This paper is about higher-order moral uncertainty: it is about what someone should do when she's not only uncertain what first-order moral theory is true, but also uncertain whether this moral uncertainty is itself morally relevant. I discuss a puzzle that arises for people, like me, who are fairly confident that the correct response to moral uncertainty is to maximize expected moral value, but also have some credence in a so-called “externalist” theory that holds that moral uncertainty is morally irrelevant and uncertain agents should simply do whatever is in fact most valuable. If the correct response to higher-order uncertainty is to maximize expected value, then we must find a way to incorporate our credence in externalism into our decision-making. This turns out to be quite difficult to do. After dismissing some unsatisfactory strategies, I introduce my preferred solution to the puzzle. I then show that my preferred solution has the surprising implication that my credence in normative externalism is itself, in a sense, morally irrelevant.
I have promised this paper to the book Meaning, Decisions, and Norms: Themes from the Work of Allan Gibbard, edited by Billy Dunaway and David Plunkett.
I previously presented versions of this paper at the REAPP workshop on Moral and Rational Uncertainty 2017 at the University of Reading, the International Formal Ethics Conference 2017 at the University of York, and the Decisions, Games, and Logic (DGL) conference 2016 at the University of Michigan. I am very grateful to particpants in all of these discussions for their formative feedback.