This
possibility seems never to have occurred to him, yet it is one which utterly
destroys the certainty and universality which he is anxious to vindicate for
arithmetical propositions. It is true that this possibility, formally, is
inconsistent with the Kantian view that time itself is a form imposed by the
subject upon phenomena, so that our real Self is not in time and has no
to-morrow. But he will still have to suppose that the time-order of phenomena is
determined by characteristics of what is behind phenomena, and this suffices for
the substance of our argument.
Reflection, moreover, seems to make it clear that, if there is any truth in
our arithmetical beliefs, they must apply to things equally whether we think of
them or not. Two physical objects and two other physical objects must make four
physical objects, even if physical objects cannot be experienced. To assert this
is certainly within the scope of what we mean when we state that two and two are
four. Its truth is just as indubitable as the truth of the assertion that two
phenomena and two other phenomena make four phenomena. Thus Kant's solution
unduly limits the scope of a priori propositions, in addition to failing
in the attempt at explaining their certainty.
Apart from the special doctrines advocated by Kant, it is very common among
philosophers to regard what is a priori as in some sense mental, as
concerned rather with the way we must think than with any fact of the outer
world. We noted in the preceding chapter the three principles commonly called
'laws of thought'. The view which led to their being so named is a natural one,
but there are strong reasons for thinking that it is erroneous. Let us take as
an illustration the law of contradiction. This is commonly stated in the form
'Nothing can both be and not be', which is intended to express the fact that
nothing can at once have and not have a given quality. Thus, for example, if a
tree is a beech it cannot also be not a beech; if my table is rectangular it
cannot also be not rectangular, and so on.
Now what makes it natural to call this principle a law of thought is
that it is by thought rather than by outward observation that we persuade
ourselves of its necessary truth. When we have seen that a tree is a beech, we
do not need to look again in order to ascertain whether it is also not a beech;
thought alone makes us know that this is impossible. But the conclusion that the
law of contradiction is a law of thought is nevertheless erroneous. What
we believe, when we believe the law of contradiction, is not that the mind is so
made that it must believe the law of contradiction. This belief is a
subsequent result of psychological reflection, which presupposes the belief in
the law of contradiction. The belief in the law of contradiction is a belief
about things, not only about thoughts. It is not, e.g., the belief that if we
think a certain tree is a beech, we cannot at the same time think
that it is not a beech; it is the belief that if the tree is a beech, it
cannot at the same time be not a beech. Thus the law of contradiction is
about things, and not merely about thoughts; and although belief in the law of
contradiction is a thought, the law of contradiction itself is not a thought,
but a fact concerning the things in the world. If this, which we believe when we
believe the law of contradiction, were not true of the things in the world, the
fact that we were compelled to think it true would not save the law of
contradiction from being false; and this shows that the law is not a law of
thought.
A similar argument applies to any other a priori judgement. When we
judge that two and two are four, we are not making a judgement about our
thoughts, but about all actual or possible couples. The fact that our minds are
so constituted as to believe that two and two are four, though it is true, is
emphatically not what we assert when we assert that two and two are four. And no
fact about the constitution of our minds could make it true that two and
two are four. Thus our a priori knowledge, if it is not erroneous, is not
merely knowledge about the constitution of our minds, but is applicable to
whatever the world may contain, both what is mental and what is non-mental.
The fact seems to be that all our a priori knowledge is concerned with
entities which do not, properly speaking, exist, either in the mental or
in the physical world. These entities are such as can be named by parts of
speech which are not substantives; they are such entities as qualities and
relations. Suppose, for instance, that I am in my room. I exist, and my room
exists; but does 'in' exist? Yet obviously the word 'in' has a meaning; it
denotes a relation which holds between me and my room. This relation is
something, although we cannot say that it exists in the same sense in
which I and my room exist. The relation 'in' is something which we can think
about and understand, for, if we could not understand it, we could not
understand the sentence 'I am in my room'. Many philosophers, following Kant,
have maintained that relations are the work of the mind, that things in
themselves have no relations, but that the mind brings them together in one act
of thought and thus produces the relations which it judges them to have.
This view, however, seems open to objections similar to those which we urged
before against Kant. It seems plain that it is not thought which produces the
truth of the proposition 'I am in my room'. It may be true that an earwig is in
my room, even if neither I nor the earwig nor any one else is aware of this
truth; for this truth concerns only the earwig and the room, and does not depend
upon anything else. Thus relations, as we shall see more fully in the next
chapter, must be placed in a world which is neither mental nor physical. This
world is of great importance to philosophy, and in particular to the problems of
a priori knowledge. In the next chapter we shall proceed to develop its
nature and its bearing upon the questions with which we have been dealing.
CHAPTER IX. THE WORLD OF UNIVERSALS
At the end of the preceding chapter we saw that such entities as relations
appear to have a being which is in some way different from that of physical
objects, and also different from that of minds and from that of sense-data. In
the present chapter we have to consider what is the nature of this kind of
being, and also what objects there are that have this kind of being. We will
begin with the latter question.
The problem with which we are now concerned is a very old one, since it was
brought into philosophy by Plato. Plato's 'theory of ideas' is an attempt to
solve this very problem, and in my opinion it is one of the most successful
attempts hitherto made. The theory to be advocated in what follows is largely
Plato's, with merely such modifications as time has shown to be necessary.
The way the problem arose for Plato was more or less as follows. Let us
consider, say, such a notion as justice. If we ask ourselves what justice
is, it is natural to proceed by considering this, that, and the other just act,
with a view to discovering what they have in common. They must all, in some
sense, partake of a common nature, which will be found in whatever is just and
in nothing else. This common nature, in virtue of which they are all just, will
be justice itself, the pure essence the admixture of which with facts of
ordinary life produces the multiplicity of just acts. Similarly with any other
word which may be applicable to common facts, such as 'whiteness' for example.
The word will be applicable to a number of particular things because they all
participate in a common nature or essence. This pure essence is what Plato calls
an 'idea' or 'form'. (It must not be supposed that 'ideas', in his sense, exist
in minds, though they may be apprehended by minds.) The 'idea' justice is
not identical with anything that is just: it is something other than particular
things, which particular things partake of. Not being particular, it cannot
itself exist in the world of sense. Moreover it is not fleeting or changeable
like the things of sense: it is eternally itself, immutable and indestructible.
Thus Plato is led to a supra-sensible world, more real than the common world
of sense, the unchangeable world of ideas, which alone gives to the world of
sense whatever pale reflection of reality may belong to it. The truly real
world, for Plato, is the world of ideas; for whatever we may attempt to say
about things in the world of sense, we can only succeed in saying that they
participate in such and such ideas, which, therefore, constitute all their
character. Hence it is easy to pass on into a mysticism. We may hope, in a
mystic illumination, to see the ideas as we see objects of sense; and we may
imagine that the ideas exist in heaven. These mystical developments are very
natural, but the basis of the theory is in logic, and it is as based in logic
that we have to consider it.
The word 'idea' has acquired, in the course of time, many associations which
are quite misleading when applied to Plato's 'ideas'. We shall therefore use the
word 'universal' instead of the word 'idea', to describe what Plato meant. The
essence of the sort of entity that Plato meant is that it is opposed to the
particular things that are given in sensation. We speak of whatever is given in
sensation, or is of the same nature as things given in sensation, as a
particular; by opposition to this, a universal will be anything which
may be shared by many particulars, and has those characteristics which, as we
saw, distinguish justice and whiteness from just acts and white things.
When we examine common words, we find that, broadly speaking, proper names
stand for particulars, while other substantives, adjectives, prepositions, and
verbs stand for universals. Pronouns stand for particulars, but are ambiguous:
it is only by the context or the circumstances that we know what particulars
they stand for. The word 'now' stands for a particular, namely the present
moment; but like pronouns, it stands for an ambiguous particular, because the
present is always changing.
It will be seen that no sentence can be made up without at least one word
which denotes a universal. The nearest approach would be some such statement as
'I like this'. But even here the word 'like' denotes a universal, for I may like
other things, and other people may like things. Thus all truths involve
universals, and all knowledge of truths involves acquaintance with universals.
Seeing that nearly all the words to be found in the dictionary stand for
universals, it is strange that hardly anybody except students of philosophy ever
realizes that there are such entities as universals. We do not naturally dwell
upon those words in a sentence which do not stand for particulars; and if we are
forced to dwell upon a word which stands for a universal, we naturally think of
it as standing for some one of the particulars that come under the universal.
When, for example, we hear the sentence, 'Charles I's head was cut off', we may
naturally enough think of Charles I, of Charles I's head, and of the operation
of cutting off his head, which are all particulars; but we do not
naturally dwell upon what is meant by the word 'head' or the word 'cut', which
is a universal: We feel such words to be incomplete and insubstantial; they seem
to demand a context before anything can be done with them. Hence we succeed in
avoiding all notice of universals as such, until the study of philosophy forces
them upon our attention.
Even among philosophers, we may say, broadly, that only those universals
which are named by adjectives or substantives have been much or often
recognized, while those named by verbs and prepositions have been usually
overlooked. This omission has had a very great effect upon philosophy; it is
hardly too much to say that most metaphysics, since Spinoza, has been largely
determined by it. The way this has occurred is, in outline, as follows: Speaking
generally, adjectives and common nouns express qualities or properties of single
things, whereas prepositions and verbs tend to express relations between two or
more things. Thus the neglect of prepositions and verbs led to the belief that
every proposition can be regarded as attributing a property to a single thing,
rather than as expressing a relation between two or more things. Hence it was
supposed that, ultimately, there can be no such entities as relations between
things. Hence either there can be only one thing in the universe, or, if there
are many things, they cannot possibly interact in any way, since any interaction
would be a relation, and relations are impossible.
The first of these views, advocated by Spinoza and held in our own day by
Bradley and many other philosophers, is called monism; the second,
advocated by Leibniz but not very common nowadays, is called monadism,
because each of the isolated things is called a monad. Both these
opposing philosophies, interesting as they are, result, in my opinion, from an
undue attention to one sort of universals, namely the sort represented by
adjectives and substantives rather than by verbs and prepositions.
As a matter of fact, if any one were anxious to deny altogether that there
are such things as universals, we should find that we cannot strictly prove that
there are such entities as qualities, i.e. the universals represented by
adjectives and substantives, whereas we can prove that there must be
relations, i.e. the sort of universals generally represented by verbs and
prepositions. Let us take in illustration the universal whiteness. If we
believe that there is such a universal, we shall say that things are white
because they have the quality of whiteness. This view, however, was strenuously
denied by Berkeley and Hume, who have been followed in this by later
empiricists. The form which their denial took was to deny that there are such
things as 'abstract ideas '. When we want to think of whiteness, they said, we
form an image of some particular white thing, and reason concerning this
particular, taking care not to deduce anything concerning it which we cannot see
to be equally true of any other white thing. As an account of our actual mental
processes, this is no doubt largely true. In geometry, for example, when we wish
to prove something about all triangles, we draw a particular triangle and reason
about it, taking care not to use any characteristic which it does not share with
other triangles. The beginner, in order to avoid error, often finds it useful to
draw several triangles, as unlike each other as possible, in order to make sure
that his reasoning is equally applicable to all of them. But a difficulty
emerges as soon as we ask ourselves how we know that a thing is white or a
triangle. If we wish to avoid the universals whiteness and
triangularity, we shall choose some particular patch of white or some
particular triangle, and say that anything is white or a triangle if it has the
right sort of resemblance to our chosen particular. But then the resemblance
required will have to be a universal. Since there are many white things, the
resemblance must hold between many pairs of particular white things; and this is
the characteristic of a universal. It will be useless to say that there is a
different resemblance for each pair, for then we shall have to say that these
resemblances resemble each other, and thus at last we shall be forced to admit
resemblance as a universal. The relation of resemblance, therefore, must be a
true universal. And having been forced to admit this universal, we find that it
is no longer worth while to invent difficult and unplausible theories to avoid
the admission of such universals as whiteness and triangularity.
Berkeley and Hume failed to perceive this refutation of their rejection of
'abstract ideas', because, like their adversaries, they only thought of
qualities, and altogether ignored relations as universals. We have
therefore here another respect in which the rationalists appear to have been in
the right as against the empiricists, although, owing to the neglect or denial
of relations, the deductions made by rationalists were, if anything, more apt to
be mistaken than those made by empiricists.
Having now seen that there must be such entities as universals, the next
point to be proved is that their being is not merely mental. By this is meant
that whatever being belongs to them is independent of their being thought of or
in any way apprehended by minds. We have already touched on this subject at the
end of the preceding chapter, but we must now consider more fully what sort of
being it is that belongs to universals.
Consider such a proposition as 'Edinburgh is north of London'. Here we have a
relation between two places, and it seems plain that the relation subsists
independently of our knowledge of it. When we come to know that Edinburgh is
north of London, we come to know something which has to do only with Edinburgh
and London: we do not cause the truth of the proposition by coming to know it,
on the contrary we merely apprehend a fact which was there before we knew it.
The part of the earth's surface where Edinburgh stands would be north of the
part where London stands, even if there were no human being to know about north
and south, and even if there were no minds at all in the universe. This is, of
course, denied by many philosophers, either for Berkeley's reasons or for
Kant's. But we have already considered these reasons, and decided that they are
inadequate. We may therefore now assume it to be true that nothing mental is
presupposed in the fact that Edinburgh is north of London. But this fact
involves the relation 'north of', which is a universal; and it would be
impossible for the whole fact to involve nothing mental if the relation 'north
of', which is a constituent part of the fact, did involve anything mental. Hence
we must admit that the relation, like the terms it relates, is not dependent
upon thought, but belongs to the independent world which thought apprehends but
does not create.
This conclusion, however, is met by the difficulty that the relation 'north
of' does not seem to exist in the same sense in which Edinburgh and
London exist. If we ask 'Where and when does this relation exist?' the answer
must be 'Nowhere and nowhen'. There is no place or time where we can find the
relation 'north of'. It does not exist in Edinburgh any more than in London, for
it relates the two and is neutral as between them. Nor can we say that it exists
at any particular time. Now everything that can be apprehended by the senses or
by introspection exists at some particular time. Hence the relation 'north of'
is radically different from such things. It is neither in space nor in time,
neither material nor mental; yet it is something.
It is largely the very peculiar kind of being that belongs to universals
which has led many people to suppose that they are really mental. We can think
of a universal, and our thinking then exists in a perfectly ordinary
sense, like any other mental act. Suppose, for example, that we are thinking of
whiteness. Then in one sense it may be said that whiteness is 'in our
mind'. We have here the same ambiguity as we noted in discussing Berkeley in
Chapter IV. In the strict sense, it is not whiteness that is in our mind, but
the act of thinking of whiteness. The connected ambiguity in the word 'idea',
which we noted at the same time, also causes confusion here. In one sense of
this word, namely the sense in which it denotes the object of an act of
thought, whiteness is an 'idea'. Hence, if the ambiguity is not guarded against,
we may come to think that whiteness is an 'idea' in the other sense, i.e. an act
of thought; and thus we come to think that whiteness is mental. But in so
thinking, we rob it of its essential quality of universality. One man's act of
thought is necessarily a different thing from another man's; one man's act of
thought at one time is necessarily a different thing from the same man's act of
thought at another time. Hence, if whiteness were the thought as opposed to its
object, no two different men could think of it, and no one man could think of it
twice. That which many different thoughts of whiteness have in common is their
object, and this object is different from all of them. Thus universals
are not thoughts, though when known they are the objects of thoughts.
We shall find it convenient only to speak of things existing when they
are in time, that is to say, when we can point to some time at which they exist
(not excluding the possibility of their existing at all times). Thus thoughts
and feelings, minds and physical objects exist. But universals do not exist in
this sense; we shall say that they subsist or have being, where
'being' is opposed to 'existence' as being timeless. The world of universals,
therefore, may also be described as the world of being. The world of being is
unchangeable, rigid, exact, delightful to the mathematician, the logician, the
builder of metaphysical systems, and all who love perfection more than life. The
world of existence is fleeting, vague, without sharp boundaries, without any
clear plan or arrangement, but it contains all thoughts and feelings, all the
data of sense, and all physical objects, everything that can do either good or
harm, everything that makes any difference to the value of life and the world.
According to our temperaments, we shall prefer the contemplation of the one or
of the other. The one we do not prefer will probably seem to us a pale shadow of
the one we prefer, and hardly worthy to be regarded as in any sense real. But
the truth is that both have the same claim on our impartial attention, both are
real, and both are important to the metaphysician. Indeed no sooner have we
distinguished the two worlds than it becomes necessary to consider their
relations.
But first of all we must examine our knowledge of universals. This
consideration will occupy us in the following chapter, where we shall find that
it solves the problem of a priori knowledge, from which we were first led
to consider universals.
CHAPTER X. ON OUR KNOWLEDGE OF UNIVERSALS
In regard to one man's knowledge at a given time, universals, like
particulars, may be divided into those known by acquaintance, those known only
by description, and those not known either by acquaintance or by description.
Let us consider first the knowledge of universals by acquaintance. It is
obvious, to begin with, that we are acquainted with such universals as white,
red, black, sweet, sour, loud, hard, etc., i.e. with qualities which are
exemplified in sense-data. When we see a white patch, we are acquainted, in the
first instance, with the particular patch; but by seeing many white patches, we
easily learn to abstract the whiteness which they all have in common, and in
learning to do this we are learning to be acquainted with whiteness. A similar
process will make us acquainted with any other universal of the same sort.
Universals of this sort may be called 'sensible qualities'. They can be
apprehended with less effort of abstraction than any others, and they seem less
removed from particulars than other universals are.
We come next to relations. The easiest relations to apprehend are those which
hold between the different parts of a single complex sense-datum. For example, I
can see at a glance the whole of the page on which I am writing; thus the whole
page is included in one sense-datum. But I perceive that some parts of the page
are to the left of other parts, and some parts are above other parts. The
process of abstraction in this case seems to proceed somewhat as follows: I see
successively a number of sense-data in which one part is to the left of another;
I perceive, as in the case of different white patches, that all these sense-data
have something in common, and by abstraction I find that what they have in
common is a certain relation between their parts, namely the relation which I
call 'being to the left of'. In this way I become acquainted with the universal
relation.
In like manner I become aware of the relation of before and after in time.
Suppose I hear a chime of bells: when the last bell of the chime sounds, I can
retain the whole chime before my mind, and I can perceive that the earlier bells
came before the later ones. Also in memory I perceive that what I am remembering
came before the present time. From either of these sources I can abstract the
universal relation of before and after, just as I abstracted the universal
relation 'being to the left of'. Thus time-relations, like space-relations, are
among those with which we are acquainted.
Another relation with which we become acquainted in much the same way is
resemblance. If I see simultaneously two shades of green, I can see that they
resemble each other; if I also see a shade of red: at the same time, I can see
that the two greens have more resemblance to each other than either has to the
red. In this way I become acquainted with the universal resemblance or
similarity.
Between universals, as between particulars, there are relations of which we
may be immediately aware. We have just seen that we can perceive that the
resemblance between two shades of green is greater than the resemblance between
a shade of red and a shade of green. Here we are dealing with a relation, namely
'greater than', between two relations. Our knowledge of such relations, though
it requires more power of abstraction than is required for perceiving the
qualities of sense-data, appears to be equally immediate, and (at least in some
cases) equally indubitable. Thus there is immediate knowledge concerning
universals as well as concerning sense-data.
Returning now to the problem of a priori knowledge, which we left
unsolved when we began the consideration of universals, we find ourselves in a
position to deal with it in a much more satisfactory manner than was possible
before. Let us revert to the proposition 'two and two are four'. It is fairly
obvious, in view of what has been said, that this proposition states a relation
between the universal 'two' and the universal 'four'. This suggests a
proposition which we shall now endeavour to establish: namely, All a
priori knowledge deals exclusively with the relations of universals. This
proposition is of great importance, and goes a long way towards solving our
previous difficulties concerning a priori knowledge.
The only case in which it might seem, at first sight, as if our proposition
were untrue, is the case in which an a priori proposition states that
all of one class of particulars belong to some other class, or (what comes
to the same thing) that all particulars having some one property also
have some other. In this case it might seem as though we were dealing with the
particulars that have the property rather than with the property. The
proposition 'two and two are four' is really a case in point, for this may be
stated in the form 'any two and any other two are four', or 'any collection
formed of two twos is a collection of four'. If we can show that such statements
as this really deal only with universals, our proposition may be regarded as
proved.
One way of discovering what a proposition deals with is to ask ourselves what
words we must understand—in other words, what objects we must be acquainted
with—in order to see what the proposition means. As soon as we see what the
proposition means, even if we do not yet know whether it is true or false, it is
evident that we must have acquaintance with whatever is really dealt with by the
proposition. By applying this test, it appears that many propositions which
might seem to be concerned with particulars are really concerned only with
universals. In the special case of 'two and two are four', even when we
interpret it as meaning 'any collection formed of two twos is a collection of
four', it is plain that we can understand the proposition, i.e. we can see what
it is that it asserts, as soon as we know what is meant by 'collection' and
'two' and 'four'. It is quite unnecessary to know all the couples in the world:
if it were necessary, obviously we could never understand the proposition, since
the couples are infinitely numerous and therefore cannot all be known to us.
Thus although our general statement implies statements about particular
couples, as soon as we know that there are such particular couples, yet
it does not itself assert or imply that there are such particular couples, and
thus fails to make any statement whatever about any actual particular couple.
The statement made is about 'couple', the universal, and not about this or that
couple.
Thus the statement 'two and two are four' deals exclusively with universals,
and therefore may be known by anybody who is acquainted with the universals
concerned and can perceive the relation between them which the statement
asserts. It must be taken as a fact, discovered by reflecting upon our
knowledge, that we have the power of sometimes perceiving such relations between
universals, and therefore of sometimes knowing general a priori
propositions such as those of arithmetic and logic. The thing that seemed
mysterious, when we formerly considered such knowledge, was that it seemed to
anticipate and control experience. This, however, we can now see to have been an
error. No fact concerning anything capable of being experienced can be
known independently of experience. We know a priori that two things and
two other things together make four things, but we do not know a
priori that if Brown and Jones are two, and Robinson and Smith are two, then
Brown and Jones and Robinson and Smith are four. The reason is that this
proposition cannot be understood at all unless we know that there are such
people as Brown and Jones and Robinson and Smith, and this we can only know by
experience. Hence, although our general proposition is a priori, all its
applications to actual particulars involve experience and therefore contain an
empirical element. In this way what seemed mysterious in our a priori
knowledge is seen to have been based upon an error.
It will serve to make the point clearer if we contrast our genuine a
priori judgement with an empirical generalization, such as 'all men are
mortals'. Here as before, we can understand what the proposition means as
soon as we understand the universals involved, namely man and mortal.
It is obviously unnecessary to have an individual acquaintance with the whole
human race in order to understand what our proposition means. Thus the
difference between an a priori general proposition and an empirical
generalization does not come in the meaning of the proposition; it comes
in the nature of the evidence for it. In the empirical case, the evidence
consists in the particular instances. We believe that all men are mortal because
we know that there are innumerable instances of men dying, and no instances of
their living beyond a certain age. We do not believe it because we see a
connexion between the universal man and the universal mortal. It
is true that if physiology can prove, assuming the general laws that govern
living bodies, that no living organism can last for ever, that gives a connexion
between man and mortality which would enable us to assert our
proposition without appealing to the special evidence of men dying. But
that only means that our generalization has been subsumed under a wider
generalization, for which the evidence is still of the same kind, though more
extensive. The progress of science is constantly producing such subsumptions,
and therefore giving a constantly wider inductive basis for scientific
generalizations. But although this gives a greater degree of certainty,
it does not give a different kind: the ultimate ground remains inductive,
i.e. derived from instances, and not an a priori connexion of universals
such as we have in logic and arithmetic.
Two opposite points are to be observed concerning a priori general
propositions. The first is that, if many particular instances are known, our
general proposition may be arrived at in the first instance by induction, and
the connexion of universals may be only subsequently perceived. For example, it
is known that if we draw perpendiculars to the sides of a triangle from the
opposite angles, all three perpendiculars meet in a point. It would be quite
possible to be first led to this proposition by actually drawing perpendiculars
in many cases, and finding that they always met in a point; this experience
might lead us to look for the general proof and find it. Such cases are common
in the experience of every mathematician.
The other point is more interesting, and of more philosophical importance. It
is, that we may sometimes know a general proposition in cases where we do not
know a single instance of it. Take such a case as the following: We know that
any two numbers can be multiplied together, and will give a third called their
product. We know that all pairs of integers the product of which is less
than 100 have been actually multiplied together, and the value of the product
recorded in the multiplication table. But we also know that the number of
integers is infinite, and that only a finite number of pairs of integers ever
have been or ever will be thought of by human beings. Hence it follows that
there are pairs of integers which never have been and never will be thought of
by human beings, and that all of them deal with integers the product of which is
over 100. Hence we arrive at the proposition: 'All products of two integers,
which never have been and never will be thought of by any human being, are over
100.' Here is a general proposition of which the truth is undeniable, and yet,
from the very nature of the case, we can never give an instance; because any two
numbers we may think of are excluded by the terms of the proposition.
This possibility, of knowledge of general propositions of which no instance
can be given, is often denied, because it is not perceived that the knowledge of
such propositions only requires a knowledge of the relations of universals, and
does not require any knowledge of instances of the universals in question. Yet
the knowledge of such general propositions is quite vital to a great deal of
what is generally admitted to be known. For example, we saw, in our early
chapters, that knowledge of physical objects, as opposed to sense-data, is only
obtained by an inference, and that they are not things with which we are
acquainted. Hence we can never know any proposition of the form 'this is a
physical object', where 'this' is something immediately known. It follows that
all our knowledge concerning physical objects is such that no actual instance
can be given. We can give instances of the associated sense-data, but we cannot
give instances of the actual physical objects. Hence our knowledge as to
physical objects depends throughout upon this possibility of general knowledge
where no instance can be given. And the same applies to our knowledge of other
people's minds, or of any other class of things of which no instance is known to
us by acquaintance.
We may now take a survey of the sources of our knowledge, as they have
appeared in the course of our analysis. We have first to distinguish knowledge
of things and knowledge of truths. In each there are two kinds, one immediate
and one derivative. Our immediate knowledge of things, which we called
acquaintance, consists of two sorts, according as the things known are
particulars or universals. Among particulars, we have acquaintance with
sense-data and (probably) with ourselves. Among universals, there seems to be no
principle by which we can decide which can be known by acquaintance, but it is
clear that among those that can be so known are sensible qualities, relations of
space and time, similarity, and certain abstract logical universals. Our
derivative knowledge of things, which we call knowledge by description,
always involves both acquaintance with something and knowledge of truths. Our
immediate knowledge of truths may be called intuitive knowledge,
and the truths so known may be called self-evident truths. Among such
truths are included those which merely state what is given in sense, and also
certain abstract logical and arithmetical principles, and (though with less
certainty) some ethical propositions. Our derivative knowledge of truths
consists of everything that we can deduce from self-evident truths by the use of
self-evident principles of deduction.
If the above account is correct, all our knowledge of truths depends upon our
intuitive knowledge. It therefore becomes important to consider the nature and
scope of intuitive knowledge, in much the same way as, at an earlier stage, we
considered the nature and scope of knowledge by acquaintance. But knowledge of
truths raises a further problem, which does not arise in regard to knowledge of
things, namely the problem of error. Some of our beliefs turn out to be
erroneous, and therefore it becomes necessary to consider how, if at all, we can
distinguish knowledge from error. This problem does not arise with regard to
knowledge by acquaintance, for, whatever may be the object of acquaintance, even
in dreams and hallucinations, there is no error involved so long as we do not go
beyond the immediate object: error can only arise when we regard the immediate
object, i.e. the sense-datum, as the mark of some physical object. Thus the
problems connected with knowledge of truths are more difficult than those
connected with knowledge of things. As the first of the problems connected with
knowledge of truths, let us examine the nature and scope of our intuitive
judgements.
CHAPTER XI. ON INTUITIVE KNOWLEDGE
There is a common impression that everything that we believe ought to be
capable of proof, or at least of being shown to be highly probable. It is felt
by many that a belief for which no reason can be given is an unreasonable
belief. In the main, this view is just. Almost all our common beliefs are either
inferred, or capable of being inferred, from other beliefs which may be regarded
as giving the reason for them. As a rule, the reason has been forgotten, or has
even never been consciously present to our minds. Few of us ever ask ourselves,
for example, what reason there is to suppose the food we are just going to eat
will not turn out to be poison. Yet we feel, when challenged, that a perfectly
good reason could be found, even if we are not ready with it at the moment. And
in this belief we are usually justified.
But let us imagine some insistent Socrates, who, whatever reason we give him,
continues to demand a reason for the reason. We must sooner or later, and
probably before very long, be driven to a point where we cannot find any further
reason, and where it becomes almost certain that no further reason is even
theoretically discoverable. Starting with the common beliefs of daily life, we
can be driven back from point to point, until we come to some general principle,
or some instance of a general principle, which seems luminously evident, and is
not itself capable of being deduced from anything more evident. In most
questions of daily life, such as whether our food is likely to be nourishing and
not poisonous, we shall be driven back to the inductive principle, which we
discussed in Chapter VI. But beyond that, there seems to be no further regress.
The principle itself is constantly used in our reasoning, sometimes consciously,
sometimes unconsciously; but there is no reasoning which, starting from some
simpler self-evident principle, leads us to the principle of induction as its
conclusion. And the same holds for other logical principles. Their truth is
evident to us, and we employ them in constructing demonstrations; but they
themselves, or at least some of them, are incapable of demonstration.
Self-evidence, however, is not confined to those among general principles
which are incapable of proof. When a certain number of logical principles have
been admitted, the rest can be deduced from them; but the propositions deduced
are often just as self-evident as those that were assumed without proof. All
arithmetic, moreover, can be deduced from the general principles of logic, yet
the simple propositions of arithmetic, such as 'two and two are four', are just
as self-evident as the principles of logic.
It would seem, also, though this is more disputable, that there are some
self-evident ethical principles, such as 'we ought to pursue what is good'.
It should be observed that, in all cases of general principles, particular
instances, dealing with familiar things, are more evident than the general
principle. For example, the law of contradiction states that nothing can both
have a certain property and not have it. This is evident as soon as it is
understood, but it is not so evident as that a particular rose which we see
cannot be both red and not red. (It is of course possible that parts of the rose
may be red and parts not red, or that the rose may be of a shade of pink which
we hardly know whether to call red or not; but in the former case it is plain
that the rose as a whole is not red, while in the latter case the answer is
theoretically definite as soon as we have decided on a precise definition of
'red'.) It is usually through particular instances that we come to be able to
see the general principle. Only those who are practised in dealing with
abstractions can readily grasp a general principle without the help of
instances.
In addition to general principles, the other kind of self-evident truths are
those immediately derived from sensation. We will call such truths 'truths of
perception', and the judgements expressing them we will call 'judgements of
perception'. But here a certain amount of care is required in getting at the
precise nature of the truths that are self-evident. The actual sense-data are
neither true nor false. A particular patch of colour which I see, for example,
simply exists: it is not the sort of thing that is true or false. It is true
that there is such a patch, true that it has a certain shape and degree of
brightness, true that it is surrounded by certain other colours. But the patch
itself, like everything else in the world of sense, is of a radically different
kind from the things that are true or false, and therefore cannot properly be
said to be true. Thus whatever self-evident truths may be obtained from
our senses must be different from the sense-data from which they are obtained.
It would seem that there are two kinds of self-evident truths of perception,
though perhaps in the last analysis the two kinds may coalesce. First, there is
the kind which simply asserts the existence of the sense-datum, without
in any way analysing it. We see a patch of red, and we judge 'there is
such-and-such a patch of red', or more strictly 'there is that'; this is one
kind of intuitive judgement of perception. The other kind arises when the object
of sense is complex, and we subject it to some degree of analysis. If, for
instance, we see a round patch of red, we may judge 'that patch of red is
round'. This is again a judgement of perception, but it differs from our
previous kind. In our present kind we have a single sense-datum which has both
colour and shape: the colour is red and the shape is round. Our judgement
analyses the datum into colour and shape, and then recombines them by stating
that the red colour is round in shape. Another example of this kind of judgement
is 'this is to the right of that', where 'this' and 'that' are seen
simultaneously. In this kind of judgement the sense-datum contains constituents
which have some relation to each other, and the judgement asserts that these
constituents have this relation.
Another class of intuitive judgements, analogous to those of sense and yet
quite distinct from them, are judgements of memory. There is some danger
of confusion as to the nature of memory, owing to the fact that memory of an
object is apt to be accompanied by an image of the object, and yet the image
cannot be what constitutes memory. This is easily seen by merely noticing that
the image is in the present, whereas what is remembered is known to be in the
past. Moreover, we are certainly able to some extent to compare our image with
the object remembered, so that we often know, within somewhat wide limits, how
far our image is accurate; but this would be impossible, unless the object, as
opposed to the image, were in some way before the mind. Thus the essence of
memory is not constituted by the image, but by having immediately before the
mind an object which is recognized as past. But for the fact of memory in this
sense, we should not know that there ever was a past at all, nor should we be
able to understand the word 'past', any more than a man born blind can
understand the word 'light'. Thus there must be intuitive judgements of memory,
and it is upon them, ultimately, that all our knowledge of the past depends.
The case of memory, however, raises a difficulty, for it is notoriously
fallacious, and thus throws doubt on the trustworthiness of intuitive judgements
in general. This difficulty is no light one. But let us first narrow its scope
as far as possible. Broadly speaking, memory is trustworthy in proportion to the
vividness of the experience and to its nearness in time. If the house next door
was struck by lightning half a minute ago, my memory of what I saw and heard
will be so reliable that it would be preposterous to doubt whether there had
been a flash at all. And the same applies to less vivid experiences, so long as
they are recent. I am absolutely certain that half a minute ago I was sitting in
the same chair in which I am sitting now. Going backward over the day, I find
things of which I am quite certain, other things of which I am almost certain,
other things of which I can become certain by thought and by calling up
attendant circumstances, and some things of which I am by no means certain. I am
quite certain that I ate my breakfast this morning, but if I were as indifferent
to my breakfast as a philosopher should be, I should be doubtful. As to the
conversation at breakfast, I can recall some of it easily, some with an effort,
some only with a large element of doubt, and some not at all. Thus there is a
continual gradation in the degree of self-evidence of what I remember, and a
corresponding gradation in the trustworthiness of my memory.
Thus the first answer to the difficulty of fallacious memory is to say that
memory has degrees of self-evidence, and that these correspond to the degrees of
its trustworthiness, reaching a limit of perfect self-evidence and perfect
trustworthiness in our memory of events which are recent and vivid.
It would seem, however, that there are cases of very firm belief in a memory
which is wholly false. It is probable that, in these cases, what is really
remembered, in the sense of being immediately before the mind, is something
other than what is falsely believed in, though something generally associated
with it. George IV is said to have at last believed that he was at the battle of
Waterloo, because he had so often said that he was. In this case, what was
immediately remembered was his repeated assertion; the belief in what he was
asserting (if it existed) would be produced by association with the remembered
assertion, and would therefore not be a genuine case of memory. It would seem
that cases of fallacious memory can probably all be dealt with in this way, i.e.
they can be shown to be not cases of memory in the strict sense at all.
One important point about self-evidence is made clear by the case of memory,
and that is, that self-evidence has degrees: it is not a quality which is simply
present or absent, but a quality which may be more or less present, in
gradations ranging from absolute certainty down to an almost imperceptible
faintness. Truths of perception and some of the principles of logic have the
very highest degree of self-evidence; truths of immediate memory have an almost
equally high degree. The inductive principle has less self-evidence than some of
the other principles of logic, such as 'what follows from a true premiss must be
true'. Memories have a diminishing self-evidence as they become remoter and
fainter; the truths of logic and mathematics have (broadly speaking) less
self-evidence as they become more complicated. Judgements of intrinsic ethical
or aesthetic value are apt to have some self-evidence, but not much.
Degrees of self-evidence are important in the theory of knowledge, since, if
propositions may (as seems likely) have some degree of self-evidence without
being true, it will not be necessary to abandon all connexion between
self-evidence and truth, but merely to say that, where there is a conflict, the
more self-evident proposition is to be retained and the less self-evident
rejected.
It seems, however, highly probable that two different notions are combined in
'self-evidence' as above explained; that one of them, which corresponds to the
highest degree of self-evidence, is really an infallible guarantee of truth,
while the other, which corresponds to all the other degrees, does not give an
infallible guarantee, but only a greater or less presumption. This, however, is
only a suggestion, which we cannot as yet develop further. After we have dealt
with the nature of truth, we shall return to the subject of self-evidence, in
connexion with the distinction between knowledge and error.
CHAPTER XII. TRUTH AND FALSEHOOD
Our knowledge of truths, unlike our knowledge of things, has an opposite,
namely error. So far as things are concerned, we may know them or not
know them, but there is no positive state of mind which can be described as
erroneous knowledge of things, so long, at any rate, as we confine ourselves to
knowledge by acquaintance. Whatever we are acquainted with must be something; we
may draw wrong inferences from our acquaintance, but the acquaintance itself
cannot be deceptive. Thus there is no dualism as regards acquaintance. But as
regards knowledge of truths, there is a dualism. We may believe what is false as
well as what is true. We know that on very many subjects different people hold
different and incompatible opinions: hence some beliefs must be erroneous. Since
erroneous beliefs are often held just as strongly as true beliefs, it becomes a
difficult question how they are to be distinguished from true beliefs. How are
we to know, in a given case, that our belief is not erroneous? This is a
question of the very greatest difficulty, to which no completely satisfactory
answer is possible. There is, however, a preliminary question which is rather
less difficult, and that is: What do we mean by truth and falsehood? It
is this preliminary question which is to be considered in this chapter. In this
chapter we are not asking how we can know whether a belief is true or false: we
are asking what is meant by the question whether a belief is true or false. It
is to be hoped that a clear answer to this question may help us to obtain an
answer to the question what beliefs are true, but for the present we ask only
'What is truth?' and 'What is falsehood?' not 'What beliefs are true?' and 'What
beliefs are false?' It is very important to keep these different questions
entirely separate, since any confusion between them is sure to produce an answer
which is not really applicable to either.
There are three points to observe in the attempt to discover the nature of
truth, three requisites which any theory must fulfil.
(1) Our theory of truth must be such as to admit of its opposite, falsehood.
A good many philosophers have failed adequately to satisfy this condition: they
have constructed theories according to which all our thinking ought to have been
true, and have then had the greatest difficulty in finding a place for
falsehood. In this respect our theory of belief must differ from our theory of
acquaintance, since in the case of acquaintance it was not necessary to take
account of any opposite.
(2) It seems fairly evident that if there were no beliefs there could be no
falsehood, and no truth either, in the sense in which truth is correlative to
falsehood. If we imagine a world of mere matter, there would be no room for
falsehood in such a world, and although it would contain what may be called
'facts', it would not contain any truths, in the sense in which truths are
things of the same kind as falsehoods. In fact, truth and falsehood are
properties of beliefs and statements: hence a world of mere matter, since it
would contain no beliefs or statements, would also contain no truth or
falsehood.
(3) But, as against what we have just said, it is to be observed that the
truth or falsehood of a belief always depends upon something which lies outside
the belief itself. If I believe that Charles I died on the scaffold, I believe
truly, not because of any intrinsic quality of my belief, which could be
discovered by merely examining the belief, but because of an historical event
which happened two and a half centuries ago. If I believe that Charles I died in
his bed, I believe falsely: no degree of vividness in my belief, or of care in
arriving at it, prevents it from being false, again because of what happened
long ago, and not because of any intrinsic property of my belief. Hence,
although truth and falsehood are properties of beliefs, they are properties
dependent upon the relations of the beliefs to other things, not upon any
internal quality of the beliefs.
The third of the above requisites leads us to adopt the view—which has on the
whole been commonest among philosophers—that truth consists in some form of
correspondence between belief and fact. It is, however, by no means an easy
matter to discover a form of correspondence to which there are no irrefutable
objections. By this partly—and partly by the feeling that, if truth consists in
a correspondence of thought with something outside thought, thought can never
know when truth has been attained—many philosophers have been led to try to find
some definition of truth which shall not consist in relation to something wholly
outside belief. The most important attempt at a definition of this sort is the
theory that truth consists in coherence. It is said that the mark of
falsehood is failure to cohere in the body of our beliefs, and that it is the
essence of a truth to form part of the completely rounded system which is The
Truth.
There is, however, a great difficulty in this view, or rather two great
difficulties. The first is that there is no reason to suppose that only one
coherent body of beliefs is possible. It may be that, with sufficient
imagination, a novelist might invent a past for the world that would perfectly
fit on to what we know, and yet be quite different from the real past. In more
scientific matters, it is certain that there are often two or more hypotheses
which account for all the known facts on some subject, and although, in such
cases, men of science endeavour to find facts which will rule out all the
hypotheses except one, there is no reason why they should always succeed.
In philosophy, again, it seems not uncommon for two rival hypotheses to be
both able to account for all the facts. Thus, for example, it is possible that
life is one long dream, and that the outer world has only that degree of reality
that the objects of dreams have; but although such a view does not seem
inconsistent with known facts, there is no reason to prefer it to the
common-sense view, according to which other people and things do really exist.
Thus coherence as the definition of truth fails because there is no proof that
there can be only one coherent system.
The other objection to this definition of truth is that it assumes the
meaning of 'coherence' known, whereas, in fact, 'coherence' presupposes the
truth of the laws of logic. Two propositions are coherent when both may be true,
and are incoherent when one at least must be false. Now in order to know whether
two propositions can both be true, we must know such truths as the law of
contradiction. For example, the two propositions, 'this tree is a beech' and
'this tree is not a beech', are not coherent, because of the law of
contradiction. But if the law of contradiction itself were subjected to the test
of coherence, we should find that, if we choose to suppose it false, nothing
will any longer be incoherent with anything else. Thus the laws of logic supply
the skeleton or framework within which the test of coherence applies, and they
themselves cannot be established by this test.
For the above two reasons, coherence cannot be accepted as giving the
meaning of truth, though it is often a most important test of truth
after a certain amount of truth has become known.
Hence we are driven back to correspondence with fact as constituting
the nature of truth. It remains to define precisely what we mean by 'fact', and
what is the nature of the correspondence which must subsist between belief and
fact, in order that belief may be true.
In accordance with our three requisites, we have to seek a theory of truth
which (1) allows truth to have an opposite, namely falsehood, (2) makes truth a
property of beliefs, but (3) makes it a property wholly dependent upon the
relation of the beliefs to outside things.
The necessity of allowing for falsehood makes it impossible to regard belief
as a relation of the mind to a single object, which could be said to be what is
believed. If belief were so regarded, we should find that, like acquaintance, it
would not admit of the opposition of truth and falsehood, but would have to be
always true. This may be made clear by examples. Othello believes falsely that
Desdemona loves Cassio. We cannot say that this belief consists in a relation to
a single object, 'Desdemona's love for Cassio', for if there were such an
object, the belief would be true. There is in fact no such object, and therefore
Othello cannot have any relation to such an object. Hence his belief cannot
possibly consist in a relation to this object.
It might be said that his belief is a relation to a different object, namely
'that Desdemona loves Cassio'; but it is almost as difficult to suppose that
there is such an object as this, when Desdemona does not love Cassio, as it was
to suppose that there is 'Desdemona's love for Cassio'. Hence it will be better
to seek for a theory of belief which does not make it consist in a relation of
the mind to a single object.
It is common to think of relations as though they always held between two
terms, but in fact this is not always the case. Some relations demand three
terms, some four, and so on. Take, for instance, the relation 'between'. So long
as only two terms come in, the relation 'between' is impossible: three terms are
the smallest number that render it possible. York is between London and
Edinburgh; but if London and Edinburgh were the only places in the world, there
could be nothing which was between one place and another. Similarly jealousy
requires three people: there can be no such relation that does not involve three
at least. Such a proposition as 'A wishes B to promote C's marriage with D'
involves a relation of four terms; that is to say, A and B and C and D all come
in, and the relation involved cannot be expressed otherwise than in a form
involving all four. Instances might be multiplied indefinitely, but enough has
been said to show that there are relations which require more than two terms
before they can occur.
The relation involved in judging or believing must, if
falsehood is to be duly allowed for, be taken to be a relation between several
terms, not between two. When Othello believes that Desdemona loves Cassio, he
must not have before his mind a single object, 'Desdemona's love for Cassio', or
'that Desdemona loves Cassio ', for that would require that there should be
objective falsehoods, which subsist independently of any minds; and this, though
not logically refutable, is a theory to be avoided if possible. Thus it is
easier to account for falsehood if we take judgement to be a relation in which
the mind and the various objects concerned all occur severally; that is to say,
Desdemona and loving and Cassio must all be terms in the relation which subsists
when Othello believes that Desdemona loves Cassio. This relation, therefore, is
a relation of four terms, since Othello also is one of the terms of the
relation. When we say that it is a relation of four terms, we do not mean that
Othello has a certain relation to Desdemona, and has the same relation to loving
and also to Cassio. This may be true of some other relation than believing; but
believing, plainly, is not a relation which Othello has to each of the
three terms concerned, but to all of them together: there is only one
example of the relation of believing involved, but this one example knits
together four terms. Thus the actual occurrence, at the moment when Othello is
entertaining his belief, is that the relation called 'believing' is knitting
together into one complex whole the four terms Othello, Desdemona, loving, and
Cassio. What is called belief or judgement is nothing but this relation of
believing or judging, which relates a mind to several things other than itself.
An act of belief or of judgement is the occurrence between certain terms
at some particular time, of the relation of believing or judging.
We are now in a position to understand what it is that distinguishes a true
judgement from a false one. For this purpose we will adopt certain definitions.
In every act of judgement there is a mind which judges, and there are terms
concerning which it judges. We will call the mind the subject in the
judgement, and the remaining terms the objects. Thus, when Othello judges
that Desdemona loves Cassio, Othello is the subject, while the objects are
Desdemona and loving and Cassio. The subject and the objects together are called
the constituents of the judgement. It will be observed that the relation
of judging has what is called a 'sense' or 'direction'. We may say,
metaphorically, that it puts its objects in a certain order, which we may
indicate by means of the order of the words in the sentence. (In an inflected
language, the same thing will be indicated by inflections, e.g. by the
difference between nominative and accusative.) Othello's judgement that Cassio
loves Desdemona differs from his judgement that Desdemona loves Cassio, in spite
of the fact that it consists of the same constituents, because the relation of
judging places the constituents in a different order in the two cases.
Similarly, if Cassio judges that Desdemona loves Othello, the constituents of
the judgement are still the same, but their order is different. This property of
having a 'sense' or 'direction' is one which the relation of judging shares with
all other relations. The 'sense' of relations is the ultimate source of order
and series and a host of mathematical concepts; but we need not concern
ourselves further with this aspect.
We spoke of the relation called 'judging' or 'believing' as knitting together
into one complex whole the subject and the objects. In this respect, judging is
exactly like every other relation. Whenever a relation holds between two or more
terms, it unites the terms into a complex whole. If Othello loves Desdemona,
there is such a complex whole as 'Othello's love for Desdemona'. The terms
united by the relation may be themselves complex, or may be simple, but the
whole which results from their being united must be complex. Wherever there is a
relation which relates certain terms, there is a complex object formed of the
union of those terms; and conversely, wherever there is a complex object, there
is a relation which relates its constituents. When an act of believing occurs,
there is a complex, in which 'believing' is the uniting relation, and subject
and objects are arranged in a certain order by the 'sense' of the relation of
believing. Among the objects, as we saw in considering 'Othello believes that
Desdemona loves Cassio', one must be a relation—in this instance, the relation
'loving'. But this relation, as it occurs in the act of believing, is not the
relation which creates the unity of the complex whole consisting of the subject
and the objects. The relation 'loving', as it occurs in the act of believing, is
one of the objects—it is a brick in the structure, not the cement. The cement is
the relation 'believing'. When the belief is true, there is another
complex unity, in which the relation which was one of the objects of the belief
relates the other objects. Thus, e.g., if Othello believes truly that
Desdemona loves Cassio, then there is a complex unity, 'Desdemona's love for
Cassio', which is composed exclusively of the objects of the belief, in
the same order as they had in the belief, with the relation which was one of the
objects occurring now as the cement that binds together the other objects of the
belief. On the other hand, when a belief is false, there is no such
complex unity composed only of the objects of the belief. If Othello believes
falsely that Desdemona loves Cassio, then there is no such complex unity as
'Desdemona's love for Cassio'.
Thus a belief is true when it corresponds to a certain
associated complex, and false when it does not. Assuming, for the sake of
definiteness, that the objects of the belief are two terms and a relation, the
terms being put in a certain order by the 'sense' of the believing, then if the
two terms in that order are united by the relation into a complex, the belief is
true; if not, it is false. This constitutes the definition of truth and
falsehood that we were in search of. Judging or believing is a certain complex
unity of which a mind is a constituent; if the remaining constituents, taken in
the order which they have in the belief, form a complex unity, then the belief
is true; if not, it is false.
Thus although truth and falsehood are properties of beliefs, yet they are in
a sense extrinsic properties, for the condition of the truth of a belief is
something not involving beliefs, or (in general) any mind at all, but only the
objects of the belief. A mind, which believes, believes truly when there
is a corresponding complex not involving the mind, but only its objects.
This correspondence ensures truth, and its absence entails falsehood. Hence we
account simultaneously for the two facts that beliefs (a) depend on minds for
their existence, (b) do not depend on minds for their truth.
We may restate our theory as follows: If we take such a belief as 'Othello
believes that Desdemona loves Cassio', we will call Desdemona and Cassio the
object-terms, and loving the object-relation. If there is a complex
unity 'Desdemona's love for Cassio', consisting of the object-terms related by
the object-relation in the same order as they have in the belief, then this
complex unity is called the fact corresponding to the belief. Thus a
belief is true when there is a corresponding fact, and is false when there is no
corresponding fact.
It will be seen that minds do not create truth or falsehood. They
create beliefs, but when once the beliefs are created, the mind cannot make them
true or false, except in the special case where they concern future things which
are within the power of the person believing, such as catching trains. What
makes a belief true is a fact, and this fact does not (except in
exceptional cases) in any way involve the mind of the person who has the belief.
Having now decided what we mean by truth and falsehood, we have next
to consider what ways there are of knowing whether this or that belief is true
or false. This consideration will occupy the next chapter.
CHAPTER XIII. KNOWLEDGE, ERROR, AND PROBABLE OPINION
The question as to what we mean by truth and falsehood, which we considered
in the preceding chapter, is of much less interest than the question as to how
we can know what is true and what is false. This question will occupy us in the
present chapter. There can be no doubt that some of our beliefs are
erroneous; thus we are led to inquire what certainty we can ever have that such
and such a belief is not erroneous. In other words, can we ever know
anything at all, or do we merely sometimes by good luck believe what is true?
Before we can attack this question, we must, however, first decide what we mean
by 'knowing', and this question is not so easy as might be supposed.
At first sight we might imagine that knowledge could be defined as 'true
belief'. When what we believe is true, it might be supposed that we had achieved
a knowledge of what we believe. But this would not accord with the way in which
the word is commonly used. To take a very trivial instance: If a man believes
that the late Prime Minister's last name began with a B, he believes what is
true, since the late Prime Minister was Sir Henry Campbell Bannerman. But if he
believes that Mr. Balfour was the late Prime Minister, he will still believe
that the late Prime Minister's last name began with a B, yet this belief, though
true, would not be thought to constitute knowledge. If a newspaper, by an
intelligent anticipation, announces the result of a battle before any telegram
giving the result has been received, it may by good fortune announce what
afterwards turns out to be the right result, and it may produce belief in some
of its less experienced readers. But in spite of the truth of their belief, they
cannot be said to have knowledge. Thus it is clear that a true belief is not
knowledge when it is deduced from a false belief.
In like manner, a true belief cannot be called knowledge when it is deduced
by a fallacious process of reasoning, even if the premisses from which it is
deduced are true. If I know that all Greeks are men and that Socrates was a man,
and I infer that Socrates was a Greek, I cannot be said to know that
Socrates was a Greek, because, although my premisses and my conclusion are true,
the conclusion does not follow from the premisses.
But are we to say that nothing is knowledge except what is validly deduced
from true premisses? Obviously we cannot say this. Such a definition is at once
too wide and too narrow. In the first place, it is too wide, because it is not
enough that our premisses should be true, they must also be known.
The man who believes that Mr. Balfour was the late Prime Minister may proceed to
draw valid deductions from the true premiss that the late Prime Minister's name
began with a B, but he cannot be said to know the conclusions reached by
these deductions. Thus we shall have to amend our definition by saying that
knowledge is what is validly deduced from known premisses. This, however,
is a circular definition: it assumes that we already know what is meant by
'known premisses'. It can, therefore, at best define one sort of knowledge, the
sort we call derivative, as opposed to intuitive knowledge. We may say: 'Derivative
knowledge is what is validly deduced from premisses known intuitively'. In this
statement there is no formal defect, but it leaves the definition of
intuitive knowledge still to seek.
Leaving on one side, for the moment, the question of intuitive knowledge, let
us consider the above suggested definition of derivative knowledge. The chief
objection to it is that it unduly limits knowledge. It constantly happens that
people entertain a true belief, which has grown up in them because of some piece
of intuitive knowledge from which it is capable of being validly inferred, but
from which it has not, as a matter of fact, been inferred by any logical
process.
Take, for example, the beliefs produced by reading. If the newspapers
announce the death of the King, we are fairly well justified in believing that
the King is dead, since this is the sort of announcement which would not be made
if it were false. And we are quite amply justified in believing that the
newspaper asserts that the King is dead. But here the intuitive knowledge upon
which our belief is based is knowledge of the existence of sense-data derived
from looking at the print which gives the news. This knowledge scarcely rises
into consciousness, except in a person who cannot read easily. A child may be
aware of the shapes of the letters, and pass gradually and painfully to a
realization of their meaning. But anybody accustomed to reading passes at once
to what the letters mean, and is not aware, except on reflection, that he has
derived this knowledge from the sense-data called seeing the printed letters.
Thus although a valid inference from the-letters to their meaning is possible,
and could be performed by the reader, it is not in fact performed, since
he does not in fact perform any operation which can be called logical inference.
Yet it would be absurd to say that the reader does not know that the
newspaper announces the King's death.
We must, therefore, admit as derivative knowledge whatever is the result of
intuitive knowledge even if by mere association, provided there is a
valid logical connexion, and the person in question could become aware of this
connexion by reflection. There are in fact many ways, besides logical inference,
by which we pass from one belief to another: the passage from the print to its
meaning illustrates these ways. These ways may be called 'psychological
inference'. We shall, then, admit such psychological inference as a means of
obtaining derivative knowledge, provided there is a discoverable logical
inference which runs parallel to the psychological inference. This renders our
definition of derivative knowledge less precise than we could wish, since the
word 'discoverable' is vague: it does not tell us how much reflection may be
needed in order to make the discovery. But in fact 'knowledge' is not a precise
conception: it merges into 'probable opinion', as we shall see more fully in the
course of the present chapter. A very precise definition, therefore, should not
be sought, since any such definition must be more or less misleading.
The chief difficulty in regard to knowledge, however, does not arise over
derivative knowledge, but over intuitive knowledge. So long as we are dealing
with derivative knowledge, we have the test of intuitive knowledge to fall back
upon. But in regard to intuitive beliefs, it is by no means easy to discover any
criterion by which to distinguish some as true and others as erroneous. In this
question it is scarcely possible to reach any very precise result: all our
knowledge of truths is infected with some degree of doubt, and a theory which
ignored this fact would be plainly wrong. Something may be done, however, to
mitigate the difficulties of the question.
Our theory of truth, to begin with, supplies the possibility of
distinguishing certain truths as self-evident in a sense which ensures
infallibility. When a belief is true, we said, there is a corresponding fact, in
which the several objects of the belief form a single complex. The belief is
said to constitute knowledge of this fact, provided it fulfils those
further somewhat vague conditions which we have been considering in the present
chapter. But in regard to any fact, besides the knowledge constituted by belief,
we may also have the kind of knowledge constituted by perception (taking
this word in its widest possible sense). For example, if you know the hour of
the sunset, you can at that hour know the fact that the sun is setting: this is
knowledge of the fact by way of knowledge of truths; but you can also, if
the weather is fine, look to the west and actually see the setting sun: you then
know the same fact by the way of knowledge of things.
Thus in regard to any complex fact, there are, theoretically, two ways in
which it may be known: (1) by means of a judgement, in which its several parts
are judged to be related as they are in fact related; (2) by means of
acquaintance with the complex fact itself, which may (in a large sense) be
called perception, though it is by no means confined to objects of the senses.
Now it will be observed that the second way of knowing a complex fact, the way
of acquaintance, is only possible when there really is such a fact, while the
first way, like all judgement, is liable to error. The second way gives us the
complex whole, and is therefore only possible when its parts do actually have
that relation which makes them combine to form such a complex. The first way, on
the contrary, gives us the parts and the relation severally, and demands only
the reality of the parts and the relation: the relation may not relate those
parts in that way, and yet the judgement may occur.
It will be remembered that at the end of Chapter XI we suggested that there
might be two kinds of self-evidence, one giving an absolute guarantee of truth,
the other only a partial guarantee. These two kinds can now be distinguished.
We may say that a truth is self-evident, in the first and most absolute
sense, when we have acquaintance with the fact which corresponds to the truth.
When Othello believes that Desdemona loves Cassio, the corresponding fact, if
his belief were true, would be 'Desdemona's love for Cassio'. This would be a
fact with which no one could have acquaintance except Desdemona; hence in the
sense of self-evidence that we are considering, the truth that Desdemona loves
Cassio (if it were a truth) could only be self-evident to Desdemona. All mental
facts, and all facts concerning sense-data, have this same privacy: there is
only one person to whom they can be self-evident in our present sense, since
there is only one person who can be acquainted with the mental things or the
sense-data concerned. Thus no fact about any particular existing thing can be
self-evident to more than one person. On the other hand, facts about universals
do not have this privacy. Many minds may be acquainted with the same universals;
hence a relation between universals may be known by acquaintance to many
different people. In all cases where we know by acquaintance a complex fact
consisting of certain terms in a certain relation, we say that the truth that
these terms are so related has the first or absolute kind of self-evidence, and
in these cases the judgement that the terms are so related must be true.
Thus this sort of self-evidence is an absolute guarantee of truth.
But although this sort of self-evidence is an absolute guarantee of truth, it
does not enable us to be absolutely certain, in the case of any given
judgement, that the judgement in question is true. Suppose we first perceive the
sun shining, which is a complex fact, and thence proceed to make the judgement
'the sun is shining'. In passing from the perception to the judgement, it is
necessary to analyse the given complex fact: we have to separate out 'the sun'
and 'shining' as constituents of the fact. In this process it is possible to
commit an error; hence even where a fact has the first or absolute kind
of self-evidence, a judgement believed to correspond to the fact is not
absolutely infallible, because it may not really correspond to the fact. But if
it does correspond (in the sense explained in the preceding chapter), then it
must be true.
The second sort of self-evidence will be that which belongs to judgements in
the first instance, and is not derived from direct perception of a fact as a
single complex whole. This second kind of self-evidence will have degrees, from
the very highest degree down to a bare inclination in favour of the belief.
Take, for example, the case of a horse trotting away from us along a hard road.
At first our certainty that we hear the hoofs is complete; gradually, if we
listen intently, there comes a moment when we think perhaps it was imagination
or the blind upstairs or our own heartbeats; at last we become doubtful whether
there was any noise at all; then we think we no longer hear anything, and
at last we know we no longer hear anything. In this process, there is a
continual gradation of self-evidence, from the highest degree to the least, not
in the sense-data themselves, but in the judgements based on them.
Or again: Suppose we are comparing two shades of colour, one blue and one
green. We can be quite sure they are different shades of colour; but if the
green colour is gradually altered to be more and more like the blue, becoming
first a blue-green, then a greeny-blue, then blue, there will come a moment when
we are doubtful whether we can see any difference, and then a moment when we
know that we cannot see any difference. The same thing happens in tuning a
musical instrument, or in any other case where there is a continuous gradation.
Thus self-evidence of this sort is a matter of degree; and it seems plain that
the higher degrees are more to be trusted than the lower degrees.
In derivative knowledge our ultimate premisses must have some degree of
self-evidence, and so must their connexion with the conclusions deduced from
them. Take for example a piece of reasoning in geometry. It is not enough that
the axioms from which we start should be self-evident: it is necessary also
that, at each step in the reasoning, the connexion of premiss and conclusion
should be self-evident. In difficult reasoning, this connexion has often only a
very small degree of self-evidence; hence errors of reasoning are not improbable
where the difficulty is great.
From what has been said it is evident that, both as regards intuitive
knowledge and as regards derivative knowledge, if we assume that intuitive
knowledge is trustworthy in proportion to the degree of its self-evidence, there
will be a gradation in trustworthiness, from the existence of noteworthy
sense-data and the simpler truths of logic and arithmetic, which may be taken as
quite certain, down to judgements which seem only just more probable than their
opposites. What we firmly believe, if it is true, is called knowledge,
provided it is either intuitive or inferred (logically or psychologically) from
intuitive knowledge from which it follows logically. What we firmly believe, if
it is not true, is called error. What we firmly believe, if it is neither
knowledge nor error, and also what we believe hesitatingly, because it is, or is
derived from, something which has not the highest degree of self-evidence, may
be called probable opinion. Thus the greater part of what would commonly
pass as knowledge is more or less probable opinion.
In regard to probable opinion, we can derive great assistance from
coherence, which we rejected as the definition of truth, but may
often use as a criterion. A body of individually probable opinions, if
they are mutually coherent, become more probable than any one of them would be
individually. It is in this way that many scientific hypotheses acquire their
probability. They fit into a coherent system of probable opinions, and thus
become more probable than they would be in isolation. The same thing applies to
general philosophical hypotheses. Often in a single case such hypotheses may
seem highly doubtful, while yet, when we consider the order and coherence which
they introduce into a mass of probable opinion, they become pretty nearly
certain. This applies, in particular, to such matters as the distinction between
dreams and waking life. If our dreams, night after night, were as coherent one
with another as our days, we should hardly know whether to believe the dreams or
the waking life. As it is, the test of coherence condemns the dreams and
confirms the waking life. But this test, though it increases probability where
it is successful, never gives absolute certainty, unless there is certainty
already at some point in the coherent system. Thus the mere organization of
probable opinion will never, by itself, transform it into indubitable knowledge.
CHAPTER XIV. THE LIMITS OF PHILOSOPHICAL KNOWLEDGE
In all that we have said hitherto concerning philosophy, we have scarcely
touched on many matters that occupy a great space in the writings of most
philosophers. Most philosophers—or, at any rate, very many—profess to be able to
prove, by a priori metaphysical reasoning, such things as the fundamental
dogmas of religion, the essential rationality of the universe, the illusoriness
of matter, the unreality of all evil, and so on. There can be no doubt that the
hope of finding reason to believe such theses as these has been the chief
inspiration of many life-long students of philosophy. This hope, I believe, is
vain. It would seem that knowledge concerning the universe as a whole is not to
be obtained by metaphysics, and that the proposed proofs that, in virtue of the
laws of logic such and such things must exist and such and such others
cannot, are not capable of surviving a critical scrutiny. In this chapter we
shall briefly consider the kind of way in which such reasoning is attempted,
with a view to discovering whether we can hope that it may be valid.
The great representative, in modern times, of the kind of view which we wish
to examine, was Hegel (1770-1831). Hegel's philosophy is very difficult, and
commentators differ as to the true interpretation of it. According to the
interpretation I shall adopt, which is that of many, if not most, of the
commentators and has the merit of giving an interesting and important type of
philosophy, his main thesis is that everything short of the Whole is obviously
fragmentary, and obviously incapable of existing without the complement supplied
by the rest of the world. Just as a comparative anatomist, from a single bone,
sees what kind of animal the whole must have been, so the metaphysician,
according to Hegel, sees, from any one piece of reality, what the whole of
reality must be—at least in its large outlines. Every apparently separate piece
of reality has, as it were, hooks which grapple it to the next piece; the next
piece, in turn, has fresh hooks, and so on, until the whole universe is
reconstructed. This essential incompleteness appears, according to Hegel,
equally in the world of thought and in the world of things. In the world of
thought, if we take any idea which is abstract or incomplete, we find, on
examination, that if we forget its incompleteness, we become involved in
contradictions; these contradictions turn the idea in question into its
opposite, or antithesis; and in order to escape, we have to find a new, less
incomplete idea, which is the synthesis of our original idea and its antithesis.
This new idea, though less incomplete than the idea we started with, will be
found, nevertheless, to be still not wholly complete, but to pass into its
antithesis, with which it must be combined in a new synthesis. In this way Hegel
advances until he reaches the 'Absolute Idea', which, according to him, has no
incompleteness, no opposite, and no need of further development. The Absolute
Idea, therefore, is adequate to describe Absolute Reality; but all lower ideas
only describe reality as it appears to a partial view, not as it is to one who
simultaneously surveys the Whole. Thus Hegel reaches the conclusion that
Absolute Reality forms one single harmonious system, not in space or time, not
in any degree evil, wholly rational, and wholly spiritual. Any appearance to the
contrary, in the world we know, can be proved logically—so he believes—to be
entirely due to our fragmentary piecemeal view of the universe. If we saw the
universe whole, as we may suppose God sees it, space and time and matter and
evil and all striving and struggling would disappear, and we should see instead
an eternal perfect unchanging spiritual unity.
In this conception, there is undeniably something sublime, something to which
we could wish to yield assent. Nevertheless, when the arguments in support of it
are carefully examined, they appear to involve much confusion and many
unwarrantable assumptions. The fundamental tenet upon which the system is built
up is that what is incomplete must be not self-subsistent, but must need the
support of other things before it can exist. It is held that whatever has
relations to things outside itself must contain some reference to those outside
things in its own nature, and could not, therefore, be what it is if those
outside things did not exist. A man's nature, for example, is constituted by his
memories and the rest of his knowledge, by his loves and hatreds, and so on;
thus, but for the objects which he knows or loves or hates, he could not be what
he is. He is essentially and obviously a fragment: taken as the sum-total of
reality he would be self-contradictory.
This whole point of view, however, turns upon the notion of the 'nature' of a
thing, which seems to mean 'all the truths about the thing'. It is of course the
case that a truth which connects one thing with another thing could not subsist
if the other thing did not subsist. But a truth about a thing is not part of the
thing itself, although it must, according to the above usage, be part of the
'nature' of the thing. If we mean by a thing's 'nature' all the truths about the
thing, then plainly we cannot know a thing's 'nature' unless we know all the
thing's relations to all the other things in the universe. But if the word
'nature' is used in this sense, we shall have to hold that the thing may be
known when its 'nature' is not known, or at any rate is not known completely.
There is a confusion, when this use of the word 'nature' is employed, between
knowledge of things and knowledge of truths. We may have knowledge of a thing by
acquaintance even if we know very few propositions about it—theoretically we
need not know any propositions about it. Thus, acquaintance with a thing does
not involve knowledge of its 'nature' in the above sense. And although
acquaintance with a thing is involved in our knowing any one proposition about a
thing, knowledge of its 'nature', in the above sense, is not involved. Hence,
(1) acquaintance with a thing does not logically involve a knowledge of its
relations, and (2) a knowledge of some of its relations does not involve a
knowledge of all of its relations nor a knowledge of its 'nature' in the above
sense. I may be acquainted, for example, with my toothache, and this knowledge
may be as complete as knowledge by acquaintance ever can be, without knowing all
that the dentist (who is not acquainted with it) can tell me about its cause,
and without therefore knowing its 'nature' in the above sense. Thus the fact
that a thing has relations does not prove that its relations are logically
necessary. That is to say, from the mere fact that it is the thing it is we
cannot deduce that it must have the various relations which in fact it has. This
only seems to follow because we know it already.
It follows that we cannot prove that the universe as a whole forms a single
harmonious system such as Hegel believes that it forms. And if we cannot prove
this, we also cannot prove the unreality of space and time and matter and evil,
for this is deduced by Hegel from the fragmentary and relational character of
these things. Thus we are left to the piecemeal investigation of the world, and
are unable to know the characters of those parts of the universe that are remote
from our experience. This result, disappointing as it is to those whose hopes
have been raised by the systems of philosophers, is in harmony with the
inductive and scientific temper of our age, and is borne out by the whole
examination of human knowledge which has occupied our previous chapters.
Most of the great ambitious attempts of metaphysicians have proceeded by the
attempt to prove that such and such apparent features of the actual world were
self-contradictory, and therefore could not be real. The whole tendency of
modern thought, however, is more and more in the direction of showing that the
supposed contradictions were illusory, and that very little can be proved a
priori from considerations of what must be. A good illustration of
this is afforded by space and time. Space and time appear to be infinite in
extent, and infinitely divisible. If we travel along a straight line in either
direction, it is difficult to believe that we shall finally reach a last point,
beyond which there is nothing, not even empty space. Similarly, if in
imagination we travel backwards or forwards in time, it is difficult to believe
that we shall reach a first or last time, with not even empty time beyond it.
Thus space and time appear to be infinite in extent.
Again, if we take any two points on a line, it seems evident that there must
be other points between them however small the distance between them may be:
every distance can be halved, and the halves can be halved again, and so on
ad infinitum. In time, similarly, however little time may elapse between two
moments, it seems evident that there will be other moments between them. Thus
space and time appear to be infinitely divisible. But as against these apparent
facts—infinite extent and infinite divisibility—philosophers have advanced
arguments tending to show that there could be no infinite collections of things,
and that therefore the number of points in space, or of instants in time, must
be finite. Thus a contradiction emerged between the apparent nature of space and
time and the supposed impossibility of infinite collections.
Kant, who first emphasized this contradiction, deduced the impossibility of
space and time, which he declared to be merely subjective; and since his time
very many philosophers have believed that space and time are mere appearance,
not characteristic of the world as it really is. Now, however, owing to the
labours of the mathematicians, notably Georg Cantor, it has appeared that the
impossibility of infinite collections was a mistake. They are not in fact
self-contradictory, but only contradictory of certain rather obstinate mental
prejudices. Hence the reasons for regarding space and time as unreal have become
inoperative, and one of the great sources of metaphysical constructions is dried
up.
The mathematicians, however, have not been content with showing that space as
it is commonly supposed to be is possible; they have shown also that many other
forms of space are equally possible, so far as logic can show. Some of Euclid's
axioms, which appear to common sense to be necessary, and were formerly supposed
to be necessary by philosophers, are now known to derive their appearance of
necessity from our mere familiarity with actual space, and not from any a
priori logical foundation. By imagining worlds in which these axioms are
false, the mathematicians have used logic to loosen the prejudices of common
sense, and to show the possibility of spaces differing—some more, some less—from
that in which we live. And some of these spaces differ so little from Euclidean
space, where distances such as we can measure are concerned, that it is
impossible to discover by observation whether our actual space is strictly
Euclidean or of one of these other kinds. Thus the position is completely
reversed. Formerly it appeared that experience left only one kind of space to
logic, and logic showed this one kind to be impossible. Now, logic presents many
kinds of space as possible apart from experience, and experience only partially
decides between them. Thus, while our knowledge of what is has become less than
it was formerly supposed to be, our knowledge of what may be is enormously
increased. Instead of being shut in within narrow walls, of which every nook and
cranny could be explored, we find ourselves in an open world of free
possibilities, where much remains unknown because there is so much to know.
What has happened in the case of space and time has happened, to some extent,
in other directions as well. The attempt to prescribe to the universe by means
of a priori principles has broken down; logic, instead of being, as
formerly, the bar to possibilities, has become the great liberator of the
imagination, presenting innumerable alternatives which are closed to
unreflective common sense, and leaving to experience the task of deciding, where
decision is possible, between the many worlds which logic offers for our choice.
Thus knowledge as to what exists becomes limited to what we can learn from
experience—not to what we can actually experience, for, as we have seen, there
is much knowledge by description concerning things of which we have no direct
experience. But in all cases of knowledge by description, we need some connexion
of universals, enabling us, from such and such a datum, to infer an object of a
certain sort as implied by our datum. Thus in regard to physical objects, for
example, the principle that sense-data are signs of physical objects is itself a
connexion of universals; and it is only in virtue of this principle that
experience enables us to acquire knowledge concerning physical objects. The same
applies to the law of causality, or, to descend to what is less general, to such
principles as the law of gravitation.
Principles such as the law of gravitation are proved, or rather are rendered
highly probable, by a combination of experience with some wholly a priori
principle, such as the principle of induction. Thus our intuitive knowledge,
which is the source of all our other knowledge of truths, is of two sorts: pure
empirical knowledge, which tells us of the existence and some of the properties
of particular things with which we are acquainted, and pure a priori
knowledge, which gives us connexions between universals, and enables us to draw
inferences from the particular facts given in empirical knowledge. Our
derivative knowledge always depends upon some pure a priori knowledge and
usually also depends upon some pure empirical knowledge.
Philosophical knowledge, if what has been said above is true, does not differ
essentially from scientific knowledge; there is no special source of wisdom
which is open to philosophy but not to science, and the results obtained by
philosophy are not radically different from those obtained from science. The
essential characteristic of philosophy, which makes it a study distinct from
science, is criticism. It examines critically the principles employed in science
and in daily life; it searches out any inconsistencies there may be in these
principles, and it only accepts them when, as the result of a critical inquiry,
no reason for rejecting them has appeared. If, as many philosophers have
believed, the principles underlying the sciences were capable, when disengaged
from irrelevant detail, of giving us knowledge concerning the universe as a
whole, such knowledge would have the same claim on our belief as scientific
knowledge has; but our inquiry has not revealed any such knowledge, and
therefore, as regards the special doctrines of the bolder metaphysicians, has
had a mainly negative result. But as regards what would be commonly accepted as
knowledge, our result is in the main positive: we have seldom found reason to
reject such knowledge as the result of our criticism, and we have seen no reason
to suppose man incapable of the kind of knowledge which he is generally believed
to possess.
When, however, we speak of philosophy as a criticism of knowledge, it
is necessary to impose a certain limitation. If we adopt the attitude of the
complete sceptic, placing ourselves wholly outside all knowledge, and asking,
from this outside position, to be compelled to return within the circle of
knowledge, we are demanding what is impossible, and our scepticism can never be
refuted. For all refutation must begin with some piece of knowledge which the
disputants share; from blank doubt, no argument can begin. Hence the criticism
of knowledge which philosophy employs must not be of this destructive kind, if
any result is to be achieved. Against this absolute scepticism, no logical
argument can be advanced. But it is not difficult to see that scepticism of this
kind is unreasonable. Descartes' 'methodical doubt', with which modern
philosophy began, is not of this kind, but is rather the kind of criticism which
we are asserting to be the essence of philosophy. His 'methodical doubt'
consisted in doubting whatever seemed doubtful; in pausing, with each apparent
piece of knowledge, to ask himself whether, on reflection, he could feel certain
that he really knew it. This is the kind of criticism which constitutes
philosophy. Some knowledge, such as knowledge of the existence of our
sense-data, appears quite indubitable, however calmly and thoroughly we reflect
upon it. In regard to such knowledge, philosophical criticism does not require
that we should abstain from belief. But there are beliefs—such, for example, as
the belief that physical objects exactly resemble our sense-data—which are
entertained until we begin to reflect, but are found to melt away when subjected
to a close inquiry. Such beliefs philosophy will bid us reject, unless some new
line of argument is found to support them. But to reject the beliefs which do
not appear open to any objections, however closely we examine them, is not
reasonable, and is not what philosophy advocates.
The criticism aimed at, in a word, is not that which, without reason,
determines to reject, but that which considers each piece of apparent knowledge
on its merits, and retains whatever still appears to be knowledge when this
consideration is completed. That some risk of error remains must be admitted,
since human beings are fallible. Philosophy may claim justly that it diminishes
the risk of error, and that in some cases it renders the risk so small as to be
practically negligible. To do more than this is not possible in a world where
mistakes must occur; and more than this no prudent advocate of philosophy would
claim to have performed.
CHAPTER XV. THE VALUE OF PHILOSOPHY
Having now come to the end of our brief and very incomplete review of the
problems of philosophy, it will be well to consider, in conclusion, what is the
value of philosophy and why it ought to be studied. It is the more necessary to
consider this question, in view of the fact that many men, under the influence
of science or of practical affairs, are inclined to doubt whether philosophy is
anything better than innocent but useless trifling, hair-splitting distinctions,
and controversies on matters concerning which knowledge is impossible.
This view of philosophy appears to result, partly from a wrong conception of
the ends of life, partly from a wrong conception of the kind of goods which
philosophy strives to achieve. Physical science, through the medium of
inventions, is useful to innumerable people who are wholly ignorant of it; thus
the study of physical science is to be recommended, not only, or primarily,
because of the effect on the student, but rather because of the effect on
mankind in general. Thus utility does not belong to philosophy. If the study of
philosophy has any value at all for others than students of philosophy, it must
be only indirectly, through its effects upon the lives of those who study it. It
is in these effects, therefore, if anywhere, that the value of philosophy must
be primarily sought.
But further, if we are not to fail in our endeavour to determine the value of
philosophy, we must first free our minds from the prejudices of what are wrongly
called 'practical' men. The 'practical' man, as this word is often used, is one
who recognizes only material needs, who realizes that men must have food for the
body, but is oblivious of the necessity of providing food for the mind. If all
men were well off, if poverty and disease had been reduced to their lowest
possible point, there would still remain much to be done to produce a valuable
society; and even in the existing world the goods of the mind are at least as
important as the goods of the body. It is exclusively among the goods of the
mind that the value of philosophy is to be found; and only those who are not
indifferent to these goods can be persuaded that the study of philosophy is not
a waste of time.
Philosophy, like all other studies, aims primarily at knowledge. The
knowledge it aims at is the kind of knowledge which gives unity and system to
the body of the sciences, and the kind which results from a critical examination
of the grounds of our convictions, prejudices, and beliefs. But it cannot be
maintained that philosophy has had any very great measure of success in its
attempts to provide definite answers to its questions. If you ask a
mathematician, a mineralogist, a historian, or any other man of learning, what
definite body of truths has been ascertained by his science, his answer will
last as long as you are willing to listen. But if you put the same question to a
philosopher, he will, if he is candid, have to confess that his study has not
achieved positive results such as have been achieved by other sciences. It is
true that this is partly accounted for by the fact that, as soon as definite
knowledge concerning any subject becomes possible, this subject ceases to be
called philosophy, and becomes a separate science. The whole study of the
heavens, which now belongs to astronomy, was once included in philosophy;
Newton's great work was called 'the mathematical principles of natural
philosophy'. Similarly, the study of the human mind, which was a part of
philosophy, has now been separated from philosophy and has become the science of
psychology. Thus, to a great extent, the uncertainty of philosophy is more
apparent than real: those questions which are already capable of definite
answers are placed in the sciences, while those only to which, at present, no
definite answer can be given, remain to form the residue which is called
philosophy.
This is, however, only a part of the truth concerning the uncertainty of
philosophy. There are many questions—and among them those that are of the
profoundest interest to our spiritual life—which, so far as we can see, must
remain insoluble to the human intellect unless its powers become of quite a
different order from what they are now. Has the universe any unity of plan or
purpose, or is it a fortuitous concourse of atoms? Is consciousness a permanent
part of the universe, giving hope of indefinite growth in wisdom, or is it a
transitory accident on a small planet on which life must ultimately become
impossible? Are good and evil of importance to the universe or only to man? Such
questions are asked by philosophy, and variously answered by various
philosophers. But it would seem that, whether answers be otherwise discoverable
or not, the answers suggested by philosophy are none of them demonstrably true.
Yet, however slight may be the hope of discovering an answer, it is part of the
business of philosophy to continue the consideration of such questions, to make
us aware of their importance, to examine all the approaches to them, and to keep
alive that speculative interest in the universe which is apt to be killed by
confining ourselves to definitely ascertainable knowledge.
Many philosophers, it is true, have held that philosophy could establish the
truth of certain answers to such fundamental questions. They have supposed that
what is of most importance in religious beliefs could be proved by strict
demonstration to be true. In order to judge of such attempts, it is necessary to
take a survey of human knowledge, and to form an opinion as to its methods and
its limitations. On such a subject it would be unwise to pronounce dogmatically;
but if the investigations of our previous chapters have not led us astray, we
shall be compelled to renounce the hope of finding philosophical proofs of
religious beliefs. We cannot, therefore, include as part of the value of
philosophy any definite set of answers to such questions. Hence, once more, the
value of philosophy must not depend upon any supposed body of definitely
ascertainable knowledge to be acquired by those who study it.
The value of philosophy is, in fact, to be sought largely in its very
uncertainty. The man who has no tincture of philosophy goes through life
imprisoned in the prejudices derived from common sense, from the habitual
beliefs of his age or his nation, and from convictions which have grown up in
his mind without the co-operation or consent of his deliberate reason. To such a
man the world tends to become definite, finite, obvious; common objects rouse no
questions, and unfamiliar possibilities are contemptuously rejected. As soon as
we begin to philosophize, on the contrary, we find, as we saw in our opening
chapters, that even the most everyday things lead to problems to which only very
incomplete answers can be given. Philosophy, though unable to tell us with
certainty what is the true answer to the doubts which it raises, is able to
suggest many possibilities which enlarge our thoughts and free them from the
tyranny of custom. Thus, while diminishing our feeling of certainty as to what
things are, it greatly increases our knowledge as to what they may be; it
removes the somewhat arrogant dogmatism of those who have never travelled into
the region of liberating doubt, and it keeps alive our sense of wonder by
showing familiar things in an unfamiliar aspect.
Apart from its utility in showing unsuspected possibilities, philosophy has a
value—perhaps its chief value—through the greatness of the objects which it
contemplates, and the freedom from narrow and personal aims resulting from this
contemplation. The life of the instinctive man is shut up within the circle of
his private interests: family and friends may be included, but the outer world
is not regarded except as it may help or hinder what comes within the circle of
instinctive wishes. In such a life there is something feverish and confined, in
comparison with which the philosophic life is calm and free. The private world
of instinctive interests is a small one, set in the midst of a great and
powerful world which must, sooner or later, lay our private world in ruins.
Unless we can so enlarge our interests as to include the whole outer world, we
remain like a garrison in a beleagured fortress, knowing that the enemy prevents
escape and that ultimate surrender is inevitable. In such a life there is no
peace, but a constant strife between the insistence of desire and the
powerlessness of will. In one way or another, if our life is to be great and
free, we must escape this prison and this strife.
One way of escape is by philosophic contemplation. Philosophic contemplation
does not, in its widest survey, divide the universe into two hostile
camps—friends and foes, helpful and hostile, good and bad—it views the whole
impartially. Philosophic contemplation, when it is unalloyed, does not aim at
proving that the rest of the universe is akin to man. All acquisition of
knowledge is an enlargement of the Self, but this enlargement is best attained
when it is not directly sought. It is obtained when the desire for knowledge is
alone operative, by a study which does not wish in advance that its objects
should have this or that character, but adapts the Self to the characters which
it finds in its objects. This enlargement of Self is not obtained when, taking
the Self as it is, we try to show that the world is so similar to this Self that
knowledge of it is possible without any admission of what seems alien. The
desire to prove this is a form of self-assertion and, like all self-assertion,
it is an obstacle to the growth of Self which it desires, and of which the Self
knows that it is capable. Self-assertion, in philosophic speculation as
elsewhere, views the world as a means to its own ends; thus it makes the world
of less account than Self, and the Self sets bounds to the greatness of its
goods. In contemplation, on the contrary, we start from the not-Self, and
through its greatness the boundaries of Self are enlarged; through the infinity
of the universe the mind which contemplates it achieves some share in infinity.
For this reason greatness of soul is not fostered by those philosophies which
assimilate the universe to Man. Knowledge is a form of union of Self and
not-Self; like all union, it is impaired by dominion, and therefore by any
attempt to force the universe into conformity with what we find in ourselves.
There is a widespread philosophical tendency towards the view which tells us
that Man is the measure of all things, that truth is man-made, that space and
time and the world of universals are properties of the mind, and that, if there
be anything not created by the mind, it is unknowable and of no account for us.
This view, if our previous discussions were correct, is untrue; but in addition
to being untrue, it has the effect of robbing philosophic contemplation of all
that gives it value, since it fetters contemplation to Self. What it calls
knowledge is not a union with the not-Self, but a set of prejudices, habits, and
desires, making an impenetrable veil between us and the world beyond. The man
who finds pleasure in such a theory of knowledge is like the man who never
leaves the domestic circle for fear his word might not be law.
The true philosophic contemplation, on the contrary, finds its satisfaction
in every enlargement of the not-Self, in everything that magnifies the objects
contemplated, and thereby the subject contemplating. Everything, in
contemplation, that is personal or private, everything that depends upon habit,
self-interest, or desire, distorts the object, and hence impairs the union which
the intellect seeks. By thus making a barrier between subject and object, such
personal and private things become a prison to the intellect. The free intellect
will see as God might see, without a here and now, without hopes
and fears, without the trammels of customary beliefs and traditional prejudices,
calmly, dispassionately, in the sole and exclusive desire of knowledge—knowledge
as impersonal, as purely contemplative, as it is possible for man to attain.
Hence also the free intellect will value more the abstract and universal
knowledge into which the accidents of private history do not enter, than the
knowledge brought by the senses, and dependent, as such knowledge must be, upon
an exclusive and personal point of view and a body whose sense-organs distort as
much as they reveal.
The mind which has become accustomed to the freedom and impartiality of
philosophic contemplation will preserve something of the same freedom and
impartiality in the world of action and emotion. It will view its purposes and
desires as parts of the whole, with the absence of insistence that results from
seeing them as infinitesimal fragments in a world of which all the rest is
unaffected by any one man's deeds. The impartiality which, in contemplation, is
the unalloyed desire for truth, is the very same quality of mind which, in
action, is justice, and in emotion is that universal love which can be given to
all, and not only to those who are judged useful or admirable. Thus
contemplation enlarges not only the objects of our thoughts, but also the
objects of our actions and our affections: it makes us citizens of the universe,
not only of one walled city at war with all the rest. In this citizenship of the
universe consists man's true freedom, and his liberation from the thraldom of
narrow hopes and fears.
Thus, to sum up our discussion of the value of philosophy; Philosophy is to
be studied, not for the sake of any definite answers to its questions, since no
definite answers can, as a rule, be known to be true, but rather for the sake of
the questions themselves; because these questions enlarge our conception of what
is possible, enrich our intellectual imagination and diminish the dogmatic
assurance which closes the mind against speculation; but above all because,
through the greatness of the universe which philosophy contemplates, the mind
also is rendered great, and becomes capable of that union with the universe
which constitutes its highest good.
