In the B-Deduction Kant states that, although it “reveals the necessity of a synthesis of the manifold given in intuition,” the “principle of the necessary unity of apperception is … an identical, and therefore analytic proposition” (B135). Moreover, as if to emphasize that this was not a momentary slip, he remarks shortly thereafter that the proposition which “makes synthetic unity a condition of all thought … is, as already stated, itself analytic.” This, he continues, is because:

But, in spite of Kant's unambiguous pronouncements, this claim has proven to be a stumbling block for even the most sympathetic and thorough commentators. To be sure, one could regard as analytic the trivial claim that all my representations must be subject to those conditions, whatever they may be, that allow them to be my representations. As the above citations indicate, however, Kant took the analyticity to extend also to the apparently substantive claim that the essential condition of the possibility of such self-ascription is that the representations be unifiable in a single self-consciousness. In short, Kant regards the principle of the necessary synthetic unity of apperception as itself analytic.