 In response, one might argue that physical theory itself is neutral between a Russellian monist interpretation according to which terms like “mass” and “charge” refer to quiddities, and a structuralist interpretation according to which such terms do not refer to quiddities (Ladyman and Ross, with Spurrett and Collier 2007). That is, one might argue that the commitments of physical theory itself, by contrast with a metaphysical interpretation of physical theory, do not go beyond the structural. Structuralism about physics could thus be viewed as a thesis only about physical theory itself. In that case, the considerations mentioned in the preceding paragraph do not challenge the claim that Russellian monists are committed to structuralism about physics.