As a consequence of the slowness of the movement of the psychological characteristics of races, great stability and fixity, which prevents the overthrow of the equilibrium of races, and their works, is the result. Only in the long run, and by slow hereditary accumulations, is it possible for the psychological and the anatomical elements of the human species to be transformed. The evolution of civilization depends wholly on these transformations. Public opinion is often made by prominent factors, such as wants, the struggle for life, the action of certain surroundings, the progress of industry and the sciences, education facilities, wars, etc. Ideas do not become public opinion, until, as the consequence of a very slow elaboration, they have descended from the mobile regions of thought, to that stable, and unconscious region of the sentiments, in which the motives of our intentions are elaborated. They then become elements of character and begin to influence conduct. It is this line up of unconscious ideas, that give us character. The idea of international Peace, has been at work for several generations, and on account of the slowness of our mental transformations, many generations of men are needed to secure the triumph of new ideas, and many generations are necessary to cause old ideas to disappear. During the Middle Ages, there were two principal ideas: Religious and feudal. Its arts, literature and whole conception of life were derived from these ideas, until the time of the Renaissance when they began to change; and also the conception of life, the arts and literature underwent an entire transformation. No matter what the nature of the ideas may be, whether scientific, artistic, philosophic, or religious, the mechanism of its propagation remains identically the same. With International Peace, it is the same, and must first be adopted, as has been done, by a small number of apostles, the intensity of whose faith and the authority of whose names give great prestige. As soon as these apostles succeed in convincing a small circle of adepts and thus form new apostles, the new idea enters into the domain of discussion, where it first arouses universal opposition, because it necessarily clashes with much that is very old and well established. The apostles who defend it are naturally greatly excited by the opposition, which causes them to defend the new idea with energy and diligence. The new idea becomes more and more a subject of discussion, and of course is entirely accepted by the one side and entirely rejected by the other side, with almost as much vehemence. These impassioned debates help the progress of the idea very materially, and it keeps going and going, and the new generations who find it controverted tend to adopt it merely because it is a progressive measure, and because young people, always eager to be independent, find wholesale opposition to old ideas to be the most accessible form of originality.