In science, each new point of view calls forth a revolution in nomenclature.

Thus at every step we are reminded that we by no means rule over nature like a conqueror over a foreign people, like someone standing outside nature - but that we, with flesh, blood and brain, belong to nature, and exist in its midst, and that all our mastery of it consists in the fact that we have the advantage over all other creatures of being able to learn its laws and apply them correctly.

The proletarians, driven to despair, will seize the torch which Stephens has preached to them; the vengeance of the people will come down with a wrath of which the rage of 1795 gives no true idea. The war of the poor against the rich will be the bloodiest ever waged.

People have learned by bitter experience that the "European fraternal union of peoples" cannot be achieved by mere phrases and pious wishes, but only by profound revolutions and bloody struggles; they have learned that the question is not that of a fraternal union of all European peoples under a single republican flag, but of an alliance of the revolutionary peoples against the counter-revolutionary peoples, an alliance which comes into being not on paper, but only on the battlefield.

The emancipation of woman will only be possible when woman can take part in production on a large, social scale, and domestic work no longer claims anything but an insignificant amount of her time.

Life is the mode of action of proteins.

The first class opposition that appears in history coincides with the development of the antagonism between man and woman in monogamous marriage, and the first class oppression coincides with that of the female sex by the male.