Cogito, ergo sum though not explicitly as "cogito, ergo sum" in Meditation II: In 1644, Descartes published (in Latin) his "Principles of Philosophy" where the phrase "ego cogito, ergo sum" appears in Part 1, article 7: Descartes's margin note for the above paragraph is: Descartes, in a lesser-known posthumously published work dated as written ca. 1647 and titled ("The Search for Truth by Natural Light"), wrote: The proposition is sometimes given as . This fuller form was penned by the eloquent French literary critic, Antoine Léonard Thomas, in an award-winning 1765 essay in praise of Descartes, where it appeared as In English, this
Cogito, ergo sum itself is good and pleasant (...) and if one who sees is conscious that he sees, one who hears that he hears, one who walks that he walks and similarly for all the other human activities there is a faculty that is conscious of their exercise, so that whenever we perceive, we are conscious that we perceive, and whenever we think, we are conscious that we think, and to be conscious that we are perceiving or thinking is to be conscious that we exist... ("Nicomachean Ethics", 1170a25 ff.) Augustine of Hippo in "De Civitate Dei" writes "Si […] fallor, sum"