relation between knowledge and practice, between knowing and doing". Here, Practice connects "contradiction" with "class struggle" in the following way, claiming that inside a mode of production, there are three realms where practice functions: economic production, scientific experimentation (which also takes place in economic production and should not be radically disconnected from the former) and finally class struggle. These are the proper objects of economy, scientific knowledge, and politics. These three spheres deal with matter in its various forms, socially mediated. As a result, they are the only realms where knowledge may arise (since truth and knowledge only make sense in relation to matter, according to Marxist epistemology). Mao emphasises—like Marx in trying to confront the "bourgeois idealism" of his time—that knowledge must be based on empirical evidence. Knowledge results from hypotheses verified in the contrast with a real object; this real object, despite being mediated by the subject's theoretical frame, retains its materiality and will offer resistance to those ideas that do not conform to its truth. Thus in each of these realms (economic, scientific, and political practice), contradictions (principle and secondary) must be identified, explored, and put to function to achieve the communist goal. This involves the need to know "scientifically" how the masses produce (how they live, think and work), to obtain knowledge of how class struggle (the central contradiction that articulates a mode of production in its various realms) expresses itself. Three Worlds Theory Three Worlds Theory states that during the Cold War, two imperialist states formed the "first world"—the United States and the Soviet Union. The second world consisted of the other imperialist states in their spheres of influence. The third world consisted of non-imperialist countries. Both the first and the second world exploit the third world, but the first world is the most aggressive party. The first- and second-world workers are "bought up" by imperialism, preventing socialist revolution. On the other hand, the people of the third world have not even a short-sighted interest in the prevailing circumstances. Hence revolution is most likely to appear in third-world countries, which again will weaken imperialism, opening up for revolutions in other countries too. Agrarian socialism Maoism departs from conventional European-inspired Marxism in that it focuses on the agrarian countryside rather than the urban industrial forces—this is known as agrarian socialism. Notably, Maoist parties in Peru, Nepal, and the Philippines have adopted equal stresses on urban and