Descartes in his two masterpieces, the Discourse on Method and Meditations on First Philosophy, attempts to establish the bare essence of what it is to be human. He distills the world into its most basic elements, and arrives at his legendary conclusion: ôCogito ergo sum,ö or I think therefore I am. Because he was unable to separate his faith in God from his reason, as we will see, Descartes has left himself and his beautiful chain of ideas wide open for criticism.
In Discourse on Methnd, Descartes prnmulgates four basic laws that he believes should be the root of all learning, whether scientific or religious. The first and most important law is ôTo accept nothing as true that is not recognized by the reason as clear and distinctö (Discourse, I). The most important thing about this law is its focus on ideas and reasonùor the subjective impressions of the human intellect. It is impossible for a human being to break the world into anything smaller than an idea, and thus the ultimate principle of truth, according to Descartes, is the clearness of an idea.
In his search for the truth, Descartes decides ôthat I ought to reject as absolutely false all in regard to which I could suppose the least ground for doubt, in order to ascertain whether after that there remained aught in my belief that was wholly indubitable" (Discourse, I). In his Meditations, Descartes decides to explore this idea to its logical conclusion and to explore the lengths to which one can doubt. One can doubt all the impressions that exist within their mind, whether those impressions enter the mind through the senses or through the intellect. While Descartes is not prepared to doubt GodÆs benevolence, he postulates that he could be under the sway of an evil genius who could be manipulating all that he observes and thinks and could pervert even mathematical truths.
Descartes thus carries doubt to its extreme end: he doubts even his own existe...