As I said, I agree with the principle but think the writing and methodology are sloppy.
That being said, it would depend on the society and the historical context. Where were the suicide bombers attacking Gheghis Khan? Why do old-line Mormon males not display the same violent tendencies as Islamic militants? Was the habit of Muslim militancy greater or lesser than that of the Christian, Hindu and Oriental societies prior to the modern period? Did they experience more or less social unrest?
I invoked Freakanomics because these are the kind of things Levitt would have stopped to ask himself and Kanakawa clearly did not stop and try.
