Descartes approached the issue external existence by been skeptical of all knowledge from his senses. He stated that since he experienced similar sensations while dreaming and awake, and there been no way of differentiating the wake and dream perceptions, Descartes noted that it was possible that he was dreaming. He then proceeded to describe possible ways through which he could learn about material objects. Descartes presupposed that the cause of his ideas on material objects was himself just as a solipsist (Sperring). However, if he could doubt the truths, how then would he come to know the true beliefs? Descartes claimed that one could distinctly and clearly perceive the truth.
The standard form
P1. One cannot distinguish sensation when awake or while dreaming. Therefore, at times, one may experience feelings that are false
P2. It follows that one can doubt the truths of beliefs
P3. If I think, I am, despite having mistaken the source of my ideas, I cannot be mistaken about them.
P4. There is no more objective reality than formal reality. It follows that if I have an idea about a perfect infinite substance; the infinite substance is the real absolute knowledge
C. Therefore, the possible cause of the knowledge of infinite substance is the substance itself. The conclusion leads to the Cartesian circle.
The Cartesian circle
Descartes set out to prove the rule of truth that all that he clearly and distinctly perceived as true. However, his arguments created vicious circles based on causal arguments that created a problem. Descartes responded by stating that one could rely on the clear and distinct perceptions without having to prove that earlier outstanding and clear sensations were real (Pynn, 2).
Works cited
Pynn, Geoff. Handout5: The Cartesian Circle. 2012. Pdf file. Available at <http://www.niu.edu/~gpynn/322_H5.pdf>
Sperring, Paul. “Descartes’ Proof of the External world.” 2005. Pdf file. Accessed on April 9, 2016. Available at <http://www.richmond- philosophy.net/rjp/back_issues/rjp15_sperring.pdf>
