It is commonly thought that the distinction between subjectively valid
judgements of perception and objectively valid judgements of experience
in the Prolegomena is not consistent with the account of judgement Kant
offers in the B Deduction, according to which a judgement is ‘nothing
other than the way to bring given cognitions to the objective unity of
apperception’. Contrary to this view, I argue that the Prolegomena
distinction maps closely onto that drawn between the mathematical and
dynamical principles in the System of Principles: Kant’s account of the
Prolegomena distinction strongly suggests that it is the Analogies of
Experience that make it possible for judgements of perception to give rise
to judgements of experience. This means that judgements of perception are
objectively valid with regard to the quantity and quality of objects, and
subjectively valid with regard to the relation they posit between objects.
If that is the case, then the notion of a judgement of perception is consistent
with the B Deduction account of judgement.