Labor in the white skin can never free itself as long as labor in the black skin is branded.

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.

The production of too many useful things results in too many useless people.

A heavy or progressive or graduated income tax is necessary for the proper development of Communism.

Darwin has interested us in the history of nature's technology.

Medicine heals doubts as well as diseases.

In proportion as capital accumulates, the lot of the laborer, be his payment high or low, must grow worse.