The notion that there is a category mistake or some other conceptual confusion in regarding seeing, hearing, and other forms of perception as events, states, or processes is incorrect. Ryle's analysis of “seeing” as an achievement word does not rule out our regarding seeing as an event, but in fact suggests that we do so when we carry the analysis beyond the point where Ryle leaves it. Furthermore there are uses of “see” not noticed by Ryle which justify our saying that within certain contexts seeing is a state and within other contexts a process. The question of what these events, states, and processes are cannot be met without recognizing a fundamental duality of aspect that characterizes perception. This duality can be formulated in terms of the way perception is known. One who observes a perceiver knows the perceiver's perception in a categorically different way than the perceiver knows it. From this it can be seen that perceptual events, states, and processes have both a physical aspect and an epistemological aspect. Any attempt to reduce one of these aspects to the other would involve a category mistake.