In very general terms, perception is a response to the world. The paradigm cases of it are responses by the five senses: we see, hear, touch, taste, taste, and smell. But we also have an awareness of states of our own body, such as the position and movement of our limbs, and that awareness is at once similar in character to perception yet not dependent on the five senses. There is a third kind of awareness, one that is distinct, at least conceptually, from our awareness of our bodily condition and movements; its object is our own mental states. The first — ordinary perception — has been called exteroception ("outer perception"), the second interoception ("inner perception") or, in a special case, proprioception, though taking this term generically in the sense of "self-perception' we might conveniently use it to designate the third case, in which the object of awareness is mental. All three are important for this study, particularly the first and third. Under the more general rubrics of perception and introspection (or self-consciousness), these are perennially basic topics in epistemology, construed as the theory of knowledge and justification.