GUNS, GERMS, AND STEEL - THE FATES OF HUMAN SOCIETIES - by Jared Diamond
This book attempts to provide a short history of everybody for the last 13,000 years. The question motivating the book is: Why did history unfold differently on different continents?
All of that human history, for the first 5 or 6 million years after our origins about 7 million years ago, remained confined to Africa.
Human history, at last, took off around 50,000 years ago, at the time of what I have termed our Great Leap Forward.
In human societies possessing domestic animals, livestock fed more people in four distinct ways: by furnishing meat, milk, and fertilizer and by pulling plows.
1. First and most directly, domestic animals became the societies’ major source of animal protein, replacing wild games.
2. In addition, some big domestic mammals served as sources of milk and of milk products such as butter, cheese, and yogurt. Milked mammals include the cow, sheep, goat, horse, reindeer, water buffalo, yak, and Arabian and Bactrian camels. Those mammals thereby yield several times more calories over their lifetime than if they were just slaughtered and consumed as meat.
3. Big domestic mammals also interacted with domestic plants in two ways to increase crop production. First, as any modern gardener or farmer still knows by experience, crop yields can be greatly increased by manure applied as fertilizer.
4. In addition, the largest domestic mammals interacted with domestic plants to increase food production by pulling plows and thereby making it possible for people to till land that had previously been uneconomical for farming.
Of equal importance in wars of conquest were the germs that evolved in human societies with domestic animals. Infectious diseases like smallpox, measles, and flu arose as specialized germs of humans, derived by mutations of very similar ancestral germs that had infected animals. When such partly immune people came into contact with others who had had no previous exposure to the germs, epidemics resulted in which up to 99 percent of the previously unexposed population was killed. Germs thus acquired ultimately from domestic animals played decisive roles in the European conquests of Native Americans, Australians, South Africans, and pacific islanders
Schematic overview of the chains of causation leading up to proximate factors (such as guns, horses, and diseases) enabling some peoples to conquer other peoples, from ultimate factors (such as the orientation of continental axes). For example, diverse epidemic diseases of humans evolved in areas with many wild plant and animal species suitable for domestication, partly because the resulting crops and livestock helped feed dense societies in which epidemics could maintain themselves, and partly because the diseases evolved from germs of the domestic animals themselves.
The importance of domesticated mammals rests on surprisingly few species of big terrestrial herbivores. If one defines big as weighing over 100 pounds, then only 14 such species were domesticated before the twentieth century. Of those Ancient Fourteen, 9 became important livestock for people in only limited areas of the globe: the Arabian camel, Bactrian camel, llama/alpaca (distinct breeds of the same ancestral species), donkey, reindeer, water buffalo, yak, banteng, and gaur. Only 5 species became widespread and important around the world. Those Major Five of mammal domestication are the cow, sheep, goat, pig, and horse.
Europeans today are heirs to one of the longest traditions of animal domestication on Earth—that which began in Southwest Asia around 10,000 years ago.
In the 19th and 20th centuries at least six large mammals—the eland, elk, moose, musk ox, zebra, and American bison—have been the subjects of especially well-organized projects aimed at domestication, carried out by modern scientific animal breeders and geneticists
In all of the world’s 148 big wild terrestrial herbivorous mammals—the candidates for domestication—only 14 passed the test. we can recognize at least six groups of reasons for failed domestication
Diet - Every time that an animal eats a plant or another animal, the conversion of food biomass into the consumer’s biomass involves an efficiency of much less than 100 percent: typically around 10 percent.
Growth rate: To be worth keeping, domesticates must also grow quickly.
Problems of Captive Breeding. We humans don’t like to have sex under the watchful eyes of others; some potentially valuable animal species don’t like to.
Nasty Disposition. Naturally, almost any mammal species that is sufficiently large is capable of killing a human.
A tendency to Panic. Big mammalian herbivore species react to danger from predators or humans in different ways. Some species are nervous, fast, and programmed for an instant flight when they perceive a threat. Most species of deer and antelope (with the conspicuous exception of reindeer) are of the former type, while sheep and goats are of the latter.
Social Structure. Almost all species of domesticated large mammals prove to be ones whose wild ancestors share three social characteristics: they live in herds; they maintain a well-developed dominance hierarchy among herd members; the herds occupy overlapping home ranges rather than mutually exclusive territories.
Axis & Climate advantage:
One advantage of the Fertile Crescent is that it lies within a zone of so-called Mediterranean climate, a climate characterized by mild, wet winters and long, hot, dry summers. That climate selects for plant species able to survive the long dry season and to resume growth rapidly upon the return of the rains. Many Fertile Crescent plants, especially species of cereals and pulses, have adapted in a way that renders them useful to humans.
The Americas span a much greater distance north-south (9,000 miles) than east-west: only 3,000 miles at the widest, narrowing to a mere 40 miles at the Isthmus of Panama. That is, the major axis of the Americas is north-south. The same is also true, though to a less extreme degree, for Africa. In contrast, the major axis of Eurasia is east-west.
Just as some regions proved much more suitable than others for the origins of food production, the ease of its spread also varied greatly around the world.
Why was the spread of crops from the Fertile Crescent so rapid? The answer depends partly on that east-west axis of Eurasia. Localities distributed east and west of each other at the same latitude share exactly the same day length and its seasonal variations. To a lesser degree, they also tend to share similar diseases, regimes of temperature and rainfall, and habitats or biomes (types of vegetation)
In contrast, crop diffusion from Indonesia south to southwestern Australia was completely impossible, and diffusion over the much shorter distance from Mexico to the U.S. Southwest and Southeast was slow because the intervening areas were deserts hostile to agriculture.
Continental differences in axis orientation affected the diffusion not only of food production but also of other technologies and inventions. For example, around 3,000 B.C. the invention of the wheel in or near Southwest Asia spread rapidly west and east across much of Eurasia within a few centuries, whereas the wheels invented independently in prehistoric Mexico never spread south to the Andes. Similarly, the principle of alphabetic writing, developed in the western part of the Fertile Crescent by 1500 B.C., spread west to Carthage and east to the Indian subcontinent within about a thousand years, but the Mesoamerican writing systems that flourished in prehistoric times for at least 2,000 years never reached the Andes.
In general, societies that engaged in intense exchanges of crops, livestock, and technologies related to food production were more likely to become involved in other exchanges as well.
There is no doubt that Europeans developed a big advantage in weaponry, technology, and political organization over most of the non-European peoples that they conquered. But that advantage alone doesn’t fully explain how initially so few European immigrants came to supplant so much of the native population of the Americas and some other parts of the world. That might not have happened without Europe’s sinister gift to other continents—the germs evolving from Eurasians’ long intimacy with domestic animals.
Knowledge brings power. Hence writing brings power to modern societies, by making it possible to transmit knowledge with far greater accuracy and in far greater quantity and detail, from more distant lands and more remote times.
Writing marched together with weapons, microbes, and centralized political organization as a modern agent of conquest. While all those types of information were also transmitted by other means in preliterate societies, writing made the transmission easier, more detailed, more accurate, and more persuasive.
A laundry list of at least 14 explanatory factors has been proposed by historians of technology. One is long life expectancy, which in principle should give prospective inventors the years necessary to accumulate technical knowledge, as well as the patience and security to embark on long development programs yielding delayed rewards. The next five factors involve economics or the organization of society:
(1) The availability of cheap slave labor in classical times supposedly discouraged innovation then, whereas high wages or labor scarcity now stimulate the search for technological solutions.
(2) Patents and other property laws, protecting ownership rights of inventors, reward innovation in the modern West, while the lack of such protection discourages it in modern China.
(3) Modern industrial societies provide extensive opportunities for technical training, as medieval Islam did and modern Zaire does not.
(4) Modern capitalism is, and the ancient Roman economy was not, organized in a way that made it potentially rewarding to invest capital in technological development.
(5) The strong individualism of U.S. society allows successful inventors to keep earnings for themselves
Another four suggested explanations are ideological, rather than economic or organizational:
(1) Risk-taking behavior, essential for efforts at innovation, is more widespread in some societies than in others.
(2) The scientific outlook is a unique feature of post-Renaissance European society that has contributed heavily to its modern technological preeminence.
(3) Tolerance of diverse views and of heretics fosters innovation, whereas a strongly traditional outlook (as in China’s emphasis on ancient Chinese classics) stifles it.
(4) Religions vary greatly in their relation to technological innovation: some branches of Judaism and Christianity are claimed to be especially compatible with it, while some branches of Islam, Hinduism, and Brahmanism may be especially incompatible with it.
The remaining four proposed factors—war, centralized government, climate, and resource abundance—appear to act inconsistently: sometimes they stimulate technology, sometimes they inhibit it.
(1) Throughout history, war has often been a leading stimulant of technological innovation.
(2) Strong centralized government boosted technology in late-19th-century Germany and Japan and crushed it in China after A.D. 1500. (3) Many northern Europeans assume that technology thrives in a rigorous climate where survival is impossible without technology, and withers in a benign climate where clothing is unnecessary and bananas supposedly fall off the trees.
(4) There has also been debate over whether technology is stimulated by abundance or by a scarcity of environmental resources. Abundant resources might stimulate the development of inventions utilizing those resources, such as water mill technology in rainy northern Europe, with its many rivers
Until around A.D. 1450, China was technologically much more innovative and advanced than Europe, even more so than medieval Islam. The long list of Chinese inventions includes canal lock gates, cast-iron, deep drilling, efficient animal harnesses, gunpowder, kites, magnetic compasses, movable type, paper, porcelain, printing (except for the Phaistos disk), sternpost rudders, and wheelbarrows. China then ceased to be innovative for reasons about which we shall speculate in the Epilogue.
Firearms reached Japan in A.D. 1543 when two Portuguese adventurers armed with harquebuses (primitive guns) arrived on a Chinese cargo ship. The Japanese were so impressed by the new weapon that they commenced indigenous gun production, greatly improved gun technology, and by A.D. 1600 owned more and better guns than any other country in the world. But there were also factors working against the acceptance of firearms in Japan. The country had a numerous warrior class, the samurai, for whom swords rated as class symbols and works of art The samurai-controlled government began by restricting gun production to a few cities, then introduced a requirement of a government license for producing a gun, then issued licenses only for guns produced for the government, and finally reduced government orders for guns until Japan was almost without functional guns again.
Why did printing spread explosively in medieval Europe after Gutenberg printed his Bible in A.D. 1455, but not after that unknown printer printed the Phaistos disk in 1700 B.C.? The explanation is partly that medieval European printers were able to combine six technological advances, most of which were unavailable to the maker of the Phaistos disk. Of those advances—in a paper, movable type, metallurgy, presses, inks, and scripts—paper and the idea of movable type reached Europe from China.
Let us now summarize how variations in these three factors:
- time of onset of food production,
- barriers to diffusion, and
- human population size—led straightforwardly to the observed intercontinental differences in the development of technology. Eurasia (effectively including North Africa) is the world’s largest landmass, encompassing the largest number of competing societies
Institutionalized religion brings two other important benefits to centralized societies. First, shared ideology or religion helps solve the problem of how unrelated individuals are to live together without killing each other—by providing them with a bond not based on kinship. Second, it gives people a motive, other than genetic self-interest, for sacrificing their lives on behalf of others.
Food production, and competition and diffusion between societies, led as ultimate causes, via chains of causation that differed in detail but that all involved large dense populations and sedentary living, to the proximate agents of conquest: germs, writing, technology, and centralized political organization. Because those ultimate causes developed differently on different continents, so did those agents of conquest.
Today, China appears politically, culturally, and linguistically monolithic, at least to laypeople. It was already unified politically in 221 B.C. and has remained so for most of the centuries since then. From the beginnings of literacy in China, it has had only a single writing system, whereas modern Europe uses dozens of modified alphabets. Of China’s 1.2 billion people, over 800 million speak Mandarin, the language with by far the largest number of native speakers in the world.
North and South Chinese are genetically and physically rather different: North Chinese are most similar to Tibetans and Nepalese, while South Chinese are similar to Vietnamese and Filipinos. North and South China differ in environment and climate as well: the north is drier and colder; the south, wetter and hotter. Genetic differences arising in those differing environments imply a long history of moderate isolation between peoples of North and South China.
States organized by or modeled on that Zhou Dynasty of North China spread to South China during the first millennium B.C., culminating in China’s political unification under the Qin Dynasty in 221 B.C. Its cultural unification accelerated during that same period, as literate civilized Chinese states absorbed, or were copied by, the illiterate barbarians. Some of that cultural unification was ferocious:
Our comparison begins with food production, a major determinant of local population size and societal complexity—hence an ultimate factor behind the conquest. The most glaring difference between American and Eurasian food production involved big domestic mammal species.
Eurasia’s 13 species, which became its chief source of animal protein (meat and milk), wool, and hides, its main mode of land transport of people and goods, its indispensable vehicles of warfare, and (by drawing plows and providing manure) a big enhancer of crop production. Until waterwheels and windmills began to replace Eurasia’s mammals in medieval times, they were also the major source of its industrial power beyond human muscle power—for example, for turning grindstones and operating water lifts.
In contrast, the Americas had only one species of big domestic mammal, the llama/alpaca, confined to a small area of the Andes and the adjacent Peruvian coast. While it was used for meat, wool, hides, and goods transport, it never yielded milk for human consumption, never bore a rider, never pulled a cart or a plow, and never served as a power source or vehicle of warfare.
In those parts of the Americas that did support Native American agriculture, it was constrained by five major disadvantages vis-à-vis Eurasian agriculture:
widespread dependence on protein-poor corn, instead of Eurasia’s diverse and protein-rich cereals.
hand planting of individual seeds, instead of broadcast sowing;
tilling by hand instead of plowing by animals, which enables one person to cultivate a much larger area, and which also permits the cultivation of some fertile but tough soils and sods that are difficult to till by hand (such as those of the North American Great Plains);
lack of animal manuring to increase soil fertility;
and just human muscle power, instead of animal power, for agricultural tasks such as threshing, grinding, and irrigation.
These differences suggest that Eurasian agriculture as of 1492 may have yielded on the average more calories and protein per person-hour of labor than Native American agriculture did.
Five areas of technology may be singled out:
First, metals—initially copper, then bronze, and finally iron—were used for tools in all complex Eurasian societies as of 1492. In contrast, although copper, silver, gold, and alloys were used for ornaments in the Andes and some other parts of the Americas
Second, military technology was far more potent in Eurasia than in the Americas.
Third, Eurasian societies enjoyed a huge advantage in their sources of power to operate machines.
Long before the wheel began to be used in power conversion in Eurasia, it had become the basis of most Eurasian land transport
The remaining area of technology to be mentioned is sea transport. Many Eurasian societies developed large sailing ships, some of them capable of sailing against the wind and crossing the ocean, equipped with sextants, magnetic compasses, sternpost rudders, and cannons.
As for Eurasia’s head start, humans have occupied Eurasia for about a million years, far longer than they have lived in the Americas.
Africa
Even before the arrival of white colonialists, Africa already harbored not just blacks but (as we shall see) five of the world’s six major divisions of humanity, and three of them are confined as natives to Africa. One-quarter of the world’s languages are spoken only in Africa. No other continent approaches this human diversity.
The traders waited for favorable winds to let them cross the Indian Ocean directly between East Africa and India. When the Portuguese navigator Vasco da Gama became the first European to sail around the southern cape of Africa and reached the Kenya coast in 1498, he encountered Swahili trading settlements and picked up a pilot who guided him on that direct route to India.
Food production was delayed in sub-Saharan Africa (compared with Eurasia) by Africa’s paucity of domesticable native animal and plant species, it's a much smaller area suitable for indigenous food production, and it's the north-south axis, which retarded the spread of food production and inventions. Let’s examine how those factors operated.
First, as regards domestic animals, domestic animals did not reach sub-Saharan Africa until thousands of years after they began to be utilized by emerging Eurasian civilizations.
A second factor is a corresponding, though less extreme, the disparity between sub-Saharan Africa and Eurasia in domesticable plants.
The remaining factor behind Africa’s slower rate of post-Pleistocene development compared with Eurasia’s is the different orientation of the main axes of these continents. Like that of the Americas, Africa’s major axis is north-south, whereas Eurasia’s is east-west.
To enjoy the satisfaction of discovering two of those geographic factors for yourself, just look at a map of Africa, with its 48 mainland countries. Divide them into two sets. In one set, put Africa’s 10 countries lying in the temperate zones: the 5 countries in the north temperate zone along the Mediterranean Sea (Algeria, Egypt, Libya, Morocco, Tunisia), plus the 5 in the south temperate zone at Southern Africa’s tip (Botswana, Lesotho, Namibia, South Africa, Swaziland). In the second set, keep Africa’s 38 other countries in Africa’s tropical center. Within those two sets, mark with a star the 16 countries that are landlocked. Those starred countries are 3 of the south temperate countries (Botswana, Lesotho, Swaziland) and 13 of the tropical countries (Burkina Faso, Burundi, Central African Republic, Chad, Ethiopia, Malawi, Mali, Niger, Rwanda, South Sudan, Uganda, Zambia, Zimbabwe). Then look up online any of several commonly tabulated wealth measures—e.g., average annual per-capita income or gross domestic product (GDP) per person, corrected or not corrected for differences in purchasing power —and compare them between your sets.
Of the 38 tropical countries, 37 are poorer than any of the 10 temperate countries. Within both your tropical and your temperate sets, the coastal countries are on average about 50 percent richer than the landlocked countries. Why does geography have these huge effects on national wealth?
A tropical location has two characteristics that are bad for the economy. you’re more likely to get sick in the tropics than in the temperate zones, either from tropical infectious diseases like malaria or dengue fever or else from tropical parasites. Hence people in tropical countries spend more time sick and unable to work than people in temperate countries. On average, they also die at a younger age. That’s not only sad for those people, but it’s also bad for their country’s economy. The other economic disadvantage of a tropical location is lower agricultural productivity, due to more infertile soils and more plant and animal diseases.
As for the disadvantages of a landlocked location, that’s also easy to understand: transport overland is about 7 times more expensive than transport by sea to a coastal port or up a navigable river. Hence landlocked countries lose much more money on transportation and freight costs than do countries with access to the sea. That’s an especially important consideration for countries whose products are much in demand in, and many of whose imports originate in, distant regions
In short, Europe’s colonization of Africa had nothing to do with differences between European and African peoples themselves, rather, it was due to accidents of geography and biogeography—in particular, to the continents’ different areas, axes, and suites of wild plant and animal species.
Why does Eurasia excel?
Why, within Eurasia, were European societies, rather than those of the Fertile Crescent or China or India, the ones that colonized America and Australia, took the lead in technology, and became politically and economically dominant in the modern world?
Why, then, did the Fertile Crescent and China eventually lose their enormous leads of thousands of years to late-starting Europe? One can, of course, point to proximate factors behind Europe’s rise: its development of a merchant class, capitalism, and patent protection for inventions, its failure to develop absolute despots and crushing taxation, and its Greco-Judeo-Christian tradition of critical empirical inquiry.
After the rise of Fertile Crescent states in the fourth millennium B.C., the center of power initially remained in the Fertile Crescent, rotating between empires such as those of Babylon, the Hittites, Assyria, and Persia. With the Greek conquest of all advanced societies from Greece east to India under Alexander the Great in the late fourth century B.C., power finally made its first shift irrevocably westward. It shifted farther west with Rome’s conquest of Greece in the second century B.C., and after the fall of the Roman Empire, it eventually moved again, to western and northern Europe.
Fertile Crescent and eastern Mediterranean societies had the misfortune to arise in an ecologically fragile environment. They committed ecological suicide by destroying their own resource base. Northern and Western Europe has been spared this fate, not because its inhabitants have been wiser but because they have had the good luck to live in a more robust environment with higher rainfall, in which vegetation regrows quickly. Much of northern and western Europe is still able to support productive intensive agriculture today, 7,000 years after the arrival of food production. In effect, Europe received its crops, livestock, technology, and writing systems from the Fertile Crescent, which then gradually eliminated itself as a major center of power and innovation.
In fact, precisely because Europe was fragmented, Columbus succeeded on his fifth try in persuading one of Europe’s hundreds of princes to sponsor him. Once Spain had thus launched the European colonization of America, other European states saw the wealth flowing into Spain, and six more joined in colonizing America. The story was the same with Europe’s cannon, electric lighting, printing, small firearms, and innumerable other innovations: each was at first neglected or opposed in some parts of Europe for idiosyncratic reasons, but once adopted in one area, it eventually spread to the rest of Europe.
These consequences of Europe’s disunity stand in sharp contrast to those of China’s unity. From time to time the Chinese court decided to halt other activities besides overseas navigation: it abandoned the development of an elaborate water-driven spinning machine, stepped back from the verge of an industrial revolution in the 14th century, demolished or virtually abolished mechanical clocks after leading the world in clock construction, and retreated from mechanical devices and technology in general after the late 15th century. Those potentially harmful effects of unity have flared up again in modern China, notably during the madness of the Cultural Revolution in the 1960s and 1970s, when a decision by one or a few leaders closed the whole country’s school systems for five years.
Hence the real problem in understanding China’s loss of political and technological preeminence to Europe is to understand China’s chronic unity and Europe’s chronic disunity.
China’s connectedness eventually became a disadvantage, because a decision by one despot could and repeatedly did halt innovation. In contrast, Europe’s geographic balkanization resulted in dozens or hundreds of independent, competing statelets, and centers of innovation. If one state did not pursue some particular innovation, another did, forcing neighboring states to do likewise or else be conquered or left economically behind. Europe’s barriers were sufficient to prevent political unification but insufficient to halt the spread of technology and ideas. There has never been one despot who could turn off the tap for all of Europe, as of China.
The histories of the Fertile Crescent and China also hold a salutary lesson for the modern world: circumstances change, and past primacy is no guarantee of future primacy. One might even wonder whether the geographical reasoning employed throughout this book has, at last, become wholly irrelevant in the modern world, now that ideas diffuse everywhere instantly on the Internet and cargo is routinely air freighted overnight between continents.
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