The weapon of criticism can never replace the criticism of weapons.

The ideas of the ruling class are in every epoch the ruling ideas, i.e., the class which is the ruling material force of society, is at the same time its ruling intellectual force.

The first requisite for the happiness of the people is the abolition of religion.

Constant labor of one uniform kind destroys the intensity and flow of a man's animal spirits, which find recreation and delight in mere change of activity.

But, you will say, we destroy the most hallowed of relations, when we replace home education by social.... The Communists have not invented the intervention of society in education; they do but seek to alter the character of that intervention, and to rescue education from the influence of the ruling class.

All science would be superfluous if the outward appearance and the essence of things directly coincided.

As for slavery, there is no need for me to speak of its bad aspects. The only thing requiring explanation is the good side of slavery. I do not mean indirect slavery, the slavery of proletariat; I mean direct slavery, the slavery of the Blacks in Surinam, in Brazil, in the southern regions of North America. Direct slavery is as much the pivot upon which our present-day industrialism turns as are machinery, credit, etc. … Slavery is therefore an economic category of paramount importance.