Principles emerge in war, we say, and then they become secondary causes. And it is precisely this emergence of principles from fields of battle that perhaps constitutes the greatest contribution of wars to the civilization of the world. We need to reflect upon this deeply, since the whole philosophy of history is concerned in it. The virtues that nations discover in themselves in war they elaborate in peace. Nations at war become conscious of their spiritual possessions. Since their existence, they believe, is at stake, it is a part of their self-defense to justify their value in the world. They discover in themselves that which is most characteristic of them, and this becomes their principle. The principle of a nation is that which the national consciousness fixates itself upon as the title of the nation to continued existence. Nations do not go to war over their causes, or about their distinctive virtues and missions in the world. Rather it is their likenesses that precipitate wars,--their resemblances and identities in being the same in ambition, and having the same conceptions of national honor and the same motives for war and desiring the same objects. Nations in general do not go to war over principles because they are not motivated by principles in their historical course. The principles of nations are aspects of their inner development. The "causes" of nations at war, according to our view, are these inner qualities of which they have become conscious. Nations discover them in the stress of war, and it is quite natural also that in such times they should not always judge them fairly, and that they should often make for themselves a fictitious character.
Philosophy, in the minds of many writers, must be given a high place among the causes of war, and a considerable fraction of the literature of the late war is devoted to the problem of discovering, in the field of abstract thought, the influences that led to the great conflict. Nietzsche, especially, seems to have been held responsible for the European conflagration. As the philosopher of the New Germany, as the chief expositor of the doctrine of force, the inventor of the super-man and of the idea of the beyond-good, Nietzsche seems to stand convicted of furnishing precisely the concepts that have become the German's gospel of war; and since the German is prone to be guided by abstractions, the evidence, even though circumstantial, seems to many to be convincing.