Note (return) — Chapter VI

The answer of common sense is that we are immediately conscious, in perception, of an ego and a non-ego known together, and known in contrast to each other; we are conscious of a perceiving subject, and of an external reality, as the object perceived. 244 To state this doctrine of natural realism still more explicitly we add, that we are conscious of the immediate perception of certain essential attributes of matter objectively existing. Of these primary qualities, which are immediately perceived as real and objectively existing, we mention extension in space and resistance to muscular effort, with which is indissolubly associated the idea of externality. It is true that extension and resistance are only qualities, but it is equally true that they are qualities of something, and of something which is external to ourselves. Let any one attempt to conceive of extension without something which is extended, or of resistance apart from something which offers resistance, and he will be convinced that we can never know qualities without knowing substance, just as we can not know substance without knowing qualities. This, indeed, is admitted by Mr. Mill. 245 And if this be admitted, it must certainly be absurd to speak of substance as something "unknown." Substance is known just as much as quality is known, no less and no more.