This essay deals with the debate between Jürgen Habermas and Albrecht Wellmer. In one way, Habermas proposes discours ethics. In other way, Wellmer proposes dialogue ethics. Wellmer emphasizes distinction between the principle of universalization (U) and the principle of generalization. The principle of universalization (U) relates to the formal condition of discours ethics. The principle of generalization relates to personal character. In this point, he criticizes Habermas' discours ethics, because Habermas did not distinction between the principle of universalization (U) and the principle of generalization. So Wellmer criticizes Habermas' strong position of consensus theory. It contains the principle of universalization (U). But According to Wellmer, the principle involves a fallacy of circulation. And Wellmer criticizes inaccordance with formal rationality and true of consensus theory in Habermas' theory. According to Wellmer, Habermas did not divide the norm of moral and the norm of law. So Wellmer takes on falsificative dialogue ethics. Habermas, in response to Wellmer, insists that we can't divide the principle of universalization (U) from the principle of generalization, once we argue on somethings. But because of Wellmer's critic, Habermas proposes somethings new, that is dividing the principle of universalization (U) from the principle of appropriateness(Angemessenheit) and dividing the principle of universalization (U) from the principle of democracy. In addition to, Habermas revises his early position of strong consensus theory. So he takes on weak consensus theory and weak transcendental position. Although debate between Habermas and Wellmer dose not have finished yet, Wellmer's dialogue ethics has had influence on Habermas' discourse ethics in various things.