1. Plato, ; Books VI–VII;
2. Aristotle, , especially Book III
3. Augustine, Books IX–X; X
4. Aquinas, I, QQ. 75–89
5. Descartes, ;
6. Hobbes, , Part I, Chapters 1–5
7. Locke, , Books I–II
8. Hume, , Book I
9. Kant, , Transcendental Analytic
10. William James,
11. Freud, ; Introductory Lectures on Psychoanalysis