KNOWLEDGE AND CERTAINTY 论文

摘要

What is the connection between knowledge and certainty? The question is vexed, in part because there are at least two distinct senses of “certainty”. According to the first sense, subjective certainty, one is certain of a proposition if and only if one has the highest degree of confidence in its truth. According to the second sense of “certainty”, which we may call epistemic certainty, one is certain of a proposition p if and only if one knows that p (or is in a position to know that p) on the basis of evidence that gives one the highest degree of justification for one’s belief that p. The thesis that knowledge requires certainty in either of these two senses has been the basis for skeptical arguments. For example, according to one kind of skeptical argument, knowledge requires epistemic certainty, and being epistemically certain of a proposition requires having independent evidence that logically entails that proposition. Since we do not have such evidence for external world propositions, we do not know external world propositions. According to another kind of skeptical argument, due to Peter Unger (1975), knowledge