If, therefore, we set out to discover the impelling forces, which, acknowledged, or unacknowledged, and for the most part unacknowledged, stand behind historical figures, and constitute the true final impulses of history, we cannot consider so much the motives of single individuals, however pre-eminent, as those which set in motion great masses, entire nations, and again, whole classes of people in each nation, and this, too, not in a momentarily flaring and quickly dying flame, but to enduring action culminating in a great historical change. To establish the great impelling forces which play upon the brains of the acting masses and their leaders, the so-called great men, as conscious motives, clear or unclear, directly or ideologically or even in a supernatural form, that is the only method which can place us on the track of the law controlling history as a whole, as well as at particular periods and in individual lands. All that sets men in motion must act upon their minds, but the force which acts upon the brain depends very largely upon circumstances. The workers have by no means become reconciled to the machine power of the capitalists although they no longer break the machines to pieces as they did on the Rhine in 1848. But while the discovery of these impelling forces of history was entirely impossible in all other periods, on account of the complicated and hidden interrelations with their effects, our present period has so far simplified these relations that the problem can be solved. Since the establishment of the great industry, at least since the peace of Europe in 1815, it has been no longer a secret to anyone in England that the whole political fight has been for supremacy between two classes, the landed aristocracy and the middle-class. In France, with the return of the Bourbons, the same fact was perceived; the writers of history, from Thierry to Guizot, Mignet, and Thiers in particular, pronounce it as a key to an understanding of French history, especially since the Middle Ages. And since 1830 the working class, the proletariat, has been recognized as the third competitor for mastery in both countries. Circumstances had become so simplified that one would have had to close his eyes not to see in the fight of these three classes and in the conflict of their interests, the moving forces of modern history, at least in the two most advanced countries.