What is knowledge? Ever since class society came into being the world has had only two kinds of knowledge, knowledge of the struggle of production and knowledge of the class struggle. Natural science and social science are the crystallization of these two kinds of knowledge, and philosophy is the generalization and summation of the knowledge of nature.
什么是知识？自从有阶级的社会存在以来，世界上的知识只有两门，一门叫做生产斗争知识，一门叫做阶级斗争知识。自然科学、社会科学，就是这两门知识的结晶，哲学则是关于自然知识和社会知识的概括和总结。
Original text (Chinese)