Over the course of thirty-five years, Habermas’s writings have maintained a striking unity of focus and concern, looking into the capacities that people have to create a more just society, which, with some qualification, may mean a more rational society. As I’ve noted, by “rational” Habermas does not mean only the instrumental rationality of bureaucratic systems but also the kind of rationality that the Enlightenment promised: a rationality that would enable human beings to become more free and equal. The bulk of Habermas’s writings has focused on the development of such rationality, specifically communicative rationality, and its applications epistemologically, socially, and morally. It has been in part an attempt to develop a nonfoundational yet transcendental basis for making judgments. That is, in a “postmetaphysical” world we can no longer appeal to metaphysical foundations on which to ground our judgments—yet there is a foundation, internal to our communicative practices, that allows us to ground our claims. In any situation in which we try to come to understanding with others, Habermas argues, we must hold certain validity claims (that as speakers we are being sincere, appropriate, and truthful), or else we would not bother to talk together at all. The necessity for holding these validity claims transcends cultures, histories, and other particularities. It is a universal feature of our communicative practices.
Understandably, this project of developing a theory of communicative action (and, from it, discourse ethics) has occupied Habermas for