  The issue of realizability has to do with a variety of constraints. On the one hand, democracy requires voluntary constraints on action, such as commitments to basic rights and to constitutional limits on political power. Social facts, on the other hand, are non-voluntary constraints, or within our problematic, constraints that condition the scope of the application of democratic principles. Taken up in a practical social theory oriented to suggesting actions that might realize the ideal of democracy in modern society, social facts no longer operate simply as constraints. For Rawls, “the fact of pluralism” (or the diversity of moral doctrines in modern societies) is just one such permanent feature of modern society that is directly relevant to political order, because its conditions “profoundly affect the requirements of a workable conception of justice” (Rawls 1999, 424).