The Equal Weight View of disagreement says that if an agent sees that an epistemic peer disagrees with her about p, the agent should change her credence in p to half way between her initial credence, and the peer’s credence. But it is hard to believe the Equal Weight View for a surprising reason; not everyone believes it. And that means that if one did believe it, one would be required to lower one’s belief in it in light of this (...) peer disagreement. Brian Weatherson explores the options for how a proponent of the Equal Weight View might respond to this difficulty, and how this challenge fits into broader arguments against the Equal Weight View. (shrink)

How should you take into account the opinions of an advisor? When you completely defer to the advisor's judgment, then you should treat the advisor as a guru. Roughly, that means you should believe what you expect she would believe, if supplied with your extra evidence. When the advisor is your own future self, the resulting principle amounts to a version of the Reflection Principle---a version amended to handle cases of information loss. When you count an advisor as an epistemic (...) peer, you should give her conclusions the same weight as your own. Denying that view---call it the ``equal weight view''---leads to absurdity: the absurdity that you could reasonably come to believe yourself to be an epistemic superior to an advisor simply by noting cases of disagreement with her, and taking it that she made most of the mistakes. Accepting the view seems to lead to another absurdity: that one should suspend judgment about everything that one's smart and well-informed friends disagree on, which means suspending judgment about almost everything interesting. But despite appearances, the equal weight view does not have this absurd consequence. Furthermore, the view can be generalized to handle cases involving not just epistemic peers, but also epistemic superiors and inferiors. (shrink)

This chapter offers a new interpretation of Nietzsche’s argument for moral skepticism, an argument that should be of independent philosophical interest as well. On this account, Nietzsche offers a version of the argument from moral disagreement, but, unlike familiar varieties, it does not purport to exploit anthropological reports about the moral views of exotic cultures, or even garden-variety conflicting moral intuitions about concrete cases. Nietzsche, instead, calls attention to the single most important and embarrassing fact about the history of moral (...) theorizing by philosophers over two millennia: namely, that no rational consensus has been secured on any substantive, foundational proposition about morality. Persistent and apparently intractable disagreement on foundational questions, of course, distinguishes moral theory from inquiry in the sciences and mathematics. According to Nietzsche, the best explanation for this disagreement is that, even though moral skepticism is true, philosophers can still construct valid dialectical justifications for moral claims because the premises of different justifications will answer to the psychological needs of at least some philosophers and thus be deemed true by some of them. The chapter concludes by considering various attempts to defuse this abductive argument for scepticism. (shrink)