Abstract

Rene Descartes's argument begins from one obviously true premise that (at the time when he was considering this argument) Descartes is thinking. It then proceeds by means of two principles about what is “conceivable” to the conclusion that Descartes is essentially “a thinking substance distinct from his body, which he calls his 'soul'”. This chapter looks in more detail at Descartes's argument. It explains some of the terminology which Descartes uses. Descartes consists of two parts ‐ an essential part (his soul) and an inessential part (his body). And, Descartes would add, what applies to Descartes, applies to all other humans. Hence substance dualism ‐ humans consist of two substances, a soul (the essential part) and a body (the inessential part). The chapter illustrates how there can be Descartes's propositions whose metaphysical modality differs from their logical modality.