Metaphysical readings of Kant’s theoretical philosophy in the Critical period are ascendant. But their possibility assumes the possibility of existence- and real-possibility-judgments about things in themselves. I argue that Kant denies the latter possibility, so metaphysical readings have dubious prospects. First, I show that Kant takes existence- and real-possibility-judgments, as necessarily synthetic, to require a relation to sensible intuition. Second, I show that the most promising metaphysical readings can ultimately neither satisfy nor explain away that requirement for existence- and real-possibility-judgments about things in themselves. I conclude with pessimistic reflections on the prospects for the metaphysical interpretive project.