Abstract

In the Aristotelian curriculum, De anima or the study of the soul fell under the rubric of physics. This area of study covered the vital (“vegetative”), sensitive, and rational powers of the soul. Descartes’ substance dualism restricted reason or intellect, and conscious sensation, to human minds. Having denied mind to nonhuman animals, Descartes was required to explain all animal behavior using material mechanisms possessing only the properties of size, shape, position, and motion. Within the framework of certainty provided by the metaphysical foundations of his physics, he posited such mechanisms in accordance with appropriately lessened standards of certainty. As Cartesianism (or the Cartesian revolution) spread, adherents offered survey textbooks or treatises of physics to replace the corresponding Aristotelian curriculum. These books typically discussed the role of experience in physics and the appropriate standard of certainty. A comprehensive Cartesian natural philosophy needed to mechanize the offices of the Aristotelian sensitive soul, including sense perception, memory, and cognitive and appetitive responses to the environment. Descartes’ Treatise on Man (1664) offered an initial explanatory program. This chapter examines the role of experience in the natural philosophy and mechanistic psychology of Descartes’ English follower Antoine Le Grand. He offered detailed accounts of the sensory and motor mechanisms shared by human and nonhuman animals (for which he claimed “physical certainty”). These frame his Cartesian psychology.