This term means to rectify our mind so as to follow moral principles in daily life. Rectifying one’s heart or mind is one of the eight notions from the philosophical text The Great Learning (a section of The Book of Rites), the other seven being “studying things,” “acquiring knowledge,” “being sincere in thought,” “cultivating oneself,” “regulating one’s family well,” “governing the state properly,” and “bringing peace to all under heaven.” These constitute important stages in the moral cultivation advocated by the Confucian school. “Rectifying one’s mind” has as its preceding stage “being sincere in thought.” In the course of following the moral principles earnestly in daily life, people are inevitably influenced by sentiments such as anger, fear, joy, and worries, which will, to some degree, lead a person astray. Therefore, one must always try to rectify one’s mind and avoid being swayed by any interference, so as to keep to the observance of moral principles in daily life.

When thought has been made sincere but the mind is perhaps still somewhat biased, then it is not possible for a person to stay pure and unbiased. Therefore one should make efforts to rectify one’s mind. (Categorized Conversations of Master Zhu Xi)

To rectify one’s mind means to cultivate one’s good conscience without the least conjecture, arbitrariness, stubbornness, or egoism. (Records of Great Learning)