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.
Frankfurt School
This was fiercely criticized by Marx and the Young Hegelians, who argued that Hegel had gone too far in defending his abstract conception of "absolute Reason" and had failed to notice the "real"—i.e. and —life conditions of the working class. By turning Hegel's idealist dialectics upside-down, Marx advanced his own theory of dialectical materialism, arguing that "it is not the consciousness of men that determines their being, but, on the contrary, their social being that determines their consciousness." Marx's theory follows a materialist conception of history and space, where the development of the productive forces is seen as the primary motive force for historical change, and according to which the social and material contradictions inherent to capitalism inevitably lead to its negation—thereby replacing capitalism with a new rational form of society: communism.