Dai Zhen, styled Dongyuan, was a critical-minded neo-Confucian in the Qing period. He is noted as a critic of neo-Confucianism of the Song (960–1279) and Ming (1368–1644) periods and made original contributions to the critical exposition of the philosophy of Mencius (c. 371–c. 289 BCE). Even though not known as a philosopher in his own time, his work in neo-Confucian criticism and exposition received more attention after Hu Shi wrote about his philosophy in the 1930s.

Dai Zhen was born in the Huizhou area of Anhui Province at a place known as Longfu (Tunxi) of Xiuling County. Although Huizhou was prosperous and produced outstanding academic talents, Dai Zhen, coming from a poor family with no academic traditions, received no good formal schooling. His success as a scholar derived from his own dedication to self-study.

Dai Zhen wrote Yuan shan (Inquiry into Goodness), his first philosophical treatise, from...