 As noted above  (section 1.1),  Russellian monism can be identified with the conjunction of the three theses: structuralism about physics, realism about quiddities, and quidditism about consciousness. But one might question whether Russellian monists are committed to structuralism about physics, at least if that thesis is understood as saying that physical theory is completely silent on the existence and nature of quiddities. Given Russellian monism, terms for the basic entities in physical theory, such as “mass” and “charge”, perhaps refer to quiddities, to entities that have quiddities. One might take that point alone to belie the structuralist’s complete-silence claim. Further, one might wonder, why should Russellian monists rule out the possibility of physical theory expressing substantive information about the referents of its terms (Hawthorne 2002)?