Thomist vs. Scotist Perspectives on Ontic Structural Realism

Structural realism has re-emerged as part of the debate between scientific realism and antirealism. Since then it has branched into several different versions, notably epistemic structural realism and ontic structural realism. The latter theory (which itself has now divided into competing formulations) is still an important perspective in the realism/antirealism dialectic; however, its significance has expanded well beyond that debate. Today ontic structural realism is also an important player in the metaphysics of science literature, engaging with a variety of ontological questions. One of these pertains to the basic categories of ontology, with the proponents of ontic structural realism typically advocating a radical rethinking of how to view substance and relation while calling into question the (allegedly) traditional privileging of the former over and against the latter. In this paper I assess ontic structural realism from the perspective of two major systems: Thomism and Scotism. I argue that the basic commitments of Thomism allow for some surprising convergences with ontic structural realism, while Scotism does not.