‘Guns, Germs, and Steel’

To the Editors:

After warmly praising my book Guns, Germs, and Steel: The Fates of Human Societies as “artful, informative, and delightful” [NYR, May 15], the distinguished historian William H. McNeill identifies two contrasting approaches to history: the traditional emphasis on autonomous cultural developments that he favors, versus my book’s emphasis on environmental factors. Without disputing the value of McNeill’s approach, I believe that our differences arise from the different historical scales that we consider. My focus is on trends over whole continents since the last Ice Age; his, on much smaller areas for shorter times.

History’s broadest pattern is its different unfolding on different continents over the last 13,000 years. In 11,000 BC, all societies everywhere were bands of preliterate hunter-gatherers with stone tools. By 1492 AD, that was still true in all of Australia, much of the Americas, and some of sub-Saharan Africa, but populous Eurasian societies already had state governments, writing, iron technology, and standing armies. Obviously, that is why Eurasians (especially Europeans) conquered peoples of other continents. Why did history unfold that way? Why didn’t Africans instead conquer Eurasia, bringing Native Americans as slaves?

That broadest pattern poses history’s biggest unsolved question, which historians scarcely discuss today. Even so-called world histories focus overwhelmingly on literate Eurasian states since 3000 BC. Yet the emergence of such societies in Eurasia was no accident. It had long antecedents with clear environmental causes. No hunter-gatherer society ever developed states, writing, metal technology, or standing armies. Those developments depended on food production (agriculture and herding), which arose independently in different parts of Eurasia by 8000 BC. The resulting dense populations, food storage, social stratification, and political centralization led in Eurasia to chiefdoms (5500 BC), metal tools (4000 BC), states (3700 BC), and writing (3200 BC). Agriculture’s rise was much slower in the Americas, such that writing, states, and so on did not appear until thousands of years after their Eurasian emergence. Multiplied over succeeding millenia, that huge head start let Eurasians eventually sail to and conquer peoples of other continents. Hence Guns, Germs, and Steel discusses the differences among continental environments responsible for Eurasia’s head start: especially the differences among plant and animal species suitable for domestication, and among continental areas, isolations, axes, and internal geographic barriers.

Mr. McNeill faults me for underemphasizing cultural autonomy—i.e., propagated cultural developments independent of environmental differences. Naturally, they are conspicuous in history over shorter times and smaller areas. But, over the hundreds of generations of post-Ice Age human history, and over a large continent’s thousands of societies, cultural differences become sifted to approach limits imposed by environmental constraints. How could cultural autonomy possibly explain the distinctive course of Aboriginal Australian history? Australia had hundreds of tribes, whose cultures diverged greatly. Some built villages with canals and intensive fish management, while others were nomads mastering the most unpredictable deserts on Earth. If any tribe had developed agriculture, armies, or metal tools, it would thereby have been able to conquer the rest of Australia. But none did.

Was that failure because of independent stultification of all those hundreds of autonomous cultural developments in Australia? Of course not. Instead, the responsible environmental factors are clear: Australia is the smallest, least productive, most isolated continent, with no domesticable wild animal species and almost no such plants. Qualitatively similar, though quantitatively milder, differences stamped the long-term, continent-wide differences in human societies among the other continents.

After noting my book’s unusual perspective, Mr. McNeill wonders whether “it is [instead] historians who err by approaching their subject upside-down, thanks to their myopic concentration on literate societies and the last 5,000 years of history.” I would answer: yes and no; it depends on the historical questions being asked. To understand the tragedy of World War II, you must understand the contrasting cultures of Germany, France, and other European countries in preceding decades. That is the traditional approach to history, and its value needs no defense. But if you instead wish to understand why Eurasian societies destroyed Native American societies, by developments leading after 13,000 years to guns, germs, and steel in Eurasia but not in the Americas, you must explore the differing biological and physical environments within which human cultures operated. Alas, the answers depend critically on biogeography, crop cytogenetics, microbial evolution, animal behavior, and other fields remote from historians’ training.

Historians’ failure to explain history’s broadest pattern leaves us with a huge moral gap. In the absence of convincing explanations, many (most?) people resort, consciously or unconsciously, to racist assumptions: the conquerors supposedly had superior IQ or culture. That prevalence of racist theories, as loathsome as they are unsupported, is the strongest reason for studying the long-term factors behind human history.

Jared Diamond
Department of Physiology
University of California at Los Angeles
Los Angeles, California

William H McNeill replies:

Jared Diamond’s letter restates his argument more concisely than I managed to do in my review, but on the central issue of how important cultural autonomy may be in the long run as well as in shorter time perspectives I still disagree with him.
How can he claim that “over the hundreds of generations of post-Ice Age human history, and over a large continent’s thousands of societies, cultural differences become sifted to approach limits imposed by environmental constraints”? Much more powerfully than any other species, we change the environment around us; and have done so ever since our ancestors began to control fire and to use tools. Learned behavior, channeled along innumerable different paths by divergent cultures, is what allows us to do so. Human beings do indeed often “approach limits imposed by environmental constraints” only to find a way to overcome and escape those constraints, as the history of technology repeatedly illustrates. I hasten to add that failures also figure largely in the historic record when environmental constraints disrupted human schemes and drastic depopulation and cultural collapse ensued.

Of course Eurasia had basic advantages over the other continents, simply because of its size and internal variability; nor do I doubt that Europeans took advantage of that fact, and of their borrowings from parts of Africa and Asia when they crossed the oceans and began colonizing and exploiting the rest of the earth. But I do deny that their culture was an automatic product of their environment “sifted” (by what mysterious hand of nature, pray tell?) across millennia to conform to “environmental constraints” as Diamond so strangely asserts.

Secondly, Diamond accuses historians of failing “to explain history’s broadest patterns.” I answer that some few historians are trying to do so, among them myself, and with more respect for natural history than Diamond has for the conscious level of human history. He wants simple answers to processes far more complex than he has patience to investigate. Brushing aside the autonomous capability of human culture to alter environments profoundly—and also irreversibly—is simply absurd.