13. They are the workmanship of the understanding, but have their foundation in the similitude of things.
I would
not here be thought to forget, much less to deny, that Nature, in the production of things, makes several of them
alike: there is nothing more obvious, especially in the race of animals, and all things propagated by seed. But yet I
think we may say, the sorting of them under names is the workmanship of the understanding, taking occasion,
from the similitude it observes amongst them, to make abstract general ideas, and set them up in the mind, with
names annexed to them, as patterns or forms, (for, in that sense, the word form has a very proper signification,) to
which as particular things existing are found to agree, so they come to be of that species, have that denomination,
or are put into that classis. For when we say this is a man, that a horse; this justice, that cruelty; this a watch, that a
jack; what do we else but rank things under different specific names, as agreeing to those abstract ideas, of which
we have made those names the signs? And what are the essences of those species set out and marked by names,
but those abstract ideas in the mind; which are, as it were, the bonds between particular things that exist, and the
names they are to be ranked under? And when general names have any connexion with particular beings, these
abstract ideas are the medium that unites them: so that the essences of species, as distinguished and denominated
by us, neither are nor can be anything but those precise abstract ideas we have in our minds. And therefore the
supposed real essences of substances, if different from our abstract ideas, cannot be the essences of the species we
rank things into. For two species may be one, as rationally as two different essences be the essence of one species:
and I demand what are the alterations [which] may, or may not be made in a horse or lead, without making either
of them to be of another species? In determining the species of things by our abstract ideas, this is easy to resolve:
but if any one will regulate himself herein by supposed real essences, he will, I suppose, be at a loss: and he will
never be able to know when anything precisely ceases to be of the species of a horse or lead.
