This argument of Descartes’ relates to two other theories laid down by him, namely, ‘the Evil Demon’ and the ‘Dreaming and Doubt’ arguments. This paper thus helps to provide an insight into the significance of the cogito ergo sum argument and its relation with these other two philosophical theories by Descartes. In his Second Meditation, Descartes has tried to explain his argument with respect to the existence of human beings. According to him, he carried out thoughts on his own doubt and was sceptical about the existence of people in order to see whether or not the doubt that he had in his mind would survive. However, as he carried out his arguments and personal belief in his existence he found that it was impossible to doubt whether or not a person was living. A God that deceived an individual and made him think twice about his existence was termed as an ‘Evil Demon’ by Descartes and he says that even if this argument were not true, one would still have to exist in order to be deceived.
“But I have convinced myself that there is absolutely nothing in the world, no sky, no earth, no minds, and no bodies. Does it now follow that I, too, do not exist? No. If I convinced myself of something [or thought anything at all], then I certainly existed. But there is a deceiver of supreme power and cunning who deliberately and constantly deceives me. In that case, I, too, undoubtedly exist, if he deceives me; and let him deceive me as much as he can, he will never bring it about that I am nothing,
so long as I think that I am something. So, after considering everything very thoroughly, I must finally conclude that the proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind.” (Descartes, Rene) (AT VII 25; CSM II 16–17) Descartes’ theory regarding the ‘evil demon’ helps to present an illusion towards an external world with respect to the senses of different individuals where there is no such existence of an external world as such. The evil demon thus helps to present an illusion of the very body of an individual including all the sensations that a person might feel because if there is no body, then one cannot feel as well. Thus, according to Descartes, the theory of the evil demon falls in relation with his theory if existence because he has tried to explain how the demon is the one aspect separating people from understanding the facts of life and comprehending whether or not matter exists in reality. (Important Arguments from Descartes' Meditations.) Descartes also put forward a theory regarding dreams that people have. According to him, this is the very postulation that dreaming is the very aspect from which an individual can comprehend whether or not to fully trust his senses in order to draw a line between dreams and reality and thus causes an illusion which might be deceiving. He stated that since dreams depend on a person’s senses and the kind of experiences that he goes through because of his senses during the course of a day, they might not be accurate and thus should be examined before being trusted and believed by a person as ‘reality’. Thus, the dream argument again signifies the use of senses in order to rely on whether or not something is real or just an illusion, just like the main argument from where Descartes has tried to prove the existence of man. The mark of a great dream has been given by the example of ‘Zhuangzi’s dream’ where Zhuangzi dreamed that he was happy and carefree butterfly but when he woke up, he was not able to determine whether the butterfly was dreaming