 This method of distinguishing categories also provides a principled way of answering some of the central questions for theories of categories, including whether or not there is a single summum genus, and what the relationship is between linguistic/conceptual and ontological categories. Such completely general terms as “thing” “entity” or “object”, on Dummett’s view, are not genuine sortal terms, since they fail to provide any criteria of identity. Thus clearly on this view (as on Aristotle’s) there is no summum genus under which categories such as artifact, animal, etc. could be arranged as species, since (lacking criteria of identity) such candidate catch-all terms as ‘object’, ‘being’, ‘entity’ and the like are not even sortal terms and so cannot be categorial terms.