Taijitu is still. In stillness it generates "yin"; yet at the limit of stillness it is also active. Activity and stillness alternate; each is the basis of the other. In distinguishing "yin" and "yang", the Two Modes are thereby established. The alternation and combination of "yang" and "yin" generate water, fire, wood, metal, and earth. With these five [phases of] "qi" harmoniously arranged, the Four Seasons proceed through them. The Five Phases are simply "yin" and "yang"; "yin" and "yang" are simply the Supreme Polarity; the Supreme Polarity is fundamentally Non-polar. [Yet] in the generation of the Five Phases, each one
Yin and yang it were, at a deeper level in Nature, and were the most ultimate principles of which the ancient Chinese could conceive. But it so happens that we know a good deal more about the historical origin of the Five-Element theory than about that of the Yin and the Yang, and it will therefore be more convenient to deal with it first." He then discusses Zou Yan (鄒衍; 305 – 240 BC) who is most associated with these theories. Although Yin and Yang are not mentioned in any of the surviving documents of Zou Yan, his school was known as the