 Picking up on this concern, Arthur Danto has famously suggested that it is in fact a non-manifest relation that makes something an artwork rather than an observable property (Danto 1981). That is to say, artworks acquire that status in virtue of their relations to the historical and social setting constituted by the practices and conventions of art, our artistic heritage, the intentions of artists, and so on — the ‘artworld’ (see also Dickie 1974). The general idea here is that artworks are generated within a social and artistic context, and so being an artwork is a function of certain social relations. Conceptual art reinforces the idea that art and non-art can be perceptually indistinguishable and so cannot be marked off from each other by ‘exhibited’ properties  alone.[5]