This term means changing element of evil in one’s intrinsic nature and developing acquired nature of goodness. This ethical principle is put forward by Xunzi （313？-238 BC）based on his belief that human nature is evil. Xunzi believes that the desire for external things is an intrinsic part of human nature. Unrestrained pursuit of such desire leads to rivalry between people and throws society into chaos. Therefore, it is imperative to rein in human desire and make people accept and observe rites and laws.

Attributes that people have and that cannot be gained by learning and practice are called intrinsic nature. Abilities learned or mastered through practice are called acquired nature. Such is the difference between intrinsic nature and acquired nature. （Xunzi）

Thus, what the sage does is to transform the evil element in people’s intrinsic nature and develop acquired nature of goodness. The acquired nature of goodness gives rise to rites and ethical standards, which in turn give birth to laws. （Xunzi）