Abstract: The cosmopolitan imagination constructs a world order in which the idea of human rights is an operative principle of justice. Does it also construct an idealisation of human rights? The radicality of Enlightenment cosmopolitanism, as developed by Kant, lay in its analysis of the roots of organised violence in the modern world and its visionary programme for changing the world. Today, the temptation that faces the cosmopolitan imagination is to turn itself into an endorsement of the existing order of human rights without a corresponding critical analysis of the roots of contemporary violence. Is the critical idealism associated with Kantian cosmopolitanism at risk of transmutation into an uncritical positivism? We find two prevailing approaches: either the constitutional framework of the existing world order is presented as the realisation of the cosmopolitan vision, or cosmopolitanism is turned into a utopian vision of a world order in which power is subordinated to the rule of international law. I suggest that the difficulties associated with both wings of cosmopolitanism threaten the legitimacy of the project and call for an understanding and culture of human rights that is less exclusively “conceptual” and more firmly grounded in social theory.