  If this were the only role of putative “facts” in Rawls’ political theory of modernity, then it would not be a full practical theory in the sense that I am using the term here. Rawls’ contribution is that social facts differ in kind, so that some, such as the fact of pluralism, are “permanent” and not merely to be considered in narrow terms of functional stability. Social facts related to stability may indeed constrain feasibility without being limits on the possibility or realizability of an ideal as such; in the case of pluralism, for example, democratic political ideals other than liberalism might be possible. Without locating a necessary connection between its relations to feasibility and possibility, describing a social fact as “permanent” is not entirely accurate. It is better instead to think of such facts as “institutional facts” that are deeply entrenched in some historically contingent, specific social order rather than as universal normative constraints on democratic institutions.