Thus this argument really begins at experience, and is not completely a priori, or ontological. The object of all possible experience being the world, it is called the cosmological proof. It contains no reference to any peculiar property of sensuous objects, by which this world of sense might be distinguished from other possible worlds; and in this respect it differs from the physico-theological proof, which is based upon the consideration of the peculiar constitution of our sensuous world.
The proof proceeds thus: A necessary being can be determined only in one way, that is, it can be determined by only one of all possible opposed predicates; consequently, it must be completely determined in and by its conception. But there is only a single conception of a thing possible, which completely determines the thing a priori: that is, the conception of the ens realissimum. It follows that the conception of the ens realissimum is the only conception by and in which we can cogitate a necessary being. Consequently, a Supreme Being necessarily exists.
In this cosmological argument are assembled so many sophistical propositions that speculative reason seems to have exerted in it all her dialectical skill to produce a transcendental illusion of the most extreme character. We shall postpone an investigation of this argument for the present, and confine ourselves to exposing the stratagem by which it imposes upon us an old argument in a new dress, and appeals to the agreement of two witnesses, the one with the credentials of pure reason, and the other with those of empiricism; while, in fact, it is only the former who has changed his dress and voice, for the purpose of passing himself off for an additional witness. That it may possess a secure foundation, it bases its conclusions upon experience, and thus appears to be completely distinct from the ontological argument, which places its confidence