Since nothing can be called gold but what has a conformity of qualities to that abstract complex idea to which that name is annexed.

But this distinction of essences, belonging particularly to substances, we shall, when we come to consider their names, have an occasion to treat of more fully.
19.

Essences ingenerable and incorruptible.
That such abstract ideas, with names to them, as we have been speaking of are essences, may further appear by what we are told concerning essences, viz.

that they are all ingenerable and incorruptible.

Which cannot be true of the real constitutions of things, which begin and perish with them.