What he did was discovered Analytic Geometry.

I Think therefore I am

Descartes' project involves starting from scratch . He wants to begin by presupposing nothing. The fact that he finds himself believing something is not automatically a reaso…n for thinking it true; neither is the fact that other people have believed it, no matter how many people, how firm their belief, how long they have believed it, or how highly regarded they are. Descartes will begin by taking nothing for granted. It may be in the end that the conventional sources of wisdom will be vindicated, but it will not do to begin by assuming that they are reliable; only a compelling argument can show that. Descartes proposes to conduct this investigation into the warrant for our beliefs by doubting everything until it has been shown to be an acceptable belief. Surely it must have struck most of us at one time or other that such a project would be extremely valuable. It is often forcibly brought home to us that we believe a good deal that is false, and when this happens we become vividly aware that our procedures for discriminating truths from falsehoods are not very reliable, and long for a more adequate procedure. The project of pure inquiry may be motivated by what Alasdair MacIntyre has called an "epistemological crisis." Such a crisis involves a discovery which forces one to reinterpret a great deal of evidence whose explanation one had felt certain one understood. One might, for example, suppose on what seemed compelling evidence that a certain person was one's friend. Despite all one's evidence it might one day become perfectly clear that this person did not care about one at all. Suddenly everything the person did would be seen in a new light: actions that had seemed spontaneous would now be seen as calculated and scheming; actions that had seemed signs of affection would now seem deliberately deceptive expressions of pure self-interest; actions that had seemed generous or selfless would now seem greedy and grasping. This sort of experience can be profoundly unsettling. One may naturally be led to the quite dismaying thought that if one could have been so mistaken about this acquaintance, one could well be mistaken about any of one's acquaintances. (One could also have the further worry that one could be mistaken about all of one's acquaintances, but this seems psychologically less likely--and for good reason, since the possibility of error about every case does not follow from the possibility of error about any case. Compare: anyone now alive could become the last person on earth, but it could not happen that everyone now alive became the last person on earth.) It may well seem at such a time that the only alternative to the discovery of a foolproof means of distinguishing true friends from false is this sort of damaging wholesale skepticism. One consequence of Descartes' determination to begin from scratch was a refusal to accept any belief on authority, and thus an increased emphasis on the importance of the individual in working out his or her own beliefs. (In this respect Descartes' influence might be compared with that of Luther a century before.) This was during a period in which the influence of the Church in matters of belief was still very strong: Descartes' principal philosophical works, the Discourse on the Method and the Meditations , were published in 1637 and 1641, respectively; it was only a few years earlier, in 1633, that Galileo was condemned and sentenced to life imprisonment by the Inquisition for maintaining that the Earth moved. (Indeed Descartes' knowledge of Galileo's condemnation led him to be fearful of condemnation by the Church; he went so far as to suppress his first scientific work, to have been called Treatise on the Universe . And it should be noted that Descartes did not mean to be subversive; indeed, he hoped that his views would become official Catholic teaching, and wrote a textbook (the Principles , 1644) in hope of furthering this end.)

Yes.

One thing that Rene Descartes did was make the connection between the mind and the brain. He developed the theory that the nonphysical mind controlled the physical body throug…h secretions in the pineal gland. Although this is incorrect, he was the first person to try to try to make this connection. In reality, we now know that our behavior is controlled by the physical body (the brain) and the mind does not exist. Rene Descartes was an innovative philosopher and a mathematician. Rene Descartes (pronounced dey-cart) was a philosopher who experimented with the method of doubt. His belief had three key phenomenons, first that our eyes were tricking us, the second is deduction, and the third is that there is a demon who is controlling us, tricking us, making us believe things that are not true. This led him to the famous quote, "I think, therefore I am," ( one of my favorite philosophical quotes)

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