- The author answers a question raised by Yali, a Papua New Guinea islander
"Why is it that you white people developed so much cargo, but we black people had little cargo of our own?"
Meaning how certain societies, particularly Western, European societies, came to be so technologically and economically powerful while other societies did not
- Continental differences in the wild plant and animal species available as starting materials for domestication
- Rates of diffusion and migration differed greatly among continents
- These different rates help build up a local pool of domesticates and technology
- Continental differences in area or total population size
- History is not "just one damn fact after another," as a cynic put it. There really are broad patterns to history, and the search for their explanation is as productive as it is fascinating
- Europe’s barriers were sufficient to prevent political unification, but insufficient to halt the spread of technology and ideas
- Physicists and chemists can formulate universal deterministic laws at the macroscopic level, but biologists and historians can formulate only statistical trends
- The coastal countries are on the average about 50 percent richer than the landlocked countries
- Transport overland is about 7 times more expensive than transport by sea to a coastal port or up a navigable river