ABSTRACT
Substance and real essence Sections II.xxiii.6-14 of the Essay constitute a single argument in which Locke explicitly brought together three ingredients of his theory: his characterization of the idea of substance as the unknown cause of the union of coexisting qualities and powers, his intimation that there is a general corporeal substance or stuff common to all sensible things, and
Some of the passages in which the two are explicitly distinguished have encouraged the unfortunate view that in Locke's mind, or in a part of his mind, the idea of substance is, after all, the notion of a naked logical subject distinct from all attributes, including essential attributes. Only in the 'real essence', it is supposed, did he offer something determinate enough to be knowable in principle, something which might figure in an ideal science and which is more than a grossly metaphysical 'x'. And it is true that he adverted more than once to what one modern commentator calls our 'twofold ignorance' of substance and of real essence.
