In the previous chapter we discussed functional differentiation as the principle that organises modern society, in the tradition initiated by Durkheim, developed by Parsons and radicalised by Luhmann to name but a few along its long trajectory. Differentiation, associated with the maintenance of the proper boundaries of systems, ensured that the legal, political, economic, etc., systems maintained consistent forms of coupling. Our own concern with political constitutionalism has been a concern about how these forms are organised under the sign of the constitution, in a way that allowed a particular constitutional reflexivity to emerge.