Abstract Summary
Nina Emery (Mount Holyoke College) - In this paper, I argue that laws metaphysically explain their instances, and show how this argument has implications for the debate over quantum ontology. I begin by revisiting an argument for the view that laws ground their instances that was originally presented in Emery 2017. I claim that everyone, regardless of whether they are Humean or non-Humean about laws of nature, ought to accept the premises of this argument. I then briefly recap the debate over quantum ontology—the debate over what the wave function of a quantum system represents—paying particular attention to two options: wave function realism, according to which the wave function represents a field in a high-dimensional space that corresponds to configuration space (Albert 1996 and 2015, Ney 2015), and the nomological view, according to which the wave function represents a law (Durr et. al. 1992 and Allori et. al. 2008). I then show how the view that laws ground their instances gives rise to a novel argument for the nomological view over wave function realism. For while both the nomological view and wave function realism posit grounding relations between the fundamental ontology (what the wave function represents) and patterns of events involving macrophysical objects, the grounding relations posited by the nomological view are of a kind with the grounding relations that we ought already accept in other areas of physics. In contrast, the wave function realist posits wholly novel grounding relations. The nomological view thus coheres better with previous physics, both in terms of the fundamental ontology that it posits and the grounding relations that connect that fundamental ontology with the objects of everyday experience. I close with some thoughts about how this point may undermine the argument found in Ismael and Schaffer 2016, according to which we ought to be wave function realists because we ought to look for a common ground explanation of certain types of quantum phenomena and the wave function realist can best provide such an explanation.
