The Importance of God

Descartes then, very quickly and cursorily, faces up to a major corner he seems to have painted himself into. How is he to have any reliable knowledge of the external world, when all his senses are deceptive and the only truth is his own inner process of thinking? How can his knowledge escape total self-consciousness, a thoroughgoing solipsism? The argument (or rather the summary sketch of the later argument) concerning God is the key stage which enables him to take this step.

It is not uncommon for first-time readers of the Discourse to find this section rather problematic and to offer the comment that Descartes is here simply placating religious authorities rather than being sincere in his affirmations of belief. Whatever the nature of Descartes' religious beliefs (and there seems little evidence that his statements about them are not sincere), it's important to note that the paragraphs about God are an essential part of the philosophical argument, a necessary logical foundation for the method he is proposing. Without them, the certainty he is seeking would not be available.

The argument for the existence of God is, in part, a traditional one, as Descartes acknowledges. Since he has ideas of perfection and all the flawless qualities of God, he questions where these might have arisen. As a limited and imperfect human being, he does not have those qualities himself. And they cannot have come from sense experience of nature or from outside natural sources (all of which he has discounted). Hence, the idea of such qualities must have come from somewhere else, from some being that manifests these qualities and is of a higher order of goodness than himself, that is, from God. The existence of God is thus necessarily true (2).

The perfection of God then enables Descartes to establish the validity of his principle that what we