To respond to techiferous quickly, I'll just point out that the author is basically advertising the fact that he is reductionist by heading sections with "The Missing Jigsaw Piece", etc. Maybe the book is different, okay.
We can use science, mathematics, and statistics to test hypothesis
You can't, though. It's really hard to make the world a laboratory, though it does sometimes happen by accident. The differences between N and S Korea, E and W Germany, China and Taiwan, I think, settled the question of Communism vs. Capitalism. But good luck in getting the grant money to set up such an experiment. I've pointed out that the USA itself is really a quite corrupt, thieving, murderous entity, but this hasn't really mattered that much. Another example? Nazi Germany. They had a ridiculous war economy, they sent all their young men to butcher people, they imprisoned millions of citizens and foreigners, they had brutal police and internal security, etc, etc. All the worst possible things. Worse than Cameroon could possibly aspire to. And yet the country was prosperous almost to the end of the regime. And this was coming off the heels of the worst historical instances of hyperinflation, depression, and world war. All of which were also caused by politicians.
That's a lot of bad government but it ultimately didn't matter at all.