茫茫九派流中国，沉沉一线穿南北。烟雨莽苍苍，龟蛇锁大江。黄鹤知何去？剩有游人处。把酒酹滔滔，心潮逐浪高！ - Mao Zedong

Man's social practice is not confined to activity in production, but takes many other forms--class struggle, political life, scientific and artistic pursuits; in short, as a social being, man participates in all spheres of the practical life of society. Thus man, in varying degrees, comes to know the different relations between man and man, not only through his material life but also through his political and cultural life (both of which are intimately bound up with material life). Of these other types of social practice, class struggle in particular, in all its various forms, exerts a profound influence on the development of man's knowledge. In class society everyone lives as a member of a particular class, and every kind of thinking, without exception, is stamped with the brand of a class.

I knew the Classics, but disliked them. What I enjoyed were the romances of Old China, and especially stories of rebellions. I read the Yo Fei Chuan, Shui Hu Chuan, Fan T'ang, San Kuo, and Hsi Yu Chi, while still very young, and despite the vigilance of my old teacher, who hated these outlawed books and called them wicked. I used to read them in school, covering them up with a Classic when the teacher walked past. So also did most of my schoolmates. We learned many of the stories almost by heart, and discussed and re-discussed them many times. We knew more of them than the old men of the village, who also loved them and used to exchange stories with us. I believe that perhaps I was much influenced by such books, read at an impressionable age.

However, we must make a concrete study of the circumstances of each specific struggle of opposites and should not arbitrarily apply the formula discussed above to everything. Contradiction and struggle are universal and absolute, but the methods of resolving contradictions, that is, the forms of struggle, differ according to the differences in the nature of the contradictions. Some contradictions are characterized by open antagonism, others are not. In accordance with the concrete development of things, some contradictions which were originally non-antagonistic develop into antagonistic ones, while others which were originally antagonistic develop into non-antagonistic ones.