1. Aristotle, , Book II; , Book I
2. Aquinas, , I, Q. 79, 84-86
3. Montaigne, , "Of Experience"
4. Descartes, ;
5. Locke, , Books I-II
6. Hume, , Sections II-V, VII
7. Kant, , Introduction and Transcendental Aesthetic
8. Hegel, , Preface and Introduction
9. William James, , Chapters IX-X;