Practical Faith and Theoretical Practice: The Single Logic Underlying Kant’s Deduction of Nature’s Purposiveness and the Deduction of the Highest Good

Abstract The present article argues that a single logic underlies Kant’s deduction of nature’s purposiveness in the Critique of Judgment and the deduction of the highest good in the Critique of Practical Reason . Both deductions are, as I would term it, transcendental deductions of success: a “success” deduction establishes the conditions for the realizability of a goal or an activity. Kant’s first developed “success” deduction is the deduction of the highest good: if the promotion of the highest good is practically necessary, then the conditions for its possibility (the existence of God) must be postulated. In the third Critique , however, the same logic is applied to theoretical cognition of empirical nature: if cognition of nature’s forms is to be possible, then nature must be assumed as purposively designed (for human cognition). Thus, I argue that in the third Critique Kant treats theoretical cognition as a practical activity, or, pari passu , Kant employs the “success” deduction model in both practical and theoretical contexts. Finally, I consider Kant’s transcendental deduction of success against the backdrop of his transcendental deduction of the categories