Only to the rude ear of one who is quite indifferent does the song of a bird seem always the same.

With the true artist, the social formula that he recommends is a matter of secondary importance; the source of his art, its animating spirit, is decisive.

Marxism is a revolutionary worldview that must always struggle for new revelations.

[Geology] opens up such wide intellectual vistas and supplies a more perfectly unified and more comprehensive conception of nature than any other science.

The victory of socialism will not descend like fate from heaven.

We stand todaybefore the awful proposition: either the triumph of imperialism and the destruction of all culture, and, as in ancient Rome, depopulation, desolation, degeneration, a vast cemetery; or, the victory of socialism.

The more that social democracy develops, grows, and becomes stronger, the more the enlightened masses of workers will take their own destinies, the leadership of their movement, and the determination of its direction into their own hands.