Epistemology could be described as "indubitably true", he advocates, would be to see things "clearly and distinctly". He argued that if there is an omnipotent, good being who made the world, then it's reasonable to believe that people are made with the ability to know. However, this does not mean that man's ability to know is perfect. God gave man the ability to know but not omniscience. Descartes said that man must use his capacities for knowledge correctly and carefully through methodological doubt. The dictum "Cogito ergo sum" (I think, therefore I am) is also commonly associated with Descartes' theory. In
Cogito, ergo sum of other minds at this point. This is something that has to be thought through by each of us for ourselves, as we follow the course of the meditations. Second, he does not say that his existence is necessary; he says that "if he thinks", then necessarily he exists (see the instantiation principle). Third, this proposition "I am, I exist" is held true not based on a deduction (as mentioned above) or on empirical induction but on the clarity and self-evidence of the proposition. Descartes does not use this first certainty, the "cogito", as a foundation upon which to build