What are ‘Universalizable Interests’?

Many of Habermas's critical commentators agree that Discourse Ethics fails as a theory of the validity of moral norms and only succeeds as a theory of the democratic legitimacy of socio‐political norms. The reason they give is that the moral principle (U) is too restrictive to count as a necessary condition of the validity of norms. Other commentators more sympathetic to his project want to abandon principle (U) and remodel Discourse Ethics without it. Still others want to downplay the role of universalizing moral discourse and to make more of Habermas's less demanding, though still somewhat vague, conception of ethical discourse. Against this chorus of critical voices Habermas maintains that his conception of moral discourse and the moral principle (U) are central to Discourse Ethics in general, and to the normative heart of his political theory in particular. The conflict may have arisen in part because the concept of a ‘universalizable interest’ which is central to Habermas's understanding of moral discourse and of the moral principle (U) remains opaque even after nearly two decades of critical debate. Actually Habermas's concept of interest is pretty obscure too. But the obscurity surrounding the concept of interest is not the source of the confusion. For our present purposes we can simply stipulate that an interest is a reason to want. The notion of reason rests loosely on the notion of a need, and the concepts of need and desire are take left deliberately vague. The source of the current confusion lies in the notion of universalizability that is in play. Once we pay due attention to the conditions of the universalizability of interests contained in Habermas's formulation of the moral principle (U), we can distinguish between a weaker and a stronger version of the principle. I argue that only the weaker version is defensible. But I also want to show that Habermas is tempted into defending the stronger version, and to explain why he does so.