In the nineteenth century, when many people were optimistic in their views of human nature, and confident that the course of progress was going to be continued into an indefinite future, there were one or two prophets who feared and foretold that the twentieth century would see great wars of peoples, popular military dictatorships and the harnessing of the machines of industry to the science of warfare. It is interesting to note that, without knowing whether one country or another was going to emerge as the chief offender, and without basing his prediction upon any view that Germany was likely to present a special problem to the European continent, a writer could still feel assured, a generation beforehand, that this age of terrible warfare was coming. He could see, in other words, that, apart from the emergence of a special criminal, the developments in the situation itself were driving mankind into an era of conflict. In the midst of battle, while we are all of us in fighting mood, we see only the sins of the enemy and fail to reflect on those predicaments and dilemmas which so often develop and which underlie the great conflicts between masses of human beings. And though these conflicts could hardly have taken place if all men were perfect saints, we often forget that many of the inhuman struggles that have divided the human race would hardly have occurred if the situation had been one of completely righteous men confronted by undiluted and unmitigated crime. Given the ordinary amount of cupidity and wilfulness in human beings, unmanageable situations are likely to develop and some of them may almost be guaranteed to end in terrible conflict. While there is battle and hatred men have eyes for nothing save the fact that the enemy is the cause of all the troubles; but long, long afterwards, when all passion has been spent, the historian often sees that it was a conflict between one half-right that was perhaps too wilful, and another half-right that was perhaps too proud; and behind even this he discerns that it was a terrible predicament, which had the effect of putting men so at cross-purposes with one another. This predicament is the thing which it is the purpose of this paper to examine; and first of all I propose to try to show how the historian comes to discover its existence.