It is peculiar circumstances that, while anarchism within a nation is generally detested, anarchism between nations has been palatable so long. Cannibalism existed for thousands of years, slavery also, yet both have been practically abandoned, and now there seems to be a chance to do away the last and greatest enemy of humanity--war. To stop an evil that has existed so long and whose roots reach back into the beginning of history will necessarily require colossal effort and great sacrifice. Such an effort has been successful only once in the history of the world. That was when the Westphalian peace treaty was signed, in 1648 after the Thirty Years' War.[4] This resulted in abolishing the most difficult kind of wars--religious wars. If the seventeenth century could accomplish this greater task, certainly the twentieth century should take courage and likewise put an end to political wars, the lesser task. It may not be possible to make war impossible, but this is no reason it should not be tried. It may be possible, however, to make war most improbable. SCIENTIFIC METHOD IN HISTORY NECESSARY. In the writing of history a common illusion is to exaggerate the future importance of contemporary events. Both sides in the French Revolution thought that the end of the world had come, as no doubt it had for some. Comparatively few men can get outside of their country and look at things as they are, but very few or none can separate themselves from their generation and look without prejudice into the future. The importance of every great event is usually exaggerated by those immediately interested. From the historical point of view, the degree of importance of current events can not be determined until some time afterwards when the sources are more accessible, and it is possible to consider them calmly, and from the point of view of strict truth, which is one of the main principles of scientific inquiry. History is continuous and not broken up by what the present generation may think to be a finality or cataclysm; there may be progress or retrogression, but neither is so great as they appear at the time of the events which cause enthusiasm and optimism in the victorious and despair and pessimism in the vanquished. These are temporary phenomena, being only links in the historical chain. The changes after this war back to normal conditions may be much greater and faster than in previous wars. In this connection it must be remembered that the humane spirit is now much more diffused in the world than in the past, which is indicated by the enormous extent of protests against the horrors of war.[5] These horrors are common to all wars and were relatively as frequent in the past, if not more so. It is true that the absolute number of outrages may have been much greater in the present war than in previous wars, but this is probably due mainly to the enormous number of individuals engaged in the war. INTERDEPENDENCE OF NATIONS A DEMOGRAPHIC LAW.