Cheng Yi (1033–1107)
Cheng Yi, or Cheng Yi-chuan, was the most outstanding Chinese teacher of his time, a lecturer to the emperor on Confucian classics, and cofounder, with his brother Cheng Hao, of the neo-Confucian school of principle (li ) that dominated Chinese thought for many centuries.
The central concept of the school is principle. The concept, negligible in ancient Confucianism, had been developed by the neo-Daoists and Buddhists, but the Cheng brothers were the first to build their philosophy primarily on it. To them, principle is self-evident and self-sufficient, extending everywhere and governing all things. It is laid before our very eyes. It cannot be augmented or diminished. It is many, but it is essentially one, for "definite principles" are but principle. "Principle is one but its manifestations are many." It is universal truth, universal order, universal law. Most important of all, it is the universal principle of creation. It is dynamic and vital. Man and all things form one body because all of them share this principle. It is identical with the mind and with the nature of man and things. Since principle is principle of creation and since life-giving is good, principle is the source of goodness. To be good is to obey principle. Thus, principle is both natural and moral and both general and specific. It has meaning as an abstract reality, but more so as the moral law of man.
The relation between principle and material force, which actualizes things, is not a dualistic one. Although Cheng Yi said that "material force exists after physical form and is therefore with it whereas the Way [principle] exists before form and is therefore without it," he also said that "what makes yin and yang [material force] is the Way." Material force is the physical aspect of principle. In the process of creation each operation is new, for material force is perpetually generated by Origination. (Origination is comparable to creation, except that it is natural and self-caused and is not an act of any being.)
To understand principle one can study one thing intensively or many things extensively. One can also read books, study history, or handle human affairs, for all things and affairs, including blades of grass, possess principle. This intellectual approach makes Cheng's system strongly rationalistic. The approach, however, is balanced by the moral, for whereas "the pursuit of learning depends on the extension of knowledge," "self-cultivation requires seriousness." This dual emphasis reminds one of the Buddhist twofold formula of meditation (dhyana) and wisdom (prajna).
The works of Cheng Hao and his brother Cheng Yi are in Er Cheng quan shu ("The Complete Works of the Two Ch'engs").
Chan, Wing-tsit. A Source Book in Chinese Philosophy. Princeton, NJ: Princeton University Press, 1963.
Fung Yu-lan. A History of Chinese Philosophy. Translated by Derk Bodde, Vol. II. Princeton, NJ: Princeton University Press, 1953.
Graham, Angus G. Two Chinese Philosophers, Ch'eng Ming-tao and Ch'eng Yi-ch'uan. London: Lund Humphries, 1958; LaSalle, IL: Open Court Press, 1992.
Graham, Angus C. "What Was New in the Ch'eng-Chu Theory of Human Nature?" In Studies in Chinese Philosophy and Philosophical Literature. Albany: SUNY Press, 1990.
Feng Youlan. "Cheng Hao and Cheng Yi." Chinese Studies in Philosophy 13 (Win–Spr 1981–82): 127–182.
Wing-tsit Chan (1967)
Bibliography updated by Huichieh Loy (2005)