To what must an epistemology be true?

J. L. Austin famously thought that facts about the circumstances in which i t is ordinarily appropriate and reasonable to make(challenge) claims to kno wledge have a great bearing on the propriety of a philosophical account of knowledge. His major criticism of the epistemological doctrines about which he wrote was precisely that they lacked fidelity to our ordinary linguisti c practices. In The Significance of Philosophical Scepticism, Barry Stroud argues that Austin was misguided: it is one thing for it to be inappropriat e under ordinary circumstances to (say) deny that someone knows that P, ano ther thing for it to be true that she knows that P. Thus, to the philosophi cal enterprise of determining which knowledge attributions are true, Austin 's form of criticism is beside the point. I argue that, attractive though i t may be, this response to Austin badly underestimates the force of his sor t of criticism.