Knowing that one wants to go to the movies is an example of self-knowledge, knowledge of one’s mental states. It may be foolish to ask the man on the Clapham Omnibus how he knows what he wants, but the question is nonetheless important – albeit neglected by epistemologists. This chapter attempts an answer.

Before getting to that, the familiar claim that we enjoy “privileged access” to our mental states needs untwining (section 1). A sketch of a theory of knowledge of one’s beliefs that has received some attention in the recent literature (section 2), and the case for extending that account to self-knowledge in general (section 3), sets the stage for our answer to the main question (section 4).