In my thesis I discuss contextualism about knowledge ascriptions. Contextualism about knowledge ascriptions is the view that the expression 'know' as it occurs in ascriptions of propositional knowledge is context sensitive. There are many context sensitive expressions in English. Consider for instance, the indexical 'I'. The contribution of 'I' to the truth conditions of utterances of sentences that contain it depends on who is speaking in the context in which it is uttered. The sentence 'I am a philosophy student' may be true as uttered by one person and false as uttered by another. Similarly, contextualists argue that the sentence 'Al Gore knows that George W. Bush is the President of the United States' may be true as uttered in one context and false as uttered in another context.
While contextualism about knowledge ascriptions has attracted a lot of attention because it offers solutions to epistemological problems such as the problem of scepticism, I focus on whether there is linguistic evidence for contextualism. I take Keith DeRose's Bank Case and Stewart Cohen's Airport Case as my starting point. DeRose and Cohen argue that our intuitions about these cases reveal that 'know' is context sensitive. I offer a critical discussion of DeRose's and Cohen's claims, with the question of whether the contextualists mistake a contextual variation in the warranted assertability conditions of utterances of sentences containing 'know' for a contextual variation in truth conditions playing a central role in the discussion.