Guns, Germs, and Steel

Guns, Germs, and Steel Summary and Analysis of Part 1: From Eden to Cajamarca


Diamond begins his text with a story that illustrates his central question. Diamond recounts his meeting with a politician from New Guinea named Yali, when the former was working as a biologist on the island. Diamond recalls that Yali had impressive charisma, energy, and intelligence, even though he had not been educated beyond high school. As they talked, Yali asked Diamond why white people had managed to develop so many goods, tools, and weapons that they brought to New Guinea, where local people had not developed the same technology. This is the central dilemma Diamond’s text confronts: why did wealth and power become distributed in the way they are today, rather than in some different pattern? For example, why were Native Americans, Africans, or Aboriginal Australians not the ones who exterminated Europeans and Asians? Diamond’s text will address this question by tracing human development and the differing rates at which it proceeded on different continents. In order to explain why modern inequalities exist, Diamond will have to begin before A.D. 1500, when technological and political differences were already apparent.

In the prologue, Diamond lays out the stakes of his topic. His question is interesting not only to academics. His research has big stakes for modern politics and practical concerns. The inequalities that first arose through the different trajectories of human development Diamond studies still have consequences today. Much of Africa now struggles with colonial legacies; it remains poorer and less developed than non-colonized places. Although the West now rejects explicit racism, many people still implicitly accept racist explanations for human development. For example, some people assume that white colonists and immigrants were biologically superior to indigenous populations, since they were able to exterminate them. Proving these people wrong is the most important driving factor for Diamond’s book. The groundbreaking explanation Diamond presents in this book is that history followed different courses for different people not because of biological differences among them, but because of differences in their environments. He explains that biological explanations don’t make sense, since many indigenous peoples today show greater intelligence than Westerners do. They tend to be quicker to learn because natural selection has promoted more genes for intelligence in societies where only the most intelligent could survive their difficult hunter-gatherer lifestyle, and more mentally sharp because they do not have passive entertainment like TV, but must instead stay active all day. Diamond’s book asks why the genetically inferior Eurasians were able to subjugate these people. He rejects explanations that point to differences in weather, irrigation systems, or immediate factors like guns, diseases, and steel tools. Instead, he looks for a new, more complete and accurate explanation. His book takes new science into account, from fields such as genetics, molecular biology, linguistics, and archeology, in order to provide an updated look at human history.

Diamond also acknowledges, however, that some people may take offense at his environmental explanation for the differences between societies. It might seem to imply that advanced societies were somehow destined, because of their environment, to dominate the less advanced ones. He counters this by arguing that interpretations of a historical explanation are separate from an explanation itself; his question does not contain a value judgment. Others might object that Diamond’s question provides a Eurocentric approach to history, meaning it glorifies the status of Western Europeans. In fact, Diamond’s answer will actually show how European civilization borrowed heavily from other people’s earlier civilizations. Finally, Diamond also responds to those who believe that using phrases like the “rise of civilization” implies that civilization is good while tribal hunter-gatherer lifestyles are inherently bad. He does not intend to celebrate one type of society over another, but simply to understand how the two forms of society came to be.

The first part of the book has three chapters. The first provides a broad overview of human evolution and history, from the time of apes until the end of the last ice age. It also traces the spread of humans from their origins in Africa to other continents and shows that human development had a head start on certain continents. The second chapter looks more closely at how the environments of different continents affected human development. It starts from smaller scale examples in order to find general patterns. The third chapter of this section then focuses on the collisions between different populations from different continents. It uses the example of the capture of the Incan Emperor, Atahuallpa, by the Spanish conquistador Francisco Pizarro. The chapter concludes that Spanish germs, horses, literacy, political organization, and technology allowed their small forces to defeat Atahuallpa’s much larger forces. This first section thus identifies the immediate, proximate causes of Eurasian dominance.

Diamond analyzes the history of human evolution throughout his first chapter. Evolving from apes, modern humans originated in Africa then migrated to other parts of the world about half a million years ago. However, it is impossible to say for sure when the evolution process and the migration started. What anthropologists call "The Great Leap Forward" took place almost 50,000 years ago when humanity invented new tools, built cities and even created art. Then humans invented ships and traveled to distant lands they could not reach before that point, such as Australia and, eventually, the Americas. The first settlers populated Eurasia and then moved to Australia and America somewhere around 14,000 years ago. Diamond supports the view that humans were the reason why some species went extinct. As humans colonized a new continent, mass extinctions would occur on that continent. This is most likely because existing animal species were not accustomed to humans and were therefore not afraid of them, and easy to hunt. The extinction of large wild animals is notable especially in the Americas, Australia, and New Guinea, where it could explain why native peoples did not have domestic animals and therefore did not develop agriculture. Some parts of the world, such as Australia and the Americas, remained unpopulated until quite recently, which some historians believe could explain the slower technological and agriculture development that occurred in those areas. But Diamond points out that the earliest humans were in Africa, which should have given this continent an advantage. Nevertheless, Africa today remains less developed than North America. This raises another question: Why were Eurasian societies the ones that developed human societies most quickly, even though this would have been impossible to predict at the time of the "Great Leap Forward"?

The Polynesian islands make a good case study for explaining how societies that started from the same point of development eventually diverged based on environmental factors. In particular, it shows why some societies remained hunter-gatherers and some turned to agriculture to survive. Diamond begins with the specific example of the aggressive and technologically advanced Maori people subjugating the peaceful and less advanced Moriori. In Polynesia, the same group of people populated many islands roughly around the same time. But because some islands were not fertile, the people there reverted to being hunter-gatherers. They had to cooperate more amongst themselves in order to share food, split tasks, and survive. Those who lived on the farmable islands developed agriculture and went on to fight amongst themselves over land. They also had enough surplus resources to have more free time, which allowed them to develop complex political structures and hierarchies; for example, they were more likely to have soldiers, politicians, and craftsmen. The islands that could provide better food became more heavily dense and populated, which meant they could develop more complex organization and technology. The environmental differences between one island and the other thus influenced the way the tribes developed: though in the beginning they were all the same, they developed different social organizations because of their differing resources. These categories of cultural difference within Polynesia are the same categories that emerged everywhere else in the world. In all parts of the world, environmental differences are what drove differences in how human societies operated.

The third chapter uses an even more specific example to illustrate larger patterns. Diamond describes the capture of Incan Emperor Atahuallpa by Spanish conquistador Francisco Pizarro in 1532. Pizarro was able to capture Atahuallpa and defeat the Incan forces even though his soldiers were greatly outnumbered by Incan soldiers. The crucial question this raises is why the Spanish were able to travel to Peru and defeat Atahuallpa, as opposed to the other way around. The answer depends on a number of factors: a writing system, new germs, centralized politics, and advanced weapons. Writing allowed the Spanish to plan ahead, while the Incas did not know what to expect from the Spanish. When the Spanish first arrived, they brought germs the Incas were not used to, which were thus able to spread and kill many Incas. Centralized political organization in Spain allowed people to finance, build, staff, and equip ships to travel to Peru. And Spanish horses and armor allowed fewer Spanish soldiers to kill a huge number of Incas.

The third chapter summarizes the proximate factors that explain how Europeans were able to colonize the New World, and not the other way around. They are the same factors listed in the title of the work, which shortens the list to a broader summary. Military technology, infectious diseases, maritime technology, centralized political organization, and writing are important to keep in mind as the biggest immediate reasons for European domination of the world. However, this book also seeks to explain how these factors came to be in the first place. It seeks not only proximate causation, but also ultimate causation. This means that, for the rest of the book, Diamond will trace how guns, germs, and steel came to exist in certain societies and not in others.


From the first chapter, Diamond guides his readers carefully and explicitly. He lays out what material readers should expect to find in the chapter and clarifies his methodology, all within the first two paragraphs. For example, he notes that he will begin the book with the date 11,000 B.C. because it corresponds to the beginnings of village life, the peopling of the Americas, etc. Diamond also makes clear that the dates he is using are quoted as “calibrated radiocarbon dates” as opposed to the conventional, uncalibrated dates used by other academics. He notes that he made this decision because calibrated dates correspond more closely to actual calendar dates. But he informs his readers they may be used to uncalibrated dates, and should keep this in mind if they are ever confused by the dates he cites for important events. By informing readers of his thinking behind beginning the book at this date and using this system for noting dates, Diamond signals the importance of the audience; he does not simply advance his argument without context, but is careful to update readers about his thought process and keep them in the loop about his methods. Diamond provides them with the tools to understand how his argument is laid out. This allows readers to follow his argument closely enough that they can even challenge the methodology or disagree with the conclusions.

Diamond also gives his readers the basic scientific knowledge necessary to read skeptically. Early in the first chapter, he introduces the concept of an “earliest X.” For example, many scientists claim to have found the earliest fossil in Europe, or earliest evidence of domesticated corn in Mexico, etc. He points out that the labeling of anything as the “earliest” invites debate. Something can only be considered to be the “earliest” of its category until another, earlier object is found to disprove this claim. Diamond explains that nearly every year brings new discoveries of earlier Xs in every category. Thus, he cautions that any time one reads about the “earliest X” of some kind, they should keep in mind that there is no guarantee this object is actually the earliest evidence that will ever be found. Thanks to this warning, readers know to be skeptical of points in the argument when he relies on evidence of something being the earliest of its kind. They are trained, from early in the chapter, to recognize the evolving nature of science and the necessity of remaining skeptical.

Readers are also given room to disagree with the author because he offers them all sides of different debates, while presenting his own as his personal opinion. For example, when explaining the extinction of large animals in Australia and New Guinea, Diamond acknowledges that there are several hypotheses. They could have been killed off by the first arriving humans. However, bones do not show definitive evidence that these animals were killed by humans. So other scientists believe giant animals could have been killed by extreme changes in climate. Diamond concludes by stating, “Personally, I can’t fathom why Australia’s giants should have survived innumerable droughts…and then have chosen to drop dead almost simultaneously…and just coincidentally when the first humans arrived.” Diamond employs irony to make clear that he strongly disagrees with the second hypothesis; he points out that it would be quite a coincidence if these animals “ drop dead” at the same time as humans first arrived. His tone is informal—using phrases like “drop dead,” or “I can’t fathom”—which signals that he is appealing to common sense, while also allowing that another explanation might supersede his argument.

Diamond also greatly varies the scale of his argument throughout this first section. He begins with a large-scale argument: he summarizes all of human evolution, from apes to the ice age, throughout his first chapter. But his second chapter introduces a new, much smaller scale: he focuses on the single instance of the Maori people defeating and enslaving the Moriori people in New Zealand. And his third chapter zooms in even further, to consider the story of one man, Francisco Pizarro, defeating another man, Incan Emperor Atahuallpa. These shifts in scale help to vary the book’s approach to its subject. Diamond makes use of many different lenses and angles from which to consider human development. This makes his argument more thorough and convincing; he is able to approach the question from various perspectives and using a wide base of evidence. Not only does he draw from scientific explanations of evolution, but also from historical events, such as the Moriori enslaving the Maori in Polynesia, and primary sources, like the Spanish letter describing the capture of Atahuallpa. These varied lenses also allow Diamond to reach a general reading public. He is not pitching his argument only to scientists, historians, or other academics. Instead, he is writing for a general public that may have limited knowledge of all these varied lenses.

Every chapter ends with a new question, which illustrates the ever-evolving nature of Diamond’s argument. After his first chapter, he asks why Eurasian societies developed most quickly, even though this trend could not have been predicted in the year 11,000 B.C. In the next chapter, he concludes by asking whether the environmentally related diversification of societies that occurred in Polynesia also happened on other continents. Finally, he ends the section by asking a fundamental question: why did advantages such as superior technology arise in Europe as opposed to elsewhere? These questions all remind readers of the main takeaway of a given chapter. For example, his last question points to the driving issue behind his description of Atahuallpa’s capture: why were the Spanish able to defeat such a great Empire so easily? They also signal what the next chapter will be about. For example, the second question hints that he will think about environmental diversification across other continents. They thus serve as important signposts for Diamond’s argument. Stylistically, they show that his argument proceeds through a series of steps: he begins with recent causes of human development, and then explores how these causes came about in the first place.