The Doctrine of the Mean was originally one of The Book of Rites for Little Wear (that is, the Book of Rites, which is common in later generations), and the Doctrine of the Mean was the thirty-first article of the fifty-second volume. The author is Zi Si, a descendant of Confucius, who was revised and collated by scholars in Qin Dynasty. It is also an important treatise of China's ancient educational theory.
The doctrine of the mean was highlighted by scholars in the Song Dynasty. There were more than one hundred articles on the doctrine of the mean in Song Dynasty, but it was not Confucian scholars who first discussed the doctrine of the mean, but Shi Zhiyuan, a foreigner who died in the first year of Ganxing in Song Zhenzong. After Zhiyuan, Sima Guang was one of the earliest golden mean theorists in Song Confucianism. Later, in the Northern Song Dynasty, Cheng Hao and Cheng Yi advocated the golden mean. In the Southern Song Dynasty, Zhu wrote The Doctrine of the Mean, which is called the "Four Books" together with The University, The Analects of Confucius and Mencius. After the Song and Yuan Dynasties, The Doctrine of the Mean became an official textbook and a must-read in the imperial examination, which had a great influence on ancient education.
Zi Cheng Zi said, "If you are not partial, you are right; It is not easy to call it mediocrity. The winner is king, and the world is right. Mediocrity is the norm of this world. This article is Confucius' teaching of mind and nature, and Zisi was afraid that he would be poor if he went on like this, so he wrote it in a book to teach Mencius. His book begins with a statement; Dispersion is everything; Compound into the end of a principle. Let it go, then Liuhe; If you throw it, you will return to the secret. Its taste is endless. They are all practical. If you are a good reader, you will enjoy it all your life and never run out.