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 light; female and male; moon and sun", however, is an exception. Scholars have proposed various explanations for why "yinyang" violates this pattern, including "linguistic convenience" (it is easier to say "yinyang" than "yangyin"), the idea that "proto-Chinese society was matriarchal", or perhaps, since "yinyang" first became prominent during the late Warring States period, this term was "purposely directed at challenging persistent cultural assumptions". Needham discusses Yin and Yang together with Five Elements as part of the School of Naturalists. He says that it would be proper to begin with Yin and Yang before Five Elements because the former: "lay, as