ABSTRACT
Contextualism about “knows” is the view that knowledge ascriptions (sentences of the form “S knows p”) may express different propositions in different contexts of utterance, even when the ascription contains no other context-sensitive vocabulary (throughout this chapter, I’ll just refer to this view as “contextualism”). This view is contrasted with invariantism about “knows,” which is the view that knowledge ascriptions containing no other context-sensitive vocabulary always express the same proposition in every context. Consider the following knowledge ascription:
Barack Obama knows that it is raining in Cambridge, MA.
The standard motivation for contextualism is that knowledge ascriptions like (1) intuitively have different truth values when uttered in different contexts, holding fixed the facts about the subject’s (in this case, Obama’s) epistemic situation (his evidence, beliefs about whether p, the truth of p, etc). Consider the following two contexts: