Self-reflection focus on the beatific vision after death. The 13th century pope Innocent III wrote about the essential misery of earthly existence in his ""On the misery of the human condition"" – a view that was disputed by, for example, Giannozzo Manetti in his treatise ""On human dignity."" A famous quote of Shakespeare's Hamlet (II, ii, 115-117), expressing the contrast of human physical beauty, intellectual faculty, and ephemeral nature: René Descartes famously and succinctly proposed: "Cogito ergo sum" (French: ""Je pense donc je suis""; English: ""I think, therefore I am""). The Enlightenment was driven by a renewed conviction, that, in the
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.