Zhou Dunyi in the context of "Cosmologist"

Cheng Yi (1033–1107), also known by various other names and romanizations, was a Chinese classicist, essayist, philosopher, and politician of the Song Dynasty. He worked with his older brother Cheng Hao. Like his brother, he was a student of Zhou Dunyi, a friend of Shao Yong, and a nephew of Zhang Zai. The five of them, along with Sima Guang, are called the Six Great Masters by his follower Zhu Xi. He became a prominent figure in neo-Confucianism, and the philosophy of Cheng Yi, Cheng Hao and Zhu Xi is referred to as the Cheng–Zhu school or the Rationalistic School.

Chéng Hào (Chinese: 程顥, 1032–1085), Courtesy name Bóchún (Chinese: 伯淳), was a Chinese philosopher and politician from Luoyang, China. In his youth, he and his younger brother Cheng Yi were students of Zhou Dunyi, one of the architects of Neo-Confucian cosmology. His philosophy was dualistic (between all that is tangible and all that is intangible) and pantheistic (believing that all that is intangible is the same thing, such as god, the human nature, feelings, actions (we see things acting, but not the action itself), movement (likewise), social roles and relations (likewise), chance, etc., and that such a unified, universal principle is in everything that is sensible [rather than in an external reality as in Platonism]); among his quotes are "outside dao there are no things and outside things there is no dao", "we call it god to emphasize the wonderful mystery of principle in ten thousand things, just as we call it lord (di) to characterize its being the ruler of events" and "in terms of the reality, it is change; in terms of principle, it is dao; in terms of its function, it is god; in terms of its destiny in a human being, it is human nature".

In Chinese philosophy, a taijitu (Chinese: 太極圖; pinyin: tàijítú; Wade–Giles: tʻai⁴chi²tʻu²) is a symbol or diagram (圖; tú) representing taiji (太極; tàijí; 'utmost extreme') in both its monist (wuji) and its dualist (yin and yang) forms. A taijitu in application provides a deductive and inductive theoretical model. Such a diagram was first introduced by Neo-Confucian philosopher Zhou Dunyi of the Song Dynasty in his Taijitu shuo (太極圖說).

The Fourth Daozang, a Taoist canon compiled in the 1440s CE during the Ming dynasty,has at least half a dozen variants of the taijitu. The two most similar are the Taiji Xiantiandao and wujitu (無極圖; wújítú) diagrams, both of which have been extensively studied since the Qing period for their possible connection with Zhou Dunyi's taijitu.