As a chief minister to the emperor Wu (c. 140–87) of the Han dynasty, Dong was chiefly responsible for the dismissal of all non-Confucian scholars from government. His proposal that Confucianism become the unifying ideology of the Han empire was put into effect, as were his proposals to set up an imperial college (taixue) for training promising students and to require nobles and governors to recommend annually persons of talent and good moral character for official appointment. Out of these institutional means developed the civil service examinations that became the basis of recruitment into the bureaucracy, guaranteeing that men of humble birth and high ability might rise to positions of power and influence.

As a philosopher, Dong made the theory of the interaction between heaven (tian) and humanity (ren) his central theme. The emperor is heaven’s ambassador on earth, and natural catastrophes such as floods and droughts are heaven’s way of warning the emperor to examine his personal conduct and correct his mistakes. Yang (light, positive, male) and yin (dark, negative, female) are the two