Descartes embarked upon his process of doubt because he had believed many falsehoods and unquestioningly accepted them. Descartes, by the end of meditation one, subjected all of his beliefs to the most strongest and hyperbolic of doubts. One, of an all powerful, malignant, and evil demon deceiving him in the realm of sensory experience, his understanding of matter and logical truths. This is known as the stages of doubt that Descartes went through. Descartes evaluates what is actually true by dividing the foundations of knowledge into three sources; the senses, reality and content.
He began by denying the information that he received through his senses, the very beginning of knowledge, as they have been known to mislead him. He calls into question some of our most trustworthy faculties. ‘Surely whatever I had admitted until now as most true, I have received either from the senses or through the senses.’ Our senses often deceive us. For example, when you look at something in the distance, it may actually be completely different to what your senses may have told you it was. However we can object to this by saying that our senses only mislead us in difficult cases i.e. our senses are able to give us a better idea of what the object is like when the object is closer to us. Our senses tell us that the sun is a small, circular and orange, it comes up in the day and goes down again at night. However, reason and science tell us that the sun is not circular, it is spherical and is a huge ball of fire. It does not actually move it is the Earth that actually spins on its axis, which gives the impression of the sun moving. Descartes tries to show that we know bodies better through reason than through our senses. For Aristotle, the senses played an essential role in knowledge of the physical world. Perception being a pre-requisite to induction, which is how we understand the universe. Descartes opposed an ancient philosophical claim by saying that nothing in the objects of the senses is stable enough for knowledge.
We can be misled in our dreams, even by the smallest of things. However, there are certain things in our dreams that we simply cannot doubt. For example, the fact that 2 + 2 = 4 and that triangles have three sides is something that is still exactly the same in dreams. Descartes retains his beliefs about the objects of mathematics. Even if all is a dream, the images in the dream conform to something more general. They have shape, size, and motion, which are all objects of geometry. Maybe arithmetic and geometry are exempt from doubt because if they were subject to doubt then this would mean the removal of a pillar of scientific method.
Descartes then puts forward the idea that we may be living a lie under a deceptive, evil demon that gives us the impression that everything around us and indeed our own self is real, but really is not.
This then brings Descartes onto the ‘Cogito.’ If this evil demon is deceiving us, then there must be something that exists, which he is able to deceive. If we do not exist, we cannot be deceived, but the fact that we are being deceived means that we exist. This is known as ‘the Litmus Test.’ Therefore, the evil demon cannot ever cause us not to exist as long as we think we exist. We must exist, if we have thinking processes going on inside us because ‘nothing’ or something that does not exist cannot exist. There has to be something, the ‘Cogito’ that does the thinking, just as a runner performs the act of running. The act of running cannot exist without someone doing the running in the same way that thinking cannot occur without someone doing the thinking. Therefore, Descartes concluded ‘Cogito, Ergo Sum’ translating from Latin as ‘I think, therefore I am’ (exist). ‘Doubtless, then, that I exist…and, let him deceive me as he may, he can never bring it about that I am nothing, so long as I shall be conscious that I am something…I am, I exist, is necessarily true each time it is expressed by me or conceived in my mind.’
Objectors have argued against Descartes by saying that this is not a very good argument because it contains ‘I think’ as a premise and then ‘I exist’ as a conclusion. A good argument would give you adequate reason to believe the conclusion yet Descartes fails to do this because he has only proved through the Meditations that a thinking thing exists, not that he exists or that we or ‘I’ exist. He uses the personal pronoun ‘I’ without actually proving that ‘I’ exist in other words, he is ‘jumping the gun.’
Therefore, I conclude that Descartes provides good debatable argument for his theory of our existence but fails to really reach some hard, infallible evidence to say that we exist and so leaves the ‘Cogito’ as something that cannot be proved. I think a more interesting question for Descartes to answer would have been ‘Why we exist?’ maybe by answering this, he could have found an answer to ‘Do we exist?’
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