对于非马克思主义的思想，应该采取什么方针呢？对于明显的反革命分子，破坏社会主义事业的分子，事情好办，剥夺他们的言论自由就行了。对于人民内部的错误思想，情形就不相同。禁止这些思想，不允许这些思想有任何发表的机会，行不行呢？当然不行。对待人民内部的思想问题，对待精神世界的问题，用简单的方法去处理，不但… - Mao Zedong

As opposed to the metaphysical world outlook, the world outlook of materialist dialectics holds that in order to understand the development of a thing we should study it internally and in its relations with other things; in other words, the development of things should be seen as their internal and necessary self-movement, while each thing in its movement is interrelated with and interacts on the things around it. The fundamental cause of the development of a thing is not external but internal; it lies in the contradictoriness within the thing. There is internal contradiction in every single thing, hence its motion and development. Contradictoriness within a thing is the fundamental cause of its development, while its interrelations and interactions with other things are secondary causes. Thus materialist dialectics effectively combats the theory of external causes, or of an external motive force, advanced by metaphysical mechanical materialism and vulgar evolutionism. It is evident that purely external causes can only give rise to mechanical motion, that is, to changes in scale or quantity, but cannot explain why things differ qualitatively in thousands of ways and why one thing changes into another.

在我们的许多工作人员中间，现在滋长着一种不愿意和群众同甘苦，喜欢计较个人名利的危险倾向，这是很不好的。我们在增产节约运动中要求精简机关，下放干部，使相当大的一批干部回到生产中去，就是克服这种危险倾向的一个方法。要使全体干部和全体人民经常想到我国是一个社会主义的大国，但又是一个经济落后的穷国，这是一个很大的矛盾。要使我国富强起来，需要几十年艰苦奋斗的时间，其中包括执行厉行节约、反对浪费这样一个勤俭建国的方针。

In the ideological field, the question of who will win in the struggle between the proletariat and the bourgeoisie has not been really settled yet. We still have to wage a protracted struggle against bourgeois and petty bourgeois ideology. It is wrong not to understand this and to give up ideological struggle. All erroneous ideas, all poisonous weeds, all ghosts and monsters, must be subjected to criticism; in no circumstance should they be allowed to spread unchecked. However, the criticism should be fully reasoned, analytical and convincing, and not rough, bureaucratic, metaphysical or dogmatic.