Can there be an aesthetic difference between an original painting and its forgery if they are visually indistinguishable? Answers of different philosophers are critically examined with the conclusion that none of them is satisfactory. Although their "solutions" stem from different views of the nature of art, they have one thing in common: They all assume that the value of an artwork consists in its aesthetic value. The author argues that this assumption--which underlies both classical and modern philosophy of art--is wrong. The conception of art evaluation based on this assumption, which is labeled as aesthetic monism, is shown to conflict with the practice of criticism and with expert analysis of particular artworks. The author offers an alternative dualist conception--based on the distinction between the aesthetic and artistic value--that is shown to have a greater explanatory power than traditional theories of art. The dualist model easily resolves the problem of forgeries and provides an explication of some aspects of critical artistic practice, which would otherwise have to be considered irrational. The implications of the proposed theory of evaluation for aesthetic education are also discussed.