  Conventionalist definitions deny that art has essential connection to aesthetic properties, or to formal properties, or to expressive properties, or to any type of property taken by traditional definitions to be essential to art. Conventionalist definitions have been strongly influenced by the emergence, in the twentieth century, of artworks that seem to differ radically from all previous artworks. Avant-garde works like Marcel Duchamp’s “ready-mades” – ordinary unaltered objects like snow-shovels (In Advance of the Broken Arm) and  bottle-racks – conceptual works like Robert Barry’s All the things I know but of which I am not at the moment thinking – 1:36 PM; June 15, 1969, and John Cage’s 4′33″, have seemed to many philosophers to lack or even, somehow, repudiate, the traditional properties of art: intended aesthetic interest, artifactuality, even perceivability. Conventionalist definitions have also been strongly influenced by the work of a number of historically-minded philosophers, who have documented the rise and development of modern ideas of the fine arts, the individual arts, the work of art, and the aesthetic (Kristeller, Shiner, Carroll, Goehr, Kivy).