Descartes's Theory of Distinction

In the first part of this paper I explore the relations among distinctness, separability, number, and non-identity. I argue that Descartes believes plurality in things themselves arises from distinction, so that things distinct in any of the three ways are not identical. The only exception concerns universals which, considered in things themselves, are identical to particulars. I also argue that to be distinct is to be separable. Things distinct by reason are separable only in thought by means of ideas not clear and distinct. In the second part I argue that the notion of separability in Descartes's account of real distinction between mind and body is subject to five different interpretations. I claim that the heart of Cartesian dualism concerns the separability of the attributes thought and extension. It does not require that mind and body are separable in the sense that each can exist without the other existing.