Andrea Salvador
University of Italian Switzerland
Lehmkuhl 2018 distinguishes between two variants of supersubstantivalism: (1) modest and (2) radical. Both have been defended in the philosophy of physics. Schaffer 2009 argues from General Relativity (GR) and Quantum Field Theory to identity-supersubstantivalism, which entails (1). Lehmkuhl and Duerr & Calosi 2021 have GR-based arguments for priority-supersubstantivalism, which is a form of (2).
But a further case can be made for (1). Identity-supersubstantivalists have argued theirs is the only theory which metaphysically explains Harmony, i.e., the thesis that necessarily, an object and its exact-location have the same shape and, necessarily, the object’s parts are exactly-located at parts of its exact-location. So identity-supersubstantivalism seems explanatorily stronger than its alternatives. In my work, I will offer an account of Harmony compatible with (2).
I first discuss two explanations of Harmony. For Leonard 2021, for an object to be located at a region just is for that material object to be identical to its location, which entails identity-supersubstantivalism. For Calosi 2022, who endorses (2), for an object to have a shape just is for it to inherit its shape from its location and for it to have a mereological structure just is for it to inherit it from its location. But while there are arguments in favour of shape being an extrinsic property of objects, the thesis that the mereological structure of an object is extrinsic still lacks a defence.
I thus assume their same line of reasoning to produce a new theory. I propose that for an object to be located at a region just is for the object and the region to be such that Harmony holds between them. I argue my proposal is (i) as explanatorily powerful as Leonard’s and Calosi’s, (ii) safe from the objections they could face, but (iii) compatible with radical supersubstantivalism. It will then offer a valuable explanation of Harmony to every metaphysician or philosopher of physics who wishes to endorse radical supersubstantivalism without having the consequences of Calosi’s theory.
Chair: Cristina Somcutean
Time: September 6th, 16:50-17:20
Location: SR 1.007
SOPhiA 2026 