We know only a single science, the science of history. History can be contemplated from two sides, it can be divided into the history of nature and the history of mankind. However, the two sides are not to be divided off; as long as men exist the history of nature and the history of men are mutually conditioned.

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

A specter is haunting Europe - the specter of communism.

Criticism has plucked the imaginary flowers on the chain not in order that man shall continue to bear that chain without fantasy or consolation, but so that he shall throw off the chain and pluck the living flower. The criticism of religion disillusions man, so that he will think, act, and fashion his reality like a man who has discarded his illusions and regained his senses, so that he will move around himself as his own true Sun. Religion is only the illusory Sun which revolves around man as long as he does not revolve around himself.

There is only one effective antidote for mental suffering and that is physical pain.

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.

You will have to go through 15, 20, 50 years of civil wars and national struggles not only to bring about a change in society but also to change yourselves, and prepare yourselves for the exercise of political power.