Guns, Germs, and Steel by Jared Diamond

A simple glance around the modern world makes it clear that some continents, some peoples, have seen greater success, at least insofar as success is measured in terms of material wealth and territorial conquest. Europeans, and their descendants, have by and large achieved the highest levels of financial, technological, and political "progress," and have successfully supplemented native populations on several continents (North and South America, Australia). In the past week, I have already reviewed two books which in some part reflect the recent aftermath of the centuries of European ascent (Robert Fisk's The Great War for Civilisation, reviewed here, and Alistair Horne's A Savage War of Peace, reviewed here).

Most people probably take this reality for granted, without wondering much why history took that particular course. Others who have considered the question have relied upon facile attributions to supposed cultural or racial advantages for Europeans vis-a-vis the rest of humanity. In his controversial, Pulitzer Prize-winning 1997 book, Guns, Germs, and Steel, UCLA professor Jared Diamond aimed to answer this immense question, offering his own provocative thesis:

We all know that history has proceeded very differently for peoples from different parts of the globe. In the 13,000 years since the end of the last Ice Age, some parts of the world developed literate industrial societies with metal tools, other parts developed only nonliterate farming societies, and still others retained societies of hunter gatherers with stone tools. Those historical inequalities have cast long shadows on the modern world, because the literate societies with metal tools have conquered or exterminated the other societies. While those differences constitute the most basic fact of world history, the reasons for them remain uncertain and controversial...

Authors are regularly asked by journalists to summarize a long book in one sentence. For this book, here is such a sentence: "History followed different courses for different peoples because of differences among peoples' environments, not because of biological differences among peoples themselves."

Diamond explains that the desire to investigate this phenomenon arose during his field research in New Guinea, the large island north of Australia that remains home to an incredibly diverse number of tribal and linguistic groups (accounting for more than 1,000 of the world's ~6,000 surviving languages). While there, he was asked by one of his New Guinean friends why it was Europeans who had come to his land, and brought all sorts of advanced tools and products, and not the other way around. Diamond was intuitively skeptical of any explanation based on innate intellectual differences, based in part of the lack of any robust studies demonstrating such difference, and in part on his own observations of the intelligence of New Guinea's native population.

Recognizing immediately that a broad cross-disciplinary approach would be necessary to approach this question, Diamond found himself well-situated. The child of a physician and a linguist, Diamond studied physiology and biophysics at Harvard and Cambridge, pursued an interest in the ornithology of New Guinea, and developed an expertise on environmental history. His Wikipedia biography claims fluency in twelve languages, and prior to Guns, Germs, and Steel, he had published works in the fields of ecology, ornithology, human evolution, and human sexuality. Throughout the book, Diamond uses a variety of well-documented historical examples to define, test, and then illustrate his thesis, from New Guinea to . In his effort to redefine human history as a science, he draws from the fields of archaeology, linguistics, botany, zoology, sociology, geology, chemistry, biology, and more. As stated in his thesis, he believes environmental factors to be the prime mover in the broad course of human history, and he identifies four in particular:

The first set consists of the continental differences in the wild plant and animal species available as starting materials for domestication. That's because food production was critical for the accumulation of food surpluses that could feed non-food-producing specialists, and for the buildup of large populations enjoying a military advantage through mere numbers even before they had developed any technological or political advantage. For both of those reasons, all developments of economically complex, socially stratified, politically centralized societies beyond the level of small nascent chiefdoms were based on food production.

But most wild animal and plant species have proved unsuitable for domestication: food production has been based on relatively few species of livestock and crops. It turns out that the number of wild candidate species for domestication varied greatly among the continents... As a result, Africa ended up biologically somewhat less endowed than the much larger Eurasia, the Americas still less so, and Australia even less so...

The early chapters devoted to food production are amongst the most interesting in the book, which might not seem intuitively obvious. I myself was a bit skeptical as to how much attention I could pay to the domestication of wheat and so on. But Diamond's exploration of the junction between random mutation, natural selection, and human intervention through selective breeding is surprisingly compelling. Even more so is his discussion of the world's wildlife, and the factors which make some large mammals (e.g. cattle, sheep) more susceptible to domestication than others (e.g. lions, rhinos). That the distribution of domestication-prone animals so greatly favored Eurasia is one of the most striking revelations in Diamond's book.

[A] second set of factors consists of those affecting rates of diffusion and migration, which differed greatly among continents. They were most rapid in Eurasia, because of its east-west major axis and its relatively modest ecological and geographical barriers. The reasoning is straightforward for movements of crops and livestock, which depend strongly on climate and hence on latitude. But similar reasoning also applies to the diffusion of technological innovations, insofar as they are best suited without modification to specific environments. Diffusion was slower in Africa and especially in the Americas, because of those continents' north-south major axes and geographic and ecological barriers.

The best examples Diamond provides of this phenomenon lay in the contrast between Eurasia and the Americas. Consider the tremendous contacts made between the civilizations of the Fertile Crescent, Europe, and China. And these contacts were not all one-way. Though evidence exists for the earliest food production arising in the Fertile Crescent, successive millennia would see innovations headed both east and west. In the Americas, however, even the great civilizations of Peru and Mesoamerica, the Incas and Aztecs, failed to engage in any analogous cultural or technological exchange. As Diamond laments, the Native Americans were never able to link up the one large domestic animal, the llama of the Andes, with that vital innovation, the wheel.

Related to these factors affecting diffusion within continents is a third set of factors influencing diffusion between continents, which may also help build up a local pool of domesticates and technology. Ease of intercontinental diffusion has varied, because some continents are more isolated than others. Within the last 6,000 years it has been easiest from Eurasia to sub-Saharan Africa, supplying most of Africa's species of livestock. But interhemispheric diffusion made no contribution to Native America's complex societies, isolated from Eurasia at low latitudes by broad oceans, and at high latitudes by geography and by a climate suitable just for hunting-gathering. To Aboriginal Australia, isolated form Eurasia by the water barriers of the Indonesian Archipelago, Eurasia's sole proven contribution was the dingo.

The chapters charting the course of intercontinental diffusion were some of the most difficult for me to work through, whether focused on the Austronesian movement through Southeast Asia or the Bantu expansion through sub-Saharan Africa. Much of the evidence for these progressions is found either in archaeological analysis of pottery or linguistic scrutiny of common words. Comprehensive? Yes. Convincing? Certainly. But this is the only place where the narrative really drags. One exception, rooted solely in the bizarre nature of the case, is the migration of Austronesian peoples all the way from their likely origins in Indonesia all the way across the Indian Ocean to the African island of Madagascar, eventually resulting in a remarkably complex demography.

The fourth and last set of factors consists of continental differences in area or total population size. A larger area or population means more potential inventors, more competing societies, more innovations available to adopt--and more pressure to adopt and retain innovations, because societies failing to do so will tend to be eliminated by competing societies. That fate befell African pygmies and many other hunter-gatherer populations displaced by farmers. Conversely, it also befell the stubborn, conservative Greenland Norse farmers, replaced by Eskimo hunter-gatherers whose subsistence methods and technology were far superior to those of the Norse under Greenland conditions. Among the world's landmasses, area and the number of competing societies were largest for Eurasia, much smaller for Australia and New Guinea and especially for Tasmania. The Americas, despite their large aggregate area, were fragmented by geography and ecology and functioned effectively as several poorly connected smaller continents.

In addition to the geological realities described above, Diamond also places heavy emphasis on various positive-feedback loops. Food production and population size are the most notable of these. Though unable to ascertain definitively which is the chicken and which the egg, it is clear that the surpluses of sustenance created by food production will support a larger population than hunting and gathering alone. Not only can this larger population then produce more food, it can spare manpower for other uses, such as professional warfare, politics, and science, which will expand the community's power and its capacity for further innovation. And so on.

Guns, Germs, and Steel was widely-read and quite controversial upon publication, and it has remained so in the years since. A quick glance at the book's Wikipedia page gives a decent summary of the various lines of criticism that have been leveled in Professor Diamond's direction, some directed at the substance of his thesis, some focused on particular gaps or weaknesses in his arguments. Some are attributable to the nature of the book, which consists of a mere 400-odd pages of non-technical prose; this ensured a wide audience, but Diamond himself admits the difficulty of purporting to examine 13,000 years of global human history in so few pages.

That said, what Diamond accomplishes in his 400-odd pages is rather impressive. He takes his reader on a rewarding survey of the chronological and geographic scope of human civilization, with fascinating insights gained from fields as diverse as agriculture and linguistics and examples from every inhabited continent. Diamond explicitly intended the book to be provocative, and in his final chapter he advocates for a more scientific approach to the field of human history. At the very least, Guns, Germs, and Steel forcefully demonstrates how vital an appreciation of ecology, biology, and the other sciences is for understanding, if not justifying, the course of our civilization.