No laws and (thin) powers in, no (governing) laws out

Abstract

Non-Humean accounts of the metaphysics of nature posit either laws or powers in order to account for natural necessity and world-order. We argue that such monistic views face fundamental problems. On the one hand, neo-Aristotelians cannot give unproblematic power-based accounts of the functional laws among quantities offered by physical theories, as well as of the place of conservation laws and symmetries in a lawless ontology; in order to capture these characteristics, commitment to governing laws is indispensable. On the other hand, ontologies that entirely exclude some kind of power ascription to worldly entities (such as primitivism) face what we call the Governing Problem: such ontologies do not have the resources to give an adequate account of how laws play their governing role. We propose a novel dualist model, which, we argue, has the resources to solve the difficulties encountered by its two dominant competitors, without inheriting the problems of either view. According to the dualist model, both laws and powers (suitably conceived) are equally fundamental and irreducible to each other, and both are needed in order to give a satisfactory account of the nomological structure of the world. The dualist model constitutes thus a promising alternative to current monistic views in the metaphysics of science.