Guns, Germs, and Steel

The Fates of Human Societies

In July 1972, a New Guinean politician named Yali walked up alongside Jared Diamond on a beach and asked him a question that would take twenty-five years to answer properly.

He asked Diamond something direct: why is it that you white people developed so much cargo and brought it to New Guinea, but we black people had little cargo of our own?

That question is not really about cargo. It is about the shape of history.

Why did wealth and power end up distributed the way they are? Why weren’t Native Americans, Africans, and Aboriginal Australians the ones who decimated, subjugated, or exterminated Europeans and Asians? Why did guns, steel, and devastating germs flow from Eurasia outward rather than from the Americas or Africa inward?

These are the questions this book spends 400 pages answering, and they are very good questions. The usual answers invoke proximate forces: the rise of capitalism, mercantilism, scientific inquiry, technology, germs. But those are just proximate factors, not ultimate explanations. Diamond insists on pushing further back. Why did all those ingredients of conquest arise in western Eurasia, and arise elsewhere only to a lesser degree or not at all?

My note: These are very good questions. And Diamond is right that the usual answers are unsatisfying because they only push the question back one step. Why did capitalism flourish in Europe and not Native Mexico? Why did scientific inquiry advance in western Eurasia and not China, which was actually more technologically advanced than western Eurasia until around AD 1400? The book’s real value is that it refuses to stop at the obvious answers. Confucian China was ahead of Europe for most of recorded history. That alone should make us suspicious of any explanation that invokes cultural superiority.

1. The One-Sentence Answer and Why It Is Not Simple

Diamond says journalists often ask authors to summarise a long book in one sentence. For this book: history followed different courses for different peoples because of differences among peoples’ environments, not because of biological differences among peoples themselves. This is so true and yet so easy to misread.

The book is not saying that geography is destiny in some rigid, mechanical sense. It is saying that the distribution of domesticable wild plants and animals, the orientation of continental axes, and the ecological barriers that slowed or blocked the spread of crops and technology created enormous structural advantages for some peoples and not others. Those advantages compounded over thousands of years. By the time Europeans encountered the Inca Empire in 1532, 13,000 years of accumulated structural advantage had already done most of the decisive work.

What Diamond explicitly rejects is the racist answer that sits behind so many accounts of this history. The racist explanation looks at Aboriginal Australians, still hunter-gatherers after 40,000 years while white English colonists built a literate industrialised democracy within a century of arrival, and concludes that the difference must lie in the people. Diamond’s response is sharp: white English colonists did not create that society. They imported it. They brought the livestock, all the crops except macadamia nuts, the metallurgical knowledge, the steam engines, the guns, the alphabet, the political institutions, even the germs. All of those were the end products of 10,000 years of development in Eurasian environments. The colonists who landed at Sydney in 1788 inherited those elements by accident of geography. The people who actually created a society in Australia were the Aboriginal Australians. The society they created matched what their environment made possible.

My note: Fully agree. This is the most important correction in the book. The experiment of Australia looks controlled because the land was the same. But the people were not starting from the same point. The English settlers arrived carrying 10,000 years of accumulated Eurasian technology, crops, and institutions that had been built by many other peoples in many other places. The Aborigines had been building their own civilisation with the tools that Australia’s environment provided. Those happened to be quite limited, but that was not their fault, and it was not evidence of their inadequacy.

2. Yali’s Question in the Flesh: The Moriori and the Maori

Before Diamond builds his full 13,000-year argument, he offers a smaller test. A story compressed into a few centuries, drawn from the Pacific, that illustrates the same forces in miniature. This is a very nice story, and it makes the point clear.

Story: The Moriori and the Maori, same ancestors, opposite fates

On November 19, 1835, a ship carrying 500 Maori armed with guns, clubs, and axes arrived at the Chatham Islands, 500 miles east of New Zealand. A second ship brought 400 more. The Chatham Islands were home to a people called the Moriori, hunter-gatherers who had developed a tradition of resolving disputes peacefully. They held a council and decided to offer peace, friendship, and a division of resources. Before they could deliver that offer, the Maori attacked. Over the following days they killed hundreds of Moriori, and enslaved the rest. A Moriori survivor recalled: they commenced to kill us like sheep. A Maori conqueror explained without apology: we took possession in accordance with our customs and caught all the people. What makes this story illuminating is that Moriori and Maori were not ancient enemies from different civilisations. They had diverged from the same ancestral Polynesian society less than a millennium earlier. Some centuries before 1835, a group of Maori had colonised the Chatham Islands and become the Moriori. The cold climate of the Chathams could not support the tropical crops that Polynesian farmers depended on. The colonists reverted to hunter-gathering. Without food surpluses, they could not feed chiefs, soldiers, or craft specialists. Without the threat from neighbouring peoples, they had no military tradition. With a total population of only 2,000 on a small island, they castrated some male infants to control overpopulation and renounced war to manage conflict. Meanwhile, the Maori remaining in warmer New Zealand grew into 100,000 farmers, chronically at war with each other, feeding craft specialists and warriors on crop surpluses. When these two groups finally met again after centuries of separation, the outcome was determined not by any inherent difference between the people but by the environments that had shaped them.

The Moriori case is Diamond’s model for the larger question. The same founding population, the same initial culture, the same starting technology. Then the environments diverged. One group had fertile soil for intensive farming, the other did not. Everything that followed, every difference in political organisation, military capacity, and technological complexity, followed from that single environmental difference.

My note: So environmental change changed them completely. The Moriori were not weak or cowardly. They had made a rational adaptation to their circumstances. They renounced war because war was not sustainable on a small island with a fixed population. They became hunter-gatherers because their crops would not grow. These were sensible responses to the place they lived. The Maori were not more virtuous or more intelligent. They had access to better land and more of it. This is the argument in miniature. Island climate, geological type, marine resources, area, terrain fragmentation, and isolation: these are the factors that shaped the Polynesian variation Diamond studies. Yes, these factors are important. They are not trivial background. They are the story.

3. The Fertile Crescent: Why Agriculture Started Where It Did

One of the strangest facts in the book is that the world’s earliest agriculture did not begin in the most fertile places. Had we surveyed the world in 4000 BC, thousands of years after the rise of food production in its oldest sites, we would have been surprised to find several modern breadbaskets still without it. England, much of France, Indonesia, all of subequatorial Africa: still without agriculture. Meanwhile the earliest sites were in places that look today like somewhat dry or ecologically degraded areas: Iraq, Iran, Mexico, the Andes, parts of China. Why did food production develop first in these seemingly rather marginal lands? It is a nice question, and it is strange.

Story: The Jordan Valley farmers and the 23 wild grasses

When researchers studied the wild grasses of the Jordan Valley in the ninth millennium BC, they found 23 species with large enough seeds and sufficiently useful properties to have been candidates for early cultivation. Two of those 23, barley and emmer wheat, became the first domesticated cereals of the Fertile Crescent and remain among the most productive crops in the world today. Were the Jordan Valley farmers who chose those two just lucky? Or did they actually make the best possible selection from what was available? Israeli botanists Ofer Bar-Yosef and Mordechai Kislev answered this by examining which of the 23 wild species was most worth growing. Emmer wheat had the biggest seeds of all 23. Barley had the second biggest. Barley was one of the four most abundant of the 23 in the wild, making it easy to collect. Both were annuals rather than perennials, meaning they evolved quickly under domestication. Both could be gathered efficiently and stored without spoiling. The other 21 candidates had smaller seeds, lower abundance, or biological features that would have made domestication slower and harder. The first Jordan Valley farmers, working without any knowledge of genetics or botany, selected the two best wild grass species available to them. They were not ignorant. They were walking encyclopedias of their local environment. They chose correctly.

The Fertile Crescent had several structural advantages that explain why agriculture began there and not in California, Chile, southwestern Australia, or South Africa, all of which have similar Mediterranean climates. First, western Eurasia has the world’s largest Mediterranean climate zone and consequently the highest diversity of wild plant and animal species. Of the 56 wild grass species worldwide with the largest and most nutritious seeds, 32 were native to the Mediterranean zone of western Eurasia, most of them in the Fertile Crescent. California and southern Africa had one each. Southwestern Australia had none at all. That fact alone goes a long way toward explaining the course of human history.

Second, the range of altitudes in the Fertile Crescent, from the Dead Sea at the lowest point on Earth to mountains of 18,000 feet near Tehran, meant staggered harvest seasons. Hunter-gatherers could follow ripening seeds up a mountainside for weeks, collecting enormous quantities. When they began to cultivate, it was a simple matter to plant the seeds of hillside cereals in the damp valley bottoms where they would grow more reliably. Third, the Fertile Crescent flora included an unusually high proportion of self-pollinating plants, meaning that a desirable mutant plant would pass on its characteristics reliably to offspring rather than being diluted by cross-pollination.

My note: The climate may be the reason. This is not a vague geographical claim. It is a specific biological one. The Mediterranean climate produced annuals that put enormous energy into large seeds because they could not store energy in roots or wood over the dry season. Those large seeds were what made the grasses worth harvesting at all. Without a Mediterranean climate of the right kind, there would have been no wild grasses large enough to be worth domesticating, no incentive to begin the millennia of trial and error that eventually produced wheat and barley. The Fertile Crescent farmers were not smarter than Californians or Australians. They had better raw material to work with.

4. Horses Were the Jeeps and Sherman Tanks of Ancient Warfare

One of the most vivid arguments in the book concerns the military role of domestic animals, and specifically horses. Horses were not incidental to the story of European conquest. They were the jeeps and Sherman tanks of ancient warfare on that continent.

The horse was domesticated around 4000 BC in the steppes north of the Black Sea. From the moment it was available for riding and later for chariot warfare, it transformed military capacity wherever it spread. In 1674 BC, a people called the Hyksos, with horses and chariots, conquered Egypt, whose pharaohs had no horses. In the 13th and 14th centuries, Mongol cavalry from the Asian steppes overran most of Asia and Russia. The horse gave cavalry the ability to cover far greater distances than infantry, to attack by surprise, to flee before a superior force could be gathered, and to project shock force that foot soldiers could not withstand in the open. It remained the primary military vehicle for six thousand years until it was finally supplanted by trucks and tanks in World War I.

Story: Cajamarca: 168 Spaniards capture an empire

On November 16, 1532, Francisco Pizarro led 168 Spanish soldiers into Cajamarca, a highland town in Peru, where the Inca emperor Atahuallpa was waiting with an army of 80,000 soldiers. By the end of the day, Atahuallpa was a prisoner, thousands of his soldiers were dead, and not a single Spaniard had been killed. Pizarro’s horses, his steel weapons, his firearms, and his ability to exploit the political chaos left by a devastating smallpox epidemic had together made the difference. Horses enabled cavalry to charge into dense masses of infantry and emerge without casualties. Steel swords and lances were devastating against the wooden clubs, maces, and quilted armour of the Inca forces. Atahuallpa offered the largest ransom in history: a room filled with gold 22 feet long, 17 feet wide, and 8 feet high. The gold was delivered. Pizarro had Atahuallpa executed anyway. Yes, horses were very much important. They, along with germs, steel, ships, and writing, were the proximate instruments of a conquest whose ultimate causes lay 10,000 years earlier.

My note: The book explains Cajamarca not as a story of Spanish courage or Inca naivety but as the meeting of two trajectories that had been diverging for 13,000 years. Atahuallpa walked into what looks to us like a transparent trap. But he had no way of knowing what he did not know. No knowledge of Spaniards, no knowledge of firearms, no knowledge that an entire civilisation with ships and writing and steel was pouring into the Americas. He had never read about previous conquests. He had no books. The Spaniards had books about Cortez’s conquest of Mexico and had modelled their strategy on it. Writing, which gave them access to the accumulated experience of their civilisation, was itself a decisive weapon.

5. The Lethal Gift of Livestock: Germs as Weapons

Far more Native Americans died in bed from Eurasian germs than on the battlefield from European guns and swords. This is one of the most important sentences in the book, and one of the most uncomfortable.

When European settlers arrived in the eastern United States after Spanish explorers had visited the coast, they found Indian town sites already abandoned. The inhabitants had died in epidemics transmitted inland from coastal Indians who had been infected by the Spanish visitors. The Spaniards’ microbes spread to the interior in advance of the Spaniards themselves. For the New World as a whole, the Indian population decline in the century or two following Columbus’s arrival is estimated to have been as large as 95 percent. When writer was young, American schoolchildren were taught that North America had originally been occupied by only about one million Indians, a number convenient for justifying the conquest of what could be viewed as an almost empty continent. Archaeological evidence now suggests the actual number was around 20 million.

Story: Measles in the Faeroes and the crowd disease that wiped out 51 of 56 Eskimos

A severe epidemic of measles reached the Faeroes, isolated Atlantic islands, in 1781 and then died out, leaving the islands measles-free. In 1846 an infected carpenter arrived from Denmark. Within three months, almost the whole population of 7,782 people had contracted measles and either died or recovered. The virus disappeared again until enough new babies had been born without immunity to sustain another epidemic. Studies show that measles dies out in any human population numbering fewer than half a million people: it requires a constant supply of susceptible individuals to keep circulating. In the winter of 1902, a dysentery epidemic brought by a sailor on a whaling ship killed 51 out of 56 Sadlermiut Eskimos, a very isolated band living on Southampton Island in the Canadian Arctic. A single infected outsider destroyed 91 percent of a people. These are not exceptional catastrophes. They are the standard experience of isolated populations meeting crowd diseases for the first time.

Why did the germ exchange flow so overwhelmingly from Eurasia to the Americas, and not in the other direction? Because crowd diseases evolve from animal diseases, and Eurasia had far more domestic animals. Measles came from cattle, who carry rinderpest. Smallpox came from livestock pox viruses. Flu came from pigs and ducks. Tuberculosis came from cattle. These diseases evolved as Eurasians lived in intimate proximity with their livestock for 9,000 years, and as agriculture produced the dense settled populations of millions needed to sustain crowd infections. Native Americans had almost no domestic animals. They had almost no crowd diseases. When the two populations met, the immunity gap was devastating.

My note: Agree. Germs that were acquired ultimately from domestic animals played decisive roles in the European conquests of Native Americans, Australians, South Africans, and Pacific islanders. It is worth noting that a book called The Mosquito explains this dimension of history at length, showing how malaria and yellow fever shaped the outcomes of colonial wars and determined where European settlement succeeded or failed. The mosquito killed more soldiers in more wars than any weapon. Africa, with its ancient tropical diseases, was largely inaccessible to European settlement until the 20th century, which is why the colonial carve-up of Africa came so late and was so brief. The germs cut in both directions. They were devastating to peoples without prior exposure and protective to peoples who had built up immunity over millennia. The disease landscape of each continent was itself a form of geography.

6. The Tilted Axis: Why East-West Beats North-South

The orientation of the continental axes, east-west in Eurasia and north-south in the Americas and Africa, is perhaps the single most elegant and surprising argument in the book. And it is so interesting and amazing.

Crops and animals are adapted to specific latitudes. Day length, temperature, rainfall seasonality, and disease regimes all vary with latitude. A crop domesticated at one latitude grows well at the same latitude thousands of miles away because the growing conditions are similar. It struggles at a different latitude because it encounters different day lengths, temperatures, and pests to which it has no adaptation. Eurasia’s east-west axis means that crops domesticated in the Fertile Crescent spread west to France and east to India without crossing a major climatic gradient. Wheat domesticated in what is now Syria grew well in England, 4,000 miles away, because both places share broadly similar temperate climates.

Mesoamerica

Story: The wheel that never met the llama

Wheels were invented in Mesoamerica. Llamas were domesticated in the central Andes by 3000 BC. Both inventions were present in the Americas simultaneously. Five thousand years later, the Americas’ sole beast of burden and its sole wheeled vehicles had still not encountered each other. The distance separating Mesoamerica’s Maya societies from the northern border of the Inca Empire was only 1,200 miles, far less than the 6,000 miles separating France and China, which shared horses and wheels within centuries of each invention. But those 1,200 miles ran north to south through radically different climate zones, across tropical forests and deserts that stopped crops, animals, and ideas from spreading. So the Maya had wheels but used them only as toys. The Inca had llamas but no wheels. Two civilisations that might have built wheeled transport 2,000 years earlier than Europe actually did, if only they could have reached each other, were separated by a climatic barrier that 1,200 miles of north-south travel created but 6,000 miles of east-west travel in Eurasia did not.

The consequences of this axis difference reached into every domain of civilisation. Crop domestication was typically a single event: once a crop was developed, it spread so fast that it pre-empted any independent re-domestication of the same wild ancestor elsewhere. In Eurasia, wheat was domesticated once and spread across 4,000 miles within a few thousand years, preempting any other attempt. In the Americas, the same crops were domesticated independently in Mesoamerica and South America because the north-south axis blocked their spread. Corn, beans, and common beans were each domesticated at least twice in different regions because neither region received the other’s version fast enough to prevent independent domestication. This pattern of multiple independent domestications is a direct signature of the axis problem.

My note: The east-west axis allowed ideas, crops, animals, and technologies to flow between societies that shared similar growing conditions. The north-south axis forced everything to cross climatic barriers that crops could not survive and that animals sickened in. It is not that Mesoamerican or Andean peoples were less inventive. They invented the wheel. They domesticated the llama. They built large empires and developed writing. But the geographical fragmentation of the Americas, the narrow isthmus at Panama only 40 miles wide, the desert north of Mexico, the tropical forests of Darien, stopped the recombination and diffusion of their inventions in ways that the broad, connected, climatically consistent Eurasian landmass did not. This is the gist of the whole book in one geographic fact.

7. Technology Begets Technology: The Autocatalytic Process

One of the most important structural arguments in the book is that technology development is not a series of isolated heroic inventions but an autocatalytic process: one that speeds itself up because each advance creates the conditions for the next advance.

Technology develops fastest in large productive regions with large human populations, many potential inventors, and many competing societies. Eurasia was the world’s largest landmass, with the two earliest centres of food production: the Fertile Crescent and China. Its east-west axis permitted inventions to spread rapidly across similar latitudes. Geographic and ecological barriers to diffusion of technology were less severe in Eurasia than in other continents. The result was a continent on which technology started its post-Pleistocene acceleration earliest and accumulated most rapidly.

Story: Japan abandons the gun and pays for it two centuries later

Firearms reached Japan in 1543, when two Portuguese adventurers arrived on a Chinese cargo ship. The Japanese were so impressed that they began manufacturing guns immediately, greatly improved the technology, and by 1600 owned more and better guns than any country in the world. Then the samurai class, for whom swords were class symbols and works of art, began to feel threatened. Guns killed with ungraceful efficiency and could be used by anyone, including peasants, which undermined the entire social order that swordsmanship supported. The samurai-controlled government began restricting gun production to a few cities, then required government licences for production, then issued licences only for guns made for the government, and finally reduced government orders until Japan was almost without functional guns. Contemporary European rulers also tried to restrict firearms but failed, because any country that temporarily abandoned guns would be overrun by neighbours still armed with them. Only because Japan was a populous isolated island could it survive its rejection of the most powerful military technology in the world. That safety ended in 1853 when Commodore Perry’s US fleet arrived with cannons. Japan had two years to resume gun manufacture before the consequence of its two-century holiday arrived. So basically, if there is an enemy with a gun, any country must start using guns too for its own protection. Japan proved this point by having to relearn in twenty years what Europe had refined over two centuries.

The autocatalytic character of technology means that even a temporary setback compounds over time. The Aboriginal Tasmanians were cut off from the Australian mainland about 10,000 years ago when rising sea levels flooded Bass Strait. Over the following millennia, their population of 4,000 people lost technologies they had previously possessed: bone tools, fishing, cold-weather clothing. The isolation that prevented them from acquiring new technologies also accelerated the loss of existing ones. By the time Europeans reached them in 1642, they had the simplest material culture of any people in the modern world. This is not evidence of Aboriginal Tasmanian inadequacy. It is evidence of what happens to any small isolated population cut off from the broader network of human invention and exchange over ten thousand years.

My note: Sedentary living was decisive for the history of technology, because it enabled people to accumulate nonportable possessions. Nomadic hunter-gatherers must carry everything they own. You cannot carry pottery and printing presses as you shift camp. This is why the earliest evidence for ceramics, fired clay figurines from Czechoslovakia 27,000 years ago, was not followed by pottery vessels for another 13,000 years. The figurines appeared before sedentary life became possible. The vessels appeared when people stayed put. The principle extends everywhere: technology requires not just invention but the social infrastructure to maintain and build on the invention. Requirement and the technology available at that time were also factors. The Phaistos Disk, the world’s earliest printed document from Crete around 1700 BC, never spread because there was no demand for printing when only a few palace scribes could read. Gutenberg’s press spread because there were millions of literate people hungry for books.

8. Africa: Why It Is So Interesting

The Africa chapters of the book are where Diamond’s argument becomes most explicit and most directly relevant to contemporary debates. Africa was the cradle of human evolution. Homo sapiens probably originated there. Africa had the world’s longest head start. An extraterrestrial visiting Earth 10,000 years ago might have been forgiven for predicting that Europe would end up as a set of vassal states of a sub-Saharan African empire. It did not happen. The proximate reasons are clear: Europeans entering Africa had guns, widespread literacy, and the political organisation needed to sustain expensive colonial programmes. But why did Europeans develop those advantages first?

Story: Egypt’s wheat that could not cross the Sahara, and why the Cape Khoisan never farmed

The Mediterranean crops that became Egypt’s staples, wheat and barley, require winter rains and seasonal variation in day length to germinate properly. South of the Sudan, they encountered summer rains and little seasonal variation in daylight. Those crops could not adapt to the different conditions fast enough to spread. Egypt’s wheat and barley never reached the Mediterranean climate of the Cape of Good Hope, 4,000 miles to the south, until European colonists brought them in 1652. The Khoisan people of the Cape, with a Mediterranean climate perfectly suited to Fertile Crescent crops, never developed agriculture because the right crops never reached them. The Bantu farmers from further north brought summer-rain crops that also failed at the Cape. So the Cape remained occupied by hunter-gatherers not because the Khoisan were incapable of farming but because no suitable crop ever arrived within reach. Africa’s north-south axis meant that crops domesticated in one climatic zone could not easily cross into another. Livestock suffered the same problem: horses and cattle were blocked by tsetse fly disease belts. Writing developed in Egypt by 3000 BC but did not spread independently through the rest of Africa. Pottery reached the southern tip of Africa around AD 1, eight thousand years after it appeared in the Sudan. Everything moved slowly or stopped entirely along Africa’s north-south axis. In contrast, across Eurasia’s east-west axis, the same processes happened in centuries rather than millennia.

The animal situation in Africa was equally limiting. Africa is famous for its large mammals. But none of Africa’s iconic species, not the zebra, the wildebeest, the buffalo, the rhino, the hippo, or the giraffe, was ever successfully domesticated. They were tamed individually on occasion, but none was bred in captivity and genetically modified to serve human purposes. Had Africa’s rhinos and hippos been domesticated and ridden, they would not only have fed armies but provided an unstoppable cavalry to cut through European horsemen. Rhino-mounted Bantu shock troops could have overthrown the Roman Empire. It never happened. The failure was not a failure of ingenuity. It was a failure of the raw material. Each African candidate for domestication failed for its own specific reason: zebras were too dangerous and unpredictable, buffalo too aggressive, rhinos too territorial and slow to reproduce, hippos too dangerous.

My note: Europe’s colonisation of Africa had nothing to do with differences between European and African peoples themselves, as white racists assume. Rather, it was due to accidents of geography and biogeography: the continents’ different areas, axes, and suites of wild plant and animal species. The different historical trajectories of Africa and Europe stem ultimately from differences in real estate. This is so so interesting. Africa had the oldest human populations, the greatest genetic diversity, and the continent where our species evolved. It lost not because its people were inferior but because its geography gave them fewer of the building blocks that the Eurasian geography provided in abundance. Limited domesticable plants. No domesticable large mammals of significance. A north-south axis that blocked diffusion. Half the area of Eurasia. Fewer competing societies. Fewer potential inventors. Each disadvantage compounded the others.

9. Intelligence, Childhood, and the Racist Assumption Turned on Its Head

Perhaps the most provocative chapter in the book is the one where Diamond directly addresses the question of whether the technological differences between peoples reflect biological differences in intelligence. His answer is carefully argued and worth sitting with.

The standard racist assumption is that peoples whose societies remained technologically simple must have lower intelligence than peoples whose societies became industrialised. Diamond considers this assumption wrong in its reasoning and probably backwards in its conclusion. IQ tests measure cultural learning, not pure innate intelligence, whatever that is. I agree with this. IQ is different for different people, different contexts, different training. A New Guinean who looks stupid to a Westerner in a town because he cannot navigate unfamiliar institutions is the same person who makes the Westerner look stupid in the jungle because the Westerner cannot follow a trail or erect a shelter.

Story: New Guineans may be genetically smarter than Westerners

Diamond argues that Europeans have for thousands of years lived in densely populated societies where infectious epidemic diseases were the major cause of death. In those societies, the genes for resisting smallpox or measles were far more valuable to survival than genes for intelligence. Most Europeans who escaped fatal infections survived to reproduce, regardless of their intelligence. In contrast, traditional New Guineans lived in small societies where epidemic diseases of dense populations could not evolve. Instead, they faced high mortality from murder, chronic warfare, accidents, and difficulty procuring food. In those conditions, intelligent people were more likely than less intelligent ones to survive. Natural selection promoting genes for intelligence has probably been far more ruthless in New Guinea than in densely populated, politically complex societies. The second reason is equally surprising: TV. Modern European and American children spend much of their time passively entertained by television, radio, and movies. The average American household has the TV on for seven hours per day. Traditional New Guinea children have virtually no such opportunities for passive entertainment. They spend almost all their waking hours actively talking, playing with others, engaging with their environment. Almost all studies of child development emphasise the role of active childhood stimulation in promoting mental development and note the irreversible stunting associated with reduced stimulation. This can also be a reason. The book The Coddling of the American Mind by Jonathan Haidt also supports this. New Guineans, developing minds through constant active engagement with the world rather than passive screen watching, may have a significant developmental advantage.

The racist assumption has to be turned on its head. New Guineans are probably genetically superior to Westerners in mental ability, and certainly superior in escaping the devastating developmental disadvantages that children in industrialised societies now routinely suffer. The question is why Europeans, despite their likely genetic disadvantage and their undoubted developmental disadvantage in modern times, ended up with so much more cargo. The answer is not intelligence. It is geography, which shaped the availability of domesticable species, which shaped the onset of food production, which shaped the development of dense populations, which created the conditions for writing, technology, political organisation, and epidemic diseases. It is a very long chain of causes. None of them requires any difference between the people.

My note: This sets a really nice premise. Diamond is not just saying that racist explanations are wrong on moral grounds. He is saying they are empirically wrong. The evidence we have about intelligence differences does not support the assumption, and the mechanisms Diamond describes suggest the opposite is at least as plausible. But more importantly, even if we could establish meaningful average intelligence differences between populations, those differences would not explain the pattern. The pattern is too large, too consistent, too clearly correlated with the geography of domesticable species and continental axes, to be explained by something as variable and context-dependent as measured intelligence.

10. The Great Man Theory, Chaos, and the Limits of the Book

Diamond is careful about what his argument can and cannot explain. He knows history is not only geography. He acknowledges that individual people, cultural idiosyncrasies, and unpredictable accidents also shape events. And he is honest that his framework explains history’s broadest pattern, not every detail within it.

Story: Hitler’s near-fatal car accident in 1930 and the chaos of history

In the summer of 1930, more than two years before Hitler’s seizure of power, a car in which he was riding collided with a heavy trailer truck. The truck driver braked just in time to avoid crushing Hitler’s car. Because of the degree to which Hitler’s specific psychology determined Nazi policy, a slightly later braking response would probably have produced a very different World War II. One can think of other individuals whose particular idiosyncrasies changed events: Alexander the Great, the Inca emperor Pachacuti, the Zulu king Shaka. Long chains of causation may separate final effects from ultimate causes in ways that make individual prediction impossible. The dinosaurs may have been exterminated by the impact of an asteroid whose orbit was completely determined by classical mechanics. But if there had been paleontologists alive 67 million years ago, they could not have predicted the impact, because asteroids belong to a field of science otherwise remote from dinosaur biology. Similarly, the Little Ice Age of AD 1300–1500 contributed to the extinction of the Greenland Norse, but no historian or climatologist could have predicted it. We don’t know.

My note: Societies developed differently on different continents because of differences in continental environments, not in human biology. And it is important to add what Diamond also emphasises: understanding these causes is not the same as justifying the outcomes. Psychologists try to understand murderers not to excuse them. Social historians try to understand genocide not to accept it. Understanding a chain of causes is the first step to interrupting it. The modern world’s inequalities were not inevitable in any cosmic sense. They resulted from specific, traceable, geographic facts that happened to favour some peoples over others at the particular moment when the contacts began. Knowing that does not make the suffering caused by conquest less real. It does open the possibility of designing responses that address structural disadvantages rather than blaming the people who suffered from them.

Final Thoughts

The central argument is solid: the broadest pattern of history, the one that determined the fate of continents, was shaped primarily by the geography and ecology of the places where different peoples happened to live, and by the specific wild plants and animals available for domestication in those places.

The peoples who happened to live where domesticable plants and large animals were abundant, and where the east-west axis allowed the rapid spread of crops and technologies across similar climatic zones, got a head start of several thousand years.

That head start compounded through every subsequent development: denser populations, more diseases, more complex political organisation, more technology, more writing.

By the time the great collisions came, around 1500 AD, the gap was so large that the outcomes were determined before the first battle was fought.

The book’s most lasting contribution may be the simplest: it shows in painful detail that the people who lost did not lose because they were inferior. They lost because the land they happened to occupy thousands of years ago had different grass species, different large mammals, and a different orientation relative to the equator. That is an enormously important thing to know. And it is so interesting.