Abstract

This chapter formulates the problem of perception, which Locke sometimes dismisses but eventually tries to solve. The formulation hinges on the “argument from the multiple possible causes of any perceptual experience,” which shows that no physical thing can be “immediately perceived,” i.e., known to exist solely on the basis of one’s current perceptual experience. This conclusion generates a regress, since any experience one might appeal to for corroboration also has multiple possible causes. The problem can’t be avoided simply by adopting a two-term rather than a three-term theory of perception, because perceptual experiences can be phenomenologically indistinguishable whether they are caused by a physical object affecting one’s sense-receptors or caused otherwise. This has led to the traditional question: can knowledge of physical things be legitimately inferred from knowledge of immediately perceived ideas, sensations, or “sense-data” (on a three-term theory), or of ways of being “appeared to” (on a two-term theory)?