戴震以字義訓詁的方式對於先秦儒學重新詮釋，以期回到先秦儒者的本意，特別就孟子性善的原意，做一說明。戴震以重氣的義理型態，反對朱子以「氣質之性」與「義理之性」兩種性的支離講法詮釋孟子性善論，因為戴震認為，這樣的詮釋方式，產生了很大的問題，例如，不能解通孟子，反而質疑孟子的講法對於氣講得太少而有所不備；又例如，如此言性，將使得告子言性的「生之謂性」等同於孔子言性的「性相近」之講法。若如此，依於戴震而言，這是程、朱學者的詮釋有誤，故戴震在義理上以重氣的方式詮釋，在方法上以訓詁字義的方式，對於孟子論性，甚至先秦儒者論性的本意，重新詮釋，以血氣、心知定義人性，以期於對《孟子》的「性善」能有前後一致的詮解，甚至以此論性，可貫通於先秦儒學經典裡對性的詮解。

Dai Zhen used scholium to reinterpret pre-Qin Confucianism with the aim of representing the original concept given by the pre-Qin Confucians. He particularly explained the original meaning of goodness of nature given by Mencius. Dai Zhen proposed Qi against Zhu Zi's dualism of a person's disposition and practice to interpret Mencius's theory on the Goodness of Human Nature. Dai Zhen thought that Zhu Zi's interpretation was with problems in logic; for instance, Zhu Zi's interpretation failed to explain Mencius's theory while Zhu Zi questioned that Mencius's theory lacked Qi, and Zhu Zi's theory on nature had made Gao Zi's being born with common features an equivalent interpretation of Confucius's common nature. in Dai Zhen's point of view, this was due to Cheng and. Zhu's false interpretation. As a result, Dai Zhen emphasized Qi and proposed a semantic reinterpretation of Mencius's theory on nature as well as pre-Qin scholars' original intention. He defined human nature by Xue-Qi (desire) and Xin-Zhi (cognition) in the hope of giving a coherent interpretation of Mencius's the Goodness of Human Nature and of even corresponding to pre-Qin scholars' definition of nature.