The flow of this paper will primarily be a series of inquiries on Rene Descartes' methodic doubt as a philosophical method which has become the foundation of his metaphysics. In other words, this paper will point out several inconsistencies in Rene Descartes' deductive process starting from its roots up to the conclusions he arrived at.
In the Rene Descartes' Meditations of First Philosophy, he expounded the epistemological problems surrounding the scholastic tradition. He furthers his argument that human knowledge is relying too much on traditional doctrines, which he said is based on unproven presuppositions. This gave way to the birth of a dilemma between what is certain knowledge and what is unwarranted belief. This mind set of Descartes led him to develop a method by which he can deduce what is true from a single fundamental principle - This is Rene Descartes' Universal Methodic Doubt.
He started by stating that in order for us to seek for truth, it was necessary, at least once in the course of our lives, to doubt, as far as possible, of all things. He said that in the course of one's life, many prejudices have been accepted as true, that in turn deviate us from knowing certain truth. He also stated that we ought to consider as absolutely false all that is doubtful. He then went on to discuss why we should doubt our senses. He stated that it is common knowledge that our sense is not infallible, our senses are subject to error, and thus it would be imprudent to put our trust onto something that deceives us on a regular basis. He further argued that we cannot really acquire certainty on what is real when in fact we experience the same stimulations whether we are asleep and dreaming, or awake.
The next subject of Descartes' universal methodic doubt is mathematical demonstrations. He argued that there was no guarantee about the certainty of such mathematical demonstrations because of man's fallibility. He said that there was no way to be sure that we are not deceived by a God who made it appear to us that things exists but in truth are non-existent. He even went on to assume that God does not exist for the sake of argument, in which he replied that a lesser cause of his being will likewise mean that there will be a greater reason for us to believe that we could be continuously be deceived.
Finally Descartes concluded that we cannot doubt our existence while we ourselves are, in fact, doubting. He stated that we cannot suppose that we are not while we doubt because we cannot possibly conceive that what thinks does not exist at the very moment when it thinks. This is how Descartes arrived at the single fundamental principle that he was seeking in order to deduce other forms of truth - Cogito, ergo sum!
At this point Rene Descartes encountered a problem in his line of thought. He cannot rely on the truth of his existence when it is based on the trustworthiness of his reasoning because his reasoning ability is also subject to the very method he created - the universal methodic doubt. This is when he demonstrated the existence of an infinitely perfect being, who gave man faculties which are trustworthy and capable of discovering truth.
His ontological argument about God's existence is as follows. He stated that we have the idea of God as an infinitely perfect being in our mind. And it is necessary for an infinitely perfect being to exist; otherwise it is not an infinitely perfect being. He also tried to prove God's existence by means of causality. He, once again, began with the premise that we have the idea of an infinitely perfect God, and since the idea represents an infinitely perfect being, we being finite, cannot have been able to produce such an idea using our limited faculties. This idea being beyond our limited capacities can only originate from a being that possess infinite perfection.
After examining Descartes metaphysics from its roots up to its conclusions, this paper will pose various inquiries regarding the inconsistencies of Rene Descartes' method. Rene Descartes began his inquiry by doubting all form of knowledge without exception, he even went further as to deem things with the slightest possibility of doubt as absolutely false. Using Descartes' very own method, what makes the idea of an infinitely perfect God true? And if the idea of an infinitely perfect God doubtful how can he deduce, from this doubtful idea, the existence of God?
Rene Descartes used the idea of the existence of God as an escape route to his philosophical dead end regarding the trustworthiness of his reasoning ability, but the idea of an infinitely perfect being is subject to his universal methodic doubt, thus he cannot prove the trustworthiness of his reasoning abilities, not to mention that the very same doubtful trustworthiness of his reasoning ability was used to prove the existence of God in the first place. In only goes to show that since the very idea of a God is doubtful, every other thing must remain doubtful.
The trustworthiness of Rene Descartes' reasoning ability was assumed as an effect of the existence of an infinitely perfect being; and this infinitely perfect being's perfection is made certain to him by means of his reasoning ability, before he was able to prove the validity of the trustworthiness of his reasoning ability. He assumed the trustworthiness of his reasoning ability in order to prove the existence of God in order to prove the trustworthiness of his reasoning ability, thus he commits a fallacy called begging the question also known as a circular argument. His line of thought was nullified because a doubtfully valid faculty can produce only a doubtfully valid argument, and a doubtfully valid argument can only lead to a doubtfully valid conclusion.
This series of inconsistencies in Rene Descartes method goes to show that the very moment Rene Descartes decided to adopt a method of universal doubt to deduce a fundamental philosophical principle in which he will deduce other forms of truth, is the same moment that he created an unsurpassable wall that will render any method of acquiring truth impossible. His actual procedure in all the arguments he presented is that he presupposes the validity of his reasoning when in fact it is also subject to the methodic doubt that he devised hindering him from accepting the validity of his reasoning before he can prove the existence of an infinitely perfect God. The only possible end for his arguments is to accept a sort of universal scepticism, because no certitude can ever be attained in a system that doubts and ultimately deem the foundations of human reason as false. If the very nature of his mind is subject to doubt, not to mention deemed as absolutely false, then all ideas, judgements, and inferences can no longer be trusted. If Descartes mistrusts the simple judgments of "2+3=5" and "A square has four sides," how can he trust his faculties in making the far more complicated arguments with which he tries to prove God's existence and infinite perfection?