p Knowledge is active not only because it has a purpose, but also because it is effected by man’s transformatoin of reality, by his practical action on the surrounding world. In cognising his environment, man cannot and must not remain a mere observer of what is happening around him. If he 136 confines himself simply to observing or contemplating the object of his study, he will learn only some of its outward properties, which will tell him nothing of the object’s essence. To reveal the essence of an object, it must be acted upon, placed in a system of relations and connections different from those characteristic of its natural state. By changing the natural state of the object of his study, man gradually penetrates its secrets, exposes its essence and expresses it in relevant ideal images. The practical transformation of reality is, therefore, a necessary condition for cognising it. Cognition may function and develop on the basis of practice alone, playing a decisive role in it.

p Being the basis of knowledge, a necessary condition for the human mind to penetrate the essence of the objects and phenomena of the outside world, practice is the final goal and motive force of knowledge. Indeed, in order to function and develop production needs knowledge of the necessary aspects and connections of the fields of reality that are involved in people’s practical activities and are subject to change in the interests of society. This knowledge, however, is acquired through cognising reality, chiefly through science. The latter’s main objective is to provide society, especially production, with the knowledge they require in order to function and develop. Social practice sets science definite tasks. By solving them, science delves deeper and deeper into the world of phenomena, discovers ever new properties and connections, and thus develops. Engels 137 wrote: “If society has a technical need, that helps science forward more than ten universities.”  [137•1 

p The history of science proves that the development of knowledge depends on practice, on the problems posed by practical necessity. Fields of scientific knowledge such as mechanics, hydrostatics and hydrodynamics developed rapidly in the period when practice raised the problem of devising suitable mechanical methods of pumping water from mines and lifting weights. Moreover, the study of electrical phenomena gained momentum only after it had been discovered that they could be used in practice. The same is true of nuclear research. The tremendous development of this field was caused by the discovery of practical uses for atomic energy.

p Thus, practice exerts a decisive influence on knowledge and is the basis for its functioning and development.

p Some pre-Marxian philosophers, including Hegel, recognised the decisive role of practice in cognition. In Hegel’s view, the process of cognition runs through creative activity. For him, however, practice was but the thinking, creative activity of the idea that created particular concepts, and then the sensuous world, in the process of self- consciousness.

In reality, however, practice is the material activity of people aimed at changing and transforming the surrounding world. It includes, primarily, production activity which changes natural 138 objects in order that they might satisfy the needs of society. But man changes not only nature. He also changes the life of society, the relations among people, various public institutions, and so forth. So, practice also includes the social activity of people, particularly the class struggle which ultimately alters the relations of production, and thus the entire life of society.