 In fact, it would seem that there can be incompatibilities even within a perceptual modality. Thus, Tye (2003: 38–39) notes that there are pictures that depict impossible situations. He also discusses the waterfall effect, in which, after staring at a waterfall for some time, if one looks at the adjacent rock face, a portion of the rock surface will appear to be moving—and not moving (relative to the area around it; not everyone accepts that both elements are simultaneously present in the waterfall illusion; see Crane 1988). These examples suggest that we can have unified consciousness of pretty much any collection of items whatsoever, no matter how they are related to one another. Indeed, it is not easy to specify any relation among unified contents or acts of experiencing (beyond their being unified) that is required for them to be unified. If so, Hurley’s (1998) suggestion that meeting a normative requirement is necessary for unified consciousness, specifically, a requirement that the experienced properties of things in unified consciousness cohere semantically, is in trouble. 