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.
Marxist philosophy
Marxist philosophy or Marxist theory are works in philosophy that are strongly influenced by Karl Marx's materialist approach to theory, or works written by Marxists. Marxist philosophy may be broadly divided into Western Marxism, which drew out of various sources, and the official philosophy in the Soviet Union, which enforced a rigid reading of Marx called dialectical materialism, in particular during the 1930s. Marxist philosophy is not a strictly defined sub-field of philosophy, because the diverse influence of Marxist theory has extended into fields as varied as aesthetics, ethics, ontology, epistemology, theoretical psychology and philosophy of science, as well as its obvious influence on political philosophy and the philosophy of history. The key characteristics of Marxism in philosophy are its materialism and its commitment to political practice as the end goal of all thought.