In the Meditations on First Philosophy, Descartes sets out to build his foundation of knowledge. To discover true knowledge, Descartes uses the Method of Doubt which states that he must “ reject whatever is open to the slightest doubt”(p. 138)1. In doing so, Descartes invokes the existence of an Evil Demon who is described to be “ supremely powerful and cunning, and works as hard as he can to deceive me” (p. 138)1. In this paper, I shall argue that Descartes would not think that his having an idea of the Evil Demon proves that the Evil Demon exists.
Descartes searches for one thing he can be certain is true. He uses the role of the Evil Demon which is to deceive Descartes’ view of the world where “ body, shape, extension, motion, and place are fantasies”(p. 138). 1 In applying the Method of Doubt, Descartes has come to one necessary truth, the cogito “ I think therefore I am”. 2 Because he is able to doubt, he must be a thinking thing, and to be able to think, he must exist. I exist as long as I think that I exist; the Evil Demon cannot deceive me in thinking otherwise. Because the cogito is a “ clear and distinct” idea, it must be true. “ Clear and distinct” ideas means to be “ open and present to the attending mind”(p. 145). 1 In order to come to a truth with certainty, Descartes came up with an idea of God, a non-deceiver who has given him a way to arrive at true beliefs. 2
Descartes is certain that God exists and that the idea of God came from God Himself. All ideas have the same degree of Formal reality, whether the idea is of a finite or infinite substance. Some things are on a higher scale of Formal reality than others. For example, God would have a higher degree than human. The Presentational reality of an idea is the amount of Formal reality the idea has. 2 Descartes states that the idea of God, who is “ eternal, infinite, omniscient, omnipotent, and creator of all things other than himself”(p. 143)1, lies on the highest degree of Presentational reality. Therefore, God has a higher formal reality than Descartes’ idea of God. God is seen to be “ omnipotent and omniscient”; he is seen to be perfect. 2 And since Descartes knows that he himself is an imperfect being, as he is able to doubt, there must exist a perfect being out there. Descartes concludes that he could not have invented the idea of God, because ideas must be at least as close as the cause – “…there is at least as much [reality] in the …cause as in its effect” (p. 143-4)1. Since Descartes could not have caused this idea himself, God must have put it there. 2 He states that, ” By God, I understand, a substance which is infinite…it must be concluded that God necessarily exists”(p. 145). 1 God must exist.
If God exists and He is not a deceiver, then He would not allow an Evil Demon to deceive my thoughts. To allow an Evil Demon to deceive me, God would be just be as bad of a deceiver, but Descartes’ idea of God is that of perfection; God would not exist to deceive me. The Evil Demon and God are not of the same entity. According to Descartes, the Evil Demon plays the role of a deceiver confusing my very view of the world, while God allows me to find my way to true knowledge. One can either be deceived or not to be. This follows that both the Evil Demon and God cannot exist at the same time, either the Evil Demon exists to deceive our views or God exists. Descartes proved that God exists, therefore the Evil Demon cannot exist.
In conclusion, Descartes would not think that having the idea of an Evil Demon would prove that the Evil Demon exists. The main purpose Descartes went out to prove the existence of God is to arrive at true knowledge. He knows for certain that the cogito is true, even the Evil Demon cannot deceive him of that. In proving the existence of God, Descartes can rule out the idea of the existence of a deceiver, the Evil Demon.
1Perry, John, Michael Bratman, and John Martin Fischer. Introduction to Philosophy: Classical and Contemporary Readings. New York: Oxford UP, 2010. Print.
2Notes taken from lecture