Habermas continues to cleave to key idealist premises and presuppositions even after the linguistic turn and detranscendentalisation. Habermas holds fast to the fundamental idealist premise that empirical order and rational order are mutually exclusive. Habermas’ claims about the detranscendentalisation of the subject and reason, and his claim that reason is a ‘thing of this world,’ does not in any way mean that he has given up the fundamental idealist belief mentioned above. Rather what he does, in his own words, is to bring down the idealisation “from transcendental heaven to the earth of the lifeworld. The theory of communicative action detranscendentalizes the noumenal realm only to have the idealizing force of context transcending anticipation settle in the . . . heart of ordinary, everyday communicative practice.” (Between Facts and Norms p. 19). Habermas does not aim to abolish the noumenal realm; so much as to bring it back to the earth.
Hence Habermas does not abolish the realm of pure intelligibility- the realm of reason devoid of any empirical impurities. He detranscendentalises it, i.e. brings it back to the earth. However by effecting this relocation he does not aim to merge the empirical and the rational order. This is what he means when he talks about the tension between facts and ideals. Habermas wants to preserve the transcending power of reason even in the face of detranscendentalisation. The problem for him now becomes how to show that the transcending power of reason emerges from within a world that is empirical and contingent. Habermas dubs his strategy ‘transcendence from within and into this world.’ Now he has to show not only how ideality and factuality coexist in this world without merging into each other, but also how ideality emerges from within the contingent world in the first place.
related posts 1: transcendence-from-within.html
related posts 2: Validity claims, Unconditionality, Universality and Modernism in Habermas: A reappraisal