Patrick Kain

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.

In his lectures, Kant suggested to his students that the freedom of a divine holy will is “easier to comprehend than that of the human will,”(28:609) but this suggestion has remained neglected. After a review of some of Kant’s familiar claims about the will (in general), and about the divine holy will in particular, I consider how these claims give rise to some initial objections to that conception. Then I defend an interpretation of Kant’s conception of the divine will, and of its historical development in relation to Leibniz and Spinoza, that identifies the content, origin, and role of God’s representations in a way that is responsive to some of the historical and contemporary problems. Finally, I trace a few of the implications of this account of the divine will for our understanding Kant’s account of freedom more generally, including human freedom.