What follows is a guest post by Lee Walters. Lee is a Lecturer in Philosophy at the University of Southampton where he teaches courses on metaphysics, philosophy of language, and fiction and fictionalism. His research focuses on the metaphysics of art; fictional characters and their names; and the logic and semantics of conditionals. It is widely, though not universally, accepted that there can be distinct allographic artworks (e.g. pieces of classical music, and novels) that are indistinguishable with respect to their intrinsic, structural or notational properties. What consequences does this claim about works have for an allographic work’s instances? In particular, can there be intrinsically indiscernible instances which fail to be instances of the same work? More generally, when is x an instance of some particular work, w?