The existence of God has been a question since the idea of God was conceived Descartes tries to prove God’s existence, and to show that there is without a doubt something external to ones own existence. He is looking for a definite certainty, a foundation for which he can base all of his beliefs and know that they are true. Descartes’ overall project is to find a definite certainty on which he can base all his knowledge and beliefs.
Descartes attacks the principles that support everything he believes with his Method of Doubt. The Method of Doubt is Descartes’ method of fundamental questioning in which he doubts everything that there is the slightest reason to doubt. Think about it like this. Almost everything you believe to be true comes from the senses or through the senses. However, the senses are sometimes deceptive. Since the senses are not completely trustworthy, it is irrational to place complete trust in them. However, it is no small leap of faith to presume that everything our senses tell us is false. In fact, it seems almost absurd to say such a thing. Nevertheless, as Descartes points out, we have dreams regularly and in these dreams, everything we experience is a figment of our imagination, or at least not real in the physical sense. So, it is reasonable to doubt everything our senses tell us, for the time being. Now, using similar logic, we can say that everything we have learned from physics, astronomy, medicine, and other such fields are all doubtful. Descartes even believed we could say that such simple, logical statements as 2+3 = 5 or a square has 4 sides could be conceived to be false. “Since I judge that others sometimes make mistakes in matters that they believe they know most perfectly, may I not, in like fashion, be deceived every time I add two and three or count the sides of a square” We are now at the point where we are doubting everything – the world around us, that we have a body, and anything else that we could possibly believe.
Perhaps I even doubt that I exist myself. In doing this, I am in the act of doubting. How can I doubt something if I do not exist? Similarly, maybe I am deceived into thinking I do not exist by some other entity. Then I must exist for it is I who is being deceived. This is the basic premise of Descartes’ famous “Cogito Ergo Sum” – “I think therefore I am.” Here Descartes is not saying anything about what we are here, just that we are. Next, his goal is to find out exactly what he is. Well, Descartes states, if I exist, for how long do I exist? I exist for as long as I think, and if I cease to think, then I shall also cease to exist. Therefore, I am nothing but a thinking thing – that is, a thing that “doubts, understands, affirms, denies, wills, refuses, and that also imagines and senses.” Although saying he is all of these things is indeed a bold statement. Descartes feels that in his attempt to prove that he exists he has done all of those things, therefore they must be a part of what he is.
Decartes goes on to prove the existence of God. He begins this by stating that nothing can be created from nothing, and that the less perfect can not create something more perfect or better than itself. He explains that he knows he is not perfect because he doubts, and knowing is more perfect than doubting. From that he determines that within him lies this idea of a perfect being, and that he is incapable of coming to such an idea by himself. If there is an idea in our minds that we didn’t create, something else created it. He saw nothing in nature that would qualify as superior in the sense that he had stated, so he determined that the only other logical answer was that God placed it in him, therefore, God exists.
Berkeley would argue that Descartes is wasting his time by trying to discover what must be absolutely true in the real world. In his Dialogue, Berkeley argues that there is no real world, and that all sensible objects, those which can be immediately perceived, exist only in the mind. He starts by proving that secondary or external qualities exist only in the mind by use of the Relativity of Perception Argument. As an example, Berkeley writes that if you make one of your hands hot and the other cold, and put them into a vessel of water, the water will seem cold to one hand and warm to the other. Since the water can not be warm and cold at the same time, it must follow that heat, a secondary quality, must only exist in the mind. Berkeley also uses the qualities of taste, sound, and color as examples to prove that all secondary qualities must reside in the mind.
However, Berkeley also says the same argument can be applied to primary or “intrinsic” qualities. He writes that his own foot might seem a considerable dimension, but to smaller creatures, that same foot might seem very large. Since an object can not be different sizes at the same time, it follows that extension must exist only in the mind. Further, since all other primary characteristics can not be separated from extension, they too must exist only in the mind.
As for what I believe about this argument, I don’t totally believe it. It makes perfect logical sense the way that he obtains many of the arguments, and while they are all built on a foundation that is strong for Descartes, himself, I do not always share the foundations that he believes in. The way that he explains it is not the only possible conclusion and it seems like he is limiting himself in his search for truth in that he does not explore the fact that maybe there is no perfect being. Just because we are not perfect certainly does not mean that there is true perfection somewhere and the idea of perfection that we have is more or less a fuzzy one and because of the fact that it is different for everyone, there might not be a true absolute definition of what it really is. While Descartes’ proof is very interesting in how he goes about deriving truths by exploring some of the options that might be the truth, I do have a hard time accepting some of the conclusions that he states as truths.