  The most prominent and influential institutionalism is that of George Dickie. Dickie’s institutionalism has evolved over time. According to an early version, a work of art is an artifact upon which some person(s) acting on behalf of the artworld has conferred the status of candidate for appreciation (Dickie 1974).  Dickie’s more recent version consists of an interlocking set of five definitions: (1) An artist is a person who participates with understanding in the making of a work of art. (2) A work of art is an artifact of a kind created to be presented to an artworld public.  (3) A public is a set of persons the members of which are prepared in some degree to understand an object which is presented to them. (4) The artworld is the totality of all artworld systems. (5) An artworld system is a framework for the presentation of a work of art by an artist to an artworld public (Dickie 1984). Both versions have been widely criticized. Philosophers have objected that art created outside any institution seems possible, although the definition rules it out, and that the artworld, like any institution, seems capable of error. It has also been urged that the definition’s obvious circularity is vicious, and that, given the inter-definition of the key concepts (artwork, artworld system, artist, artworld public) it lacks any informative way of distinguishing art institutions systems from other, structurally similar, social institutions (D. Davies 2004, pp. 248–249, notes that both the artworld and the “commerceworld” seem to fall under that definition). Early on, Dickie claimed that anyone who sees herself as a member of the artworld is a member of the artworld: if this is true, then unless there are constraints on the kinds of things the artworld can put forward as artworks or candidate artworks, any entity can be an artwork (though not all are), which appears overly expansive. Finally, Matravers has helpfully distinguished strong and weak institutionalism. Strong institutionalism holds that there is some reason that is always the reason the art institution has for saying that something is a work of art. Weak institutionalism holds that, for every work of art, there is some reason or other that the institution has for saying that it is a work of art (Matravers 2000). Weak institutionalism, in particular, raises questions about art’s unity: if absolutely nothing unifies the reasons that the artworld gives for conferring art-hood on things, then the unity of the class of artworks is vanishingly small.  Conventionalist views, with their emphasis on art’s heterogeneity, swallow this implication. From the perspective of traditional definitions, doings so underplays art’s substantial if incomplete unity, while leaving it a puzzle why art would be worth caring about.  