1. Plato, Books I, IX; ;
2. Aristotle, Books I, X
3. Epictetus, ;
4. Augustine, X; XIX; On the Happy Life
5. Aquinas, I–II, Questions 1–5
6. Montaigne, , "Of Experience"; "That to Philosophize is to Learn to Die"
7. Locke, II.xxi
8. Kant, ;
9. Mill, , Chapters II, IV
10. Freud,