Rawls proposes justice as fairness, his favored liberal theory of justice, as the best account of institutional or distributive justice for any modern liberal democratic society. He addresses his arguments primarily to readers already committed to the ideals implicit in such a society. In order to orient himself and his audience in advance of making his arguments, Rawls characterizes such a society in terms of three fundamental ideas. Each is normative and so also an ideal. These are the idea(l)s of (i) fair social cooperation among (ii) moral persons as free and equal within (iii) a well-ordered basic institutional structure. These are among the most basic idea(l)s undergirding Rawls’s arguments for justice as fairness. The original position organizes them into a heuristic that those committed to determining and realizing institutional or distributive justice for a modern liberal democracy might use to organize and check their deliberation and judgment and guide their political activity.

While abstract and in need of further specification and interpretation, the three fundamental idea(l)s that Rawls takes as his point of departure are already specifications or interpretations of still more abstract idea(l)s familiar from the history of moral and political thought. For example, the idea(l) of fair social cooperation is a specification or interpretation of the more general and long familiar idea(l) of society as a cooperative undertaking for the common good. And the idea(l) of moral persons as free and equal is a specification or interpretation of persons as responsible participants in social life. Rawls assumes that the three fundamental idea(l)s are expressed by the public political culture of a liberal democratic society and are common ground among those committed to such a society but divided over pressing political issues of constitutional design, basic justice, and public policy.