The bodies of Descartes’ hypothetical men are nothing but machines: “I suppose the body to be nothing but a statue or machine made of earth, which God forms with the explicit intention of making it as much as possible like us” (AT XI:120, CSM I:99). The working of these bodies can be explained in purely mechanical terms. Descartes tried to show that such a mechanical account can include much more than one might expect because it can provide an explanation of “the digestion of food, the beating of the heart and arteries, the nourishment and growth of the limbs, respiration, waking and sleeping, the reception by the external sense organs of light, sounds, smells, tastes, heat and other such qualities, the imprinting of the ideas of these qualities in the organ of the ‘common’ sense and the imagination, the retention or stamping of these ideas in the memory, the internal movements of the appetites and passions, and finally the external movements of all the limbs” (AT XI:201, CSM I:108). In scholastic philosophy, these activities were explained by referring to the soul, but Descartes proudly pointed out that he did not have to invoke this notion: “it is not necessary to conceive of this machine as having any vegetative or sensitive soul or other principle of movement and life, apart from its blood and its spirits, which are agitated by the heat of the fire burning continuously in its heart—a fire which has the same nature as all the fires that occur in inanimate bodies” (AT XI:201, CSM I:108).