Summary — This article is a slightly modified version of the text of the inaugural lecture given at the University of Pavia on December 2nd, 1996, to mark the beginning of the academic year 1996-97. The author holds that the vagueness of a term like ‘fairness’ can only be reduced by reference to a wider normative theory that includes it. Referring to John Rawls’s theory of justice as fairness, the author illustrates the intuitive argument in favour of the difference principle, which is based on the idea of the moral arbitrariness of the initial distribution of natural and social endowments. This argument, which is considered as logically prior to the expository device of the original position, can throw light on the principle political conflicts found in fin de siècle liberal societies. In the author’s view, the essential tension is between some sort of libertarianism and some sort of liberal egalitarianism, or, in Rawls’s terms, between the system of natural liberty and democratic equality.