is a property of the one substance. Each in its sphere is the counterpart of the other. This is the meaning of the definition, "Soul is the Idea of Body". Soul is the counterpart within the sphere of the attribute of thought of that particular mode of the attribute of extension which we call the body. Such was the fate of Cartesianism. English Idealism had a different course. Berkeley had begun by denying the existence of material substance, which he reduced merely to a series of impressions in the sentient mind. Mind is the only substance. Hume finished the argument by dissolving mind itself into its phenomena, a loose collection of "impressions and ideas". The Sensist school (Condillac etc.) and the Associationists (Hartley, the Mills, and Bain) continued in similar fashion to regard the mind as constituted by its phenomena or "states", and the growth of modern positive psychology has tended to encourage this attitude. But to rest in Phenomenalism as a theory is impossible, as its ablest advocates themselves have seen. Thus J.S. Mill, while describing the mind as merely "a series [i.e. of conscious phenomena] aware of itself as a series", is forced to admit that such a conception involves an unresolved paradox. Again, W. James's assertion that "the passing thought is itself the Thinker", which "appropriates" all past thoughts in the "stream of consciousness", simply blinks the question. For surely there is something which in its turn "appropriates" the passing thought itself and the entire stream of past and future thoughts as well, viz. the self-conscious, self-asserting "I" the substantial ultimate of our mental life. To be ...