Discourse on the Method by Rene Descartes - 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" ("I think, therefore I am", or "I am thinking, therefore I exist"), which occurs in Part IV of the work. A similar argument, without this precise wording, is found in Meditations on First Philosophy (1641), and a Latin version of the same statement Cogito, ergo sum is found in Principles of Philosophy (1644).The book is divided into six parts, described in the author's preface as: Various considerations touching the SciencesThe principal rules of the Method which the Author has discoveredCertain of the rules of Morals which he has deduced from this MethodThe reasonings by which he establishes the existence of God and of the Human SoulThe order of the Physical questions which he has investigated, and, in particular, the explication of the motion of the heart and of some other difficulties pertaining to Medicine, as also the difference between the soul of man and that of the brutesWhat the Author believes to be required in order to greater advancement in the investigation of Nature than has yet been made, with the reasons that have induced him to write