Periodically, the workers do revolt against bourgeois society, not by a hundred, five hundred, or a thousand, but by the millions.

Factions are a sign of illness in a party.

There is a process of social and of political differentiation going on in the real working class all the time.

Mistakes in themselves are unavoidable.

Precisely because Marx was convinced that the cause of the proletariat was of decisive importance for the whole future of mankind, he wanted to create for that cause not a flimsy platform of rhetorical invective or wishful thinking, but the rock-like foundation of scientific truth.

Marxism is always open, always critical, always self-critical.

There are no conditions in which we subordinate the interests of the class as a whole to the interests of any sect, any chapel, any separate organization.