TaiJi

The Taiji is the infinite, or the principle that embodies all potential things including all possible time and space. This is seen as the perpetual cycle of yin and yang, as reflected in the taijitu, which is simply referred to as the "yin-yang" in the West. Taiji is itself part of a progression similar to yin and yang. "Existence," the Taiji, arose from "non-existence," or Wuji, the "Great Emptiness."

The Taiji is understood to be the ideal of existence. Yin and yang are used to illustrate the contrasting qualities within reality and experience. For example, light contrasts with darkness, providing them both with context and therefore meaning. Taiji is not perceived as a simple list of all things and potential things, but rather a complex interconnection of all things in all possible contexts. This concept is often used to illustrate the doctrine of cosmological unity. It is also used to explain the creation of the "myriad things" (i.e., everything in existence) through the dialectical process of alternating polarity between yin and yang. Western proponents of Taoism sometimes conflate Taiji and the "myriad things," but Taiji is not only representative of what exists, but also that which has existed, will exist, and could potentially exist.

The concept of Taiji was introduced in the Zhuang Zi, showing its early place in Taoism. It also appears in the Xì Cí (Great Appendix) of the I Ching, a fundamental Taoist classic.

When Confucianism came to the fore again during the Song Dynasty as Neo-Confucianism, it synthesized aspects of Chinese Buddhism and Taoism, and drew them together using threads that traced back to the metaphysical discussions in the Book of Changes.