674 THE AMERICAN JOURNAL OF SOCIOLOGY
remain impossible, at any moment of history to bring about the existence of a political group embracing exclusively one single race, and the whole of this race within a territory which is physi- cally delimited. I add that all attempts of this sort are reaction- ary, since progress is realized above all by the increasing multi- plication of the differentiations, the only natural process which permits the fusion of all the social parts with the least correlative and parallel intensity of strain as between these parts. The true and the noblest aim of social science is to lead the different varie- ties of the human species not to take up positions apart from one another, but to live together, and that without any sacrifice of either their individual or collective characteristics with their greater or less degrees of originality, which, far from hindering the unification of the race, is in reality the only thing which makes it possible. It is through variability and selection that the species has better and better adapted itself to the planet, and that the planet has better and better adapted itself to humanity. Such is the natural process to which it is necessary to conform, and which even military societies have followed, in a violent and rude fashion, in the determination of their political frontiers. It is impossible to interpret their evolution otherwise; at least, to accept the hypothesis which consists in regarding as irrational and contrary to nature all that was accomplished before the epoch in which we have the exceptional advantage of living and thinking wisely.
Among all the races which we have mentioned, the Romance populations, at this time the most civilized, were also the most mixed. As to religions, we have already seen that they are more widely extended than races, or than geographic and political divi- sions. Neither was feudal law contained within the limits of a single state; it had become uniform in its main lines in all the social groups equally evolved. This law itself corresponded to an economic structure, whose characteristics I have explained else- where. The external frontiers of each political group corre- sponded then at this time not only to the mode of sovereignty, but both corresponded to the whole of the internal organization of the group in relation with the same external elements. Thus the
