The schema of a pure concept of the understanding, on the contrary, is something that can never be brought to an image at all, but is rather only the pure synthe sis, in accord with a rule of unity according to concepts in general, which the category expresses, and is a transcendental product of the imagination, which concerns the determination of the inner sense in general, in accordance with conditions of itsa form (time) in regard to all representations, insofar as these are to be connected together a priori in one concept in accord with the unity of apperception.