1. Change (变易 biànyì): The fundamental principle that everything in the universe is in a constant state of flux.
2. **Simplicity (简易 jiǎnyì):** The idea that behind all the complex changes, the underlying principles (yin and yang) are simple and easy to grasp. 3. **Invariability (不易 bùyì):** The law of change itself is the one thing that never changes. * Together, **周易 (zhōu yì)** literally means "The Changes of the Zhou Dynasty," identifying this specific, foundational version of the classic on change.