Friedrich Engels — "Every step of real movement is more important than a dozen programmes."

"It is precisely the alteration of nature by men, not solely nature as such, which is the most essential and immediate basis of human thought."

"It is characteristic of dialectics to regard all forms of life, society and thought as being in a state of constant motion, change, transformation."

"The development of large-scale industry has not only created the classes which are revolutionary, but has also created the means of their liberation."

"It is no longer a question of whether the proletariat will seize power, but when."

"The ruling ideas of each age have ever been the ideas of its ruling class."