Utopian socialism belongs to one of the first branches of socialist thought. Major representatives of this branch of thought were Charles Fourier, Robert Owen and Saint-Simon (Baradat, 2000, p. 310). The key idea of utopian socialism was the existence of social ownership for the means of production, which could be reached peacefully with the voluntary help of those who possessed property (Baradat, 2000, p. 310). Later socialist thinkers (e.g. scientific socialists) have found that utopian socialist ideas were unreachable in reality. An important concept of equal society has been adopted by further socialist branches from utopian socialism.
Dialectic means in general a method of argument, which is expressed in the form of a dialogue with reasonable arguments. Dialectic has become a leading method of discussion in modern philosophy, and was in particular revived in the works of Marx and Engels. In the works of socialists, dialectic meant a general theory of factors ruling the development of society, thought and nature (Baradat, 2000, p. 171).
Historical materialism is an approach created by Marx, and expanded by other Marxism supporters. It is an approach to studying history and society based on the premise that material economic base is the driving factor for the creation and stabilization of social relations and institutions (Baradat, 2000, p. 173).
Surplus value was a concept also created by Marx, which denotes the difference between the market value of products or work done and the salaries paid by employers (Baradat, 2000, p. 179). The notion of surplus value was used to formulate the principles of capital accumulation which laid the basis for socialist economic reasoning in favor of equal society.
Labor theory of value was created by David Ricardo, and further developed and used by Marx (Baradat, 2000, p. 146). According to this theory, the true value of any product or service can be determined by the amount of labor spent on it (Baradat, 2000, p. 147). Using the labor theory of value, such concepts as use value and exchange value were defined, and the idea of exploitation of workers in capitalism was developed by Marxist thinkers.
Dictatorship of the proletariat is also a Marxist concept, which describes the socialist state where proletariat has ultimate control of political power. According to Marxists, the long-term goal of the dictatorship of the proletariat was to eliminate all other social classes, and lead the society to one proletarian group (Baradat, 2000, p. 181).