Hence, if in any process there are a number of contradictions, one of them must be the principal contradiction playing the leading and decisive role,… - Mao Zedong

按照唯物辩证法的观点，自然界的变化，主要地是由于自然界内部矛盾的发展。社会的变化，主要地是由于社会内部矛盾的发展，即生产力和生产关系的矛盾，阶级之间的矛盾，新旧之间的矛盾，由于这些矛盾的发展，推动了社会的前进，推动了新旧社会的代谢。唯物辩证法是否排除外部的原因呢？并不排除。唯物辩证法认为外因是变化的条件，内因是变化的根据，外因通过内因而起作用。鸡蛋因得适当的温度而变化为鸡子，但温度不能使石头变为鸡子，因为二者的根据是不同的。各国人民之间的互相影响是时常存在的。在资本主义时代，特别是在帝国主义和无产阶级革命的时代，各国在政治上、经济上和文化上的互相影响和互相激动，是极其巨大的。十月社会主义革命不只是开创了俄国历史的新纪元，而且开创了世界历史的新纪元，影响到世界各国内部的变化，同样地而且还特别深刻地影响到中国内部的变化，但是这种变化是通过了各国内部和中国内部自己的规律性而起的。两军相争，一胜一败，所以胜败，皆决于内因。

Recently there has been a falling off in ideological and political work among students and intellectuals, and some unhealthy tendencies have appeared. Some people seem to think that there is no longer any need to concern oneself with politics or with the future of the motherland and the ideals of mankind. It seems as if Marxism was once all the rage but is currently not so much in fashion. To counter these tendencies, we must strengthen our ideological and political work. Both students and intellectuals should study hard. In addition to the study of their specialized subjects, they must make progress both ideologically and politically, which means that they should study Marxism, current events and politics. Not to have a correct political point of view is like having no soul [...] All departments and organizations should shoulder their responsibilities in ideological and political work. This applies to the Communist Party, the Youth League, government departments in charge of this work, and especially to heads of educational institutions and teachers.

The basic contradiction the great proletarian Cultural Revolution is trying to resolve is the one between the proletariat and the bourgeoisie, between the proletarian and bourgeois roads. The main point of the movement is to struggle against the capitalist roaders in authority in the party.