Introduction

Perception, or what we think of as perception, is studied by both science and philosophy. That there are significant theoretical questions about perception which scientific study of it leaves unanswered is something which needs both a justification to be accepted and an explanation as to how it is possible. I shall not attempt to provide either justification or explanation here, but it is to be expected, surely, that the existence of philosophical questions (if they do exist) derives, in part at least, from the existence of intelligible and interesting categories, in terms of which we wish to frame questions about perception, which questions, because of some feature of those categories, do not belong to science in the ordinary sense.

This is one reason why it has an importance which cannot be exaggerated to ensure that the categories in terms of which philosophers incline to discuss perception are in good conceptual order. One sort of philosophical question can be called compositional: what are the ingredients in, what elements compose, the perceptual relation? The sound categories that are needed here are those for candidate ingredients. However, a second sort of traditional question has been, or appears to have been, functional. Do our perceptual experiences enable us to directly perceive external objects? How should we interpret that question? Is it in good conceptual order?