ABSTRACT
A key Cartesian doctrine is the claim that ideas are the materials of knowledge; ideas are contained in the mind and can be surveyed there by their owner. The author examines this doctrine in this chapter as the foundation for John Locke's philosophy of mind. Rene Descartes promises to prove the mind's distinctness from the body. The distinctness of mind's nature will provide a measure of its complete difference from body. Descartes attempts to solve the puzzle of how one might know that another mind exists by offering criteria for inferring mind from the activities of a human body. Since no animal could satisfy the criteria for having reason or soul, all animals are machines, acting only in accordance with "the disposition of their organs". Descartes's view here is, of course, consistent with the claim that the mind is in a space of its own, absolutely distinct from the body.
