On Pragmatic Encroachment in Epistemology

We argue, contrary to epistemological orthodoxy, that knowledge is not purely epistemic—that knowledge is not simply a matter of truth-related factors (evidence, reliability, etc.). We do this by arguing for a pragmatic condition on knowledge, KA: if a subject knows that p, then she is rational to act as if p. KA, together with fallibilism, entails that knowledge is not purely epistemic. We support KA by appealing to the role of knowledge-citations in defending and criticizing actions, and by giving a principled argument for KA, based on the inference rule KB: if a subject knows that A is the best thing she can do, she is rational to do A. In the second half of the paper, we consider and reject the two most promising objections to our case for KA, one based on the Gricean notion of conversational implicature and the other based on a contextualist maneuver.