This is a collective study of the epistemic significance of disagreement: twelve contributors explore rival responses to the problems that it raises for philosophy. They develop our understanding of epistemic phenomena that are central to any thoughtful engagement with others' beliefs.

You and I have been colleagues for ten years, during which we have tirelessly discussed the reasons both for and against the existence of God. There is no argument or piece of evidence bearing directly on this question that one of us is aware of that the other is not—we are, then, evidential equals1 relative to the topic of God’s existence.2 There is also no cognitive virtue or capacity, or cognitive vice or incapacity, that one of us possesses that the (...) other does not—we are, then, also cognitive equals relative to the question at issue.3 Given this evidential and cognitive equality, combined with the fact that we have fully disclosed to one another all of our reasons and arguments relative to this topic, we are epistemic peers with respect to the question whether God exists.4 Yet despite the symmetry of our epistemic positions, we deeply disagree about the answer to this question. What response does rationality require in such a case, where epistemic peers disagree over a question despite there being no apparent asymmetries between them?5 There are two main answers to this question in the recent literature. First, there is the view of the nonconformists, who maintain that one can continue to rationally believe that p despite the fact that one’s epistemic peer explicitly believes that not-p, even when one does not have a reason independent of the disagreement itself to prefer one’s own belief.6 Otherwise put, nonconformists argue that there can be reasonable disagreement among epistemic peers. There are two central explanations of the nonconformist response to peer disagreement.7 On the one hand, there is the egocentric view, which holds that I am justified in giving my belief extra weight8 in the face of peer disagreement because the belief in question is mine.9 On the other hand, there is the correct reasoning view, according to which I am justified in giving my belief extra weight in the face of peer disagreement because the belief in question is in fact the product of correct reasoning.10 Despite these.... (shrink)

One of the most salient features of forming beliefs in a social context is that people end up disagreeing with one another. This is not just an obvious fact about belief-formation; it raises interesting normative questions, especially when people become aware of the opinions of others. How should my beliefs be affected by the knowledge that others hold contrary beliefs? In some cases, the answer seems easy. If I have reason to think that my friend is much better informed than (...) I am, her dissent will often require substantial revision in my belief. If I have reason to think she's mentally deranged, her dissent may require no revision at all. But other cases are more difficult. For example, how confident should I be about my views in epistemology, knowing that they are denied by philosophers at least as intelligent, sane, knowledgeable, diligent and honest as I am? (shrink)