ABSTRACT
Descartes himself declares that the proof of God's existence has retrospective effect. The Metaphysic is an inquiry into the nature of material and spiritual reality. But the doubt not only forces us to question whether material things exist, but also whether ideas which we have of the essences both of material and spiritual things truly represent their natures. He has to prove that his ideas correspond with the reality which he suspects to exist beyond his own substance. The proof cannot be made from the side of the external reality because it is doubtful whether that exists. The proof must therefore start from the nature of our ideas taken as not known to correspond with anything external to them. Hence Descartes commences his proof that we have knowledge of the real from ideas taken as entities not truly representing anything actual but only as seeming to do so. This is the course taken by the first proof of God's existence.
