Religion is the impotence of the human mind to deal with occurrences it cannot understand.

The product of mental labor - science - always stands far below its value, because the labor-time necessary to reproduce it has no relation at all to the labor-time required for its original production.

The education of all children, from the moment that they can get along without a mother's care, shall be in state institutions.

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

The Tories in England had long imagined that they were enthusiastic about the monarchy, the church and beauties of the old English Constitution, until the day of danger wrung from them the confession that they are enthusiastic only about rent.

Once the inner connection is grasped, all theoretical belief in the permanent necessity of existing conditions collapses before their collapse in practice -- Letter to Ludwig Kugelmann (July 11, 1868)

Advances in science help to delegitimize the rule of kings and the power of the Church.