Sima Guang’s theory of “medium harmony” was the most important idea interpreted in his Golden Mean. According Sima Guang, a gentleman learns to control his mind, and the key to control his mind is to adhere to “medium harmony” in keeping his mind. The “medium harmony” refers to the moral of “nonexcess and nonlack”, meaning a scholar should make his best adhere to the “medium harmony” prior to “mental excitement”. However, a “mental excitement” has occurred in the context of “nonexcess and nonlack”, then how should the gentleman adhere to the “medium harmony” prior to “mental excitement” in the context of “mental excitement” that occurred. In terms of Taoist theory, this offers a problem, which was already criticized by Cheng Ying and Zhu Xi. However, the problem Sima raised offered a guide to Taoist consideration. In this sense, Sima Guang theory was of rather active significance to the later development of Taoist ideology.

Sima Guang; Golden Mean; Medium Harmony; Taoism