He would be thought to do little lens than trifle,
who, for the enlightening the understanding in any
part of knowledge, should be busy with identical pro-
positions, and insist on such maxims as these: sub-
stance is substance, and body is body ; a vacuum is a
Vacuum, and a vortex is a vortex; a centaur is a
centaur, and a chimera is a chimera, &c. For these
and all such are equally true, equally certain, and
equally self-evident. But yet they cannot but be counted
trifling, when made use of as principles of instruction^
and stress laid on them, as helps to knowledge : since
they teach nothing but what every one, who is capable
of discourse, knows without being told ; viz. that the
same tie^m is the same term, and the same idea the
same idea. And upon this account it was that I
formerly did, and do still think, the offering and in-
culcating such propositions, in order to give the un-
derstanding any new light or inlet into the knowledge
of things, no better than trifling. >

Instruction lies in something very different ; and he
that would enlarge his own, or another's mind, to
truths he does hot yet know, must find ojit inter*
mediate ideas, and then lay them in such order one by
another, that the understanding may ^e the agree-
ment or disagreement of those in questioir. Proposi-



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4<( IV^ing Propodthni. Book *•

tbns that do this are instructihre; but they are far
from such as affirm the same term of itself: which is
no way to advance one's self or others in any sort of
knowledge. It no more helps to that^ than it would
help any one^ in his learning to read^ to have such
propositions as these inculcated to him. An A is an
A^ and a B is a B ; which a man may know as well as
any schoolmaster^ and yet never be able to read a word
as long as he lives. Nor do these, or any such identical
propositions, help him one jot forwards in the skill of
reading, let him make what use of them he can.
