Descartes' first meditation, his main objective is to present three skeptical arguments to bring doubt upon what he considers his basic beliefs. Descartes believes this to be an intricate part of his complete epistemological argument. Descartes skeptical arguments are not intended to be a denial of his basic beliefs. On the contrary, he uses these arguments to help prove one of his main theses, which is the existence of God. One of the main premises that Descartes uses in his proof for the existence of God comes from the evil demon argument, which he proposed, in the first meditation. It is this evil demon argument, which will be the topic of the following discussion.
The purpose of Descartes' evil demon argument is to establish doubt upon his belief that God is the sole figure who puts thoughts into his mind. A God that he believes to be an omnipotent supremely good being, not capable of deceiving him or imposing falsehoods upon him. Out of the three skeptical arguments that Descartes proposes in the first meditation, it is the evil demon argument that is the most important. Both of Descartes other two arguments succeeded in their goal to establish doubt upon the existence of the outside world, which were the sensory illusion and dreaming arguments. However, people such as Descartes who believe in an omnipotent supremely good being, called God, could easily refute these arguments. Therefore, in order for Descartes to start from the very beginning, in terms of knowledge, he needed to find a way to bring doubt upon the very thing that was the basis for all his knowledge, which was God.
In the evil demon argument, Descartes is not denying the existence of God. The way the argument is presented, Descartes makes it seem as if the evil demon coexists with God. Therefore, when his mind is being deceived or being given false information it is not from God but from the evil demon. From this skeptical argument, one would come to doubt the existence of the external world. If an evil demon really existed there would be the possibility that the only part of our being that exists would be our minds, in whatever form that maybe, probably incorporeal. Therefore meaning that the world that we live in, the external world, is non-existent and merely a mirage placed into our minds by an evil demon.
Obviously, to any sane person, this would sound irrational, but this is the possible world that Descartes presents to establish doubt in his common beliefs, mainly his belief that there exists an external world. One of the questions that needs to be raised when discussing Descartes' first meditation and his skeptical arguments is; is it possible to completely separate one's self from all their current beliefs? For this is what Descartes sets out to do in the first meditation. This question is highly relevant in terms of Descartes evil demon argument, for it appears no matter what, he is not able to separate himself from his belief in God. Descartes' argument is not that the evil demon is replacing God, which would seem to be the logical view. Instead, Descartes says that the evil demon is coexisting with God. Therefore, even though Descartes claims to be starting at ground zero and proceeding to prove that his common beliefs are true, he never actually denies the existence of God.
In the later meditations, he reveals his belief in innate ideas and the existence of God is one of them. Yet as far as Descartes evil demon argument is concerned, the fact that he maintains this belief in God throughout causes problems, as will be shown. The problem that arises when Descartes believes that the evil demon and God co-exist is that he is contradicting himself. When the situation is looked at more carefully, it can be seen that the evil demon can actually be more powerful than the God that Descartes believes exists. If that is the case then there is the possibility that God really does not exist, for the evil demon could just be deceiving Descartes' mind into believing that a God exists. Therefore, since Descartes assumes the existence of God and by using his own evil demon argument, it can be proven that God does not exist, there is a contradiction in his argument.
Descartes though could easily avoid this contradiction by saying that God is also all-powerful. Meaning nothing can be more powerful than God, considering Descartes already believes God to be omnipotent and supremely good, being all-powerful does not seem to be too much of a stretch. However, this argument could end up being never ending when one is talking about which supernatural being is more powerful than another one. Nonetheless putting aside Descartes somewhat circular reasoning, his arguments for doubting his basic beliefs, are very strong and convincing. When analyzing Descartes' evil demon argument it is important to keep in mind his initial goal, which was to establish a certain amount of doubt into the beliefs which he took for granted, such as the existence of the external world. So he would be able to disprove these doubts in order to prove his original beliefs.
Looking at Descartes argument in these terms it can be seen that he did accomplish the task that he set out to do, even though one has to except the fact that he will always believe in the existence of God.