 Block (1995), like many other writers, fails to distinguish WIL properties from sensory qualities. But Carruthers (2000) elaborates nicely on the distinction: A quality in the first-order sense presents itself as part of the world, not as part of one’s mind. It is, e.g., the apparent color of an apparently physical object (or, if you are a Russellian, the color of a sense-datum that you happen to have encountered as an object of consciousness). A sensory quality is what the world is or seems like. But what it is like to experience that color is what your first-order perceptual state is like, intrinsically mental and experienced as such.