Discourse on the Method which I did not clearly know to be such." This method of pro-foundational skepticism is considered to be the start of modern philosophy. Discourse on the Method Discourse on the Method of Rightly Conducting One's Reason and of Seeking Truth in the Sciences () is a philosophical and autobiographical treatise published by René Descartes in 1637. It is best known as the source of the famous quotation ""Je pense, donc je suis"" (English: "I think, therefore I am", or "I am thinking, therefore I exist"), which occurs in Part IV of the work. The similar Latin statement, "Cogito, ergo sum",
Cogito, ergo sum of other minds at this point. This is something that has to be thought through by each of us for ourselves, as we follow the course of the meditations. Second, he does not say that his existence is necessary; he says that "if he thinks", then necessarily he exists (see the instantiation principle). Third, this proposition "I am, I exist" is held true not based on a deduction (as mentioned above) or on empirical induction but on the clarity and self-evidence of the proposition. Descartes does not use this first certainty, the "cogito", as a foundation upon which to build