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

... as far as the conquests of science are concerned, they are the foundation on which an obscurantism flourishes, with which the obscurantism of the Middle Ages pales in comparison.

Russian society before the revolution was torn between three forces: a disappearing nobility system, embryonic capitalism and a state bureaucracy. The latter was so predominant in our "hole" that the mass of the population hardly noticed the other two. For this reason, the February revolution went unnoticed. p. 36

All in all, Engels talked so much rot of every kind, that now all the world’s academies of science should be directed to rectify his mistakes and idiocies.