"A proletarian forced to exist under such conditions is truly a being without will, without self-respect, without any sense of responsibility."

"The old society, with its classes and class antagonisms, is to be replaced by an association, in which the free development of each is the condition for the free development of all."

"The bourgeois family will vanish as a matter of course when its complement vanishes, and both will vanish with the vanishing of capital."

"The more a science advances, the more it is divided into separate branches, and the more these branches, in turn, are further subdivided."

"Communism is not a doctrine but a movement; it proceeds from facts and not from principles."