明清之交，儒家思想在基本形態上經歷了一種重大的轉型。這種轉型主要表現於兩方面：儒者一方面針對明末王學空疏之病，強調實踐與致用，另一方面否定宋儒理氣二分的義理間架，以及理之超越意義。在戴震的思想中，我們可以清楚地見到這種思想特徵：在自然觀方面，他主張「氣化即道」；在倫理學方面，他主張「理存乎欲」。就在這種思想史的背景下，焦循著手編纂《孟子正義》。焦循基本上繼承載震的思想方向，而回歸漢儒「以氣論性」的傳統，並以此來詮釋孟子的心性論。在詮釋方法上，焦循和其他乾嘉漢學家一樣，採取「以訓詁學方法解決詮釋學問題」的方法。 本文首先根據《孟子》書中有關心性論的重要章節，從哲學的角度檢討焦循對孟子心性論的詮釋，指出焦循對孟子心性論的根本誤解。其次，筆者從詮釋學的角度來說明此種誤解的原因，指出焦循和其他乾嘉學者一樣，欠缺「詮釋學循環」的概念。

Confucianism underwent a grand transformation in the late Ming and the early Ch'ing period. First, Confucians at that time emphasized practice and utility as a remedy for the practical impotence of Ming scholars' ideas; second, they refuted the duality of "li" and "ch'i" as well as the transcendence of "li" found in Sung Confucianism. Tai Chen clearly exemplifies these two traits by arguing that moral norms consist in cultivated human desires. Following the direction of Tai Chen, Chiao Hsün compiled commentaries to the Meng-tzu. In his interpretation of Mencius' theory of heart/mind, Chiao Hsün returned to the Han Confucians' approach of explicating heart/mind in terms of "ch'i". Like most early Ch'ing scholars, Chiao Hsün adopted the philological method to resolve hermeneutic problems. From a philosophical perspective, this paper reviews Chiao Hsün's interpretation of related passages in the Meng-tzu and comes to the conclusion that he misunderstood Mencius' theory of heart/mind. Furthermore, this paper traces the source of Chiao Hsün's misunderstanding by pointing out the absence of the idea of "hermeneutic circle" in his methodology.