The worker of the world has nothing to lose, but their chains, workers of the world unite.

Religion is the opium of the masses.

On a level plain, simple mounds look like hills; and the insipid flatness of our present bourgeoisie is to be measured by the altitude of its great intellects.

The only antidote to mental suffering is physical pain.

History does nothing; it does not possess immense riches, it does not fight battles. It is men, real, living, who do all this.

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.