Mental Representation

Humans are surrounded by representations. Some of these occur naturally—for example, tree rings and footprints—while others are artificial—for example, words and photographs. Whatever their origins, all share a fundamental feature: they stand for something. Tree rings stand for the age of the tree; footprints stand for the entity that made them; a photograph stands for that which it pictures; and a proper name stands for the person so named.

There is considerable evidence that representations are not confined to the external world; they figure in people's mental lives as well. Perceptual illusions provide intuitive motivation: a straight oar in water appears bent, amputees may experience "phantom" tactile sensations in a missing limb, and some series of tones sound as if they are continually rising in pitch. In each of these cases, it is natural to explain the phenomenon by positing mental representations (albeit incorrect ones).