This chapter lays out the framework for our analysis of perception, including the philosophical assumptions we'll be making. We have mentioned some of the practical and theoretical reasons for wanting to know more about perception. And we have outlined three distinct, though complementary, ways of understanding perception: the psychological, biological, and theoretical approaches. Once that this general framework is in place, the next chapter begins to fill in the pieces, starting with some fundamentals about the organ we use for seeing-the eye. Although this book also covers hearing, taste, smell, and touch, it devotes more space to seeing. We know more about vision than the other senses, and we believe vision represents the richest source of environmental information. This preeminence of vision is mirrored in the proportion of the human brain devoted to vision.