<p align="right">Last Update: <font color="#4f81bd">July, 14, 2024</font></p>
## BIG IDEAS
- Natural philosophy
- Structuring of the cosmos into concentric spheres
- Aristotle divided his universe into "terrestrial spheres" and "celestial spheres."
- The Aristotelian explanation of gravity is that all bodies move toward their natural place.
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>[!important] The acceptance of Aristotelian physics
>By the late 17th century, Aristotelian physics had largely been supplanted by Newtonian physics. Thus, the period of widespread acceptance of Aristotelian physics can be considered to span from the 4th century BCE to the late 17th century CE.
>
- **Natural Motion**: Objects have a natural place and will move toward it. For example, heavy objects fall towards the Earth (their natural place), while fire rises.
- **Unnatural Motion**: Requires an external force. For example, pushing a cart or throwing a stone.
- **Four Elements**: Everything is made of four elements—earth, water, air, and fire. Each element has its natural place and natural motion.
- **Terrestrial vs. Celestial**: Earthly (terrestrial) and heavenly (celestial) realms operate under different principles. Terrestrial bodies (earth, water, air, fire) move naturally, while celestial bodies (stars, planets) move in perfect circles.
- **Finite Universe**: The universe is finite and geocentric (Earth is at the center).
- **Impetus**: An early concept suggesting that objects need a continuous push to keep moving.
- **Qualitative Approach**: Focus on qualitative explanations (why things happen) rather than quantitative measurements (how much/many).
- **Rest as Natural State**: Objects at rest are in their natural state and do not require a force to remain at rest.
- **Void**: Aristotle denied the existence of a vacuum (void), believing that nature abhors it.
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