” The correct approach is to restrain and admit self-interest as justice.

Fifth, to recognize that personal gain is justice. Epicurus said: “A happy life is our highest supreme kindness.” He believes that wisdom, restraint, courage and justice are necessary only as a means of their own happiness.Confucius did not regard desire as the source of all evil. “When the national politics is clear, it is shame that some people are still poor and their status are low and humble.” Sima Qian said: “Everyone flocks for the benefit, also drift apart for it.” The recognition of the legitimacy of self-interest is an improvement, but it's not enough.

Six, to see the unity of profit and justice. Adam Smith, the father of economics, said: “Our dinner is not from the favor of chefs and butchers, but doing this way is good for them. The market system ensures that businessmen increase social benefits while maximizing their own interests, and the effect is better than when the traders take the initiative to do it.” 

Seventh, to see the importance of self-interest for the evolution of society. Humanitarianism and liberalism which rising from the beginning of the Renaissance promote the liberation of humanity. Marx believes that the economic foundation determines the superstructure. The economic foundation is the activity that satisfies the desires of human beings. Hegel discusses the impact of the need for self-esteem on history. Freud discusses the impact of sexuality on social life.

Eight, scientific meta-ethics. We should regard the individualism, humanism and evolutionism as the ultimate standard of value, have a comprehensive understanding of the unity of opposites of them, and regard the meta-ethics as the basis of epistemology and ontology.