My aim in this paper is to discuss the theory of morality that appears as Chapter 8 of CastaŇeda"s Structure of Morality.Though CastaŇeda"s theory is set forth in only twenty-seven pages of text, it is one of the most intricate theories of morality to have appeared in recent years and also, to my mind, one of the most interesting. Since CastaŇeda"s exposition is both complicated and highly condensed, it is difficult to understand even on second or third reading — the reason, no doubt, why his theory has provoked little response from other writers on morality. In what follows I shall try to explain the main points of Castaiieda"s theory, place some of those points in historical perspective, and then offer some critical remarks