Zhang Zai (Chang Tsai, 1020—1077 CE)

Zhang Zai was one of the pioneers of the Song dynasty philosophical movement called “Study of the Way,” often known as Neo-Confucianism. One of the most distinctive features of many of these new ways of thought being formulated at the time was an increased interest in metaphysics, usually influenced by the Classic of Changes (Yijing). Zhang’s most significant contributions to Chinese philosophy were primarily in the area of metaphysics, where he came up with a new theory of qi that was very influential. He is also credited with differentiating original nature and physical nature, which was to become a key concept in the most prominent Song philosophers, the Cheng brothers and Zhu Xi (Chu Hsi). Ethically, his most influential doctrines were found in the brief essay “Western Inscription,” where he propounded the ideas of being one body with all things and universal caring. After his death, most of his disciples were absorbed into the Cheng brothers’ school and his thought become known primarily through the efforts of the Cheng brothers and Zhu Xi, who honored Zhang as one of the founders of the Study of the Way.

Source: http://www.iep.utm.edu