Contextualism and the Semantics of Knowledge Claims

Epistemic contextualism is, at its core, a semantic thesis about the word "know" rather than a first-order theory of what makes belief justified. It holds that the truth conditions of sentences of the form "S knows that p" vary systematically with the conversational context in which the sentence is uttered or evaluated, because the epistemic standard that "knows" invokes in that context, roughly, how good S's evidence must be, or how many possible alternatives to p must be ruled out, shifts depending on features of the context, such as which error possibilities have been made conversationally salient, what is practically at stake, or how careful the conversation demands one be. On this view, the very same speaker, describing the very same subject and the very same evidence, can truly say "I know that p" in an ordinary, low-stakes context and truly say "I don't know that p" in a more demanding, skeptical context, without either utterance being mistaken, because "knows" itself picks out a different, more or less demanding relation in the two contexts, much as "tall" picks out a different height threshold when applied to a basketball player than when applied to a building.