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, ergo sum and let him deceive me as much as he can, he will never bring it about that I am nothing, so long as I think that I am something. So, after considering everything very thoroughly, I must finally conclude that the proposition, "I am, I exist," is necessarily true whenever it is put forward by me or conceived in my mind. (AT VII 25; CSM II 16–17) There are three important notes to keep in mind here. First, he claims only the certainty of "his own" existence from the first-person point of view — he has not proved the existence