What follows is a brief account of the third and fifth meditations, which provide Descartes' response to the masked question, "What is God?" Can one perceive or confirm the existence of an idea that is external to him, an idea such as God?.
According to him in order to determine the answer one must start by understanding the ways in which he can conclude an objects' existence. Descartes set out to build a set of arguments designed to prove God's existence. On those, he constructed all of his other arguments. Descartes explains three proofs in which a person might come to such a conclusion - the first, through nature; the second, through fueling a value that is independent of the will of the object; and the third, the objective reality of an idea, or the "cause and effect profile." The third point is the one that I will primarily spend my time with. .
Descartes drills us with the idea that an object will have an effect when it stems from a legitimate cause, or an initial idea that precedes with equal or superior properties in one's intellect. In other words, the mind generates thoughts and ideas about a physical form, and develops a reality for this form, through previous schema and beliefs. "And although an idea may give rise to another idea, this regress cannot, nevertheless, be infinite; we must in the end reach a first idea, the cause of which is, as it were, the archetype in which all the reality that is found objectively in these ideas is contained formally." The only problem with Descartes' argument is when the existence of God arises as a notion, for there is no sustenance or idea for the notion of God to originate from. Is it possible, then, to create the idea of a finite being from an infinite existence, outside of the physical and mental, in a state all of it's own? Descartes quickly answers that the response would be that a finite being couldn't completely, if at all, comprehend the ideas that would cause God to exist, and therefore the basis for doubt is lost in an intangible proof.