DESCARTES 



theory of gravitation ; but he was contented to rest 

 satisfied with vain conjectures. It is often said that 

 Descartes had created Newton. So far as Geometry 

 is concerned, it is undoubtedly true; but if experi- 

 mental philosophy is spoken of, it is absolutely false. 

 In Descartes' celebrated " Discours sur la methods 

 pour bien conduire sa raison et chercher la verite 

 dans la science," and in the "Meditations touchant 

 la premiere philosophic ou Fon demontre Pexistence 

 de Dieu et Pimmortalite cle Tame," he started with 

 the fundamental maxim : " In order to attain to the 

 truth, one must strip oneself of all the opinions that 

 one has received, and reconstruct anew the founda- 

 tions of the whole system of one's knowledge." 

 Obedient thereto, he stripped himself of belief in the 

 testimony of the senses, the existence of the body, 

 of himself, and even of God, and reduced his sci- 

 ence to the single fact, the single proposition, the 

 only evidence for him: "Cogito ergo sum" (I think, 

 therefore I am). From the certitude to him of the 

 mind, or of thought, Descartes passed suddenly to 

 the certitude of the existence of God, by means of 

 the axiom in Logic, which he transformed into a 

 metaphysical principle : " The mind can affirm of a 

 thing all that is contained in the idea of a thing." 

 This certitude became for him the base and the guar- 



67 



