Cartesian doubt him. While methodic doubt has a nature, one need not hold that knowledge is impossible in order to apply the method of doubt. Indeed, Descartes' attempt to apply the method of doubt to the existence of himself spawned the proof of his famous saying, ""Cogito, ergo sum"" (I think, therefore I am). That is, Descartes tried to doubt his own existence, but found that even his doubting showed that he existed, since he could not doubt if he did not exist. Cartesian doubt Cartesian doubt is a form of methodological skepticism associated with the writings and methodology of René Descartes
Cogito, ergo sum further knowledge; rather, it is the firm ground upon which he can stand as he works to discover further truths As he puts it: Archimedes used to demand just one firm and immovable point in order to shift the entire earth; so I too can hope for great things if I manage to find just one thing, however slight, that is certain and unshakable. (AT VII 24; CSM II 16) According to many Descartes specialists, including Étienne Gilson, the goal of Descartes in establishing this first truth is to demonstrate the capacity of his criterion — the immediate clarity and