Mencius reckons that all men in their original nature possess "four beginnings", the feeling of commiseration, shame and dislike, modesty and yielding and the sense of right and wrong. And these four, if fully developed and completed, become the four "constant virtues", human-heartedness, righteousness, propriety and wisdom. Mencius also argues that the four beginnings differentiate man from beasts.
人皆有不忍人之心。恻隐之心，仁之端也；羞恶之心，义之端也；辞让之心，礼之端也；是非之心，智之端也。人之有是四端也，犹其有四体也。……凡有四端于我者，知皆扩而充之矣，若火之使然，泉之始达。苟能充之，足以保四海；苟不充之，不足以事父母。
