1. Plato, 27d–58c
2. Aristotle, Books I–II
3. Lucretius, Books I–II
4. Thomas Aquinas, I, Q.44–46; Book II
5. Francis Bacon, Book I; Book II
6. Isaac Newton, , Preface; General Scholium; Query 31
7. Antoine Lavoisier, Preliminary Discourse; Part I
8. David Hume, Sections IV–VII
9. Immanuel Kant, , Transcendental Analytic: Principles of Pure Understanding