The English have all the material requisites for the revolution. What they lack is the spirit of generalization and revolutionary ardour.

History calls those men the greatest who have ennobled themselves by working for the common good; experience acclaims as happiest the man who has made the greatest number of people happy.

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.

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)

Philosophy stands in the same relation to the study of the actual world as masturbation to sexual love.

The development of civilization and industry in general has always shown itself so active in the destruction of forests that everything that has been done for their conservation and production is completely insignificant in comparison.

[Napoleon] swept away everywhere the establishments of feudality. ... [He was] Caesar himself.