Habermas is simply the worst writer, relative to the complexity of his ideas, that I have ever come across: others are worse writers (Hegel), but have more difficult ideas which they struggle to express. Others have less complex ideas (many analytic philosophers) but express them more clearly. Urgh.
This should have been an essay arguing for the 'interested' nature of reason: the claim being that any form of argument or communication at all is necessarily aiming at 'enlightenment,' freeing us from dogmatism. This is interesting. Habermas wants to get to this claim through an immanent critique of positivism. This too is interesting. But giving us a complete rundown of Comte's, Mach's (!!!), Dilthey's, and Peirce's philosophies of science? Not so interesting, or necessary. It's rigorous, sure. But sometimes you just want the straight dope. Not here.
Also, part III, on Freud and Nietzsche, is a complete and utter waste of time, even if you buy the idea that psychoanalysis shows one possible way to combine Peirce's philosophy of science approach with Dilthey's hermeneutics. ( )