 We will consider two approaches to answering this question. The first is known as inference to the best explanation. Such inferences generate what is called explanatory coherence (see chapter 7 in Harman 1986). According to this approach, we must suppose you form a belief about the way the hat appears to you in your perceptual experiences, and a second belief to the effect that your perceptual experience, the hat’s looking blue to you, is best explained by the hypothesis that (H) is true. So the relevant set of beliefs is the following: