As for the commercial business, I can no longer make head or tail of it. At one moment crisis seems imminent and the City prostrated, the next everyt… - Karl Marx

These contradictions, of course, lead to explosions, crises, in which momentary suspension of all labour and annihilation of a great part of the capital violently lead it back to the point where it is enabled [to go on] fully employing its productive powers without committing suicide. Yet, these regularly recurring catastrophes lead to their repetition on a higher scale, and finally to its violent overthrow. There are moments in the developed movement of capital which delay this movement other than by crises; such as e.g. the constant devaluation of a part of the existing capital: the transformation of a great part of capital into fixed capital which does not serve as agency of direct production; unproductive waste of a great portion of capital etc.

Man makes his own history, but he does not make it out of the whole cloth; he does not make it out of conditions chosen by himself, but out of such as he finds close at hand.

Both for the production on a mass scale of this communist consciousness, and for the success of the cause itself, the alteration of men on a mass scale is necessary, an alteration which can only take place in a practical movement, a revolution; this revolution is necessary, therefore, not only because the ruling class cannot be overthrown in any other way, but also because the class overthrowing it can only in a revolution succeed in ridding itself of all the muck of ages and become fitted to found society anew.