K Reason or Revolution
Popper is certainly not a positivist, and only someone who has not read his work could think that he is [Popper says people have been misled because his earliest work was published under the aegis of the Vienna Circle, but he was never a memeber and has always been critical]. There is no correlation between his revolutionary theory of scientific method, and his piecemeal social theory. Despite having started the whole thing off at a Conference, this particular book contains subsequent pieces by Adorno ( and Habermas) that are not about positivism nor are they a detailed discussion of critical rationalism. For example, there is no account at all in Adorno's Introduction of Popper's '27 Theses'.
Critical rationalism requires a clear and simple language. It also needs a rational framework shared by a scientific community, rather than free-floating intellectuals. Critical rationalists do not see complex language as the hallmark of the intellectual (294). Such language merely conceals any truth and its criticisms. For such intellectuals, anyone who understands is held to be in agreement!
Clarity is important for social sciences but also for mathematicians [who started it all, says Popper. There is a useful footnote about Kuhn's notion of normal science here -- it is only normal or routinised today according to Popper -- until recently it was revolutionary and turbulent]. Critical rationalism opposes routinisation as well.
[Popper then proceeds to translate Adorno into less complex language -- 297. In so doing, he reduces it to utter banality, of course. He then attacks Habermas for being unable to put anything simply but always trying to impress!]
In Habermas's view, Popper must be a positivist, and he must incorporate the dominant values of existing society. This argument is grounded in the old sociology of knowledge-based social determinism, though. Protest or criticism is not a sufficient guarantee of avoiding these influences anyway. Popper does not wish to monopolise methods or simply copy natural science, nor keep observation separate from theory, nor banish metaphysics -- in fact, he is a metaphysical realist. The real issue that divides Popper from the Frankfurt School is a political one -- revolution versus piecemeal reform.