Descartes set for himself the ambitious program of accounting for the functions of the Aristotelian vegetative and sensitive souls without invoking souls or the faculties or powers of souls in his explanations. He rejects the notion that the soul is hylomorphically present in the organs of the body so as to carry out vital and sensory functions. Rather, the body’s organs operate in a purely mechanical fashion. That is what is involved in “mechanizing” these phenomena. The role of the soul (...) is restricted to properly mental functions: to the conscious aspects of sensations and other mental operations; to intellectual acts; and to acts of volition. In effect, soul becomes mind. In order to understand the extent of Descartes’ ambition, this chapter first considers more fully the functions attributed to the soul or to the vital faculties in the Aristotelian and Galenic traditions, and especially the functions of the sensitive soul or power. It draws attention to the cognitive aspects of these functions, beyond the mere operation of the external senses. Then it turns to Descartes’ mechanistic explanations for these cognitive functions. Finally, it situates Descartes’ new mechanistic psychology within the larger context of his novel anthropology, or theory of the human being. (shrink)