Mathematics and Knowledge of the Outside WorldJune 27, 2021
Descartes, based on the idea that God is not a deceitful being, on the contrary, is an extremely perfect being, states that he will not deliberately leave our memory to be mistaken, and therefore our mathematical knowledge, in its known forms, has emerged as a result. This information has been given to our minds clearly and distinctly.
It is possible to intuitively grasp their truth. And these are the universal truths that are innate in our minds. At this stage, an important question remains for Descartes to be asked: How can the knowledge of the outer world beings, to which we turn mostly with our senses, be justified at this point? This type of knowledge also includes the knowledge of our body as an external world entity. Can being a thinker alone prove the existence of our body? For the thinking self is wholly and absolutely different from my body and can exist without it. So how can I know the existence of my body and other physical things?
Descartes seems to have dealt with the existence of bodies quite succinctly. But his general reasoning is more or less as follows: it is clear that we receive impressions and ideas, and since we have a natural tendency to attribute them to the activity of material causes outside ourselves, no one but God could have given us this tendency, and it would be deceptive if God had both given this natural tendency and created these impressions himself. would have happened. However, we have already proved that he is not deceitful and that he is in the perfection of his goodness. Therefore, external material objects, which are the source of these impressions, must also have existed.
This is how we understand that our life is not a dream: We experience clearly and distinctly that the situation we are in is constantly changing, moving left and right, changing our direction. This experience indicates that we have a body. This leads us to the existence of “extended substance” (res extensa). And the fact that we are exposed to some sensory effects such as seeing, hearing and touching outside of our own will is a very strong proof of the existence of the objects that cause them. And since we receive some influences from other bodies as well, they must have existed in the same way. Thus, Descartes proved all external world beings, including his own bodily life, in terms of their existence. As it is seen, for Descartes, cogito knowledge has formed a basis for knowledge of God, and cogito and God knowledge together constituted a basis for knowledge of external world beings, leading to clear knowledge. At this point, Descartes got rid of this methodical pressure of doubt by saying, “I have to cast aside all doubts as hyperbolic and ridiculous, especially the very general uncertainty about the sleep state that we cannot distinguish from the waking state…” (cited in Copleston, 1996, p.119). happens. At this point, we need to take a closer look at Descartes’ dualistic substance system regarding the structure of nature.
Prepared by: Sociologist Ömer YILDIRIM
Source: Omer YILDIRIM’s Personal Lecture Notes. Atatürk University Sociology Department 1st Year “Introduction to Philosophy” and 2nd, 3rd, 4th Grade “History of Philosophy” Lecture Notes (Ömer YILDIRIM); Open Education Philosophy Textbook