Cheng Hao, also called Cheng Mingdao, was cofounder, with his brother Cheng Yi, of the neo-Confucian school of Nature and Principle (li). He held some minor official posts but devoted most of his life to teaching.

By making principle the foundation of his philosophy and identifying it with the nature of man and things, Cheng Hao and his brother set the pattern for the neo-Confucian philosophical movement known since the eleventh century as the school of Nature and Principle. To Cheng Hao principle was the principle of nature (tian li), a concept that he evolved himself; it was the natural law. It had all the characteristics of principle as conceived by Cheng Yi, but as the principle of nature it was self-existent and unalterable. Whereas Cheng Yi stressed the doctrine that principle is one but its manifestations are many, Cheng Hao emphasized more strongly...