One single force impels all life; one force developed it, from the single cell, the particle of albumen floating about in the warm ocean of prehistoric time, up to the vertebrates, and then to man. This one force, according to Lippert, is the tendency to provide for life, bifurcated into “hunger and love.” With man, however, philosophy also enters into the play of these forces, in order hereafter, together with “hunger and love, to hold together the structure of the world of men.” To be sure, this philosophy, this “idea” of Schopenhauer’s, is at its source nothing else than a creature of the provision for life called by him “will.” It is an organ of orientation in the world, an arm in the struggle for existence. Yet in spite of this, we shall come to know the desire for causation as a self-acting force, and of social facts as coöperators in the sociological process of development. In the beginning of human society, and as it gradually develops, this tendency pushes itself forward in various bizarre ideas called “superstition.” These are based on purely logical conclusions from incomplete observations concerning air and water, earth and fire, animals and plants, which seem endowed with a throng of spirits both kindly and malevolent. One may say that in the most recent modern times, at a stage attained only by very few races, there arises also the younger daughter of the desire for causation, namely science, as a logical result of complete observation of facts; science, now required to exterminate widely branched-out superstition, which, with innumerable threads, has rooted itself in the very soul of mankind. But, however powerfully, especially in the moment of “ecstasy,”[2] superstition may have influenced history, however powerfully, even in ordinary times, it may have coöperated in the development of human communal life, the principal force of development is still to be found in the necessities of life, which force man to acquire for himself and for his family nourishment, clothing and housing. This remains, therefore, the “economic” impulse. A sociological--and that means a socio-psychological--investigation of the development of history can, therefore, not progress otherwise than by following out the methods by which economic needs have been satisfied in their gradual unfolding, and by taking heed of the influences of the causation impulse at its proper place. (a) POLITICAL AND ECONOMIC MEANS