Academic journal article The Review of Metaphysics

Kant on the Unity of Theoretical and Practical Reason

Academic journal article The Review of Metaphysics

Kant on the Unity of Theoretical and Practical Reason

Article excerpt

Kant famously asserts that reason is one and the same, whether it is applied theoretically, to the realm of what is, or practically, to the realm of what ought to be. His view that theoretical and practical reason are two different applications of "one and the same reason"(1) is known as the doctrine of the unity of reason. Yet Kant himself seems to contradict this doctrine in two ways. In some passages in the very same works in which he asserts the unity of reason, he also states that this unity has yet to be demonstrated. According to the Foundations of the Metaphysics of Morals, demonstrating the unity of practical and theoretical reason is one of the tasks of a critique of practical reason.(2) In the Critique of Practical Reason, Kant further postpones this task by saying that we can expect this unity only to be demonstrated "some day."(3) Moreover, Kant also claims that theoretical and practical reason are "united" through the idea of the purposiveness of nature, suggesting an original disunity.(4) Thus, it seems that Kant defends three incompatible claims regarding the unity of reason. It would seem that he cannot consistently hold at the same time that (1) theoretical and practical reason are one and the same reason, applied differently, (2) that he still needs to show that they

are, and (3) that they are united.

The assessments in the literature are as divergent as Kant's statements. Some authors have argued that Kant does not give a coherent account of the unity of theoretical and practical reason at all. In his article, "The Unity of Reason: Pure Reason as Practical Reason in Kant's Early Conception of the Transcendental Dialectic," Paul Guyer argues that early in the critical period, Kant wisely realized that the notion of a unity of reason can refer only to completed systematicity in the sphere of practice, thereafter gradually giving up the idea of a unity of theoretical and practical reason, and finally reassigning theoretical reason's regulative ideal of systematicity to reflective judgment.(5) Others, most recently Jurg Freudiger, have argued that Kant does present a coherent account of the unity of theoretical and practical reason, but not until the Critique of Judgment.(6) This view that Kant does not present an account of the unity of reason until the third critique is often based on a stylized view of the three critiques, according to which the first critique establishes the a priori laws of nature, the second critique the a priori law of freedom, and the third critique the harmony between the laws of nature and freedom. In this vein, Henry Allison argues that before the Critique of Judgment, Kant defends "a rigid separation between the realms of freedom and nature," whereas in the third critique, he "now insists on the necessity of a mediating concept (the purposiveness of nature), which would make possible the transition from the concept of nature to the concept of freedom."(7) Despite their differences, these assessments share one assumption, namely, that before the Critique of Judgment (1790), Kant does not adequately address the relationship between theoretical and practical reason.

Other commentators, by contrast, argue that Kant does present a coherent account of the unity of reason in his critical work of the 1780's. Susan Neiman and Klans Konhardt maintain that Kant develops this account in the first two critiques. On their view, the unity of theoretical and practical reason consists in the fact that they share structural and functional features.(8) Konhardt also argues that because Kant's account of the unity of reason was in essence ready as early as the Critique of Pure Reason, the Critique of Judgment brings "no essential modifications" in this account at all.(9)

In this paper, I propose a new reading of Kant's doctrine of the unity of reason. I argue that this doctrine should be viewed as reaching a coherent form in the 1780's, but for reasons other than those asserted by Neiman and Konhardt. …

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