Fixed-point solutions to the regress problem in normative uncertainty

Abstract

When we are faced with a choice among acts, but are uncertain about the true state of the world, we may be uncertain about the acts' "choiceworthiness". Decision theories guide our choice by making normative claims about how we should respond to this uncertainty. If we are unsure which decision theory is correct, however, we may remain unsure of what we ought to do. Given this decision-theoretic uncertainty, metatheories attempt to resolve the conflicts between our decision theories…but we may be unsure which meta-theory is correct as well. This reasoning can launch a regress of ever-higher-order uncertainty, which may leave one forever uncertain about what one ought to do. There is, fortunately, a class of circumstances under which this regress is not a problem. If one holds a cardinal understanding of subjective choiceworthiness, and accepts certain other criteria (which are too weak to specify any particular decision theory), one's hierarchy of metanormative uncertainty ultimately converges to precise definitions of "subjective choiceworthiness" for any finite set of acts. If one allows the metanormative regress to extend to the transfinite ordinals, the convergence criteria can be weakened further. Finally, the structure of these results applies straightforwardly not just to decision-theoretic uncertainty, but also to other varieties of normative uncertainty, such as moral uncertainty. Keywords Decision theory • Moral uncertainty • Normative uncertainty • Uncertaintism My thanks to Anubav Vasudevan, Christian Tarsney, and two anonymous referees for helpful comments and suggestions. All errors are my own.

Metanormative regress: an escape plan

“…But why think that it's true? The most promising argument in this direction comes from Trammell (2021), who shows that convergence is guaranteed under certain strong assumptions: in particular, when for every n, A has positive credence in only finitely many nth-order norms, all of which are complete, cardinal (assigning each option a degree of subjective choiceworthiness on a shared cardinal scale), and "compromising" (meaning that the n th-order subjective choiceworthiness of an option must be strictly between its minimum and maximum degrees of (n −1)-order subjec-tive choiceworthiness, unless these are the same). 14 But various natural and widely discussed metanormative theories violate these conditions-e.g., My Favorite Theory is not compromising, and My Favorite Option is at least apparently non-cardinal.…”