accidents: another illustration of the truth that all created perfection is only relative, not absolute. To the notion of “inherence” we shall return in connexion with our treatment of accidents (65). (_b_) Again, substance is wrongly conceived as an _inert_ substratum underlying accidents. This false notion appears to have originated with Descartes: he conceived the two great classes of created substances, matter and spirit, as essentially inert. For him, matter is simply a _res extensa_; extension in three dimensions constitutes its essence, and extension is of course inert: all motion is given to matter and conserved in it by God. Spirit or soul is simply a _res cogitans_, a being whose essence is thought; but in thinking spirit too is passive, for it simply receives ideas as wax does the impress of a seal. Nay, even when soul or spirit wills it is really inert or passive, for God puts all its volitions into it.(241) From these erroneous conceptions the earlier disciples of Descartes took the obvious step forward into Occasionalism; and to them likewise may be traced the conviction of many contemporary philosophers that the human soul—a being that is so eminently vital and active—cannot possibly be a substance: neither indeed could it be, if substance were anything like what Descartes conceived it to be. The German philosophers, Wundt and Paulsen, for example, argue that the soul cannot be a substance. But when we inquire what they mean by substance, what do we find? That with them the concept of substance applies only to the _corporeal_ universe, where it properly signifies the atoms which are “the absolutely permanent substratum, qualitatively and quantitatively unchangeable, of all corporeal reality”.(242) No wonder they would argue that the soul is not a substance! No actually existing substance is inert. What is true, however, is this, that when we conceive a being as a substance, when we think of it under the abstract concept of substance, we of course abstract from its concrete existence as an active agent; in other words we consider it not from the _dynamic_, but from the _static_ aspect, not as it is in the concrete, but as constituting an object of abstract thought: and so the error of Descartes seems to have been that already referred to,—the mistake of transferring to the real order conditions that obtain only in the logical order.