16. We come, then, to this definite and, as Berkeley considered,
conclusive argument which begins in paragraph 16. What are we to make
of this notion of matter as conceived by Locke?. Matter, according to
this conception, is something which supports extension, i.e., we have the
have the quality of extension and we know that it is a quality of
something but we cannot further define that something than by saying
that it is that which has the quality or which supports the quality.
We are to think of the substance or ultimate nature of a thing as
something which lies under the various particular characters it can
have and which cannot itself be given any particular character. In
taking this view Locke diverges from the position of Descartes who
had said that man's whole nature consisted in thinking and that the
whole nature of matter consisted in extension.

Now Locke very rightly points out that extension is a character
of things and cannot be regarded, in so far as it is a character, as in
any way superior to any other character so that it might be said to be
that which has these other characters; and the same applies, of course,
to mind, i.e., if we can truly say that mind thinks we cannot possibly
mean that mind and thinking are absolutely identical. So that Locke
tries to solve the difficulty by maintaining that the substance or the
reality of the thing is not any particular character that it has but
is that which has the character and which cannot otherwise be defined.
In that way he is simply trying to make Descartes' position consistent;
in particular, to take account of the argument from the existence
of thought to the existence of a thinker which implies that the
thinker is something distinct from his thinking. If that were not so,
no argument would be required---whenever we knew any character we
should, by that very act of thought, know the thing that had the character
and so all Descartes' proofs of existence fall to the ground.

If Descartes, then, is to be justified in talking about being, being
must be different from any particular character and therefore “being”
must be quite indescribable: We cannot, Locke admits, say what substance
is; we can only say that it has a certain relation to qualities,
namely, that it supports them. But the difficulty that Berkeley now
points out is that, if we know nothing at all about substance itself
we are not in a position to say that it supports qualities; we are not

  ― 31. ―
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in a position to say what the nature of supporting is unless at some
time we have obsrved some thing supporting another.

Now we do in ordinary speech speak about one thing supporting
another but then, as Berkeley points out, the two things are existences
of the same kind and there is nothing essential to them about the
relation which they have. In fact that which supports something else
may at the same time be supported and indeed the relation between any
two given things could quite commonly be reversed; so that in considering
such a fact as that pillars support a building (Berkeley's example)
we have a perfectly definite sense of the term “support” but we have no
clue at all as to the meaning of this ultimate support to which Locke
refers. He is apparently using the term in a metaphorical way but the
metaphor requires an explanation which he is unable to give; so that
Berkeley is quite correct in saying that if we could know, nothing about
this substance except that it had a certain relation to other things so
that Locke considers it possible that even the substance of matter and
the substance of mind may be precisely the same---if we have no knowledge
except of its relation to other things---then we cannot argue that
it has that relation; we do not in the least know what it is and therefore
we cannot say that it exists. We cannot argue that qualities
require support if we have not at some time seen a quality being supported
and therefore observed that which supported it in the same way as
we observed the quality itself.

This argument is exactly parallel to the argument which Berkeley
employs in connection with the causes of our ideas. Locke says that
our ideas are caused by material bodies outside of us but admits that
we have never observed material bodies and therefore can never have
observed their causing our ideas; so that we have no reason whatever
when we find that we do not know the cause of some idea for supposing
it to have been caused by something material. As far as our experience
has gone we have not observed matter causing ideas and we do not, as
Berkeley points out, know how it could cause ideas; and moreover, what is
said to be the cause is something so vague and indefinable that the
argument cannot possibly be a conclusive one.

Well, then, as Berkeley puts it, this notion of material substance
which is supposed to support extension is found to be reducible to the
idea of being in general or, as Locke himself puts it, to “something we
know not what”, together with the relative notion of its supporting
accidence (quality).

Now this supporting, as has already been shown, must be understood in
some metaphorical way which is not explained by Locke so that he is
considering, as a necessary part of his system, something of which he can
give no coherent account. We cannot, therefore, say that there is a material
substance or sub-stratum which supports figure, extension or
motion and which we can regard as establishing the existence of unthinking
things. How, Berkeley asks, are we to know that matter exists?-we
cannot know it by sense since we only know ideas by sense; and by
definition substance is something beyond ideas or anything resembling
ideas; but equally we cannot know it by reason, that is to say, by inference
because that which we observe can give us no reason for supposing
the existence of something which cannot be observed in order to account
for it, i.e., the supposition of external bodies cannot be shown to be
necessary for the production of our ideas and it cannot be shown to
be sufficient for the production of our ideas if we have had no

  ― 32. ―
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experience of its producing ideas. And, as Berkeley points out, even
Locke himself has to admit that he does not know how material bodies
could produce the ideas in our minds; he does not know how body can
act upon spirit or how it is possible that it should imprint any idea
upon the mind. Therefore Locke's arguments for the existence of
external bodies are seen to be fallacious and, as we have already seen,
in discussing the characters of external bodies, he implies that we
have not merely an inferential but a direct knowledge of these independently
existing things. But so long as he explicitly adheres to
the position that we do not have a direct knowledge of external things;
that what we directly know is something different and belonging to
the class of ideas, he is quite unable to meet Berkeley's criticisms;
and the position that we know only ideas is so far established. Locke
himself says that we have ideas of material bodies and substances and
if this does not simply mean that we know these things and hence that
they are ideas in our minds just as much as anything else that we know,
then Locke is using the term “idea” ambiguously and is bound to fall
into difficulties. If, on the other hand, he had maintained that we do
know external bodies directly and that what we directly know is by no
means bound to be in our minds, then he could have worked out a position
for which it would have been much more difficult to answer. In fact
the sole issue would have been the essentially perceived nature of
what is perceived; so that if an answer to Berkeley is to be supplied,
the conception of ideas must be dispensed with, and what Berkeley has
shown is that we cannot work out a consistent theory in which both
ideas and things figure.