Moderate Dispositional Structuralism

Dispositionalism holds that at least some fundamental physical properties are ungrounded dispositional ones. Unfortunately, the very scientific practice that dispositionalists invoke to support their view undermines the dispositional thesis: putative fundamental properties such as mass, charge, and spin appear to be grounded in symmetry structures. Can the dispositionalist hold that fundamental symmetry structures are dispositional? Livanios (2019) defends a negative answer: symmetry structures do not satisfy the truthmaking principle of dispositionality. By contrast, I offer a positive answer. Here I argue that if dispositionalists adopt an identity-based criterion of dispositionality, they can endorse what I shall call moderate dispositional structuralism: the view that the identity of fundamental symmetry structures is partially but not exhaustively fixed by their dispositional character. The purpose of this paper is to articulate moderate dispositional structuralism and its merits. To defend the plausibility of this view, I compare it with its radical counterpart: the view that the identity of symmetry structures is fully or wholly fixed by their dispositionality.