with this hypothesis; since it is as impossible that two things
partaking exactly of the same real essence should have different
properties, as that two figures partaking of the same real essence of a
circle should have different properties. But were there no other reason
against it, yet the supposition of essences that cannot be known; and
the making of them, nevertheless, to be that which distinguishes the
species of things, is so wholly useless and unserviceable to any part of
our knowledge, that that alone were sufficient to make us lay it by, and
content ourselves with such essences of the sorts or species of things
as come within the reach of our knowledge: which, when seriously
considered, will be found, as I have said, to be nothing else but, those
ABSTRACT complex ideas to which we have annexed distinct general names.


18. Real and nominal Essence

Essences being thus distinguished into nominal and real, we may further
observe, that, in the species of simple ideas and modes, they are always
the same; but in substances always quite different. Thus, a figure
including a space between three lines, is the real as well as nominal
essence of a triangle; it being not only the abstract idea to which the
general name is annexed, but the very ESSENTIA or being of the thing
itself; that foundation from which all its properties flow, and to which
they are all inseparably annexed. But it is far otherwise concerning
that parcel of matter which makes the ring on my finger; wherein these
two essences are apparently different. For, it is the real constitution
of its insensible parts, on which depend all those properties of colour,
weight, fusibility, fixedness, &c., which are to be found in it; which
constitution we know not, and so, having no particular idea of, having
no name that is the sign of it. But yet it is its colour, weight,