Those causes have been, in the religious field, of a twofold nature, both having direct bearing on the problem with which we are dealing. The first cause is that at which I have already hinted, the general shifting of the ideals from sterile aims to those concerned with the improvement of society; the second one being that development of communication which has destroyed the spiritual homogeneity of States. A given movement of religious opinion is not confined to one State, transforming it completely, while another current of opinion transforms completely in another sense another State; but it goes on piecemeal, _pari passu_, in the various States. Very early in the religious development of Europe there ceased to be such a thing as a purely Catholic or a purely Protestant State: the religious struggle went on inside the political frontiers--between the people of the same State. The struggle of political and social ideas must take a like course. Those struggles of ideas will be carried out, not between States, but between different groups in the same State, those groups acting in intellectual co-operation with corresponding groups in other States. This intellectual co-operation across frontiers is a necessary outcome of the similar economic co-operation athwart frontiers which the physical division of labor, owing to the development of communication, has set up. It has become impossible for the army of a State to embody the fight for an ideal, for the simple reason that the great moral questions of our time can no longer be postulated in national terms. What follows will make this plain. There remains a final moral claim for war: that it is a needed moral discipline for nations, the supreme test for the survival of the fittest. In the first chapter of this section, I have pointed out the importance of this plea in determining the general character of European public opinion, on which alone depends the survival or the disappearance of the militarist regimen. Yet in strict logic there is no need to rebut this claim in detail at all, for only a small fraction of those who believe in it have the courage of their convictions. The defender of large armaments always justifies his position on the ground that such armaments ensure peace. _Si vis pacem_, etc. As between war and peace he has made his choice, and he has chosen, as the definite object of his endeavors, peace. Having directed his efforts to secure peace, he must accept whatever disadvantages there may lie in that state. He is prepared to admit that, of the two states, peace is preferable, and it is peace towards which our efforts should be directed. Having decided on that aim, what utility is there in showing that it is an undesirable one?