In the letter to the Sorbonne that prefaces the Meditations Descartes writes that whereas “many people have considered that it is not easy to discover [the soul's] nature” he thinks the nature and existence of the soul are matters capable of demonstration, that is, they are knowable with the utmost certainty (AT.VII.3; CSM.II.4). He concludes the synopsis by declaring his intention to prove that “knowledge of our own minds and of God … are the most certain and evident of all possible objects of knowledge for the human intellect” (AT.VII.16; CSM.II.11).

These passages, together with the fact that he subtitles the Second Meditation “The Nature of the Human Mind, and How it is Better Known than the Body”, strongly suggest that Descartes thinks self-knowledge of some kind is within the grasp of anyone who makes the effort to reflect and find it. But what sorts of self-knowledge does Descartes think possible? Does he take himself to have knowledge of his existence and essential nature? Does he think that it is possible to obtain knowledge of the contents and capacities of one's own individual mind?

Interwoven with these questions is another question: what does Descartes regard as the referent of the word “self” and also the words “mind”, “soul” and “human person or man”? In other words, what is the self whose selfknowledge is in question?