§ 62. The causes of war are innumerable. They are involved in the fact that the development of mankind is indissolubly connected with the national development of States. The millions of individuals who as a body are called mankind do not face one another individually and severally, but in groups as races, nations, and States. With the welfare of the races, nations, and States to which they belong the welfare of individuals is more or less identified. And it is the development of races, nations, and States that carries with it the causes of war. A constant increase of population must in the end force upon a State the necessity of acquiring more territory, and if such territory cannot be acquired by peaceable means, acquisition by conquest alone remains. At certain periods of history the principle of nationality and the desire for national unity gain such a power over the hearts and minds of the individuals belonging to the same race or nation, but living within the boundaries of several different States, that wars break out for the cause of national unity and independence. And jealous rivalry between two or more States, the awakening of national ambition, the craving for rich colonies, the desire of a land-locked State for a sea coast, the endeavour of a hitherto minor State to become a world-Power, the ambition of dynasties or of great politicians to extend and enlarge their influence beyond the boundaries of their own State, and innumerable other factors, have been at work ever since history was first recorded in creating causes of war, and these factors likewise play their part in our own times. Although one must hope that the time will come when war will entirely disappear, there is no possibility of seeing this hope realised in the near future. The first necessities of the disappearance of war are that the surface of the earth should be shared between States of the same standard of civilisation, and that the moral ideas of the governing classes in all the States of the world should undergo such an alteration and progressive development as would create the conviction that decisions of international courts of justice and awards of arbitrators are alone adequate means for the settlement of international disputes and international political aims. So long as these first necessities are not realised, war will as heretofore remain the _ultima ratio_ of international politics. [Sidenote: Just Causes of War.]