 Finally, how should we decide between ontological and ascriptive supervenience theses? Proponents of ascriptive supervenience take on the obligation of making precise the sort of mistake that ‘supervenience-violators’ are allegedly making, and defending the idea that this is a mistake. The most prominent approach takes the mistake to be conceptual, which involves commitments similar to those taken on by defenders of the conceptual supervenience theses just discussed.