was, of course, not a skeptic, since his purpose was to arrive at the ultimate base of certainty and truth and to rebuild on this indubitable foundation the edifice of knowledge. He compared himself to Archimedes. "Archimedes, that he might transport the entire globe from the place it occupied to another, demanded only a point that was firm and immovable; so also, I shall be entitled to entertain the highest expectations, if I am fortunate enough to discover only one thing that is certain and indubitable." (6) Descartes was fortunate enough to discover his firm and immovable fulcrum: his own existence -- "I think, therefore I am." He had now his fulcrum; what would be his lever?It would have to be the trustworthiness of his reasoning powers. But how could he establish this, seeing that this also was involved in universal doubt and destroyed with all other spontaneous convictions? Descartes hit upon an ingenious idea. He would demonstrate the existence of an infinitely perfect Being, who must have given man faculties which are trustworthy and capable of discovering truth. The only thing absolutely certain so far for Descartes was his own existence; and from this fact alone he would be obliged to deduce God's existence.Here is his line of thought: We have in our mind the idea of God as an infinitely perfect Being. But an infinitely perfect Being must have existence, otherwise it would not be infinitely perfect. Ergo, God exists. (7) This is an a priori or ontological argument.Descartes attempts to prove God's existence a posteriori, by means of an argument from causality: We have the idea of God in our mind. Since this idea represents an infinitely perfect Being, we, as finite beings, cannot have originated such an idea in virtue of our own powers. This idea being beyond our mental capacity, it could have originated only from a Being who possesses such infinite perfection. Ergo,...
