than where a man goes to explain his terms to one who is supposed or
declares himself not to understand him; and then it teaches only the
signification of that word, and the use of that sign.


8. But adds no real Knowledge.

We can know then the truth of two sorts of propositions with perfect
certainty. The one is, of those trifling propositions which have
a certainty in them, but it is only a verbal certainty, but not
instructive. And, secondly, we can know the truth, and so may be certain
in propositions, which affirm something of another, which is a necessary
consequence of its precise complex idea, but not contained in it: as
that, the external angle of all triangles is bigger than either of the
opposite internal angles. Which relation of the outward angle to either
of the opposite internal angles, making no part of the complex idea
signified by the name triangle, this is a real truth, and conveys with
it instructive real knowledge.


9. General Propositions concerning Substances are often trifling.

We having little or no knowledge of what combinations there be of simple
ideas existing together in substances, but by our senses, we cannot make
any universal certain propositions concerning them, any further than our
nominal essences lead us. Which being to a very few and inconsiderable
truths, in respect of those which depend on their real constitutions,
the general propositions that are made about substances, if they are
certain, are for the most part but trifling; and if they are
instructive, are uncertain, and such as we can have no knowledge of