UC Davis

This dissertation is an attempt to make sense of the possibility that, as a matter of metaphysics, some acts lack a determinate deontic status. While philosophers are increasingly sympathetic to this idea, the literature on moral indeterminacy remains small and has focused primarily on its implications for various metaethical theories. In what follows, I address some questions that have received less attention.

In Chapter 1, I consider how two influential theories of metaphysical indeterminacy explain moral indeterminacy, assuming that it exists. I argue that one account, due to Elizabeth Barnes and J. Robert G. Williams, cannot accommodate the widespread view that the normative supervenes on the non-normative—roughly, that as a matter of metaphysical necessity, if two entities are exactly alike in all non-normative respects, they are exactly alike in all normative respects. The other account, due to Jessica Wilson, does not face this problem, and I take it to be preferable on this basis. But the upshot of my argument is not that we should all be Wilsonians—I do not commit to any particular theory here. The takeaway is rather that some accounts of metaphysical indeterminacy better explain moral indeterminacy than others.

In Chapter 2, I step back from moral indeterminacy to ask how reasons determine deontic status. Answering this question will help me explain how the reasons that bear on an act can leave it without a determinate deontic status, a question I take up in Chapter 3. I survey, and ultimately reject, three existing accounts before developing and defending a novel approach. The core of my account is the idea that morality obligates us when, and only when, there is a sufficiently great disparity between the moral weight of the reasons for and against an act.

In Chapter 3, I make a direct case for the existence of moral indeterminacy. After presenting a positive argument to this effect, I spend most of the chapter fielding objections. These include, among others, the concerns that indeterminate permissibility is incompatible with the view that acts are permissible by default and that it is ruled out by the assumption that deontic status is determined by reasons.

In Chapter 4, I address the concern that there is no way for morality to guide our actions in the face of moral indeterminacy. My response is twofold. First, I point out that moral indeterminacy does not always significantly undermine morality’s ability to guide our actions. And second, I argue that, even when indeterminacy does pose a significant threat to action guidance, there are still ways to base our actions on morally relevant considerations.