Title: Reflection and Disagreement

Abstract:

How should you take into account the opinions of an advisor?  When you
completely defer to the advisor's judgment (the manner in which she
responds to her evidence), 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.