adapting Diamond’s thesis: as we have already seen,
whatever the drawbacks of the Inca and Aztec empires
were in 1532, Peru and Mexico were undoubtedly more
prosperous than those parts of the Americas that went on
to become the United States and Canada. North America
became more prosperous precisely because it
enthusiastically adopted the technologies and advances of
the Industrial Revolution. The population became educated
and railways spread out across the Great Plains in stark
contrast to what happened in South America. This cannot
be explained by pointing to differential geographic
endowments of North and South America, which, if
anything, favored South America.
Inequality in the modern world largely results from the
uneven dissemination and adoption of technologies, and
Diamond’s thesis does include important arguments about
this. For instance, he argues, following the historian William
McNeill, that the east–west orientation of Eurasia enabled
crops, animals, and innovations to spread from the Fertile
Crescent into Western Europe, while the north–south
orientation of the Americas accounts for why writing
systems, which were created in Mexico, did not spread to
the Andes or North America. Yet the orientation of
continents cannot provide an explanation for today’s world
inequality. Consider Africa. Though the Sahara Desert did
present a significant barrier to the movement of goods and
ideas from the north to sub-Saharan Africa, this was not
insurmountable. The Portuguese, and then other
Europeans, sailed around the coast and eliminated
differences in knowledge at a time when gaps in incomes
were very small compared with what they are today. Since
then, Africa has not caught up with Europe; on the contrary,
there is now a much larger income gap between most
African and European countries.
It should also be clear that Diamond’s argument, which is
about continental inequality, is not well equipped to explain
variation within continents—an essential part of modern
world inequality. For example, while the orientation of the
Eurasian landmass might explain how England managed to
benefit from the innovations of the Middle East without
having to reinvent them, it doesn’t explain why the Industrial
Revolution happened in England rather than, say, Moldova.