Value-form
The Western Left academics are nowadays very happy to talk about "varieties of capitalism", but talking about "varieties of socialism" remains almost an absolute "no-no". Most Marxists continue to believe in "only one" (Marxian) socialism: either that, or nothing at all. "Either" a society or movement conforms to the true concept of socialism, "or" it does not; and if it does not, it "cannot be" socialism. However, precisely "because" there are many different Marxist beliefs about socialism, Marxists cannot agree among themselves whether Soviet-type societies were socialist, capitalist, or something else. Some countries meet with the moral expectations which Marxists have, and others do not.Originally Marx and Engels themselves had heckled the advocates of "true socialism", but later Friedrich Engels and Karl Kautsky promoted Marxist socialism as the one and true "scientific socialism" within the Socialist International. When he was 43 years old, Lenin stated: "The Marxist doctrine is omnipotent because it is true". Lenin's Communist International (a deliberate split with the social democrats) adopted Marxist socialism as its official political doctrine.
Types of socialism
There is a considerable variety of views among self-identified communists. However, Marxism and Leninism, schools of communism associated with Karl Marx and of Vladimir Lenin respectively, have the distinction of having been a major force in world politics since the early 20th century. Class struggle plays a central role in Marxism. This theory views the formation of communism as the culmination of the class struggle between the capitalist class, the owners of most of the capital and the working class. Marx held that society could not be transformed from the capitalist mode of production to the communist mode of production all at once, but required a transitional state which Marx described as the revolutionary dictatorship of the proletariat.