Let us examine with serious attention, not the very words of Descartes, as an historian might do, but the course of thought of which Descartes is one of the most illustrious representatives. To recognize in the reason traces of God, and to show that in faith in God consists the only warrant of the reason, is not to argue in a vicious circle, because, in this way of proceeding, what we are employed in is not reasoning, but analysis; we are establishing a fact in order to ascertain what that fact implies and supposes. This fact is the natural faith which man has in his own reason, when his reason reveals to him the immediate light of evidence, or the mediate light of certainty. Now, when man confides in his reason, it is not in his individual reason that he confides, for he has no doubt that what is evident for him is so also for others. If, tossed by a tempest, he were thrown upon an island of savages, he would not think that those savages, when they came to reflect, would be able to discover that the axioms of our geometry are false, or to make elements of logic which would contradict our own. We believe in a general reason, everywhere and always the same, and in which the reason of each individual participates. We believe therefore that there is a principle of truth which exists in itself, a reason which is eternal and everywhere present; in other words, we believe in God considered as the source of the universal intelligence. To believe in one's reason, is to believe in God, in this sense: the fact of the confidence which we place in our own faculty of thought, supposes a concealed faith in eternal truth. This is the analysis of which I was speaking. It is a circle if you please, but it is a circle of light, outside of which there is, as we shall see by and by, nothing but darkness and hard contradictions.