Cogito, ergo sum “I am thinking, therefore I exist” appears in the CSMK translation of Descartes's correspondence in French (“, ”) to colleagues at CSMK III 247. The earliest known translation as "I am thinking, therefore I am" is from 1872 by Charles Porterfield Krauth. As put compactly by Prof. Krauth (1872), "That cannot doubt which does not think, and that cannot think which does not exist. I doubt, I think, I exist." The phrase "cogito, ergo sum" is not used in Descartes's "Meditations on First Philosophy" but the term "the "cogito"" is used to refer to an argument from it. In the
Cogito and the History of Madness his point of departure for "Cogito and the History of Madness" is Foucault's 1961 book "Folie et déraison". Derrida's paper primarily relies on two sections of Foucault's work, the original 1961 preface in which Foucault makes a number of general comments about the book, setting forth his intentions and methodology, and two and a half pages at the start of the second chapter where Foucault links Descartes to an historical event that silenced madness at the end of the classical age. Foucault's 1961 text was heavily abridged for a popular edition in 1964 that formed the basis for Richard Howard's