This dissertation examines the question of when and whether one should adjust one's credence in a proposition when one finds that one disagrees with someone else that one takes to be one's epistemic peer ---that is, someone who is roughly as well-informed and intelligent as oneself. There is a spectrum of views that have been proposed in answer to this question. Steadfastness is the view that sometimes one need not adjust one's credence at all in such a case. Conciliationism is the view that you must always adjust your credence in such a case. And there are various forms of conciliationism that vary in their recommendations regarding how much one should adjust in particular cases.

I critically examine the most prominent arguments that have been put forward in favor of versions of steadfastness and conciliationism. I examine arguments for steadfastness that take uniqueness (the view that a body of evidence can only support one doxastic attitude towards some proposition) as a premise, and examine arguments for conciliationism that take permissivism (the denial of uniqueness) as a premise. I argue that both types of arguments fail, and thus that the truth of uniqueness and permissivism does not directly bear on the problem of peer disagreement.

I also examine arguments for the view that in some cases, when you disagree with someone you take to be your epistemic peer, you may favor your own opinion to some degree because you have some sort of epistemic entitlement to favor your own opinion. I argue that such arguments do not succeed.

My take on the problem of peer disagreement is that there are too many variables in play to be able to say anything that is both precise and generally applicable about what the epistemically rational way to respond to peer disagreement is. To illustrate this point, I examine the question of how the evidence one has for thinking that someone is one's epistemic peer will bear on how one should respond when one knows one disagrees with an epistemic peer.