本文期對於漢宋之爭的背後義理作一述說，故兩派雙方各舉一人，漢學家以清代的戴震為主，而宋學家以朱子及方東樹為主，視其二派的爭論焦點何在，並對此做一分疏與判定。主要的爭論焦點，吾人分為三點，作為分章節的依據，首先漢學家所批評的宋儒為虛玄之學，對此爭論的兩方，做一判定；第二，對於程朱所言的「性是理」，而戴震認為性是氣稟的講法，見誰是誰非。第三，對於孟子的詮釋，是否如同程朱所言，孟子對於氣講得不夠，而需要後人的補充呢？此二派的看法不同。依於以上三點的討論，吾人做一總結，以見方東樹與戴震相爭之倫理義涵。

This paper intends to interpret the argumentations behind the dispute between Han and Song Dynasty. Therefore, one scholar from each of the schools of thoughts was given as examples, respectively. Dai Chen was chosen as the representative of Confucianism in the Han Dynasty, while Zhuzi was chosen as the representative of the Song Dynasty. This study interprets and judges the focus of contention between these two schools as follows. First, the scholars supporting Confucianism in the Han Dynasty criticized that the Confucianism in the Song Dynasty is an empty and mysterious study. Secondly, this study investigates Cheng-Zhu,s statement conc e rning“r e a l na tur e i s Li”and Da i Chen, s s t a t ement concerning“real nature is Qi.”Thirdly, this study also discusses whether the statement of Cheng-Zhu is correct, which claims that Mencius, study neglected Qi and thus it is necessary for later scholars to provide supplementary information. The differences in the opinions between these two scholars were discussed as mentioned above to reflect the ethical meaning of Fang Dong-shu,s criticism of Dai Chen.