The theory taking human nature as good held by Mencius is in essence admitting goodness is real human nature.Mencius discovered a basic "truth" in humanity:Everyone enjoys goodness by nature.He pointed out further that only by extending and fulfilling goodness,can we feel the value,dignity,equality,and happiness of being human,and so achieve the ultimate goal of "realizing the full measure of our heart-and-mind,knowing our nature,and knowing Heaven".Thus,he established the aim and direction for human beings,which has produced far-reaching influences in history.In fact,the core of Mencius'theory does not lie in the reason why human nature is good,but the fact whether man has goodness and the reason why goodness should be viewed as nature.The inner logic of Mencius in establishing this theory gives evidence for this conclusion.