Mencius believes that "good nature" is a natural morality of human beings; The foundation of this is the "four-terminal" heart. "Mencius? "On Ugly Sun" says: "Compassion is benevolence; "The heart of shame and evil is the end of righteousness; The words of the heart are the end of the ceremony; The heart of right and wrong is also the end of wisdom. People have four ends, but they still have four bodies. " In other words, people's four basic moral qualities-benevolence, righteousness, courtesy and wisdom-come from four natural "hearts" of sadness, shame, resignation and right and wrong, which can also be said to be "sadness and benevolence"; Shame and nausea, righteousness also; Respect and courtesy; The heart of right and wrong, wisdom. " Therefore, Mencius concluded that "benevolence, righteousness, propriety and wisdom are not external explanations, but I am also internal, and I am full of wisdom." It means that these four kinds of hearts or qualities are not imposed by the outside world, but are inherent in life, but people have not discovered them through thinking. Mencius believes that these four kinds of hearts are shared by all people: "Everyone has compassion; Everyone has a heart of shame and evil; Everyone has a respectful heart. " (ditto) Among them, "compassion"-the purpose of benevolence-is the core. For example, Mencius said: "Everyone has a heart that cannot bear others. So everyone has a heart that can't bear others. At first glance, people nowadays are afraid of compassion. If you don't do what your parents did, you should be praised by your friends in the countryside. If you don't hate your own voice, you will naturally. " ("Mencius? This example shows that the generation of good thoughts is not out of some utilitarian consideration, but the mobilization of compassion. It is in this sense that Mencius said that human nature is good. Mencius' theory of "goodness of human nature" has an obvious theoretical dilemma: since people have goodness and goodness of human nature, why can they have evil? If there is no evil nature and no evil ending, where does evil come from? Mencius also said: "The rich rely on more brothers, while the fierce brothers are violent. This is like talking about the good and evil of human nature with the acquired environment, which is obviously quite different from his "theory of good nature"

The incompleteness of the theory of "good nature" creates conditions for denying itself; Xunzi's "theory of evil nature" finally replaced it. Xunzi believes that the so-called "goodness" generally means that all behaviors conform to moral norms and obey the etiquette system; The so-called "evil" means ulterior motives, improper behavior, committing crimes and disturbing the ruling order. This kind of "goodness" does not exist in human nature, and it is impossible for people to be born with moral norms and political systems. On the contrary, people are naturally greedy, jealous and happy. If we continue to develop without restraint, we will struggle, offend and * *, and there will be no morality such as benevolence, righteousness, propriety and wisdom. Therefore, in fact, people are born "evil". Because of this, we need saints and monarchs to educate our subjects, and we need etiquette system and moral norms to guide people. If, as Mencius said, human nature is good, what is the use of monarch, sage, etiquette and morality? Xunzi said: "Human nature is evil, and the good are also false" (inherent vice). It means that human nature is "evil", so there is "good", which is the result of man-made. He criticized Mencius for not distinguishing between nature and man-made, so he could not correctly understand the relationship between them and the important role of saints and gentlemen. Generally speaking, Xunzi's theory of "evil nature" is more flexible than Mencius' theory of "good nature", but it still has the fatal weakness of self-contradiction: since human nature is "evil"-there is no "good" component in the internal cause of human nature, and the institutional norms are acquired, imposed and exogenous, there is no internal basis. Or, why do people have moral behavior? How can I be good? Xunzi's explanation is that this is due to the opposite requirement, that is, the need for what it lacks, "mortals want good and evil." The husband is thin and willing to be thick, and the evil is willing to be beautiful. "Logically speaking, however, the so-called inherent negative requirement is actually a requirement for goodness, so Xunzi's theory of evil nature has virtually developed from monism of evil nature to dualism of good and evil.