This thesis argues that certain kinds of our beliefs and desires—what I call “peripheral attitudes”—are expressions of rational agency. In addition, I argue that knowing about these kinds of states self-interpretively (on the basis of evidence, such as our thoughts, feelings and behaviour) is a feature of being a functional rational agent. I seek to account for self-knowledge—our ability to correctly identify mental states that we undergo—in a way that respects key intuitions of both the interpretationist and agentialist positions. For the agentialist, self-knowledge is importantly distinct from other-knowledge—the knowledge we have of the external world, where this includes the mental states of others. In contrast, for the interpretationis...