Ted A. Warfield reviews the history of epistemology and argues that epistemologists mistakenly take for granted the inference that the failure of closure of some necessary condition on knowledge is sufficient for the failure of epistemic closure. So he concludes that epistemologists should avoid using this inference to explain the failure of epistemic closure. However, I will defend the inference that epistemologists often employ in their discussions. My thesis is that although this inference is invalid, one can still legitimately conclude (...) the failure of epistemic closure from the failure of closure of some necessary condition on knowledge. (shrink)