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.
19th-century philosophy
Developed by Karl Marx and Friedrich Engels in the mid-to-late-19th Century, Marxism is a sociopolitical and economic view based on the philosophy of dialectical materialism, which opposes idealism in favour of the materialist viewpoint. Marx analysed history itself as the progression of dialectics in the form of class struggle. From this it is argued that "the history of all hitherto existing society is the history of class struggles." According to Marx, this began with the phase of primitive communism (hunter-gatherer society), after which the Neolithic Revolution gave way to slave societies, progressing into the feudal society, and then into his present era of the Industrial Revolution, after which he held that the next step was for the proletariat to overthrow the owners of industry and establish a socialist society, which would further develop into a communist society, in which class distinctions, money, and the state would have withered from existence entirely.