Descartes and Other Minds

Descartes's distinction between material and thinking substance gives rise to a question both about our knowledge of the external world and about our knowledge of another mind. Descartes says surprinsingly little about this second question. In the Second Meditation he writes of our (single) judgement that the figures outside his window are men and not automatic machines. It is argued in this paper that to think of judgement as operating in this way is to overlook the fact that, given the Cartesian metaphysics, our judgement here is susceptible of double error. I may be in error that the figure before me is a human being; and I may be in error that the figure before me has a mind. It is suggested that one reason for Descartes overlooking the possibility of this double error is his assumption that, of corporeal beings, all and only human animals have minds. It is also argued that the suggestion that Descartes overlooks the possibility of a double error here is supported by his proposal, in Discourse V, of a “test of a real man”: the other's use of language.