On Critical philosophy
. . . But the Critical philosophy expands the opposition in such a way that experience in its entirety, i.e., both those elements together, belongs to subjectivity and NOTHING remains opposite it but the thing-in-itself.
The specific forms of the a priori, i.e., of thinking, taken as merely subjective activity despite its objectivity, results as follows -- a systematization that, by the way, rests on merely psychological-historical foundations.
. . .
However, the misunderstanding of wanting already to know prior to knowing or
of wanting not to set foot in the water before one has learned to swim, very quickly creeps into the process.
To be sure, the forms of thought should not be employed unexamined, but examining them is already itself a process of knowing.
. . .
They themselves examines themselves and they must determine for themselves their limits and point up their deficiency in themselves.
the forms of thought must be considered in and of themselves [an und für sich]
[dialectic] , namely that it is to be regarded not as something brought to bear on thought-determinations from outside of them, but instead as immanent in them.