Referring to Descartes', Meditations on First Philosophy

(1) Why doesn’t Descartes simply determine what's real by looking around him and use his sense experience?  (2) In Meditation II, Descartes states, "I am; I exist - this is certain." Explain why Descartes claims that his knowledge here about this cannot be doubted? (3) What is the nature of the "I" for Descartes and why doesn't it refer to the physical body of Descartes?

“The Aristotelian tenet stated that everyone is born with a clean slate and that all material for intellectual understanding must be provided through sensation. Descartes argued that since the senses sometimes deceive, they cannot be a reliable source for knowledge”. (1) He claimed that even though you see it, it may not be real. After all, we cannot yet differentiate between dream and reality. So, who’s to say life itself is nothing but an illusion?

 “All sensory beliefs had been found doubtful in the previous meditation, and therefore all such beliefs are now considered false. This includes the belief that I have a body endowed with sense organs. But does the supposed falsehood of this belief mean that I do not exist? No, for if I convinced myself that my beliefs are false, then surely there must be an “I” that was convinced. Moreover, even if I am being deceived by an evil demon, I must exist in order to be deceived at all”. (1) “So, I must finally conclude that the proposition ‘I am,’ ‘I exist,’ is necessarily true whenever it is put forward by me or conceived in my mind” (AT VII 25: CSM II 16-17) (1). In conclusion, Descartes believes that there has to be a ‘self’ but that ‘self’ is not necessarily physical. It is simply a form of ‘being’. What we perceive ourselves to look like may in fact be wrong. But, the thought that we do indeed exist must be true simply because if it were not, how would we have ever had the thought?

                                                                                                Jessica Burnett

(1) Justin Skirry. (September 13, 2008). Rene Descartes (1596-1650): Overview. In Internet Encyclopedia of Philosophy. Retrieved August 20, 2013, from http://www.iep.utm.edu/desarte/#Sh2b.