 Political Liberalism shifts the focus from a philosophical conception of justice, formulated abstractly and meant to apply universally, to a practical conception of legitimacy where consensus is reached without pretension of deep metaphysical roots for the principles in question. More than merely a “modus vivendi” for the participating parties, justice must be affirmed in a way that finds a moral basis for all participating citizens, albeit from different frameworks of value and moral obligation. The operation of public reason, then, serves as the means by which such a consensus might be established, and hence public discussion and democratic institutions must be seen as a constitutive part of the justification of principles of justice rather than merely a mechanism for the collective determination of the social good.