I mean to present and defend a theory of sense perception—not, of course, a physiological theory or a psychological one, but a philosophical theory of sense perception. At the end of this opening chapter, I shall say something about what I take a theory of that kind to be. My remarks on this topic will be brief and dogmatic, for two reasons. First, an adequate discussion of it would embroil us in huge issues—for example, about the nature of philosophy: and I do not want to engage in metaphilosophical inquiries, but only in a philosophical one. And second,...

It does not seem possible to deny that the physiologist’s causal account of perception, as far as it goes and in its main lines, is correct. It cannot be denied that in the case of vision, for example, light rays reflected or emitted from objects enter the eyes of the perceiver and form images on his retinas, that electro-chemical signals are sent along the nerve fibres making up his optic nerves, and that the visual centers in his brain are thus stimulated. There is, of course, a tremendous amount that we do not yet know about what goes on in...

I have now presented the outline of a (philosophical) theory of perception. What I propose to do in the present chapter is to put some flesh on the bare bones of this theory, primarily by examining some of its implications. I shall also describe some experimental evidence, culled from the psychological literature, showing that many of these implications are fully borne out by the facts of sense perception. In this way, I hope to make clearer exactly what the theory amounts to, and at the same time to persuade the reader that he ought to accept it.

It seems to...

The broad outlines of our theory of perception, some of its consequences, and some of the experimental evidence that lends it a measure of support have now been presented. A complete exposition of the theory in all its details, and a full defense of it against all possible objections, are tasks that will not be undertaken in this book; such an effort, I suspect, would take us into virtually every field of philosophy. One must limit the scope of one’s investigations somewhere, and except for the two issues I shall be discussing in this final chapter, I propose to go...