 At a basic level, the debate about structuralism in the philosophy of physics concerns how to think about the “objects” of modern physics, given the revolutionary changes quantum mechanics and relativity theory have brought with them. More particularly, it concerns the suggestion to refer to “structures” in this connection (cf. French 2014, Ladyman 2007 [2019], etc.), in a way that is closely related to the philosophy of mathematics. At another level, this debate concerns how to conceive of what, if anything, remains constant through theory changes in the ontology of physics (cf. Worrall 1989, and see the  entry on structuralism in physics in this encyclopedia). Third, there are debates about representation  in science that are related to structuralism (cf. van Frassen 2008). While  there are several points of contact one could pursue further (e.g., concerning “structural indiscernibles”  and versions of “set-theoretic versus  category-theoretic structuralism” in the context  of physics), we refrain from doing so here.