Kant on the Cosmological Argument

In the Religion Lectures, Kant remarks that the ontological argument gives the cosmological argument “all its probative force [Beweiskraft]” (28: 1006–7; compare A 607/B 635). We shall shortly consider why he should say such a thing. But the point to note for now is just that the first phase of the cosmological argument, even when it is supplemented by the argument for AC, will not have shown that there is an absolutely necessary being (understood as a being that cannot fail to exist), for it will not have shown that the most real being cannot fail to exist. This point, I take it, is what Kant is driving at when he says, “The greatest perfection, no less than the smallest, hovers without support before speculative reason” (A 613/B 641). He means that, unless we assume the ontological argument as an inferential subroutine — and unless that argument is sound — even the most real (or most “perfect”) being will lack a proof of its necessary existence. Accordingly, Kant supposes that the ontological argument is required to license the inference from the most real being’s (supposed) existence to its necessary existence. Since this extra step is required, the cosmological argument, as it stands, establishes — at best, and waiving certain other objections that Kant will make — only the existence but not the necessary existence of an ens realissimum. Since the argument establishes less than it purports to establish, its proponent (who fails to recognize this fact) commits an ignoratio elenchi (A 609/B 637). The second of Kant’s three main charges against the cosmological argument is thus substantiated.