China & East Asia · 1033–1107
Cheng Yi
Younger Cheng brother who made “principle” central
Taught that “human nature is principle” and that one approaches principle by investigating things one by one while holding reverent seriousness (jing).
Life and thought
Cheng Yi, called Yichuan, made his name as a student at the Imperial University with an essay on what Confucius’s best disciple loved to learn. He long declined office, briefly tutored the boy emperor Zhezong from 1086, and was caught up in the factional fights of the late Northern Song: his teachings were banned and he was exiled before his death in 1107. His sternness became legendary; two disciples, the story goes, waited outside his door in the snow until he finished meditating.
He made principle (li) the central idea of Confucian thought. Every thing and every relation has its principle, the reason it is so and the way it ought to be, and human nature is that principle in us, which is why it is good. Principle is one, yet its manifestations are many, as one family love differs towards father, brother and stranger. His method has two parts: “cultivation requires reverence; advancing in learning lies in extending knowledge” by investigating things one by one, until understanding breaks through. Zhu Xi built his synthesis on these foundations, and the school is called Cheng–Zhu after them.