The article argues that light itself is invisible and serves only as the medium for sight, not its object. This view, traced to Aristotle and Alhazen, holds that colors are independent of light, which merely enables their visibility. The author contends that this invisibility resolves problems with color constancy—the perception of stable object colors despite changing illumination. Traditional theories explain constancy by the visual system discounting the illuminant's chromatic component, but if light is colorless, no such component exists. Drawing on Husserl's perspectivism, the author proposes that color variations under different lights are perspectival presentations of a single color, analogous to spatial shape variations. This approach avoids difficulties faced by color relationalism, reflectance physicalism, and enactivism.
Smell and taste, unlike vision, touch, and hearing, are directly oriented toward stuffs rather than individual objects. Stuff constitutes an irreducible ontological category distinct from both individuals and universals. Chemistry itself is best understood as a science of stuffs rather than of atoms or molecules. The distinctive phenomenology of smell and taste—including mixture, concentration, and the sense of presence—is best explained by a stuff theory of their proper objects. This view has implications for how to individuate the senses of smell and taste.