The
philosophy of perception is concerned with the nature of
perceptual experience and the status of perceptual data, in particular how they relate to beliefs about, or knowledge of, the world. Any explicit account of perception requires a commitment to one of a variety of
ontological or
metaphysical views. Philosophers distinguish
internalist accounts, which assume that perceptions of objects, and knowledge or beliefs about them, are aspects of an individual's mind, and
externalist accounts, which state that they constitute real aspects of the world external to the individual. The position of
naïve realism—the 'everyday' impression of physical objects constituting what is perceived—is to some extent contradicted by the occurrence of perceptual illusions and hallucinations and the relativity of perceptual experience as well as certain insights in science.
Realist conceptions include
phenomenalism and
direct and indirect realism.
Anti-realist conceptions include
idealism and
skepticism.