Know thyself know what are the thoughts and passions of all other men upon the like occasions." In 1734 Alexander Pope wrote a poem entitled "An Essay on Man, Epistle II", which begins "Know then thyself, presume not God to scan, The proper study of mankind is Man." In 1735 Carl Linnaeus published the first edition of "Systema Naturae" in which he described humans ("Homo") with the simple phrase ""Nosce te ipsum"". In 1750 Benjamin Franklin, in his "Poor Richard's Almanack", observed the great difficulty of knowing one's self, with: "There are three Things extremely hard, Steel, a Diamond, and to know
Peter Abelard in the 12th–13th centuries. Abelard was an enormous influence on his contemporaries and the course of medieval philosophical thought, but he has been known in modern times mainly for his connection with Héloïse. Only one of his strictly philosophical works, the ethical treatise "Scito te ipsum", had been published before the 19th century, in 1721. It was only with the publication by Cousin in 1836 of the collection entitled "Ouvrages inedits d'Abelard" that Abelard's philosophical work began to be studied more closely. Cousin's collection gave extracts from the theological work "Sic et Non" ("Yes and No") which is an assemblage