Clear your mind, if you will, of everything you have ever seen or known to be true. To begin understanding Rene Descartes' method of doubt, you need to suspend all prejudice and prior judgments and start with a clean slate "for the purpose of discovering some ultimate truth on which to base all thought." (Kolak, Pg.225). Discouraged with much skepticism from his own beliefs, Descartes was embarrassed of his own ignorance. He set out to try and accomplish the task of finding an absolute truth in which he would base his beliefs. Placing upon himself a task to find an axiom or absolute truth to base all thought, "he ventured as a youth in travel to collect a variety in experiences to derive some profit in which he would be benefited." (Kolak, Pg.225). When analyzing the method of doubt "you must take complex conceptions into their constituents until the irreducible elements are simple, clear, and distinct ideas, and show that all such basic ideas can be derived from, or can depend upon, the primary consciousness of a being that it thinks." (Durant, Pg.639).
Two types of "knowing"
First, understanding that there are conceptually two types of "knowledge or knowing" aposteriori, and apriori, you can further understand where Descartes is coming from with his representations of his elucidations. Knowledge that is based solely on the sense and reasoning that comes through the senses is understood as aposteriori, and its foil a priori is understanding through reasoning. At this point, Descartes has already discarded aposteriori knowledge on the basis that his senses are deceiving and it is not a credible way to base one's beliefs. (Descartes, Pg.19). On the other end of the spectrum, apriori knowledge ,which is an understanding based on reasoning, is a more efficient way of explaining the method of doubt presented by Descartes.
Method of Doubt Step One
On the journey to find truth to base all thought...