Phenomenalism
Most philosophers have been led by the argument from illusion, by the causal argument, or by the introspective analysis advocated in the sense-datum theory to conclude that our immediate awareness in perception is not, as direct, or commonsense, realism claims, of material objects (of distinct, external physical entities perceptible by different persons at once) but of sensa (private, transitory, probably mental existents that may also be called sensations, sense data, ideas, representations, or impressions). Once this position is adopted, a serious difficulty arises concerning the nature and status of material objects. Representative realism claims that they exist external to us and cause the sensa or representations that correspond to them. The notorious difficulty of this view is that if all our direct awareness is concerned with the alleged effects, or sensa, how do we ever find out that material objects exist as their causes or what characteristics they possess? The theory seems to make material objects unobserved, and indeed unintelligible, causes of our perception. Although representative realism, especially in modern versions, tries to deal with this difficulty, it is still widely felt to be unsatisfactory. Therefore, alternative attempts have been made to deal with the problem of the nature of material objects.
This page contains 201 words.

Phenomenalism article
Read the rest of this article.
This article contains 5,154 words
(approx. 17 pages at 300 words per page).