History, as well as life itself, is complicated; neither life nor history is an enterprise for those who seek simplicity and consistency. - Jared Diamond

Technological advances seem to come disproportionately from a few very rare geniuses, such as Johannes Gutenberg, James Watt, Thomas Edison, and the Wright brothers. They were Europeans, or descendants of European emigrants to America. So were Archimedes and other rare geniuses of ancient times. Could such geniuses have equally well been born in Tasmania or Namibia? Does the history of technology depend on nothing more than accidents of the birthplaces of a few inventors?

The central principle of Fritz Bauer's career was that Germans should hold judgement upon themselves. That meant prosecuting ordinary Germans, not just the leaders whom the Allies had prosecuted. [...] The Nazi defendants being prosecuted by Bauer all tended to offer the same set of excuses [...]. Bauer's response, which he formulated again and again at the trials and in public, was as follows. Those Germans whom he was prosecuting were committing crimes against humanity. The laws of the Nazi state were illegitimate. One cannot defend one's actions by saying that one was obeying those laws. There is no law that can justify a crime against humanity. Everybody must have his own sense of right and wrong and must obey it, independently of what a state government says. Anyone who takes part in what Bauer called a murder machine [...] thereby becomes guilty of a crime.

The societies to which most readers of this book belong represent a narrow slice of human cultural diversity. Societies from that slice achieved world dominance not because of a general superiority, but for specific reasons: their technological, political, and military advantages derived from their early origins of agriculture, due in turn to their productive local wild domesticable plant and animal species. Despite those particular advantages, modern industrial societies didn’t also develop superior approaches to raising children, treating the elderly, settling disputes, avoiding non-communicable diseases, and other societal problems. Thousands of traditional societies developed a wide array of different approaches to those problems.