本文旨在對《孟子》一書的仁觀提出一個較新穎的詮釋，並由此論證孟子仁觀存在不一致之處，以及嘗試找出該不一致之處產生的原因。本文亦會指出孟子心性論的主要困難。 本文共分為六節。第一節旨在證明，孟子所謂「仁」是指在依循「（自）有所不忍，達之於其所忍」的（踐仁）原則下，於親親而仁民、仁民而愛物的過程中所表現的價值。第二節主要指出，孟子認為仁者雖無所不愛，但仁者之愛必涉差等。第三節則證明，孟子視親親為踐仁的起點，而以仁為自親親為起點的推愛是孔學觀點的承繼和發展。第四節集中討論孟學中「仁根於心」或「仁根於包含以親親為大本能的不忍之心」的主張，以及對有關主張的其中一個證明。它主要是訴諸人的良知良能。可是，這證明的說服力並不強。第五節討論孟學對「仁根於心」的另一個證明，亦即著名的孺子入井論證。有關論證中以不必涉及差等的惻隱之心為仁之端的主要立埸是與「仁者之愛必涉差等」的主張相抵觸的。這顯示孟學存在不一致之處。第六節指出，任何企圖承繼和發展孟子心性論的嘗試，除了必須放棄孺子入井論證和提出更強的理據外，更要反駁任何以孟子所提出的孺子入井論證，來倡議墨家兼愛之類的無差等價值的敵論的企圖。

　　　　　This paper aims at putting forward a novel interpretation of the view of benevolence in the book Mencius and, by means of the interpretation, proves that the view contains a logical inconsistency, as well as finding out the cause of the inconsistency. This paper will also locate some major difficulties of Mencius' Doctrine of Heart and Essence（心性論）. This paper is divided into six sections. In the first two sections, we argue that, for Mencius, benevolence is the value actualized in the process of “being affectionate to parents and then being benevolent to people generally, being benevolent to people generally and then being kind to creatures（親親而仁民、仁民而愛物）” according to the principle of extending what one cannot bear to what she can bear（自有所不忍，達之於其所忍）. It follows that a benevolent person should love all people and things but there must be gradations in her love. The third section proves that Mencius takes “being affectionate to parents” as the point of departure of the practice of benevolence, and this together with the aforementioned views shows that Mencius' view of benevolence is inherited and developed from Confucian philosophy. The fourth section focuses on the proposition “Benevolence is rooted in the heart which contains the ability of being affectionate to parents” and discusses one of its proofs. But the proof lacks force. The fifth section discusses another proof of the proposition, namely, the famous “child-about-to-fall-into-well” argument. The step of identifying the heart of compassion（惻隱之心）with the germ of benevolence（仁之端）in the proof is inconsistent with the claim that there must be gradations in the love of a benevolent person. This shows that Mencius?view of benevolence is inconsistent. The sixth section points out that any attempt to inherit and further develop Mencius' Doctrine of Heart and Essence, besides giving up the “child-about-to-fall-into-well” argument and providing strong grounds for the doctrine, must also refute any attempt to employ Mencius' “child-about-to-fall-into-well” argument to support any rival theory upholding values without gradations, e.g., the Mohist universal love（墨家兼愛）.