Much has been said and written about the causes of the war; and it is inevitable that the immediate causes (for they alone are discussed) should be thoroughly investigated. But the deeper underlying causes of the recent war, and of every war, are not those upon which diplomatists and politicians and journalists and historians are intent: they must be sought in that callous and selfish habit of mind—common to all races, and as such accepted without thought, and transmitted from one generation to another—which exhibits itself not in war only, but in numerous other forms of barbarity observed in so-called civilized life.