Abstract

A recent methodological approach at the interface of metaphysics and philosophy of science suggests that just like causal laws govern causation, there needs to be something in metaphysics that governs metaphysical relations. Such laws of metaphysics would be counterfactual-supporting general principles that account for the explanatory force of metaphysical explanations. There are various suggestions about how such principles could be understood. They could be based on what Kelly Trogdon calls grounding-mechanical explanations, where the role that grounding mechanisms play in certain metaphysical explanations mirrors the role that causal mechanisms play in certain scientific explanations. Another approach, by Gideon Rosen, takes it that there are essentialist principles or laws that tell us about what grounds what. Finally, Jonathan Schaffer defends an approach that he considers to be neutral regarding grounding or essences. In this paper I will assess these suggestions and argue that for those willing to invoke a non-modal notion of essence, there is a more promising route available: metaphysical and scientific explanations may be unified in terms of general essences. Accordingly, essentialists may be better viewed as outlaws when it comes to laws of metaphysics.