Ren Descartes (1596 - 1650) was a French philosopher and mathematician who was often called the father of modern philosophy and a pioneer of the flow of rationalism.
Descartes used the critical analytical method through skepticism in his search for truth; namely by doubting the existence of objects around him, even doubting the existence of himself. He was afraid that maybe thinking did not lead him to the truth, but to mistakes. This means that it is possible that the human mind in essence does not bring people to the truth, but instead leads to mistakes. There is a certain kind of power greater than himself that controls his mind and always directs his mind to the wrong path. At this point, Descartes suddenly realized that however the mind turns itself to error, it keeps thinking. Until finally he concluded that when he thought, he was there. Or in Latin: COGITO ERGO SUM, which means I think, therefore I am - I think, then I exist
