The general aim of this paper is to question the idea that hermeneutic and critical social sciences have to be conceived as specific embodiments of the scientific enterprise. This idea is rather implicit in Habermas's work, but has its grounds in his thesis about the argumentative unity of all sciences, upheld for the first time in 1973. Such a point of view turns out to be untenable for two reasons. First, the indiscriminating inclusion of the hermeneutic and critical social sciences in scientific enterprise raises problems of consistency with regard to the systematic guidelines of The Theory of Communicative Action. Moreover, the thesis of argumentative unity of the sciences itself is incompatible with Habermas's methodological conception of the role of Verstehen in the social sciences developed in section 1.4 of the book. Finally, the author argues that this conception calls for another understanding of the status and role of the hermeneutic and critical disciplines, which is outlined in some detail.