UC Berkeley

For most of your moral beliefs, there is at least someone out there who disagrees with you, but who is equally well informed and conscientious. How should you respond in situations of this kind? In my dissertation, I explain and defend a novel evaluative requirement for dealing with so-called peer moral disagreement. The evaluative requirement calls on us to assess our reasons for taking our interlocutor to be an epistemic peer. More specifically, it says that if these reasons are equally compelling to our reasons for accepting that our epistemic peer has made a mistake, then—and only then—are we warranted to substantially revise our belief or suspend judgment in our answer. This requirement has been ignored in the literature about peer disagreement. Without it, however, it is very difficult to make sense of our intuitive verdicts in cases of ordinary and extreme disagreement. According to the evaluative requirement, you are required to revise your belief in cases of ordinary disagreement but not in cases of extreme disagreement because in the former type of cases, but not the latter, our reasons for taking our interlocutor to be an epistemic peer are virtually equal to our reasons for accepting that our epistemic peer has made a mistake. The evaluative requirement is especially significant when we think about the problem of moral disagreement. There are two different forms that this problem can take. The first starts from the fact that there is no independent check that would confirm your moral beliefs over the beliefs of those who disagree with you, which allegedly undermines your moral knowledge. In response to this type of skeptical problem, I argue that it delivers the wrong verdict in cases involving cross-temporal disagreement. In the recent past, for example, there are many individuals who believed that slavery is morally permissible. This fact coupled with the independent check requirement implies that I do not know that slavery is morally wrong. Applying the evaluative requirement, I argue that our reasons for the claim that we know slavery to be morally wrong are much stronger than our reasons for the claim that we need an independent check to verify that our beliefs are true in a case of widespread moral disagreement. Thus, we should reject this independent check requirement. I then consider a second type of problem from moral disagreement. This problem starts not from the absence of an independent check in cases of disagreement, but from the fact of disagreement itself. A natural thought about such situations is that you are warranted to revise your moral beliefs in cases in which someone who is your cognitive and evidential equal disagrees with you. I argue that there is something else you can do in these situations besides revise your first-order beliefs, namely take steps to improve your epistemic position. Specifically, you can either improve your understanding of the reasons for thinking that your peer is mistaken (e.g. through additional research or reflection); or you can significantly improve your cognitive abilities in a way that's relevant to the disputed claim. It turns out that it is easier for the novice, as opposed to the expert, to escape this problem of moral disagreement because the novice has less epistemic work to do than the expert. The dissertation concludes by applying these lessons to the case of philosophical disagreement. Some philosophers have thought that any position like mine can be self-undermining. If, according to my position, we should substantially revise our beliefs in the face of peer disagreement, and if there are peer disagreements about views of disagreement, then we should substantially revise our belief in my position. Applying the evaluative requirement, I argue that in most cases of disagreements about views of disagreement, the individual who already accepts my position has compelling reasons for accepting it over accepting that so-and-so is her or his epistemic peer. This, of course, does not apply to everyone who accepts my position. Some might accept it for bad reasons, but this is not true of everyone who accepts it. Solving this self-undermining problem is another reason for accepting the peer evaluative requirement.