敌我之间的矛盾是对抗性的矛盾。人民内部的矛盾，在劳动人民之间说来，是非对抗性的；在被剥削阶级和剥削阶级之间说来，除了对抗性的一面以外，还有非对抗性的一面。 - Mao Zedong

I welcome Nixon's winning the election. Why? There is a deceptive side of him as well, but there is less of it. Do you believe it? He is accustomed to use hard tactics, but sometimes also soft ones. If he wishes to come to Beijing, please tell him he should do it secretly, not openly-just get on a plane and come. It doesn't matter whether negotiations succeed or fail. Why should we maintain such a deadlock? However, there is no secret in the United States. If the president goes abroad, it is impossible to keep it secret. In coming to China, he is sure to declare his aim is to draw in China in order to make things difficult for the Soviet Union. Hence he does not dare to act this way at present. To punish the Soviet Union is disadvantageous to the U.S., and to punish China is equally disadvantageous.

Our agrarian revolution has been a process in which the landlord class owning the land is transformed into a class that has lost its land, while the peasants who once lost their land are transformed into small holders who have acquired land, and it will be such a process once again. In given conditions having and not having, acquiring and losing, are interconnected; there is identity of the two sides. Under socialism, private peasant ownership is transformed into the public ownership of socialist agriculture; this has already taken place in the Soviet Union, as it will take place everywhere else. There is a bridge leading from private property to public property, which in philosophy is called identity, or transformation into each other, or interpenetration.

马克思主义的哲学辩证唯物论有两个最显著的特点：一个是它的阶级性，公然申明辩证唯物论是为无产阶级服务的；再一个是它的实践性，强调理论对于实践的依赖关系，理论的基础是实践，又转过来为实践服务。判定认识或理论之是否真理，不是依主观上觉得如何而定，而是依客观上社会实践的结果如何而定。真理的标准只能是社会的实践。实践的观点是辩证唯物论的认识论之第一的和基本的观点。