Alisdair MacIntyre

 "... it was because a moral tradition of which Aristotle's thought was the intellectual core was repudiated during the transitions of the fifteenth to seventeenth centuries that the Enlightenment project of discovering new rational secular foundations for morality had to be undertaken. And it was because that project failed, because the views advanced by its most intellectually powerful protagonists, and more especially by Kant, could not be sustained in the face of rational criticism that Nietzsche and all his existentialist and emotivist* successors were able to mount their apparently successful critique of all previous morality. Hence the defensibility of the Nietzschean position turns in the end on the answer to the question: was it right in the first place to reject Aristotle?" After Virtue, 3rd ed., p 117

*emotivism: the doctrine that all moral positions are subjective emotions masquerading as objective truths