1. Plato, 47e–57c
2. Aristotle, Book II; Book I, Ch. 4–6; Book V, Ch. 3
3. Lucretius, Books I–II
4. Aquinas, I, Q. 66, a. 2; II, Ch. 43
5. Bacon, Book II, Aph. 5, 48
6. Descartes, Part II
7. Newton, Book III; Query 31
8. Locke, Book III, Ch. 6
9. Lavoisier, Part I