The firmest proof that Marxism is not science but an ideology is Marxism’s attitude to the experience of the real communist (or socialist) societies. - Alexander Zinoviev

None of the Marxist concepts (literally – not a single one!) matches the logical rules of scientific concepts.

Every war reveals in one way or another the fundamental characteristics of the societies involved in it. p.196

It follows that, to make a communist country, it is not enough to take power, collectivize the economy or impose a state ideology. We need deeper transformations, namely: organizing the masses differently, in accordance with community laws to which all aspects of life must be subject. (…) p. 14-16