Descartes’s words in Skepticism demonstrate that in order to reestablish the authority of philosophy, we must achieve certainty. To achieve this certainty, we must first start by doubting the things around us. Universal Skepticism It is to rethink and criticize all the unshakable scholastic dogmas that imprison people's thoughts, so as to reconstruct their own understanding. Descartes skepticism tells people a specific way of thinking, which is not biased towards anything or anything. Obsession, finding true knowledge from doubt; of course, we cannot be shaken by the truth and the construction of thousands of years of knowledge system due to general skepticism, and we must still continue to pursue the truth, goodness and beauty in the world. Descartes has a famous saying, "I think, therefore I am." What this sentence actually means is that Descartes has to doubt everything, but there must be a starting point. Therefore, I am doubting, that is, I am thinking, this matter is real and beyond doubt. This is the starting point of my doubting everything. Descartes published a book in 1637: "On the Correct Use of One's Reason to Seek Truth in Various Sciences." He said, "The only thing I can be sure of is the existence of my own thoughts, because when I doubt Other times, I cannot simultaneously doubt my own thoughts.” Someone translated this sentence into a very elegant language: I think, therefore I am. This book has three articles as appendices, namely "Geometry" (Analytical Geometry), "Refractometry" and "Meteorology".