THE CONQUISTADORS WERE CONvinced that God was on their side, and the bloody evidence backed them up. What else but divine favor could explain how 168 Spaniards under Francisco Pizarro could, in 1589, massacre an army of 80,000 Incas? Over the years historians trying to come up with a better explanation have suggested that either the intellectual superiority of Europeans over Native Americans or differences in world outlook led one civilization to invent swords and steel shields and the other to progress no further than clubs and quilted armor. But a new book offering what the eminent historian William McNeill calls "a radically new vision" argues that neither God nor IQs determined history's winners and losers. In Guns, Germs, and Steel: The Fates of Human Societies (480 pages. Norton. $27.00), biologist Jared Diamond of the University of California, Los Angeles, argues that the most basic fact of world history--who conquered or exterminated whom--is explained by one thing: real estate.
Diamond is trying to resuscitate the theory known as geographic determinism. Largely abandoned by historians some 60 years ago, this view holds that where people lived determined their degree of civilization. Yes, the immediate reason that Pizarro defeated the Incas was that the Europeans had steel swords, horses, ships and writing, and they carded germs like smallpox that wiped out some 95 percent of the Americas' pre-Columbian population. But the ultimate cause-why did the Europeans have these things?--turns on bio-geography: how plants and animals are distributed over the world.
At the base of the great pyramid of causes is food growing crops and raising animals. Until about 11,000 B.C., everyone everywhere was a hunter-gatherer. But soon after, people in the Fertile Crescent (present-day Iraq) and China began to settle down and produce food. That meant that, for the first time, they could store it, too (hunter-gatherers, who are forever on the move, cannot). Food storage permitted food surpluses. Surpluses allowed populations to grow to 10 to 100 times the s@e of hunter-gatherer ba@ds. Most important, surpluses freed some members of a group from having to produce food themselves. All of a sudden, full-time speci@sts, such as toolmakers; scribes, metalworkers and soldiers, could emerge. Food production thus led directly to both technological and social complexity. It also led to germs. Domesticated animals were literally a breeding ground for disease, Diamond argues: smallpox originated as cowpox, measles as rinderpest in catfie, flu in pigs and ducks. Societies that @d not domesticate animals, such as Native Americans before the Spanish, would not have been exposed to these killers, and so would not have developed resistance. "The ultimate cause of food production," Diamond concludes, "led to the proximate causes of germs, literacy, technology and centralized government."
If agriculture and animal husbandry were the path to world conquest, the crucial question is why Eurasians developed them but Africans, Americans and Australians did not, or at least did not until millennia later, when it was too late to catch the Eurasians. It wasn't a difference in intelligence, says Diamond. Rather, some people had the luck to live where the plants and animals were easy to domesticate. Very few were. Australia had only a single domesticable plant (the macadamia nut). America's candidates, including teosinte (the ancestor of corn) and sumpweed, all had drawbacks such as seeds so tiny they were hardly worth harvesting or a nasty propensity to cause hay fever and skin irritation. In Africa, every worthwhile crop originated north of the Sahara; none could cross the desert and adapt to the southern climate. In contrast, 82 of the 56 wild grasses (which include rice and wheat) are native to Eurasia. Eurasia was also home to all five of the world's major domesticated species, including cattle, sheep and goats. Australia had none. The Americas had only the llama; Africa, only the guinea fowl.
The fortunes, or misfortunes, of a specific region shaped the fate of its entire continent. Crops and animals domesticated in the Near East and the Mediterranean were easy to transplant across Eurasia because and climate do not vary as one travels east or west, the orientation of Eurasia. In contrast, the north-south orientation of Africa and the Americas meant that Andean crops and llamas suited to the cool highlands could not spread through Central America's hot lowlands. And trading crops led to trading ideas. "Societies that engaged in intense exchanges of crops, livestock and [farming implements] were more likely to" exchange other inventions, argues Diamond. Those that did not interact were cut off from new ideas and technologies.
Diamond's unified field theory of history has triggered an intense debate. One criticism is that, as MeNeill puts it, "it's a brilliant book, but he neglects the power of ideas to spur civilizations." Geographic predestination does not explain why Europe subjugated China for years, even though China was the most advanced nation in the world in 1400. Nor does it explain why Europe, not China, produced a Euclid and a Newton and "led the world into the modern age," says physicist Gregory Benford of the University of California, Irvine. "Geography is powerful, but you need something more subtle to explain this." Whatever its flaws, Diamond's attempt to explain the past is one of the boldest in generations. If he's right, then pride in the power and the glories of European civilization should be tempered with a little humility: were it not for cowpox, history might have been very different.