We perceive the world as organized in certain ways. The scene in front of you consists of arrangements of objects, each having shapes, sizes, colors, textures, and so on. A large part of the philosophy of perception is dedicated to better understanding how perception delivers the complex world that one represents. At the same time, there is good reason to think that perceptual states are themselves complex. You do not just perceive a table as having parts. When you perceive the table, the state you are in itself has parts-states of perceiving the sizes, shapes, and colors of the tabletop and of the legs. These perceptual states themselves have parts. The idea that perceptual states have parts that can combine and recombine in rulegoverned ways pervades much of contemporary psychology. Over the last century, perceptual psychologists have closely investigated the ways in which our perceptual states are structured.