《人性論》與《道德原理探索》之間存在微妙的轉變，認真看待這些轉變有助於我們理解休謨的道德哲學。本文以同情共戚與效益為 線索，仔細比較了休謨於前述兩書中對於德行的觀察與闡釋，進以指出兩書之間的差異並非來自於休謨在輿論的壓力下被迫修改其理論，而是由於其立論觀點發生了變化，即從著重於探索德行的根源過渡為彰顯德行的效用。然而，在差異之外，休謨的基本立場在兩部著作之 間並無實質的改變，他始終以人性的解剖學家自居而致力於建立一個描述性的理論。

While there are some delicate differences between Hume’s Treatise of Human Nature and his Enquiry Concerning the Principles ofMorals, to take these differences seriously is essential to an adequate understanding of Hume’s moral thought. This essay examines Hume’s ideas of justice and benevolence elaborated in those works. My main contention is that the differences between the two works are caused not by Hume’s revision of his theory under the pressure of public opinion, but by the change of the perspective from which he observes virtues, namely his focus has been transferred from the different origins of virtues to the utility they bring about. In spite of the differences, however, the nature of Hume’s theory remains the same. Hume is faithful to his position as an anatomist of human nature, and his aim is to provide a descriptive rather than prescriptive theory.