In Meditations on First Philosophy, Descartes attempts to prove the theory of Cogito, commonly known in popular culture as "I think, therefore I am." (AT 27) The Cogito is significant in Descartes' foundationalist project. Descartes foundationalist project consists of finding basic indubitable beliefs to base his future knowledge. This is because he believes that all knowledge processed through the senses can possibly be deceptive and misleading.
The Cogito is very significant in respect to Descartes' foundationalist project. The Cogito to Descartes is an indubitable belief which he uses to prove his existence and to prove his ways of thinking. Descartes believes the senses can be deceptive in many ways and that one can't always rely on the senses to form beliefs or theories. "I will believe that my memory tells me lies, and that none of the things that it reports ever happened. I have no senses."
(AT 24) The Cogito is significant because Descartes is going to base all of his future beliefs from the basic foundational thoughts that he finds in the Cogito and his correspondence of thinking and his existence.
The Cogito could encounter problems though. One could say, what is special about thinking? Couldn't one say, I run, therefore I am, or I eat, therefore I am? "You could have mad the same inference from any one of your other actions." (OR5, pg68) How does Descartes know that he is thinking, running, or eating? Also, how does Descartes know that he is thinking with certainty? How does one know what thinking actually is? If one we do not know what thinking is for certain, then we cannot come to the conclusion of one existing. How can one know for sure that we are even thinking or saying anything in our so-called existence? (OR6...