What is an antinomy of the power of judgment?

The determining power of judgment by itself has no principles that ground concepts of objects. It is no autonomy, for it merely subsumes under given laws or concepts as principles. For that very reason it is not exposed to any danger from its own antinomy and from a conflict of its principles. Thus the transcendental power of judgment, which contains the conditions for subsuming under categories, was not by itself nomothetic, but merely named the conditions of sensible intuition under which a given concept, as a law of the understanding, could be given reality (application) – about which it could never fall into disunity with itself (at least in the matter of principles).

But the reflecting power of judgment is supposed to subsume under a law that is not yet given and which is in fact only a principle for reflection on objects for which we are objectively entirely lacking a law or a concept of the object that would be adequate as a principle for the cases that come before us. Now since no use of the cognitive faculties can be permitted without principles, in such cases the reflecting power of judgment must serve as a principle itself, which, since it is not objective, and cannot be presupposed as a sufficient ground for cognition of the intention of the object, can serve as a merely subjective principle for the purposive use of the cognitive faculties, namely for reflecting on one kind of objects.