 The
Problems of Philosophy
Bertrand Russell
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 mus 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 argument 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.
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