Epistemology of Disagreement: The Good News

We all live out our lives in states of epistemic imperfection. Most obviously, this is true because the evidence on which we base our beliefs is limited. Only a little less obviously, we live in states of epistemic imperfection because we do not always respond to the evidence we have in the best way. Given that our epistemic condition consists in imperfect responses to incomplete evidence, part of being rational involves taking account of these sources of imperfection. Fortunately, each of us is confronted every day by opportunities for epistemic self-improvement. Most frequently, opportunity arrives in the form of evidence that bears directly on the subject matters of our beliefs: hearing the evening weather report, I can revise upward my con-fi dence that it will rain tomorrow. Other opportunities for epistemic self-improvement address, not our defi cits in evidence, but our defi cits in responding to the evidence: reading a study showing that professors vastly overrate their teaching abilities, I can revise downward (at least temporarily)1 my confi dence that I’m a dynamite teacher. One fairly common situation that may present opportunities for improvement is that of discovering that another person’s belief on a given This essay was read in fall 2004 at Princeton University, and I’d like to thank the audi-ence at that talk for stimulating discussion. I’d also like to thank the following people