Bourgeois class domination is undoubtedly an historical necessity, but, so too, the rising of the working class against it. Capital is an historical necessity, but, so too, its grave digger, the socialist proletariat.

Social democracy... is only the advance guard of the proletariat, a small piece of the total working masses; blood from their blood, and flesh from their flesh.

The very action of the proletariat is a determining factor in history. And although we can no more jump over the stages of historical development than a man can jump over his shadow, nevertheless, we can accelerate or retard that development.

History is the only true teacher, the revolution the best school for the proletariat.

I want to burden the conscience of the affluent with all the suffering and all the hidden, bitter tears.

Democracy is indispensable, not because it renders superfluous the conquest of political power by the proletariat, but, on the contrary, because it makes this seizure of power both necessary and possible.