本文嘗試分析《孟子》倫理學論證之問題，用以證成它在倫理學史中的地位。其論證可分為三個層次：1.人心在或順於本心或順於耳目中作成道德決意，而決意之可能性又在於人作為責任主體之自我。2.人心乃在道德高低貴賤的秩序中決意，本心為高，耳目為低，所謂不善之惡，乃意謂人心在決意中顛倒了這秩序。3.而這秩序之所以可能，又在於理義源於本心，本心悅於理義；悅，乃表示心對理義之心悅誠服；在人之道德決意中，順從本心理義之願意，乃表示：本心不是被動地被選擇者，而是直貫到在人心中揭示其自己。依此，理義因本心而獲得主體性之根據，本心悅於理義而揭示人本願於理義，揭示本心乃道德事實，它作為根源的善，乃是第一序者，人之為不善之惡，在道德上之後悔等，也只在於此這道德事實下才成為可能。

In this paper I would like to analyze the problems of the argument of ethics in ”Mencius”, in order to justify its position in the history of ethics. There are three levels in the ethics of ”Mencius”: 1. Human mind makes a decision of moral only in the willing between original mind and its body, and its possibility depends only upon human as a self of subject for its responsibility. 2. A decision of human mind bases on an order of moral high value belonging to original mind and low value belonging to its body, and the so called moral evil is nothing but the reverse of this order by its decision. 3. The possibility of such order depends upon that the moral norms come from the original mind, and the moral norms please the original mind, and the pleasure means nothing but the willing of the mind for the moral norms. In a decision of moral the willing of original mind reveals itself, and therefore it is nothing that passively chosen. Therefore the moral norms can have a ground from subject, and the pleasure of the moral norms explores that human wills originally the moral norms, and that the moral mind is a fact of moral which as a original good is the first order of moral, and moral evil and regret become possible only under such moral fact.