We know only a single science, the science of history. History can be contemplated from two sides, it can be divided into the history of nature and the history of mankind. However, the two sides are not to be divided off; as long as men exist the history of nature and the history of men are mutually conditioned.
Karl MarxSurplus-value and the rate of surplus-value are... the invisible essence to be investigated, whereas the rate of profit and hence the form of surplus-value as profit are visible surface phenomena
Karl MarxIn a word, the free trade system hastens the social revolution. It is in this revolutionary sense alone, gentlemen, that I vote in favor of free trade.
Karl Marx...the very cannibalism of the counterrevolution will convince the nations that there is only one way in which the murderous death agonies of the old society and the bloody birth throes of the new society can be shortened, simplified and concentrated, and that way is revolutionary terror.
Karl Marx