The Doctrine of the Mean is an ancient Chinese treatise in moral philosophy on the cultivation of human character and the highest reaches of self-development. It is one of the Confucian classics and was originally the thirty-first chapter of the Book of Rites. Tradition attributes it to Zisi, who lived during the Warring States period. The text upholds the mean as the highest standard of moral conduct, regards sincerity as the substance of the world, and holds that perfect sincerity leads to the highest state of human life. It also sets out a process of learning and a method of inquiry: “Study broadly, question carefully, think things through, distinguish clearly, and put what you have learned into practice with dedication.” During the Song dynasty, it was separated from the Book of Rites and grouped with the Great Learning, the Analects, and the Mencius as the Four Books. From the Song and Yuan dynasties onward, it became an officially prescribed school textbook and required reading for the civil service examinations, profoundly influencing education and society in ancient China. Its major commentaries include Cheng Hao’s Meaning of the Doctrine of the Mean, Cheng Yi’s Explanation of the Doctrine of the Mean, Zhu Xi’s Chapters and Sentences of the Doctrine of the Mean, Li Gong’s Commentary on the Doctrine of the Mean, Dai Zhen’s Supplementary Commentary on the Doctrine of the Mean, Kang Youwei’s Notes on the Doctrine of the Mean, Ma Qichang’s Exegesis of the Doctrine of the Mean, and Hu Huaichen’s A Concise Explanation of the Doctrine of the Mean.
