Quotes from book
On Contradiction
On Contradiction is a 1937 essay by the Chinese Communist revolutionary Mao Zedong. Along with On Practice it forms the philosophical underpinnings of the political ideology that would later become Maoism. It was written in August 1937, as an interpretation of the philosophy of dialectical materialism, while Mao was at his guerrilla base in Yanan. Mao suggests that all movement and life is a result of contradiction. Mao separates his paper into different sections: the two world outlooks, the universality of contradiction, the particularity of contradiction, the principal contradiction and principal aspect of contradiction, the identity and struggle of aspects of contradiction, the place of antagonism in contradiction, and finally the conclusion. Mao further develops the theme laid out in On Contradiction in his 1957 speech On the Correct Handling of Contradictions among the People.

On Contradiction (1937)
Original: (zh-CN) 共产党内正确思想和错误思想的矛盾,如前所说,在阶级存在的时候,这是阶级矛盾对于党内的反映。这种矛盾,在开始的时候,或在个别的问题上,并不一定马上表现为对抗性的。但随着阶级斗争的发展,这种矛盾也就可能发展为对抗性的。苏联共产党的历史告诉我们:列宁、斯大林的正确思想和托洛茨基、布哈林等人的错误思想的矛盾,在开始的时候还没有表现为对抗的形式,但随后就发展为对抗的了。中国共产党的历史也有过这样的情形。我们党内许多同志的正确思想和陈独秀、张国焘等人的错误思想的矛盾,在开始的时候也没有表现为对抗的形式,但随后就发展为对抗的了。目前我们党内的正确思想和错误思想的矛盾,没有表现为对抗的形式,如果犯错误的同志能够改正自己的错误,那就不会发展为对抗性的东西。因此,党一方面必须对于错误思想进行严肃的斗争,另方面又必须充分地给犯错误的同志留有自己觉悟的机会。在这样的情况下,过火的斗争,显然是不适当的。但如果犯错误的人坚持错误,并扩大下去,这种矛盾也就存在着发展为对抗性的东西的可能性

“Qualitatively different contradictions can only be resolved by qualitatively different methods.”
On Contradiction (1937)
Original: (zh-CN) 不同质的矛盾,只有用不同质的方法才能解决。

“Contradiction and struggle are universal and absolute”
On Contradiction (1937)
Context: 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 and 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.