The Highest Good as the Ideal of Reason in the Canon of the first Critique

Abstract In the Dialectic of the first Critique, Kant claims that a highest being is the transcendental ideal of speculative reason. However, the Canon of the Doctrine of Method presents the highest good as an ideal of both the speculative and the practical use of reason. In this paper, I argue (1) that the highest good is the ideal of the unity of reason – unlike the ideal in the Dialectic – insofar as (2) the highest good serves both the speculative and the practical employment of reason. Accordingly, I also argue that (3) these two employments are complementary, not alternative. Kant’s argument for the ideal of the highest good in the Canon shows that the unity of reason combines the two lawful employments of reason. In order to be reason’s highest ideal, this ideal cannot just mirror the demands of speculative reason – it must also involve the other fundamental employment of reason, i. e., the practical. This highest standpoint cannot be merely speculative but must be moral as well: not just a highest ideal, but also a good (the highest good).