Reasonable pluralism is a thesis about the operation of human reason under conditions of liberty. A diversity of irreconcilable but reasonable religious, philosophical, and moral doctrines is “the inevitable long-run result of the powers of human reason at work within the background of enduring free institutions” (PL4; cf. 36, 135). The precursor of this idea in A Theory of Justice is the assumption that among the circumstances of justice is doctrinal diversity that does not spring simply from moral faults such as selfishness or negligence (TJ 110, 112; compare PL 36–37, 55). Reasonable pluralism gives rise to the practical and moral problem to which political liberalism is a response: “how is it possible for there to exist over time a just and stable society of free and equal citizens, who remain profoundly divided by reasonable religious, philosophical and moral doctrines?” (PL 4). This doctrinal diversity is the consequence of the burdens of judgment, which are the obstacles to agreement between reasonable persons: empirical complexity, diversity of relevant values, conceptual vagueness, etc. (PL 54–58). Reasonable pluralism helps justify the claim that the exercise of political power must be publicly justifiable, an idea that finds expression in the “liberal principle of legitimacy” (PL xlvi, 217), the “criterion of reciprocity” (PL xlvi, li, 446–447), and the ideal of “public reason” (PL l, 226). Although from some points of view reasonable pluralism may seem unfortunate, Rawls insists that it is not a disaster, because if the theory of political liberalism is correct reasonable pluralism does not make it impossible to have a stable, approximately just society (PL xxvi, 37, 144). Thus we can be reconciled with this fixed point of the (modern) human condition, and not lose hope that over time we will make progress towards justice (LP 124–128).