Surplus value is thus the driving force of the history of modern capitalist society. This principle is rigidly followed out by Marx in his theoretical system, which aims at showing the rise and growth of Capitalism. The capitalist is no scientific investigator: he is not clear himself whether profit is created by a portion of the capital, or is the result of personal productive forces, but he knows one thing--without living labour power, without the wage worker, his whole capital remains dead and does not increase; all the fixed capital and raw materials are of no use to him so long as they are not set in motion by living labour power and transformed into commodities. His efforts are, therefore, primarily directed to making proper use of the living labour power. Historically considered, little constant and relatively much variable capital was employed in the primitive stage of the large scale industry: there was as yet little machinery, and the chief thing was the living labour power. The workers were not yet factory proletarians in the modern sense, but artisans who had lost their independent existence. The capitalist harnessed them and utilised their labour power and special ability. Consequently, he strives to lengthen the working day, in order that as many commodities and as much profit as possible may be produced. If previously the wage worker had laboured ten hours, of which five were devoted to the production of the value of his wages and five to surplus value, he is now obliged to work for twelve hours, which increases the period for surplus labour to seven hours. The surplus value which is extracted through the lengthening of the working day is called by Marx "absolute surplus value."