When and Why to Trust One’s Senses and Memory

Abstract

One’s knowledge of a fact is either inferential or non-inferential, and either fallible or infallible, depending on the sort of externally conclusive justification one has for claiming to know it. All one’s inferential knowledge of contingent facts in the world outside one’s current state of consciousness is justified ultimately by one’s non-inferential knowledge. Although infallible knowledge (of necessary truths and of one’s current states of consciousness) comes into it, the principal part of this non-inferential basis of one’s knowledge of the `external’ world is formed by one’s fallible non-inferential knowledge. This fallible non-inferential knowledge consists of one’s non-inferential knowledge of one’s current perceptions of directly specifiable appearances of things around one (direct perceptions, let us call them) and of one’s memory knowledge (retained and original, of previous perceptions and of other sorts of facts, including general facts).