Contextualism, scepticism and warranted assertibility manoeuvres

Attributer contextualists maintain that the verb 'knows' is context-sensitive in the sense that the truth conditions of a sentence of the form "S knows that p" can be dependent upon the ascriber's context. One natural objection against attributer contextualism is that it confuses the impropriety of certain assertions which ascribe knowledge to agents with the falsity of those assertions. In an influential article, Keith DeRose has defended attributer contextualism against this charge by proposing constraints on what he calls "warranted assertibility manoeuvres" of this sort. This paper argues that, contra DeRose, the warranted assertibility manoeuvre directed at attributer contextualism is able to meet the constraints that DeRose lays down.