A Priority and Externalism

Introduction If an epistemological distinction fails to carve at the epistemological joints, then it is not worthy of serious and protracted discussion. The residual issue of whether the putative distinction is incoherent or merely gerrymandered ought not to strike anyone as especially important. My own externalist commitments – epistemological and semantic-lead me to think that the a priori-a posteriori distinction is not a particularly natural one, and hence that its importance to epistemology has been grossly overestimated. 2 I shall be defending that perspective in what follows. Discussions of a priority typically assume that there is a distinguished subclass of beliefs whose epistemic status does not depend upon experiential encounter with the world. Yet the project of delimiting such a class in a non-gerrymandered fashion turns out to be surprisingly difficult. As an organizing theme, I shall examine the bearing of a safety based account of knowledge on the traditional conception of a priori knowledge. #1 Environment Independence Epistemologists divide according to whether they take knowledge or, instead, some kind of justification (or ‘warrant’ or ‘rationality’ or ‘entitlement’) as the starting point for foundational inquiry. In line with my preferred orientation, much of the discussion that follows will concern a priori knowledge. In a final section, I shall speak to the topic of a priori justification. Let us begin with a simple externalist picture of knowledge, a version of the safety account: 3 S knows p iff there is no close world where S makes a mistake that is relevantly similar to his actual belief that p. 4 That there is a close world where S is mistaken about p does not show that he does not actually know p, since he may use a relevantly different method at that close world. (I could easily have asked an unreliable informant the score of the game rather than checked the scoreboard, and at a close world where the score is different the informant provides me with the score that obtains at the actual world.) And that there is no close world where 1 I am grateful to Elizabeth Camp, Maya Eddon and Sanford Goldberg for comments on an earlier draft, and to Timothy Williamson and an audience at Oxford for helpful discussion. I am especially grateful to David Manley for discussions that helped to develop and sharpen the material in this paper.