Abstract of this paper under review: Metaethical non-naturalists sometimes insist they don’t believe acts to be right and wrong because of some sui generis piece of ontology. On the other hand, work scrutinizing this ‘because’ relation – the literature on grounding – seems to have the reached the conclusion that the tenability of non-naturalism depends on whether moral laws can stand in such a relation to an action’s moral properties. If true, that puts certain constraints on what non-naturalist-friendly moral laws can be. I argue that those constraints are inconsistent with denying that, given non-naturalism, acts are right and wrong (partly) in virtue of some sui generis piece of ontology. This is because per those constraints and non-naturalism, those laws themselves are both sui generis ontology and something that makes acts wrong. The upshot is that non-naturalism is committed to non-natural ontology playing a role in moral justification. Accordingly, common claims on behalf of non-naturalism that it is not so committed, seem inconsistent with the view’s grounding structure.
