When the train of history hits a curve, the intellectuals fall off.

If emancipation of the working classes requires their fraternal conncurrence, how are they to fulfill that great mission with a foreign policy in pursuit of criminal designs, playing upon national prejudices, and squandering in piratical wars the people's blood and treasure? It was not the wisdom of the ruling classes, but the heroic resistance to their criminal folly by the working classes of England, that saved the west of Europe from plunging headlong into an infamous crusade for the propagation of slavery on the other side of the Atlantic.

Without doubt, machinery has greatly increased the number of well-to-do idlers.

The French need a thrashing. If the Prussians win, the centralization of state power will be useful for the centralization of the German working class. German predominance would also transfer the center of gravity of the workers' movement in Western Europe from France to Germany, and one has only to compare the movement in the two countries from 1866 until now to see that the German working class is superior to the French both theoretically and organizationally.

Communism deprives no man of the ability to appropriate the fruits of his labour. The only thing it deprives him of is the ability to enslave others by means of such appropriations.

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)

Social progress can be measured exactly by the social position of the fair sex.