Abstract

KANT ARGUES AT GREAT LENGTH in the Critique of Pure Reason that the existence of God cannot be demonstrated by means of theoretical reason. For after dividing all traditional theistic proofs into three different kinds—the ontological, the cosmological, and the physico-theological—Kant argues first that the cosmological and physico-theological implicitly assume the ontological argument and then that the ontological argument is necessarily fallacious. By restricting knowledge in this manner Kant notoriously makes room for faith, that is, in this case, for a practical proof of the existence of God, which he develops in the Critique of Practical Reason. Kant’s reasons for rejecting theoretical proofs of the existence of God have received considerable attention. In particular, Kant’s objection to the ontological argument, namely that existence is not a real predicate, still seems relevant in contemporary philosophy of religion. What has not received much attention, however, is the relationship between Kant’s rejection of theistic proofs in his critical period and his views on the matter in his pre-critical period. For throughout his pre-critical period, but especially in his The Only Possible Argument in Support of a Demonstration of the Existence of God, Kant believes that there is a theoretical proof of the existence of God. One would naturally expect Kant’s criticisms of theistic proofs as developed in the “ideal of pure reason” to apply in straightforward ways to his earlier attempts at a theistic proof. However, Kant rejects the three traditional arguments in The Only Possible Argument just as he does in the first Critique. Further, his reason for rejecting the ontological argument in particular is identical to the one presented in the first Critique: “Existence is not a predicate or a determination of a thing.” Accordingly, Kant understood himself to be developing a theistic proof in The Only Possible Argument that is distinct from the three traditional arguments and is also not subject to the objections he raises against them. Given that Kant rejects all theoretical proofs of God’s existence in his critical period and given that he did not take his critical objections to the traditional proofs to apply to the theistic proof developed in The Only Possible Argument, what is his justification for rejecting his pre-critical argument for God’s existence?