A Virtue Reliabilist Error-Theory of Defeat

Knowledge defeat occurs when a subject knows that p, gains a defeater for her belief, and thereby loses her knowledge without necessarily losing her belief. It’s far from obvious that externalists can accommodate putative cases of knowledge defeat since a belief that satisfies the externalist conditions for knowledge can satisfy those conditions even if the subject later gains a defeater for her belief. I’ll argue that virtue reliabilists can accommodate defeat intuitions via a new kind of error theory. I argue that in cases where the subject holds dogmatically onto her belief in the face of an apparent defeater, her belief never qualified as knowledge, since the belief was not gained via an exercise of her epistemic virtues. In cases where the subject suspends her judgment upon receiving the putative defeater her original belief might have qualified as knowledge, but crucially, in such cases knowledge is lost due to loss of belief, rather than due to the epistemic force of the defeater. Therefore, knowledge defeat isn’t a genuine phenomenon even though there are no cases where a subject knows what she originally believed after receiving the putative defeater.