  A fifth argument against defining art, with a normative tinge that is psychologistic rather than sociopolitical, takes the fact that there is no philosophical consensus about the definition of art as reason to hold that no unitary concept of art exists.  Concepts of art, like all concepts, after all, should be used for the purpose(s) they best serve.  But not all concepts of art serve all purposes equally well. So not all art concepts should be used for the same purposes. Art should be defined only if there is a unitary concept of art that serves all of art’s various purposes – historical, conventional, aesthetic, appreciative, communicative, and so on.  So, since there is no purpose-independent use of the concept of art, art should not be defined (Mag Uidhir and Magnus 2011; cf. Meskin 2008). In response, it is noted that some account of what makes various concepts of art concepts of art is still required; this leaves open the possibility of some degree of unity beneath the apparent multiplicity. The fact (if it is one) that different concepts of art are used for different purposes does not itself imply that they are not connected in ordered, to-some-degree systematic ways.  The relation between (say) the historical concept of art and the appreciative concept of art is not an accidental, unsystematic relation, like that between river banks and savings banks, but is something like the relation between Socrates’ healthiness and the healthiness of Socrates’ diet.  That is, it is not evident that there exist a mere arbitrary heap or disjunction of art concepts, constituting an unsystematic patchwork. Perhaps there is a single concept of art with different facets that interlock in an ordered way, or else a multiplicity of concepts that constitute a unity because one is at the core, and the others depend asymmetrically on it. (The last is an instance of core-dependent homonymy; see the entry on  Aristotle, section on Essentialism and Homonymy.) Multiplicity alone doesn’t entail pluralism.