Patrick Kain

Several interpretive disagreements about Kant's theory of divine commands (esp. in the work of Allen Wood and John E. Hare) can be resolved with further attention to Kant's works. It is argued that Kant's moral theism included (at least until 1797) the claim that practical reason, reflecting upon the absolute authority of the moral law, should lead finite rational beings like us to believe that there exists an omnipotent, omniscient and holy being who commands our obedience to the moral law and proportions happiness to virtue. Kant's apparently contradictory claims about the relationship between morality and religion reflect his view that our acceptance of the authority of the moral law is incomplete or rationally unstable absent such a theological postulate.

Kant’s claims about supersensible objects, and his account of the epistemic status of such claims, remain poorly understood, to the detriment of our understanding of Kant’s metaphysical and epistemological system. In the Critique of Practical Reason, and again in the Critique of Judgment, Kant claims that we have practical cognition (Erkenntnis) and knowledge (Wissen) of the moral law and of our supersensible freedom; that this cognition and knowledge cohere with, yet go beyond the limits of, our theoretical cognition; and that this knowledge grounds rational belief (Vernunftglaube) in the existence of God, the immortality of our soul, and the real possibility of the “highest good.” This essay untangles some of these claims about practical cognition, practical knowledge, and practical belief and their relation to Kant’s account of theoretical cognition and theoretical knowledge. There is a core conception of cognition and knowledge underlying the accounts of theoretical cognition and practical cognition, which allows for a principled distinction between cases of practical knowledge and practical belief. Kant’s doctrine of the “fact of reason” turns out to be crucial to his claims about legitimacy of and distinction between the two forms of practical cognition, one which constitutes knowledge and another which cannot.

This critical survey of recent work on Kant's doctrine of the fact of reason and his doctrine of the practical postulates (of freedom, God, and immortality) assesses the implications of these doctrines for the debate about realism and antirealism in Kant's moral philosophy. Section 1 briefly surveys some salient considerations from the first Critique and Groundwork. In section 2, I argue that recent work on the role, content, "factual" nature, and epistemic status of the fact of reason does not support an anti-realist interpretation of Kant's ethics. In section 3, I argue that recent work on the derivation and epistemic and ontological status of the practical postulates does not support an anti-realist interpretation of Kant's ethics.