18. VI. Putting them for the real Essences of Substances.

It is true the names of substances would be much more useful, and
propositions made in them much more certain, were the real essences of
substances the ideas in our minds which those words signified. And it
is for want of those real essences that our words convey so little
knowledge or certainty in our discourses about them; and therefore the
mind, to remove that imperfection as much as it can, makes them, by a
secret supposition, to stand for a thing having that real essence, as if
thereby it made some nearer approaches to it. For, though the word MAN
or GOLD signify nothing truly but a complex idea of properties united
together in one sort of substances; yet there is scarce anybody, in the
use of these words, but often supposes each of those names to stand for
a thing having the real essence on which these properties depend. Which
is so far from diminishing the imperfection of our words, that by a
plain abuse it adds to it, when we would make them stand for something,
which, not being in our complex idea, the name we use can no ways be the
sign of.


19. Hence we think Change of our Complex Ideas of Substances not to
change their Species.

This shows us the reason why in MIXED MODES any of the ideas that make
the composition of the complex one being left out or changed, it is
allowed to be another thing, i.e. to be of another species, as is plain
in CHANCE-MEDLEY, MANSLAUGHTER, MURDER, PARRICIDE, &c. The reason
whereof is, because the complex idea signified by that name is the real