Dai Zhen (1724-1777), a native of Longfu (now Tunxi), Xiuning of Anhui Province, was a progressive philosopher and a textologist in textual research of the Qing Dynasty as well as one of the representatives of the Han-Learning School in Emperor Qianlong and Jiaqing Periods.

Knowledgeable and versatile, he was a professional in astronomy, mathematics, history and geography. He was once appointed as the editor and Bachelor of the Hanlin Academy to compile Complete Library in Four Divisions (Siku Quanshu).

In terms of philosophy, Dai Zhen believed that qi of the matter was the first principle of the universe. Yin and yang, five elements (metal, wood, water, fire and earth) and dao were the materialized forms of qi. He also believed that the universe was the overall process of the flow of qi.

In terms of epistemology, he believed that if one made contact with the nonego through the organs such as ears, eyes, nose and the mouth, the heart would find the rules about the nonego. One could only acquire knowledge about the things through intense investigation on them. Besides, he raised the "Illumination Theory", which believed that the knowledge about all things acquired by heart was similar to the fire shone on the things nearby. A weak light could reach this far, while a strong light could reach even further. In fact, it was a simple and an intuitionistic Theory of Reflection.

In terms of ethics, he believed that it was human nature to possess desire, passion and knowledge. The denial of desires meant the denial of human nature. He proclaimed that a distinction should be made between desire and selfishness. It was true that selfishness was a result of desire abuse; yet it was not right to deny the existence of desires. Reasonable natural desires of human beings should be satisfied. It was not right to "preserve the rationality and prohibit the desires".