 The bottom-up problem has a metaphysical mirror-image, which can be called the top-down problem. This problem afflicts Kant’s transcendental doctrine of judgment, and consequently also his theory of the principles of pure understanding (see the supplement  Completing the Picture of Kant’s Metaphysics of Judgment).  The worry here is simply that even allowing for the transcendental schematism of the judgment, there is still no absolute guarantee that a given universal transcendental principle or transcendental concept of the understanding, construed as a rule for ordering sensory appearances or sensory objects, has been completely applied to sensory appearances or objects. In other words, even allowing for his transcendental doctrine of the judgment, Kant has not given us good reason to think that there cannot be any sensory appearances or objects that fail to be subsumed under the transcendental principles of nature. In the Critique of Pure Reason, Kant calls the specifically causal-law-governed or nomological interconnection of all sensory appearances or objects under transcendental principles the “transcendental affinity”of the sensory manifold of intuitions (A114). In the A edition of the first Critique, Kant asserts that if the categories are objectively valid, then the transcendental affinity of the manifold automatically follows. Then, assuming the strongest version of transcendental idealism, he further asserts that from transcendental affinity, an “empirical affinity” of the sensory manifold of intuitions also directly follows (A115). Now since empirical affinity is the complete application to actual empirical nature of the system of causal laws under transcendental principles, it follows that empirical affinity is the same as the systematic unity of nature. So Kant is saying that the systematic unity of nature is a trivial consequence of transcendental affinity.