This refers to people’s innate moral nature. The term first appeared in The Book of Rites. Ancient Chinese people widely believed that inborn human nature had feelings and a craving for knowledge of the outside world. However, they had different views as to whether morals were included in innate human nature. The majority of Confucian scholars held that human nature had in itself a basic sense of benevolence, righteousness, rites and wisdom, and together they constituted the virtuous nature. Still these scholars maintained that self-cultivation was required for such nature to develop into conscious benevolence.

Therefore, a man of integrity should revere the virtuous nature of human beings and constantly pursue knowledge. This way, he will acquire extensive knowledge and gain command of it in an in-depth way. He can thus reach mastery and observe the doctrine of the mean. (The Book of Rites)

The virtuous nature is not that of ears, eyes, mouth and body, rather it is the source from which benevolence, justice, rites, and wisdom emerge. They actually come forth from one’s heart. (Wang Fuzhi: Annotations to Zhang Zai’s Enlightenment Through Confucian Teachings)