This is an excerpt from a short note, which I will post latr. I think it clarifies an important point about Habemras' formalism:
"Admittedly Habermas still insists on a certain sort of formalism and takes procedural rationality as central to his project of postmetaphyscial thinking. However it would be an error to construe Habermas’ conception of formalism and procedural thinking as a form of abstraction. Habermas’ formal conditions of pragmatic rationality are not the formal grid imposed on the existing practices from “without” but are the conditions that are immanent to those practices themselves and hence conditions that emerge from “within” those practices rather than imposed on them from without. Similarly Habermas’ proceduralism has specific meaning to it which must be understood on its own ground rather than construed in Kantian terms. Proceduralism for Habermas derives from his rejection of the metaphysical conception of reason. Reason does not have the capability to tell us about the nature of things or of morals. From this Habermas infers that the only way for reason to exist in the postmetaphycial world is to go procedural, that is, to become a practice of raising and defending claims within conversation (within dialogue). This conception of proceduralism obviously has nothing to do with what Adorno or Bernstein are criticising."