 One might reject quidditism about consciousness even if one accepts structuralism about physics and realism about quiddities. For example, one might combine the latter two theses with a dualist theory on which quiddities categorically ground the most basic physical dispositions physics describes but are not relevant to consciousness (perhaps on this theory consciousness is fundamental and not constituted by anything). By contrast, according to quidditism about consciousness, quiddities play both of those roles.