Rawls took very seriously the views of W. D. Ross (1877–1971), as representing two of the main traditions in moral and political philosophy that he sought to unsettle.

Pluralistic intuitionism is the normative view that there is a plurality of basic and conflicting values or principles that have to be weighed against one another on the basis of intuition to determine how we ought to act – Ross, for example, proposes seven prima facie duties that pick out features of acts that count for or against them but he also claims that there are no further principles, only bare intuitions, to help us decide what our duty is all things considered. Rawls regarded this view as the default position in moral and political theory because it captures core features of commonsense moral reasoning without oversimplifying the moral facts, so we ought to admit “the possibility that there is no way to get beyond a plurality of principles” (TJ 36). Yet he thinks that pluralistic intuitionism is “but half a conception” because “assignment of weights is an essential and not a minor part” of a moral and political theory (TJ 37).