Abstract: Classification deduced from classes according to the differences and similarities of events and phenomena has always been a reductive form and ideological method widely used in ancient China,which not only has influenced art techniques of scholars but also has been an important way for thinkers to expound their ideas.Mencius,who has been regarded by Confucian scholars as "second saint",used a lot of methods of classification in expressing his political ideas.He raised the conception of"all in the same clas...