The Communists have no need to introduce free love; it has existed almost from time immemorial.

Labour is ... not the only source of material wealth, i.e, of the use-values it produces. As William Petty says, Labour is the father of material wealth, the earth is its mother.

The history of all previous societies has been the history of class struggles.

In the domain of Political Economy, free scientific inquiry meets not merely the same enemies as in all other domains. The peculiar nature of the material it deals with, summons as foes into the field of battle the most violent, mean and malignant passions of the human breast, the Furies of private interest.

Necessity is blind until it becomes conscious. Freedom is the consciousness of necessity.

It is absolutely impossible to transcend the laws of nature. What can change in historically different circumstances is only the form in which these laws expose themselves.

All forms of the state have democracy for their truth, and for that reason are false to the extent that they are not democracy