ls, called by the same name, are, in
their internal constitution, as different one from another as several of
those which are ranked under different specific names. This supposition,
however, that the same precise and internal constitution goes always
with the same specific name, makes men forward to take those names for
the representatives of those real essences; though indeed they signify
nothing but the complex ideas they have in their minds when they use
them. So that, if I may so say, signifying one thing, and being supposed
for, or put in the place of another, they cannot but, in such a kind of
use, cause a great deal of uncertainty in men's discourses; especially
in those who have thoroughly imbibed the doctrine of SUBSTANTIAL
FORMS, whereby they firmly imagine the several species of things to be
determined and distinguished.

21. This Abuse contains two false Suppositions.

But however preposterous and absurd it be to make our names stand for
ideas we have not, or (which is all one) essences that we know not,
it being in effect to make our words the signs of nothing; yet it is
evident to any one who ever so little reflects on the use men make
of their words, that there is nothing more familiar. When a man asks
whether this or that thing he sees, let it be a drill, or a monstrous
foetus, be a MAN or no; it is evident the question is not, Whether that
particular thing agree to his complex idea expressed by the name man:
but whether it has in it the real essence of a species of things which
he supposes his name man to stand for. In which way of using the names
of substances, there are these false suppositions contained:--

First, that there are certain precise essences according to which nature
makes all particular things, and by which they are distinguished into
species. That everything has a real constitution, whereby it is what it
is, and on which its sensible qualities depend, is past doubt: but I
think it has been proved that this makes not the distinction of species
as WE rank them, nor the boundaries of their names.

Secondly, this tacitly also insinuates, as if we had IDEAS of these
proposed essences. For to what purpose else is it, to inquire whether
this or that thing have the real essence of the species man, if we did
not suppose that there were such a specifick essence known? Which yet
is utterly false. And therefore such application of names as would make
them stand for ideas which we have not, mu