In the "Mediations of First Philosophy" Descartes tries to prove the existence of God in the third meditation. He does this by coming up with several premises that eventually add up to a solid argument. First, I will explain why Descartes ask the question, does god exist? And why does Descartes think he needs such and argument at this point in the text. Secondly, I will explain, in detail, the arguments that Descartes makes and how he comes to the conclusion that God does exist.
Next, I will debate some of Descartes premises that make his argument an unsound one, including circular reasoning. Finally, I will see if his unsound argument has diminished and undermined his principal goals and the incorrigible foundation of knowledge. In earlier meditations Descartes proved that he existed through the Cogito argument. Descartes must now move on to examine and explore questions about the world around him, but instead of doing this he first stop to examine the question of whether or not God exists. Descartes wants to know that he was created by an all knowing, perfect creator that is good and wants to make sure that he was not created by an evil spirit or demon. If Descartes can prove that he was created by a perfect all knowing creator then his ideas must carry some semblance of truth, because God is not a deceiver and he must of placed these ideas in Descartes.
Descartes has good reasons for searching for the answer to the question of God's existence, now he has to come up with a good sound argument to prove it. Throughout the "Meditations on First Philosophy" Descartes gives a couple of major arguments about the existences of god, he gives one argument in the third meditation and on in the fifth meditation. The argument in meditation three and the one we will focus on is known as the "Trademark Argument." This argument comes from the fact claimed by Descartes that inside of everyone is a supreme being, which is placed there by whatever created us. From this statement Descartes can say that a mark from a God has been place inside of every one of us. This argument involves the acknowledgement of such an idea is within ourselves, this idea that God is a being who is eternal and infinite and a creator of all things.
This is Descartes first premise. His second premise is the "Causal Adequacy Principle." The principle says that if there is an item A having the property of B, then whatever causes A must have at least as much B as does A. Descartes gives an example of a stone, stating that the stone can't be made by anything that doesn't contain everything found in a stone. Basically the premise is based on a more general one that, it is not possible for something to come from nothing. Descartes then applies the Causal Adequacy Principal to ideas.
Descartes claims that just in the case of how objects must contain at least as much reality as what created it, then the cause of an idea must contain at least as much reality as the idea itself. So if an idea I represents some object O as having property P then the cause of I must have as much F as O is represented as having. Descartes puts these premises together and arrives at the fact that God exists in the following way. Since my idea of God represents God has being infinite and perfect whatever causes this idea must be infinite and perfect as well. Descartes then realizes that he cannot be the cause of his idea, of God, because he is not perfect or infinite. The definition of God as being "the perfect being" shows that the only thing that can cause this idea of the perfect being is God himself.
Therefore a being that is perfect and infinite exists. Since an infinite perfect being exist God must exist. Descartes has arrived at a conclusion and has proved his argument. There were a few smaller argument that Descartes offers throughout the third meditation. One of them suggest that it is not possible to exist without the existence of God, given that I have an idea of him. This argument is sort of goes along with the Causal Adequacy Principle.
It isn't a huge part of his argument, but does add another premise to it. Another argument that Descartes suggest in trying to prove that there is an existence of God is with the Evil Demon Theory. Descartes tries to prove that there is a God by proving that there is no evil demon and if there is no evil demon than there must be a God. This works of the premise that if there is no evil demon giving Descartes the ideas then it must be a good creator, Supreme Being or God.
Now that Descartes has established his argument and proven it, we can now see whether or not his argument is sound or unsound. Descartes laid out several premises and eventually came to the conclusion that God does exist, but some of his premises can be debated and make his argument unsound. The main objection to Descartes arguments is that he uses circular reasoning. Circular reasoning is basically defining something with itself or proving something exists with itself, for example, defining water as water. Descartes uses this all the time in is arguments. The circularity can be seen by his statements being entailed by such clear and distinct perceptions that they themselves are reliant upon certain knowledge of God's existence for their truth, yet such knowledge itself requires these perceptions.
The fact that Descartes uses circular reasoning a lot is a reason why none of his arguments can really be taken seriously. One big example of this is when Descartes says he needs to be certain of some thing before he can prove the existences of God, but in order to have this certainty he must already know that God exists and thus he is caught in a circle. Another example is with the Evil Demon Theory, if one doesn't exist then the other does. This is just another on of many way that Descartes use circular reasoning. The objections of circular reasoning have undermined Descartes goals and writings.
The circular reasoning really confuses his arguments and makes them very hard and impossible to believe. It doesn't seem like Descartes ever has any real concrete arguments for the existence or God or himself existing or any of his theories. In conclusion, Descartes made an argument to prove God's existence and seemed to be able to prove that he existed, but after a taking a closer look and re valuating his theories you see that he uses a lot of circular reasoning. It is really tough to believe any of what Descartes is saying. After reading his meditations you are left confused, mostly because you are trying to decipher what he is saying and you end up going around and around because of the circular reasoning. Even without the circular reasoning the argument just doesn't make any sense, especially in today's world, without any data.
To be able to fathom a sound argument for the existence of God just sounds too preposterous to believe. To believe that God exists based of faith and religion is what people today and in Descartes time, as well, believed. To say that God exists because there must have been some superior creator that put this idea in my head is very far fetched. People don't need to be told that God exists because most people already believe and most of them know that he does.