Guns, Germs and Steel: The Fates of Human Societies by Jared Diamond
Guns, Germs and Steel by physiologist/ecologist/environmental historian Jared Diamond is an attempt to explain why technologically advanced societies developed faster in certain parts of the world. Its main thesis is that geography defines the constraints and opportunities for what a civilization can do: Groups of humans take their cues from their environment and follow these cues to develop tools and guns and spaceships or happily continue being stone age hunter-gatherers or anything else in between. Diamond sets out by tracing the different initial conditions that promoted the advent of agriculture and animal husbandry in different parts of the world and then follows the downstream effects and feedback loops that lead to Age of Discovery Europeans having the technological edge that allowed them to colonize the whole planet. In the meantime he presents accounts of the history of plant and animal domestication, the invention of writing, the biology of zoonotic diseases, the spread of technological innovation, the development of different modes of government, as well as crash courses in the history of New Guinea, China, Polynesia, the Americas, sub-Saharan Africa and Japan, and his ideas about the study of history in general.
The main part of the book begins around 11,000 BC, a time when everybody is a hunter-gatherer and nothing particularly interesting is happening anywhere. Humans have long spread through mainland Africa, Asia and Europe, have already reached Australia, New Guinea and inhospitable places like Siberia, have recently crossed the Bering Strait and discovered North America and will arrive in South America in another thousand years or so. At this stage (Diamond argues) it would not be obvious to a visiting Martian historian where technological civilizations are going to spring: Africa is the cradle of humanity and has the greatest human genetic diversity which could arguably lead to diverse cultures and inventions. The recently discovered Americas are huge and have great environmental diversity working in their favor. Eurasia is also huge, second only to Africa in its history of human habitation and already is showing some promise with its cool Cro-Magnon cave paintings. Australasians on the other hand have cave paintings at least as cool as the Cro-Magnons, have already invented boats sophisticated enough to have allowed them to reach Australia and New Guinea and have adapted to each successive island they hopped on. So what exactly was it that made Eurasia the right bet?
The first step down the road to technological civilization is to develop food production. An agricultural society will have a denser population because an acre of farming will produce more calories than an acre of hunting and gathering. Population will rise faster as well, as nomadic hunter-gatherers have fewer children and longer spacing between births. Becoming settled farmers allows people to store food, so their societies have room for kings and bureaucrats and craftsmen and soldiers and other people not occupied with producing food full-time and free to focus on other things, like crafts and technology and cruelly subjugating their neighbors. For societies that domesticated animals as well as plants the effects synergize nicely: They can use manure as fertilizer for their crops and oxen to till soil that is too hard to till by hand.
Still, Diamond warns us not to make the stereotypical sharp distinction between nomadic hunter-gatherers and settled god-king-worshiping farmers, at least not straight away: No civilization suddenly woke up one day and decided to settle down and become farmers. It is better to think of agricultural practices not so much as a separate lifestyle but initially as a parallel evolved strategy for survival that was helpful in certain places and times. Many hunter-gatherers became settled long before adopting farming. Many cultures adopted some agricultural practices without abandoning hunter-gathering or switched back and forth between the two. Some hunter-gatherers actively managed their territory, for example by clearing weeds in order to protect the bushes they gathered from, in a way that set the scene for plant domestication later. Some early food producers planted seeds, went away to do some hunting and gathering for a few months and went back to the fields in time for harvest. The point is that adopting agriculture became autocatalytic; it led to positive feedback loops. As population rises, wild foods are gradually depleted. As more domesticable species are discovered, farming becomes more rewarding. Tools and techniques initially developed by hunter-gatherers are adopted and refined to improve farming. Gradually, groups that predominantly farm outcompete groups of hunter-gatherers, through the use of greater numbers and technology. As farmer civilizations expand, hunter-gatherers are pushed away or killed or forced to become farmers themselves.
The Fertile Crescent, a boomerang-shaped part of the Middle East covering the area roughly between the Levant and Mesopotamia, was the first place where the scale actually tipped against the hunter-gatherers. This was partly because that whole area was never particularly well suited for hunter-gathering in the first place but mainly because it happened to have the perfect mix of climate, topographical variation and presence of a vast array of domesticable plants (especially annuals) and animals ready to become domesticated: So by 6,000BC Mesopotamians were growing at least wheat, barley, lentils, peas and chickpeas, flax (to make linen) and keeping goats, sheep, pigs and cows; more than enough to feed a purely agricultural civilization, with wool, plowing and transport as added benefits on top of that.
Where else did agriculture spontaneously arise? Mesoamericans finally settled as farmers in a kind of similar way around 1,500BC, with maize as their primary grain (far harder than wheat to domesticate, so it took a longer time) and only dogs and turkeys available to them. At the same time the natives of the eastern U.S. domesticated the plants they had available, which turned out to be a type of squash, a type of spinach, sunflowers and sumpweed. Mexican corn finally reached them by 200 A.D., a version of corn that could actually be effectively grown in their climate showed up by 900 A.D., and two hundred after that (while Europe and the Middle East was going through the High Middle Ages) they got beans (also from Mexico), dumped sumpweed (on account of nobody knowing what that even was) and settled down to farm and form chiefdoms around the Mississippi. Other places fall somewhere between these extremes: China trailed the Fertile Crescent by maybe 500 to a thousand years with rice, soybeans and pigs as their most important domesticated species. The peoples of the Amazon river settled by 6,000BC but got agriculture around the same time as the Mesoamericans. Various parts of Africa like the Sahel region (just south of the Sahara), West Africa (between modern Ivory Coast and Nigeria) and Ethiopia also domesticated some of their local species (sorghum, african rice, palms, coffee) between 5,000 and 3,000BC, mostly after Fertile Crescent crops were introduced there.
(A quick side-note on animal domestication: It is no accident that only a handful of animals have ever been domesticated, even today. There are various reasons an otherwise domesticable-seeming animal species may be unsuited to being a farm animal, including their diet (for example carnivores), slow growth rate (for example elephants), unwillingness to breed under captivity (for example andean camels), panicky disposition (for example gazelles) or general tendency of the animal to be a complete asshole (for example zebras). The people of the Fertile Crescent lucked into having most domesticable species in their backyard. The people of Africa did not.)
Apart from the starting conditions, geography shaped the way food production spread: Looking at a map, on Eurasia most other civilizations will be to your east or west; on Africa and the Americas they will be on your north or south. This is important, as crops and livestock are adapted to a particular climate and climate differences are more dramatic along the north-south axis. Agriculture had an easier time spreading westward from Mesopotamia to Southern Europe than spreading southward from Egypt to the rest of Africa.
As Diamond describes it, once agriculture and population density reach a critical mass a whole lot of other things follow:
Germs: Living in close proximity with animals allows viruses to hop from animals to humans. You get epidemics of flu, smallpox, measles etc. but you also get populations that over time develop resistance to the same viruses. Hunter-gatherers never got exposed to these germs and never got the antibodies for them, so an entire population of hunter-gatherers is in danger of being wiped out from an epidemic brought by a single outside visitor, as it happened with the native population of North America.
Technology: Settled, agricultural people have two big advantages in developing technology. They have the capacity to feed full time specialist craftsmen and they can accumulate more possessions than they can carry. Innovations breed more innovations, as people build upon or combine their technologies with new ones that spread to them from neighboring civilizations. Eurasia and North Africa got agricultural settlements early and, lacking any important geographical/ecological barriers for diffusing innovations, they developed faster. Western Europe took longer to develop, as innovations from the Middle East took some time to reach there. So why did Western Europe eventually surpass the Middle East? The answer lies again in geography: The Fertile Crescent was ecologically fragile and agriculture over time depleted its resources, turning it to mostly desert that we see today. Western Europe took initial crops and technology from outside to kickstart its food production but its land was more robust in the long term. So, as the Middle East and eastern Mediterranean slowly exhausted themselves the centers of power moved westward.
Writing: Writing is the odd one out, in the sense that for all we know it may have arisen independently only twice in history, by the Sumerians in Mesopotamia and by Mexican Indians in Mesoamerica. (China and Egypt are the other two possible independent origins, which may or may not have been influenced by the Sumerians). Many agricultural societies (like the Aztecs) never invented it at all. In any case it spread the same way all technologies spread, and although its use was limited at first it gave literate societies a huge edge down the line.
Institutions: Bigger denser societies inevitably develop centralized governments and institutions. After a certain population size, communal decision-making is no longer efficient and interpersonal conflicts can only be resolved through force monopolized by a central authority. Once civilizations get centralized governments, nearby populations are pressured to do the same, either through the threat of an external enemy or outright conquest.
Continue the above dynamics over a few thousand years after food production developed and you get the entire human history as a result.
So, what should we think about all of this? The explanation Diamond presents feels intuitive and compelling, at least in the broad, zoomed out view of history. It's also the kind of big picture explanation that feels particularly hard to think about and I am not sure what is the right level of abstraction here. History is this super complicated experiment that ran only once and you have no way to replicate. So how important was blind chance in the whole scheme of things? How much of what happened is a pattern that is reducible to the geographical and ecological landscapes of 11,000BC and how much is noise? I am reminded of an anecdote about biologist J.B.S Holdane, who was asked by an overzealous Popperian student about what evidence might falsify evolution and he replied “rabbit fossils in the Precambrian”. And looking at the various criticisms of the book, while I found several historians and anthropologists nitpicking or poking holes at Diamond's account of the history of various places (which I expected; if you summarize the 13 thousand years in 500 pages a few things will end up oversimplified or wrong), I didn't find anyone suggesting any conspicuous civilizations that developed in a way that directly contradicts Diamond's story. Criticism focuses on the book downplaying the importance of cultures or historical accidents, on it being too reductive, not on directly refuting its main thesis.
Or perhaps the entire book should be read backwards? Guns, Germs and Steel was written in 1997 and reading it more than 20 years later it felt that I already had absorbed some of its ideas by osmosis. Maybe it was more ground-breaking and surprising when it was written? The book begins with Diamond telling a story about how he was embarrassed by a New Guinea native named Yali who matter-of-factly asked Diamond how it happened that white people invented all the “cargo” (the local word for every material good brought to New Guinea by westerners, from steel and medicine to soft drinks and plastic toys) and his people invented so little of their own. This question brings up the whole terrible debate regarding possible innate genetic differences between populations, that this review will gingerly ignore. Diamond rejects it quickly, based mostly on his experience of having lived among New Guinea natives and finding them at least as smart as anyone else. The whole book is a reply to Yali's question. And Diamond presents it as the first convincing reply that does not require any assumptions about innate biological differences. And of course he has still been called a racist because he, to quote some critiques, “makes all the factors of European domination a product of a distant and accidental history” and "lets the West off the hook". So it goes.
And cultural differences must play be role, at least some of the time. There are examples of societies rejecting technologies for cultural reasons. Confucian China did not go about exploring the New World. Was its insularity a quirk of its culture? Or was the Age of Exploration a quirk of European cultures? Diamond makes an argument that China's geography predisposed it to political unity and the isolationist policy of its government applied to the whole region. Whereas the fierce competition of nations and exhaustion of Europe's resources encouraged a few of them to go about what eventually became the Age of Exploration in the West. In any case, this feels like a classic chicken and egg problem that is hard to pin down to anything more concrete than “it was a mix of geography and culture kind of affecting each other in complicated ways”. But something like geographic reductionism must be true in many cases: Australia was populated by many different cultures, with completely different languages and lifestyles, adapted to every nook and cranny of the place; still, they were all stone age hunter-gatherers until Europeans showed up. Once the first humans stepped on Australia, unbeknownst to them, they locked all their descendants to the stone age as there was simply no ramp to anything else to be found anywhere in the whole continent. So, a lot of what we call culture is a downstream effect of more distant causes like geography or ecology, which may or may not then affect history in its own surprising ways.
I am not sure if I am convinced of every argument and every explanation of history that is presented in the book. But, kind of like the theory of evolution that I alluded to earlier, Diamond's theory makes a lot of different data points and intuitions click together in a particularly satisfying fashion. If we are to have a general framework to think about history in a global/general way, well I am not sure that Guns, Germs and Steel is necessarily the complete answer. But something pretty close to it must be true.