Say we have a war and - after its over - a couple of million people are dead and the survivors all say, 'Gee - I'm not gonna do that again in a hurry!'
Then, a couple of years down the line, guess what - we're marching off to war again!
So the theory goes: the first war was the result of a mistake that somebody made. The second war was the result of us not learning from the mistake that started the first war. Hmmm.
Get your heads round this folks. All wars are planned. They are not mistakes. They are opportunities for certain individuals, families, dynasties to make lots and lots of money!
Wars are not inevitable. They are not the totally random, unpredictable outcome of introducing chaos into an otherwise ordered social, political and economic system. They are the result of direct manipulation of that system by those that have the power to do so. And if you want to know he they are (the manipulators) just follow the money.