  Thus Spinoza identifies human desire with human essence and especially with consciousness of one’s essence, the striving for perseverance in being. Spinoza’s theory of consciousness is notoriously difficult, and it is not clear which ideas in a human mind are conscious or the extent to which things other than human beings have consciousness. For human beings, at least, however, what seems to us to cause us to act, our desire, does, on Spinoza’s view, do just that. If I am asked for the proximate cause of my action in picking up my coffee cup, for example, I will respond that it was my desire for the coffee. In identifying the cause of human action, striving, with conscious desire, then, IIIp9s vindicates common sense to a degree. Had Spinoza identified desire with something other than striving, then he would have committed himself to the view that my desire does not in fact cause me to pick up the cup. (Desire for Spinoza, in its narrow definition at IIIp9s, is both psychological and physical, and in its broader definition at III, Definitions of the Affects I, it may be either. This example therefore, perhaps despite appearances, need not run afoul of Spinoza’s denial of mind-body interaction.)