Kant is committed to the reality of a subject self, outside time but active in forming experience. Timeless activity is problematic, but that can be dealt with. But he holds that the subject of experience is not an object of experience, so nothing can be known about it; this raises a problem about the status of his own theory. But he ought to allow that we can know of its existence and activity, as preconditions of experience: the Critique allows that synthetic a priori truths can be known in this way. However, its identity conditions remain unknowable. Kant’s unity of apperception shares much with Locke’s continuity of consciousness, but does not determine the identity of a thing. Personal identity is bodily identity. Only Kant’s moral philosophy justifies recognizing other selves; it could warrant ascribing a similar status to animals.
Two Kindred Neo-Kantian Philosophies of Science: Pap’s The A Priori in Physical Theory and Cassirer’s Determinism and Indeterminism in Modern Physics