principles, resembles that antiquated and so much ridiculed notion of
MATERIA PRIMA, to be met with in Aristotle and his followers. Without
extension solidity cannot be conceived; since therefore it has been shown
that extension exists not in an unthinking substance, the same must also
be true of solidity.

12. That NUMBER is entirely THE CREATURE OF THE MIND, even though the
other qualities be allowed to exist without, will be evident to whoever
considers that the same thing bears a different denomination of number as
the mind views it with different respects. Thus, the same extension is
one, or three, or thirty-six, according as the mind considers it with
reference to a yard, a foot, or an inch. Number is so visibly relative,
and dependent on men's understanding, that it is strange to think how any
one should give it an absolute existence without the mind. We say one
book, one page, one line, etc.; all these are equally units, though some
contain several of the others. And in each instance, it is plain, the
unit relates to some particular combination of ideas arbitrarily put
together by the mind.

13. UNITY I know some will have to be A SIMPLE OR UNCOMPOUNDED IDEA,
accompanying all other ideas into the mind. That I have any such idea
answering the word UNITY I do not find; and if I had, methinks I could
not miss finding it: on the contrary, it should be the most familiar to
my understanding, since it is said to accompany all other ideas, and to
be perceived by all the ways of sensation and reflexion. To say no more,
it is an ABSTRACT IDEA.

14. A THIRD ARGUMENT AD HOMINEM.--I shall farther add, that, after
the same manner as modern philosophers prove certain sensible
qualities to have no existence in Matter, or without the mind,