There are two themes that run parallel in Habermas.
On the one hand:
1) There is what I call “transcendental theme” in the context of which Habemras forcefully argue for:
a) A sharp distinction between facticty and validity.
b) A sharp distinction between nature and human (social and cultural) world.
c) What following Allison we can term as absolute spontaneity of reason.
d) Spontaneity of human subjectivity and agency.
e) Typically Kantian notions of Reflection, thought and critique.
On the other hand:
2)there is a parallel “detranscendentalization theme” in Habermas as well where he equally forcefully argues for:
a) detranscendentalization of reason.
b) Embeddedness of human agency.
c) Our status as “Being in the world”
d) Critique of transcendental subjectivity and consciousness.
e) Critique of all types of metaphysics that locates reason beyond this world.
Habermas commentators tend to emphasize one theme at the expense of the other depending on their own preferences. However what needs to be done is to understand how we can systematically synthesise these two themes in one coherent “theory” without down plying one theme at the expense of the other.
If we want to do justice two both themes in Habermas then in my opinion the only way out is to emphasise and highlight the theme of “transcendence from within”. This is the only way to go in my opinion.
If we want to say on the one hand that there is a sharp distinction between ‘facticity’ and ‘validity’ while on the other hand we also want to emphasise that ultimate ‘detranscendentalsied’ character of the ‘validity’, the only way out possible is to show how a sharp distinction between facticity and validity can emerge from within, i.e. to show how ‘factual' can produce what is not only sharply distinct from it but also in some sense antithesis of it.