The history of mankind for thousands of years has been a history of incessant warfare and the new economic and industrial conditions which have made war irrational are not more than about one hundred years old, while the human brain is practically the same old brain of our fathers and forefathers, deeply stamped with ancestral traits and primitive instincts, which cannot thus suddenly be outgrown. It is society which has suddenly changed, not the units of society. Ever since the war began, sociologists, economists, philosophers and political theorists have tried their hands at explaining the causes of the war and with small success...