At the heart of Guns, Germs, and Steel is a theory that has since become known as “geographic determinism”: the idea that civilizations develop over time in different ways in response to environmental factors such as temperature, soil fertility, availability of large mammals, and physical barriers to travel. While Diamond wasn’t the first to propose such a theory, he was the first to compile all the existing data to paint a convincing picture of how environment has influenced the development of civilization throughout human history, not just in a few isolated areas.
Diamond traces the cause of differences between civilizations—for example, the differences between the Inca Empire, which had no guns, swords, ships, or written language, and the Spanish nation-state, which had all four—to one underlying cause: the geographical features and locations of the Earth itself. As a result of the Earth’s angle of rotation, there are certain parts of the planet where large, nutritious seeds grow easily, the soil is fertile, and there are a greater number of large mammals. The people who live in such areas are likely to develop forms of agriculture; i.e., a society founded on the organized cultivation of crops. In other regions, geography makes human beings more likely to be hunter-gatherers, meaning that they migrate between areas, hunting game and picking fruits and nuts.
So environmental differences lead to differences in how societies feed themselves. These differences in turn trigger further, even more pronounced differences between societies. Members of agricultural societies, because they have to migrate less and have more leisure time, can then develop specializations in certain professions. Social specialization in turn leads to the need for and discovery of new technologies, giving agricultural societies a big advantage over hunter-gatherer societies in warfare. Furthermore, agricultural societies’ proximity to large domesticated animals tends to make them immune to more deadly diseases, another big advantage in clashes with societies that lack domesticated animals. Thus, as a result of basic environmental differences, different peoples of the world develop in different ways over history, so that in the end, certain of these peoples are more capable of conquering and dominating other peoples.
Geographic determinism is the central idea of Guns, Germs, and Steel (in a way, the other four themes discussed here are particularly important aspects of the theory of geographic determinism), but it can also be a counterintuitive way to think about human history. A “deterministic” model of history suggests that there are limits on how greatly human beings can change their own societies. Individual humans can strive for greatness or success (or do whatever they want), but their freedom has always been constrained by what resources and ideas are available to them—and therefore, by geographic factors. Diamond acknowledges some examples of human beings who have “shaped history,” but admits that he doesn’t have a good theory for the relationship between individual achievement and history, diluting some of his claims for strictly geographic determinism (see the “Technology and Creativity” theme for more on the limits of Diamond’s model of human individuality and free will).
Diamond’s theory has come under fire in the academic world for many other reasons, mostly notably that it’s an overly general, vague idea. Diamond argues for why agricultural societies defeated hunter-gatherer societies in warfare, but by his own admission, he lacks a full geographic explanation for why certain agricultural societies prevailed over other agricultural societies—again suggesting that geography is important but perhaps not as central to explaining history as Diamond maintains. Guns, Germs, and Steel is an ambitious book, but it wasn’t written to be the final word on history: even if it can explain a lot, the theory of geographic determinism needs further analysis, and Diamond hopes that other thinkers will refine and strengthen his ideas.
Geographic Determinism ThemeTracker
Geographic Determinism Quotes in Guns, Germs, and Steel
"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?"
Thus, an observer transported back in time to 11,000 B.C. could not have predicted on which continent human societies would develop most quickly, but could have made a strong case for any of the continents. With hindsight, of course, we know that Eurasia was the one.
In short, Polynesia furnishes us with a convincing example of environmentally related diversification of human societies in operation. But we thereby learn only that it can happen, because it happened in Polynesia.
As we'll see, food production was indirectly a prerequisite for the development of guns, germs, and steel. Hence geographic variation in whether, or when, the peoples of different continents became farmers and herders explains to a large extent their subsequent contrasting fates.
That higher birthrate of food producers, together with their ability to feed more people per acre, lets them achieve much higher population densities than hunter-gatherers.
The same pattern of an abrupt start of food production dependent on domesticates from elsewhere, and an abrupt and massive population replacement, seems to have repeated itself in many areas in the prehistoric era. In the absence of written records, the evidence of those prehistoric replacements must be sought in the archaeological record or inferred from linguistic evidence.
Early farmers surely didn't use molecular genetic techniques to arrive at their results. The first farmers didn't even have any existing crop as a model to inspire them to develop new ones. Hence they couldn't have known that, whatever they were doing, they would enjoy a tasty treat as a result.
Plant domestication is not a matter of hunter-gatherers domesticating a single plant and otherwise carrying on unchanged with their nomadic lifestyle. Suppose that North American wild apples really would have evolved into a terrific crop if only Indian hunter-gatherers had settled down and cultivated them. But nomadic hunter-gatherers would not throw over their traditional way of life, settle in villages, and start tending apple orchards unless many other domesticable wild plants and animals were available to make a sedentary food-producing existence competitive with a hunting-gathering existence.
Domesticable animals are all alike; every undomesticable animal is undomesticable in its own way.
Why was the spread of crops from the Fertile Crescent so rapid? The answer depends partly on that east-west axis of Eurasia with which I opened this chapter. 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).
The earliest wheels were parts of ox-drawn carts used to transport agricultural produce. Early writing was restricted to elites supported by food-producing peasants, and it served purposes of economically and socially complex food-producing societies (such as royal propaganda, goods inventories, and bureaucratic record keeping). 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.
The New Guineans whom I know include potential Edisons. But they directed their ingenuity toward technological problems appropriate to their situations: the problems of surviving without any imported items in the New Guinea jungle, rather than the problem of inventing phonographs.
This cultural barrier at Torres Strait is astonishing only because we may mislead ourselves into picturing a full-fledged New Guinea society with intensive agriculture and pigs 10 miles off the Australian coast. In reality, Cape York Aborigines never saw a mainland New Guinean. Instead, there was trade between New Guinea and the islands nearest New Guinea, then between those islands and Mabuiag Island halfway down the strait, then between Mabuiag Island and Badu Island farther down the strait, then between Badu Island and Muralug Island, and finally between Muralug and Cape York.
Europeans have never learned to survive in Australia or New Guinea without their inherited Eurasian technology. Robert Burke and William Wills were smart enough to write, but not smart enough to survive in Australian desert regions where Aborigines were living.
The Americas' population now consists of a mixture of peoples originating from all continents except Australia. That demographic shift of the last 500 years—the most massive shift on any continent except Australia—has its ultimate roots in developments between about 11,000 B.C. and A.D. 1.
I would say to Yali: the striking differences between the long-term histories of peoples of the different continents have been due not to innate differences in the peoples themselves but to differences in their environments.
It remains an open question how wide and lasting the effects of idiosyncratic individuals on history really are.