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
Zhou Dunyi that "the many are ultimately one and the one is ultimate." This was the first 11th-century Chinese text to argue for the inseparability of metaphysics or cosmology and ethics, as well as the first major Chinese text to explore the concept of the taijitu or "yin-yang symbol". It contained his theory of creation, which can be summarized in the following paraphrase of its first section: "In the beginning, there was t'ai chi (taiji) (the great ultimate of being), which was fundamentally identical with wu chi (wuji) (the ultimate of non-being). Because of the abundance of energy within t'ai chi, it