Upon the development, the configuration, and the differentiation, of the spiritual elements of sexual love are alone based the intimate relations of love with the process of civilization. This fact is again reflected in the manifold phases of the evolution of the sentiment of love. For the human spirit in the course of its development has become not merely lord of the earth and of the elementary forces of Nature: it has become also lord and master, interpreter and guide, of the sexual impulse; for this impulse owes to the human spirit its new and peculiar life, its life =capable of further development= as manifested in the history of human love. The history of love is the history of mankind, of civilization. For love manifests a continual =progress=, which can be denied by those only who have failed to understand the deep significance of human love in the entire civilized life of all times, and who, observing the persistence of the primeval and ever-active sexual impulse, elemental in its nature, are led only to a hopeless doubt as to the possibility of all love, and thus justify the pessimism with which Schopenhauer has condemned the significance of human sexual love. Undoubtedly this elemental impulse persists for ever, and to follow it =alone= leads to death, to utter desolation, to nothingness, as Tolstoi, Strindberg, and Weininger, the bitter opponents of modern “love,” have so vehemently declared. But did these men know true love? Had they become conscious of the inevitable =necessity= with which civilization in the course of ages and generations had transformed the human sexual impulse into love as it now exists, transformed it in so manifold and so wonderful a way? Had they any idea of the =development= of love, and of its place and its significance in history? Let them believe this, these doubting and despairing souls--=nothing= has been destroyed of all the spiritual relations, of all the wonderful possibilities of development, which have manifested themselves in the course of the long and varied history of the evolution of love. To describe this evolution, it is necessary to draw attention to all those elements of civilization which =remain at present= influential in love, but it is further indispensable to forecast their future development. Once again we stand at an important turning-point in the history of love. The old separates itself from the new, the better will once more be the enemy of the good. But love regarded, as it must now be regarded, in its inner =nature=, as a sexual impulse most perfectly and completely infused with a spiritual content, will remain the inalienable gain of civilization; it will stand forth ever purer and more promotive of happiness, like a mirror of marvellous clearness, wherein is reflected a peculiar and accurate picture of the successive epochs of civilization.