Yin and yang and yang are bound together as parts of a mutual whole (for example, there cannot be the bottom of the foot without the top). A way to illustrate this idea is to postulate the notion of a race with only men or only women; this race would disappear in a single generation. Yet, men and women together create new generations that allow the race they mutually create (and mutually come from) to survive. The interaction of the two gives birth to things, like manhood. Yin and yang transform each other: like an undertow in the ocean, every advance is complemented
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