orth be no red and blue, no hot and cold;
but things would still be big or small, round or square, solid or
fluid. Yet, even with these 'primary qualities' the reference to mind
is really there just as much as in the case of the secondary qualities;
only the fact is not quite so obvious. And one reason for this is that
these primary qualities involve, much more glaringly and unmistakably
than the secondary, something which is not _mere_ sensation--something
which {10} implies thought and not mere sense. What do we mean by
solidity, for instance? We mean partly that we get certain sensations
from touching the object--sensations of touch and sensations of what is
called the muscular sense, sensations of muscular exertion and of
pressure resisted. Now, so far as that is what solidity means, it is
clear that the quality in question involves as direct a reference to
our subjective feelings as the secondary qualities of colour and sound.
But something more than this is implied in our idea of solidity. We
think of external objects as occupying space. And spaciality cannot be
analysed away into mere feelings of ours. The feelings of touch which
we derive from an object come to us one after the other. No mental
reflection upon sensations which come one after the other in time could
ever give us the idea of space, if they were not spacially related from
the first. It is of the essence of spaciality that the parts of the
object shall be thought of as existing side by side, outside one
another. But this side-by-sideness, this outsideness, is after all a
way in which the things present themselves to a mind. Space is made up
of relations; and what is the meaning of relations apart from a mind
which relates, or _for_ which the things are related? If spaciality
were a quality of the thing in itself, it would exist no matter what
became of other things. It would be quite possible, therefore, {11}
that the top of this table should exist without the bottom: yet
everybody surely would admit the meaninglessness of talking about a
piece of matter (no matter how small, be it an atom or the smallest
electron conceived by the most recent physical speculation) which had a
top without a bottom, or a right-hand side without a left. This
space-occupying quality which is the most fundamental element in our
ordinary conception of matter is wholly made up of the relation of one
part of it to another. Now can a relation exist except for a