To begin this approach, Descartes introduces formal reality and objective reality. Formal reality is said to be what humans can actually see and prove to be their senses, and objective reality is what is in their minds. Descartes goes on to say, 'Hence it follows, both that nothing can come from nothing, and that what is more perfect cannot derive from what is less perfect' (Third Meditation 29). In this quote Descartes believes that nothing can come from nothing: a person cannot get one from zero; for an effect to happen their must be a cause, and an effect must have as much reality as its cause, as so, something that is perfect cannot come from something that is less perfect. For example, it is not possible to have hot water without a thing that creates heat. Also, electricity is what causes a light bulb to turn on, but a light bulb cannot cause electricity. After realising this, Descartes uses this argument to sum up how the idea of God came to be. He believes that he is not perfect and has limits, so how can the idea of an all knowing and all powerful being with no limits be even thought of. All real ideas come from other real ideas, and even unreal ideas have real qualities in them. A flying pig might not be real, but the idea comes from a pig, and a flying object put together; fairies might not be real, but the idea comes from putting flying qualities to a person. So this Idea of God came from something as real as God, and since there is nothing on earth that is as real as God, we must have been born with the idea, so therefore God exists.
In Descartes meditation his premises are structured. One must first accept that the idea of God is more real than anything that is limited; after accepting that, one must accept that an effect cannot be greater than its cause; and after accepting that, one must accept that the idea of God cannot be thought off with out a cause, or without it being real. Once you have accepted all of these it is clear to say that God exists, but if one denies any one of these premises the conclusion fails.
Although Descartes believes to have solved the existence of God, many other people such as Atheists have went on to argue that God does not exist. A popular argument against the existence of God is the paradox of the stone: 'Can God create a stone so heavy that he cannot lift?'(Arguments for Atheisms). God is known to have unlimited power, so if God cannot create a stone more powerful than him, then he does not have unlimited power; if he is able to create such a stone that he cannot lift, then he still does not have unlimited power. So either way God is not all powerful; something that is all powerful can do everything, and since God cannot do everything, God does not exist. Though this argument is seemingly legit, there are many arguments that proves its falseness. Descartes believes that God can do the logically impossible, so God can make two plus two equal five. However, Thomas Aquinas (A Christian philosopher) believed that God can possibly do anything, but he cannot go against the laws of logic. With Aquinas' argument, it proves that God cannot do something, which has to be false because God has to be able to do everything. So if we go with Descartes argument that God can make two plus two five, it also means that God can Create a stone that he cannot lift, and then lift it. This argument may seem difficult to understand, but Descartes tells us not to try and understand God because it is not possible. This proves that the argument of the paradox is false, a simple way to prove that it is false, is that God is known to be a spirit that cannot be seen, but here the paradox argument gives God human qualities (The Paradox of the Stone).
The stone argument failed to prove that God does not exist, so Descartes argument about God's existence still stands. But looking at it in a different way, say that a person is stuck on an island, and this person cannot escape, so he/she builds some type of shelter to be protected from the bad weather such as, rain and cold temperatures. Now, this person does not know what perfect is, but while building this shelter, this person will not attempt to make it bad seeing he/she wants good protection; this person will attempt to make a perfect shelter, so can the idea of something perfect not come from our selves? Descartes' answer to this question would be no: everything has its opposites, and one opposite cannot be without the other. For example, there cannot be heat without cold, and one would not know what pain is without joy. Which must mean that God exist because humans are imperfect, and the opposite of imperfect is perfect.
It is very difficult to disprove God's existence, but if God exists, and everything has a cause; what caused God? Scientist hold this point strongly as to disprove the existence of God. Descartes, however, says not to try and understand God, but his whole meditation attempts to find if God exists which is trying to understand. Descartes somehow goes around the question 'what caused God'. In the world we live in today, one should not be surprised if one does not believe that God exists. It is simple, in our society proof is necessary; if a close friend was to threaten to kill themselves, it would not be all that believable, but when the friend shows a weapon to be used, then the belief will increase. Also, one cannot go to a court room and say to a judge, 'He is the murderer, you might not understand your honour, but he killed an old lady'. One would need some type of convincing proof to prove that someone is a murderer. It is just how the world works. Descartes believes that God is not a Deceiver, and that God is supremely Good, if it is so, why does God allow suffering? If a father, that is known to be good, one day sees his twenty three year old son on the street begging for food and money, and the father realizes this and walks away, is it reasonable to say that the father is good? Not at all, in fact one would believe that the father has abandoned his son. This argument has been used countless times to disprove the existence of God.
Arguments can go both ways, and this argument about the existence of God is ridiculously difficult. One can conclude that God exists, but until physical evidence or something more real is shown, saying that God exists will just be a theory, at least in this world. Perhaps if one was in a world where there is simply one religion and one belief, then the idea of a God would be easy to believe, even if it is false. So Descartes has reasonable ideas of the existence of God, but as long as we are in a world filled with many different race, religion, and ideas, Descartes argument about God's existence will always be plausible.