Paul Coates

Experiences of all kinds have a distinctive character, which marks them out as intrinsically different from states of consciousness such as thinking. A plausible view is that the difference should be accounted for by the fact that, in having an experience, the subject is somehow immediately aware of a range of phenomenal qualities. For example, in seeing, grasping and tasting an apple, the subject may be aware of a red and green spherical shape, a certain feeling of smoothness to touch, and a sweet sensation. Such phenomenal qualities are also immediately present in hallucinations. According to the sense-data theory, phenomenal qualities belong to items called “sense-data.” In having a perceptual experience the subject is directly aware of, or acquainted with, a sense-datum, even if the experience is illusory or hallucinatory. The sense-datum is an object immediately present in experience. It has the qualities it appears to have

In this paper I introduce and critically examine a paradox about perceiving that is in some ways analogous to the paradox about meaning which Kripke puts forward in his exegesis of Wittgenstein's views on Rule-following. When applied to vision, the paradox of perceiving raises a metaphysical scepticism about which object a person is seeing if he looks, for example, at an apple on a tree directly in front of him. Physical objects can be seen when their appearance is distorted in various ways by illusions. The question therefore arises as to how can we answer the sceptic who suggests the following: although the viewer appears to be seeing the green apple in front of him, he is actually suffering a bizarre illusion of a blue car situated somewhere behind him. The sceptic is not concerned with epistemic problems about how we know which object, if any, the subject is seeing; the sceptic is raising the more fundamental question: whatfact of the matter underlies a person's perceptual relation to the physical world, in virtue of which that person may be justified in arriving at a perceptual belief about the environment? Among the various different issues raised by the sceptic, I focus on the question: what determines the perceiving relation? I canvass a number of possible proposals in answer to it, concentrating mainly on two opposed accounts: the Disjunctive View and the Causal Theory of Perception. I argue in particular for the following two claims: that the paradox highlights the fact that the Disjunctive View fails to provide a coherent positive account of what perceiving is. that the problem of 'deviant causal chains', often thought to raise particular difficulties for the Causal theorist, can also be raised against other accounts of perception, including versions of the Disjunctive View. I conclude that unless the Causal Theory of Perception can be upheld, there will be no way of answering the sceptic.