Life as "self-motion": Descartes

DESCARTES'S ARGUMENTS THAT THE BODY can be considered a selfpropelled machine rely on a misuse of the Aristotelian concept of "self-motion." They depend upon the premise that life is self-motion, the Aristotelian definition which Descartes learned from Latin handbooks at La F16che. By retaining this premise, Descartes believed he was defeating the Aristotelians on their own turf when he argued that soul is unnecessary for explaining life functions (self-motion). However, his arguments fail to establish what he intended them to, because whereas Aristotle meant the capacity for self-induced alteration (qualitative motion), Descartes interpreted "self-motion" as a reference to the local motions of the constitutive parts of a body. That this was a misunderstanding, and not simply a disagreement with Aristotle's meaning, can be demonstrated from the Meditations, the Discourse, the Treatise on Man, the Passions of the Soul, The World, and the letters. Owing to this misinterpretation, Descartes never actually addressed the Aristotelian theory, and so his physics leaves unresolved a problem that Aristotle is able to solve by positing the soul as the life of the body, namely: Why do some things metabolize, but others do not? Surprisingly, these points have not yet been made. Though Des Chene has recently drawn attention to the question of "life" in Descartes, he has not noticed this.1 Michael Frede has noted that from