| 22171 | If only natural substances exist, science is first philosophy - but not if there is an immovable substance [Aristotle] |
| 20770 | Philosophy has three parts, studying nature, character, and rational discourse [Zeno of Citium, by Diog. Laertius] |
| 20771 | Six parts: dialectic, rhetoric, ethics, politics, physics, theology [Cleanthes, by Diog. Laertius] |
| 20772 | Three branches of philosophy: first logic, second ethics, third physics (which ends with theology) [Chrysippus] |
| 20806 | Stoic physics concerns cosmos, elements and causes (with six detailed divisions) [Stoic school, by Diog. Laertius] |
| 20839 | Ethics studies impulse, good, passion, virtue, goals, value, action, appropriateness, encouragement [Stoic school, by Diog. Laertius] |