ns, and powers are owing to something
without them; and there is not so complete and perfect a part that we
know of nature, which does not owe the being it has, and the excellences
of it, to its neighbours; and we must not confine our thoughts within
the surface of any body, but look a great deal further, to comprehend
perfectly those qualities that are in it.

12. Our nominal essences of Substances furnish few universal
propositions about them that are certain.

If this be so, it is not to be wondered that we have very imperfect
ideas of substances, and that the real essences, on which depend their
properties and operations, are unknown to us. We cannot discover so much
as that size, figure, and texture of their minute and active parts,
which is really in much less the different motions and impulses made in
and upon them by bodies from without, upon which depends, and by which
is formed the greatest and most remarkable part of those qualities we
observe in them, and of which our complex ideas of them are made up.
This consideration alone is enough to put an end to all our hopes of
ever having the ideas of their real essences; which whilst we want, the
nominal essences we make use of instead of them will be able to
furnish us but very sparingly with any general knowledge, or universal
propositions capable of real certainty.

13. Judgment of Probability concerning Substances may reach further: but
that is not Knowledge.

We are not therefore to wonder, if certainty be to be found in very few
general propositions made concerning substances: our knowledge of their
qualities and properties goes very seldom further than our senses reach
and inform us. Possibly inquisitive and observing men may, by strength
of judgment, penetrate further, and, on probabilities taken from wary
observation, and hints well laid together, often guess right at what
experience has not yet discovered to them. But this is but guessing
still; it amounts only to opinion, and has not that certainty which is
requisite to knowledge. For all general knowledge lies only in our own
thoughts, and consists barely in the contemplation of our own abstract
ideas. Wherever we perceive any agreement or disagreement amongst them,
there we have general knowledge; and by putting the names of those ideas
together accordingly in propositions, can with certainty pronounce
general truths. But because the abstract ideas of substances, for
which their specific names