MacIntyre’s mature ethical philosophy was the result of his becoming aware of trends in the philosophy of science in the 1970s when MacIntyre had reached a block in the development of his ethical theory. MacIntyre translated Kuhn’s theory of “paradigms” and Lakatos’s “research programmes” into his richly developed theory of ethical “traditions,” which constitutes a historicist ethical philosophy. This point is argued by a detailed comparison of Kuhn’s theory of paradigms with MacIntyre’s traditions; emphasizing paradigms rather than research programs is (...) more productive for highlighting the historicist aspects of MacIntyre’s ethical philosophy. Paradigms and traditions are compared in four areas. Both philosophies deny the validity of the Enlightenment ideal of universal reason, and of social science. Kuhn never resolves the issues connected with the radical incomparability of paradigms. MacIntyre does derive a method of comparing ethical traditions in favor of the Augustinian/Aristotelian/Thomistic one. Questions of ontology remain. (shrink)