 Kant’s assessment of the Physico-Theological (Design) Argument is substantially different from his treatment of the other two classic proofs. While he still contends that it, like the Cosmological argument, remains ultimately grounded upon the Ontological Argument’s assumption that existence is a predicate, this objection does not fully undo the force of the Physico-Theological Argument. Kant in fact expresses sympathy for this argument, writing, for instance, that it “always deserves to be mentioned with respect” (A623/B651) and that it is “the oldest, the clearest, and the most accordant with the common reason of mankind” (A623/B651). He further claims that the argument succeeds in at least establishing “an architect of the world” and a cause “proportioned” to the order of nature. So, up to this point in the argument, he writes, “we have nothing to bring against the rationality and utility of this procedure, but have rather to commend it further” (A624/B652). What Kant cannot accept, however, is its advance from a “Wise Author of Nature” to an infinite creator. When it moves from architect to creator, it proposes an “original” and “supreme” cause, and in so doing, it calls for a being whose existence depends upon nothing but itself. This returns us to the Cosmological/Modal argument, and thus to its dependency on the Ontological. Despite, however, the failure of the argument to establish the existence of an infinite creator, Kant does not abandon the relevance, particularly the regulative relevance of the idea of a “Wise Author of Nature” for the natural sciences, a point he repeats in both the Appendix to the Transcendental Dialectic and in the Canon of Pure Reason.