In his moral theory, named ‘discourse ethics,’ Jürgen Habermas holds that a norm is morally valid only when it is universalizable. He establishes the principle of universalization (U) as the procedural principle for testing the moral validity of norms in moral discourse. He argues that this principle can be derived from the pragmatic presuppositions of argumentation in general. By explicating the fiduciary status of pragmatic presuppositions of argumentation, and by distinguishing perspectival from comprehensive universalization, I argue that Habermas fails to justify his moral principle.
