It will be seen, then, that the principle of sociality or of association plays a specially important part in human development. Yet in close connection with it we again observe the wide operation of the struggle for existence. The struggle for existence is not only a struggle of individuals against each other. It has also been a struggle of tribe against tribe, of city against city, of nation against nation, and race against race. In the existing society it is, moreover, a struggle of classes against each other. Considered in this aspect, which is too obvious to require illustration, the struggle for existence has assumed the most complicated forms, and has had the greatest influence in the history of the world. And the intensity of the struggle has called forth some of the highest human qualities—inventiveness, capacity for organisation, submission to discipline, enthusiasm, heroism, and self-sacrifice. The struggle, hateful though it be in many respects, has been one of the great training schools of the human race. Modern European history is an impressive example of the importance of this struggle for existence. The progress of Europe is greatly owing to the fact that in this continent we have a group of communities which are closely related, yet independent, and rivals. In every department of activity they learn from each other, and spur one another on by continual emulation. Each must follow its rivals in the adoption of every new improvement, under penalty of decline and even ruin. Communities like China and India in the old world, and the native States of Mexico and Peru in the new world, were isolated, and therefore stationary. Under the existing conditions, a social organisation favourable to the development of the intelligence, energy, and enthusiasm of the mass of the people is more and more necessary to success in the keen and arduous struggle waged by the European communities. The future both of democracy and of socialism will largely depend on how far they can supply these advantages of organisation. For it is a struggle also between forms of social organisation. Any better form of organisation, when adopted by one of the communities, must also be adopted by its rivals. As soon as it was recognised that universal education and universal liability to military duty gave Prussia an exceptional advantage in the European struggle, other nations have been eager to follow. Thus, through the development of the principle of sociality in the history of civilisation, the struggle for existence is not abolished. It is continued under more complex conditions, on a wider scale, over larger areas, by greater masses of organised men, with mightier weapons and vaster resources.