 Interestingly, Descartes would agree that experiential resources cannot solve the problem. By the Sixth Meditation, however, Descartes purports to have the innate resources he needs to solve it – notably, innate ideas of mind and body. Among the metaphysical theses he develops is that mind and body have wholly distinct essences: the essence of thinking substance is pure thought; the essence of body is pure extension. In a remarkable maneuver, Descartes invokes this distinction to refute the sceptical worry that sensations are produced by a subconscious faculty of the mind: “nothing can be in me, that is to say, in my mind, of which I am not aware,” and this “follows from the fact that the soul is distinct from the body and that its essence is to think” (13 Dec 1640 letter to Mersenne, AT 3:273, CSMK 165f). This result allows Descartes to supplement the involuntariness argument, thereby strengthening the inference. For from the additional premise that nothing can be in my mind of which I am unaware, it follows that if sensations were being produced by some activity in my mind, I’d be aware of that activity on the occasion of its operation. Since I’m not thus aware, it follows that the sensation I’m having is produced by a cause external to my mind. As Descartes writes, this cause