Certainty the fact that he was one of the first to write on the topic and acted as a comparison for the traditional and definitive works of the Western tradition. Descartes' "Meditations on First Philosophy" is a book in which Descartes first discards all belief in things which are not absolutely certain, and then tries to establish what can be known for sure. Although the phrase "Cogito, ergo sum" is often attributed to Descartes' "Meditations on First Philosophy", it is actually put forward in his "Discourse on Method". Due to the implications of inferring the conclusion within the predicate, however, he
Cogito, ergo sum ("If I am mistaken, I am") (book XI, 26), and also anticipates modern refutations of the concept. Furthermore, in the "Enchiridion" Augustine attempts to refute skepticism by stating, "[B]y not positively affirming that they are alive, the skeptics ward off the appearance of error in themselves, yet they do make errors simply by showing themselves alive; one cannot err who is not alive. That we live is therefore not only true, but it is altogether certain as well" (Chapter 7 section 20). In 1640 correspondence, Descartes thanked two colleagues for drawing his attention to Augustine and notes similarity and difference.