What is "unity of knowledge and action"? Knowledge refers to the understanding and recognition of social phenomena and life affairs. If you want to acquire knowledge, you must get in touch with things and study their principles in depth. Behavior refers to active participation and practical activities. A person who can rule the country and rule the world must have a process of personal practice and experience of various social things and phenomena. The so-called unity means that knowledge is not absolutely dominant and action is not the only role, but that knowledge and action are interrelated and cooperate with each other. A correct understanding of social affairs in the world is the premise of correct behavior, and correct behavior practice is the inevitable result of a correct understanding of world principles. The same is true of reverse reasoning. Behavioral social practice can sum up corresponding social experience. The essence of education is education closely combined with practice, and the so-called modern education for education's sake has gone astray.