Descartes' meditations are created in pursuit of certainty, or true knowledge. He cannot assume that what he has learned is necessarily true, because he is unsure of the accuracy of its initial source. In order to purge himself of all information that is possibly wrong, he subjects his knowledge to methodic doubt. This results in a (theoretical) doubt of everything he knows. Anything, he reasons, that can sustain such serious doubt must be unquestionable truth, and knowledge can then be built from that base. Eventually, Descartes doubts everything.
But by doubting, he must exist, hence his "Cogito ergo sum." It is from this thought that Descartes is able to determine God exists and create his first argument for this idea in the Third Meditation. He does this by beginning with the only thing he knows to be true: That, through doubt, he must exist. By knowing he doubts, he then knows that he doesn't know everything. This make him imperfect.
But to know you are imperfect, Descartes reasons, must mean that you have a concept of perfection (Thomson 26). This allows him to verify how he has a rational idea of a prefect being, God. Knowing that he has an idea of perfection, Descartes continues to prove God's existence by assuming everything must have a cause. This is known as the Principal of Sufficient Reason. For Descartes, this principal allows the acceptance of another, called the Principal of Sufficient Reason. "There must beat least as much reality in the total efficient cause as in the effect" (Thomson 27).
He gives an analogy of heat, and how heat cannot be produced in an object devoid of heat unless it is acted upon by something containing a greater amount of heat (Baird, Kaufmann 33). And because Descartes refutes the idea of infinite regression, God must be the initial cause. He also claims God as the cause of his idea of God. He reasons that, through these principals, his idea of Go cannot have come from himself, as he is an imperfect being.
He does not have the capability of thinking of an infinite substance or a perfect substance, such as God, because he has lesser reality than these ideas and cannot be the cause of them. The only way these ideas could exist is if they were created by something of equal (greater being impossible, as infinite perfection cannot have a superior) reality. Because God is the only infinite Descartes can recognize at this state, it must be God that planted the idea in his mind. Descartes' first argument for the existence of God can be summarized as follows: 1) I have an idea of a perfect being 2) There are two forms existence- contingent and necessary 3) Necessary existence has greater reality than contingent 4) A perfect being must have necessary existence 5) A perfect being must exist, if it has necessary existence 6) Therefore, God exists (Notes) This allows Descartes to begin to gain true knowledge, because his perfect being exists and would not allow him to be deceived all the time because perfection does not allow for that behavior. In the Fifth Mediation, Descartes purports his ontological argument for the existence of God. It is simpler than his first and based on God's essence.
For anything else that exists, the essence of that thing only implies it's existence. For God, however, essence is existence. God is perfection, and existence is a type of perfection. So an absence of existence would be an absence of perfection, which is impossible in God.
Descartes's e cond argument for the existence of God is then: 1) By definition, God has all perfections 2) Existence is a perfection 3) Therefore, God exists Despite his efforts to remove all imprecise information from his thoughts, Descartes' proofs of God have some errors, or at least shortcomings, that have been pointed out over time. One problem with his first proof is his idea of God. To see where the fallacy lies, an understanding of Descartes' understanding of ideas is needed. "Now as far as ideas are concerned, provided they are considered solely in themselves and I do not refer them to anything else, they cannot strictly speaking be false; for whether it is a goat or a chimera that I am imagining, it is just as true that I imagine the former as the latter." (Baird & Kaufmann 31) "Thus the only remaining thoughts where I must be on my guard against making a mistake are judgments.
And the chief and most common mistake which is to be found here consists in my judging that the ideas ideas which are in me resemble, or conform to, things located outside me" (Baird & Kaufmann 31) Descartes formed an idea of God as an infinitely good being. He would have had to discover this idea within his own mind. According to his principle of universal doubt, he cannot simply know whether his conception of God is correct or incorrect, just that he has it. He would have, as a matter of his own principle, considered it as false until proven otherwise. Therefore, since the idea of God is in doubt, the trustworthiness of man's reasoning must also be doubtful. Another problem with his first proof is that he uses his powers of reason without first proving that they are beyond doubt.
The validity of Descartes reasoning is supposed to flow as a consequence of the infinite perfection of God; and God's infinite perfect is made certain through the very same powers that he has not proven trustworthy. Descartes assumes the very thing beforehand, which he intends to prove afterwards. Descartes accepts the trustworthiness of his faculties in demonstrating the existence and infinite perfection of God, and that is illegitimate. A doubtfully valid faculty will produce a doubtfully valid argument, which will, in turn, produce a doubtfully valid conclusion. The entire argument for God's existence is therefore nullified by a suspect reasoning process. Descartes reasoning of God's existence hinges on his use of 3 principals: the Principal of Contradiction, the Principal of Adequate Reality, and the Principal of Sufficient Reason.
But these ideas seem to be preconceived in his mind, before he goes through his doubt. How, then, can they be preserved and used in his arguments Even if they are logical, they must be doubted under his methodic doubt structure. Without them, he cannot prove the existence of God, and is mired in his own doubt. Other objections to Descartes first proof include his use of language.
While it is difficult to relay abstract ideas without language, it is nonetheless a human idea that he has learned and needs to doubt, according to his specifications. His use of a heat analogy to explain his Principal of Adequate Reality is inappropriate, as it uses material (heat is a result of the senses) that he doubts. Also, the principal itself questionable in that it is ambiguous in its terminology and measurement of reality. For instance, World War I and the years of fighting and millions of deaths can be traced back to the assassination of Archduke Ferdinand. Does this mean that the War (effect) contained less reality than the single death (cause) This would seem to trivialize one of the largest conflicts in human history. Yet another critique of Descartes proof of God is his claim that the idea of God is innate.
He does not recognize the fact that many cultures would consider the idea of multiple gods innate, nor does he give credence to the possibility that a sense of wonder is innate and is birthplace of the idea of God. The ontological argument for God also has merits that are invalid. One such is a point made by Kant, that the second portion of Descartes' proof is inaccurate because existence is not necessarily a property, as Descartes uses it as (Thomson 30). Another philosopher, Gassendi, said in his work Objections, "something which does not exist is neither perfect nor imperfect" (qty Thomson 30).
This would imply that existence is not perfection and God needn't exist. Kant also had misgivings about Descartes' definition of the concept of God as a means to prove his existence. To use a concept to prove itself real is irrational. 321.