Evaluate Descartes' Argument

Descartes, in his meditations rejects all truths he believes to be even slightly dubitable thus establishing a concrete foundation for knowledge. His belief is that the senses are not reliable and might be deceptive which is why only mathematical statements are certain. He considers the possibility of being deceived by a powerful being that may be misleading him to believe that certain truths are accurate; a being he initially states to be God later refuting it on the basis that God is good and hence does not deceive, instead, an evil demon is leading him astray.

Descartes having convinced himself of the belief that nothing exists (in order to venture upon the reality of his own existence), realizes that the mere action of him persuading himself proves that he does exist. Yet another proof of his existence is his capacity to think which stems from the evil demon argument. Since the evil demon is deceiving him, it necessarily follows that something must exist which is being deceived. Hence, Descartes concludes that the proposition 'I am, I exist' is necessarily true regardless of the nature of his thoughts. In doing so, he also doubts the existence of his body as he believes the mind is more real and superior to body.

In Descartes' argument, there are a few crucial things which need to be taken into consideration. For instance, the use of 'I' is essential in the argument, for, one cannot be sure of someone else's thinking and existence as it is always subject to doubts. The only certainty is that 'I' exists and thinks. Secondly, thinking alone is sufficient to prove existence regardless of the kind of thinking that is done. That is, rejecting, doubting etc. are modes of thought are acceptable. However, all non-thinking actions such as eating, drinking, walking and so forth, do not provide ample proof of existence. Furthermore, the statement holds true only in the present tense for one cannot be certain of his existence based on the belief that he thought a month ago or that he will think in the future.

The phrase 'I am I exist' has its roots in Descartes' doubts which lead him to believe that he thinks and consequently exists. The argument that he exists because he thinks is not phrased in the same way in Descartes' meditations. The actual argument is 'I am I exist'. By fashioning the statement in this way, Descartes avoids generating the perception that it is an argument of the form: 'I think, therefore, I exist' which would be more prone to doubts regarding its validity.