Book Summary: Guns, Germs and Steel by Jared Diamond

This is a detailed summary of Guns, Germs and Steel by Jared Diamond, which tries to understand why human development proceeded at such different rates on different continents.

I read the 20th anniversary edition of the book published in 2017, which includes a chapter on the Japanese and a 2017 afterword.

Buy Guns, Germs and Steel at: Amazon | Kobo (affiliate links)

You may also want to check out:

• Book Summary: Sapiens: A Brief History of Humankind by Yuval Noah Harari
• Criticisms of Guns, Germs and Steel
• Book Summary: The Lessons of History by Will and Ariel Durant

Key Takeaways from Guns, Germs and Steel

• Guns, Germs and Steel is really about food production. It explains:
  • why food production developed at different times in different places, and
  • how food production then led to other advantages like germ resistance, technology (including guns, steel and writing), and centralised government.
• Food production started at different times in different areas because of the differing environmental factors in those areas. For example, the Fertile Crescent had many plant and animal species that were suitable for domestication, whereas Africa and Australia had virtually none.
• Most hunter-gatherer societies were nomadic. Food production allowed societies to become sedentary and to generate food surpluses. This in turn allowed allowed societies to significantly grow their populations.
• As populations increased, societies became more centralised. Centralised governments were able to mobilise labour resources to build large public works (e.g. pyramids, aqueducts, large-scale irrigation systems).
• Food surpluses also enabled societies to support “specialists” not involved in food production. For example, blacksmiths, warriors, and government bureaucrats. These specialists could then spend their time improving the society’s technology (e.g. steel, weapons, writing).
• Most societies acquired more technology from other societies than they developed themselves. For example, writing arose independently probably just 2 or 3 times in history. Geographical and ecological barriers between societies greatly impacted the spread of technologies. Eurasian societies could develop quickly as technologies spread along the Silk Road and other trade routes. Isolated societies such as the Aboriginal Australians and New Guineans developed slower as they received very few technologies from other societies.
• People in sedentary farming societies often had exposure to domesticated animals’ germs. These societies therefore developed immunity or resistance to crowd infectious diseases such as influenza and measles. When people from these farming societies came into contact with other societies that had never been exposed to such germs (e.g. in the Americas), the diseases spread quickly and wiped out enormous numbers of their populations.
• To support his points, Diamond goes into quite detailed and interesting examples of the early histories of Australia and New Guinea, China, Polynesia, the Americas, Africa, and Japan. (The Japan chapter was not in the original version of the book, but in the 2017 edition I read.)

Diamond’s summaries

In the prologue, Diamond summarises Guns, Germs and Steel in one sentence:

In Chapter 15 (about New Guinea and Australia), he has another quote summarising his points quite well. Diamond points out that Europeans never learned to survive in Australia or New Guinea without their inherited Eurasian technology:

In the epilogue, Diamond summarises the following 4 sets of differences among the continents as being the most important in answering his original question:

1. Wild plant and animal species available for domestication. This is important because food production (i.e. farming and herding) was so critical.
2. Factors affecting diffusion and migration within a continent. For example, east-west major axis and other ecological or geographical barriers. This is important because most societies acquire more technologies from other societies than they invent themselves.
3. Factors affecting diffusion between continents. These negatively affected the Americas and particularly Australia.
4. Area or total population size. This is important because a larger area or population means more potential inventors and more competition and pressure to adopt innovations. But Diamond notes that even though the Americas were large in area, they were fragmented by geography and ecology and were effectively more like several separate smaller continents. [Seems to overlap a bit with the second factor then]

Detailed Summary of Guns, Germs and Steel

Question posed by the book

Gun, Germs and Steel focuses on a question that Yali, a New Guinean politician, asked Diamond in 1972:

(In New Guinea, “cargo” refers to the material goods that white people brought to New Guinea when they colonised it.)

Diamond extends Yali’s questions to try to understand why people of Eurasian origins (including those who later migrated to America) dominate the modern world in wealth and power. He rephrases it to ask: “why did human development proceed at such different rates on different continents?”.

Answers rejected at outset

Not biological differences

Diamond makes it clear from the outset that he rejects the idea that biological differences between people (i.e. differences in innate ability) explains the differing rates of development. He objects to such racist explanations as being not only loathsome, but also wrong. (If anything, he suggests that New Guineans, and members of other technologically primitive societies, might be more intelligent on average than Europeans or Americans. But nothing in his book hangs on this.)

Not the cold climate in itself

Another answer Diamond quickly rejects is the idea that Europe’s cold climate encourages people to develop technology. The theory is that cold climates require people to be more inventive to survive. Alternatively, since people have to spend a lot of time sitting indoors in long winters, they have nothing better to do than invent stuff.

Diamond points out that the people of northern Europe didn’t contribute any important technology to Eurasian civilisation until the last thousand years. Instead, they received technology (e.g. agriculture, wheels, writing, metallurgy) developed in warmer parts of Eurasia.

Ultimate vs Proximate causes

Despite being the title of the book, Diamond believes that guns, germs and steel were just the immediate or proximate cause that allowed Europeans to conquer other people.

In understanding why things are the way they are, it’s easy to focus on proximate causes, which are more visible. But to truly understand causation, you also need to look at ultimate causes that led to those proximate causes. For example, economists often explain why some countries are rich and others are poor by their institutions. That is a proximate cause. Why did some countries have good institutions and others don’t? That requires looking for the ultimate cause.

Pre-history is often underrated

• Most history books focus on relatively recent history. People pay very little attention to history before writing emerged around 3,000 BC, even though that makes up 99.9% of the human species’ multi-million year history.
• Diamond argues that by 1500 AD, when Europe just started its colonial expansion, there were already large differences between people on different continents in terms of technology and political organisation.
• At the end of the last Ice Age, around 11,000 BC, all humans were hunter-gatherers. This is the earliest we have evidence for signs of village life in some parts of the world. Between 11,000 BC to 1500 AD, people on different continents developed at different rates, which led to the technological and political inequalities existing in 1500 AD.

Origins in Africa

• Human history began in Africa around between 5 to 9 million years ago.
• For the first 5 or 6 million years our history remained confined to Africa. The first known human ancestor to spread beyond Africa was homo erectus, found in Southeast Asia (Java man). Earliest unquestioned evidence for humans in Europe is around 500,000 years ago.

Food production

• “Food production” refers to domesticating wild animals and plants and eating the resulting livestock and crops.
• Humans only started food production within the last 11,000 years. It arose at different times in different areas. Radiocarbon dating domestic plant and animal remains in one site is one way to work out when food production occurred at that site.
• There are currently five places in the world with compelling evidence of independent food production: Southwest Asia (aka the Fertile Crescent), China, Mesoamerica, the Andes of South America, and eastern United States. Food production may also have arisen independently in West Africa, the Sahel, Ethiopia, New Guinea and Amazonia but this is unclear.
• In large parts of the world, food production never arose in prehistoric times at all even if they were ecologically suitable.

Why was food production so significant?

Once one group of humans engages in food production, it can move to other areas as well. This can be through hunter-gatherers adopting the crops from their neighbouring farmers and thus becoming farmers themselves, as was likely the case in Egypt. Usually this will be a more gradual process. But it can also arise abruptly through farmers invading and killing or outbreeding the local hunter-gatherers (e.g. Australia, North America).

Diamond argues that food production was an indirect prerequisite for the development of guns, germs and steel (and writing and centralised government) for the following reasons:

1. More consumable calories means more people.

A small minority of wild plant and animal species are edible. By selecting and growing the edible plants and species we can eat and deliberately cultivating them, we can obtain far more calories per acre. One acre can therefore feed 10 to 100 times more farmers than hunter-gatherers.

Diamond points out that after the sweet potato arrived in New Guinea and squash, corn and beans arrived in the eastern US, a population boom followed.

2. Food production enabled sedentary lifestyles, which came with other advantages

Hunters and gatherers are typically nomadic (there are some exceptions to this in resource-rich environments). Farmers are typically sedentary as they have to remain close to their fields and orchards. There are exceptions – there have been some nomadic farmers as well as some sedentary hunter-gatherers.

Advantages of a sedentary lifestyle include:

• Shortened birth interval. Nomadic hunter-gatherers space their children about 4 years apart because a mother can only carry one child at a time when shifting camp. Farmers do not have this problem, so can have children in shorter birth intervals. The birth interval for many farm peoples is around 2 years.
• Storage of food surpluses. Even if hunting-gathering had a food surplus, they couldn’t keep it for long if they couldn’t stay nearby to guard it. Stored food is essential for feeding non-food-producing specialists, such as kings, bureaucrats, professional soldiers, metalworkers, and scribes.

3. Other uses for crops and livestock

Food production was often linked with the use of crops and livestock for other purposes. Humans use fibre crops to make clothing, blankets, nets and ropes. Domestic mammals can also provide transport and horses can be used in wars. It was only by the time of WWI that trucks and tanks supplanted horses to become the main assault vehicle and means of transport in war.

4. Domesticated animals led to germ resistance

Many infectious diseases come from domesticated animals. Humans who domesticated animals evolved resistance to their diseases. When they came into contact with populations had no previous exposure to those diseases, the diseases largely wiped out those previously unexposed populations.

Why did hunter-gatherers start farming?

Most initial farmers and herders spent more time working than hunter-gatherers, and were less healthy than hunter-gatherers. Many hunter-gatherers were in contact with farmers but chose not to adopt farming – at least not for a long time. There were also hunter-gatherers that adopted farming but then went back to hunting-gathering, at least for a while (e.g. in Sweden).

Food production was not an invention or discovery. It was an evolution.

Some hunter-gatherers manage their land in ways that are similar to, but fall short of, “food production”. For example, they may clear away competing trees, promote growth of new shoots by cutting down mature trees, or burn an area to encourage edible seed plants to grow. They could also cut off the edible part of a yam and replace the stems and tops in the ground so that they’d regrow.

Early in the stages of food production, people were both farmers and hunter-gatherers. In places like Japan, the hunter-gatherer lifestyle was very productive so the adoption of food production was piecemeal. Whereas in parts of Europe, the hunter-gatherer lifestyle was less productive so adoption of food production may have been faster and more wholesale.

Nomadic hunter-gatherers would not give up their way of life and start settling down and farming unless there were enough suitably domesticable plants and animals available to make a sedentary farming lifestyle competitive with a hunting-gathering one.

Fertile Crescent advantages in food production

The Fertile Crescent had a number of advantages that led it to develop food production earlier. Those advantages included:

• Mediterranean Climate leading to good crops.
• Many “selfer” crops.

Mediterranean climate leading to good crops

The Mediterranean climate has mild, wet winters and long, dry summers. In that climate, many native plants are annuals, meaning they dry up and die in the dry season and resume growth rapidly when the rains return.

Since annual plants only live for one year, they will remain small herbs. They put most of their energy into producing big seeds, and waste little energy on making inedible wood or fibrous stems (i.e. tree bark and bushes). These big seeds are edible by humans. They constitute 6 of the modern world’s 12 major crops. The wheats in particular had a high protein content of around 8-14%.

So the wild ancestors of many Fertile Crescent crops, like wheat and barley, were already plentiful and productive. Some hunter-gatherers in the Fertile Crescent had already settled down into sedentary villages before they began to cultivate plants. Not many changes were needed to domesticate them.

Diamond does point out that there were other Mediterranean zones that did not give rise to any indigenous agriculture at all. But he suggests that western Eurasia’s Mediterranean zone (particularly its Fertile Crescent part) had at least 5 advantages over those zones:

1. It is larger and therefore had a higher diversity of wild plant and animal species.
2. It has the greatest climactic variation from season to season and year to year of any Mediterranean zone. That variation caused more plants to be annuals.
3. It has a wider range of altitudes and topographies within a short distance. This leads to greater diversity and allowed for staggered harvest seasons. People could move up a mountainside harvesting plants as they matured, instead of having to harvest everything at the same time.
4. It also had useful big mammals suitable for domestication. The goat, sheep, pig and cow were all domesticated very early in the Fertile Crescent. This made it easier for people to make up a balanced “package” of food production that would rival the hunting-gathering lifestyle.
5. The hunting-gathering lifestyle may have been worse than in other areas. Fish and shellfish were limited and the gazelle, an important source of meat, was overexploited.

In contrast to all these advantages of western Eurasia, Diamond refers to New Guinea and the Americas. The main crop of the Americas was corn. Corn’s wild ancestor was probably teosinte. Teosinte looks quite different from corn. It was less productive in the wild than wheat, produced less seed, and enclosed its seeds in inedible hard coverings. The protein content was also much lower. For teosinte to become a useful crop, it had to undergo a lot of changes – including increasing its seeds and losing its hard coverings. It took several thousand years for corn to reach modern sizes.

Diamond is careful to point out that he’s not suggesting that people in the Americas (or New Guinea or other areas) would have remained hunter-gatherers forever if foreign species or peoples had not arrived. Rather, he’s just pointing out that the lack of plants suitable for domestication meant that some places got a later start in food production.

Many “selfer” crops

The Fertile Crescent had a high percentage of hermaphroditic plants that usually pollinate themselves (“selfers”). The first 8 significant crops domesticated in the Fertile Crescent were all selfers.

This was beneficial for food production because useful mutant plants that pollinate themselves will retain their advantages. Whereas if a useful mutant interbred with a normal plant, it would dilute or lose the mutation.

Plant domestication

How plant domestication works

• Some plants disperse their seeds by having the animal eat the fruit and defecate the seeds somewhere.
• Many domesticated plants have much bigger fruits than their wild ancestors because humans prefer larger fruits, so unconsciously select for size. Cultivated peas are 10 times heavier than wild peas.
• Similarly, domesticated plants will often be tastier and less bitter (and less poisonous!) than wild ancestors. For example, wild almonds generally have a bitter chemical amygdalin, which breaks down into the poisonous cyanide. Occasionally an almond tree will have a mutation that does not produce amygdalin. Humans will only plant non-bitter almond trees, which is why domesticated almonds are not bitter. Other examples of plants whose wild ancestors were bitter or poisonous include watermelons, potatoes, eggplants and cabbages.
• Wild peas have a gene that causes the pod to explode, shooting the peas onto the ground to germinate. Occasionally a mutant pea pod doesn’t have that gene. These mutant peas tare the only ones available to humans to harvest.
• Wild plants often spread out the germination of their seeds over several years. That way, even if a bout of bad weather kills most seedlings, some seeds can still germinate later. The plants often do this by enclosing their seeds in a thick coat. Occasionally a mutant plant wouldn’t have any germination inhibitors. These are the ones that farmers would have selected to sow.
• Plants that don’t normally reproduce or fertilise themselves may have a mutation that allows them to do so. So that is why we have seedless bananas, grapes and pineapples, which develop fruit without pollination. We also have many fruit trees (e.g. plums, peaches, apples, cherries) that can fertilise themselves, even though their wild ancestors couldn’t.
• The wild ancestors of the earliest Fertile Crescent crops (wheat, barley and peas) already had many advantages. They were edible and had high yields. They were mostly self-pollinating and required very little genetic change to convert into crops.
• In Eurasia, the ability to use mammals to plough fields allowed people to sow seeds by throwing handfuls of them, resulting in fields devoted to a single crop. In places where humans tilled fields with sticks or hoes, they planted seeds individually by hand.

Difficult plants to domesticate

• Acorns are a nutritionally valuable food and were a stable of Native Americans. But we have never been able to domesticate acorns. Diamond offers up three reasons for this:
  • First, oak trees grow slowly. A planted acorn may not be productive for over a decade.
  • Second, oaks evolved to make nuts suitable for squirrels. With so many squirrels spreading acorns, humans didn’t have much chance to select oaks for the acorns we wanted.
  • Lastly, many genes affect bitterness in acorns, rather than a single dominant gene in almonds.
• Strawberries and raspberries remained small for a long time because there are so many birds defecating wild strawberry seeds everywhere. Only with the recent development of protective nets and greenhouses, were we able to make improvements we wanted to strawberries and raspberries.
• Diamond points to evidence that hunter-gatherers have an incredible understanding of the plants around them. He argues that the failure to find good plants to domesticate in areas like New Guinea and the US was mostly because there weren’t any, rather than because the people couldn’t find them or were too conservative to exploit them.

Most plants are not that useful for humans

• Of the 200,000 wild plant species, humans eat only a few thousand and have only domesticated a few hundred. Even then, most are just minor supplements to our diet.
• Twelve plant species account for 80% of the world’s annual tonnage of all crops: wheat, corn, rice, barley, sorghum, soybeans, potato, manioc, sweet potato, sugarcane, sugar beet and banana.
• Many areas of the world did not have any wild native plants suitable for domestication at all. We have not domesticated even one major new food plant in modern times.

Animal domestication

• The book focuses on big mammals weighing over 100 pounds. Diamond accepts that small mammals, birds and insects have also been useful to humans in terms of food, clothing or warmth, but points out that big domestic mammals are useful to humans because of their milk, manure (fertiliser) and power (pulling ploughs, transport and in war).
  • Mammals that provide a source of milk yield several times more calories over their lifetime than if they had just been killed and consumed for meat.
  • Manure can greatly increase crop yields. It can also be a source of fuel.
  • Pulling ploughs allows people to till land that may otherwise be uneconomical for farming (e.g. heavy soils, tough sods).
• More specifically, he focuses on big land mammals that are herbivores or omnivores.

Domesticated vs tamed animals

• A domesticated animal is not the same as a tamed wild animal.
• Most domesticated animals (and plants) are physically different from their wild ancestors in some way. For example, domestic chickens and apples are larger than wild ones; domestic sheep and cattle are smaller; the horns of domestic goats look different from wild goats’; domestic cows yield more milk.
• Diamond defines a domesticated animal as: “an animal selectively bred in captivity and thereby modified from its wild ancestors, for use by humans who control the animal’s breeding and food supply”. For example, people have tamed elephants but have never domesticated them, as elephants are not bred in captivity.

What makes an animal domesticable or undomesticable?

Diamond cites Tolstoy’s Anna Karenina principle but modifies it to say: “Domesticable animals are all alike; every undomesticable animal is undomesticable in its own way”.

He offers up 6 reasons why an animal may not be domesticable:

1. Diet. Humans have never domesticated a carnivore for food. This is because when an animal eats a plant or other animal, food biomass is inefficiently converted into the consumer’s biomass. The rate is around 10% – i.e. it takes 10,000 pounds of corn to grow a 1,000 pound cow. The closest thing to an exception is a dog, but Diamond points out that:
   1. Most societies raised dogs for hunting and guarding, rather than for food.
   2. Dogs are actually omnivores. Aztecs and Polynesians did raise dogs for food but they fed them vegetables and garbage.
2. Growth rate. To be worth keeping, an animal has to grow quickly. Elephants take around 15 years to mature so it is much cheaper to capture wild elephants and tame them than to domesticate them.
3. Unable to breed in captivity. Some animals don’t breed in captivity. For example, cheetahs’ courtship ritual involves a long chase over several days.
4. Nasty disposition. Some animals are more likely to kill humans, such as the grizzly bear. The Ainu people in Japan raised grizzly cubs but would kill them when they reached the age of one. Hippos are also surprisingly dangerous – they kill more people each year than any other African mammals, including lions. Zebras are also dangerous as they tend to bite people and not let go (they are also virtually impossible to lasso).
5. Tendency to panic. Some animals will panic in a cage and die of shock or in their attempts to get out. For example, gazelles will blindly bash themselves against walls.
6. Social structure. Almost all domesticated large mammals:
   1. live in herds – this is good because they can be bunched up. Solitary animals do not tolerate each other well. Cats and ferrets are the only territorial mammal species that were domesticated because we didn’t want to herd them in large groups for food but to keep them as hunters or pets. Some herd species still can’t be domesticated because they are territorial during breeding season (e.g. deer and antelope).
   2. maintain a well-developed dominance hierarchy among the herd members – this is useful as the human can take over as “leader”.
   3. occupy overlapping rather than mutually exclusive herd territories – if herds maintain mutually exclusive territories you can’t put two herds together.

Why were all domesticated animals in Eurasia?

• Only 14 big herbivorous land mammal (the “Ancient Fourteen”) were domesticated before the 20th century. Only 5 of those became widespread and important around the world: the cow, sheep, goat, pig and horse.
• 13 of the 14 wild ancestors of the Ancient Fourteen were confined to Eurasia. (The remaining one was the guanaco, ancestor to the llama and alpaca in South America.) Diamond argues that this very unequal distribution was an important reason why Eurasians were the ones to end up with guns, germs and steel.
• One reason for this simply that Eurasia had the world’s largest landmass and is also very ecologically diverse. It has the most candidates for domestication (being any herbivorous or omnivorous land mammal weighing over 100 pounds) at 72; sub-Saharan Africa had 51; the Americas had 24 and Australia had 1.
• Diamond rejects the idea that people outside Eurasia could’ve domesticated their local wild mammals but didn’t, either because of some cultural taboo or because they found it unnecessary to do so. He cites the following 5 reasons for this conclusion:
  1. When the Eurasian domestic mammals reached other areas, people eagerly adopted them.
  2. In all those other continents, people kept wild animals as pets. Pets are a first stage in domestication. There are far more tamed wild animals than domesticated ones. New Guineans keep pet kangaroos, some Asians tame eagles for hunting, and Egyptians, Assyrians and Indians have tamed cheetahs for hunting. Egyptian paintings even indicate that they may have tamed gazelles, giraffes and even hyenas! The Ainu people of Japan regularly kept the brown grizzly bears as young animals (they later ate them).
  3. No big mammals have been domesticated since camels in 2500 BC.
  4. Some species have been independently domesticated multiple times. Examples include wolves (to dogs), aurochs (to cattle), and boars (to pigs).
  5. Modern efforts to domesticate large animals have not been very successful. In the 19th and 20th centuries, modern breeders and geneticists have attempted to domesticate the eland, elk, moose, musk ox, zebra, and bison with little success.
• Many big animals in the Australian and American continents became extinct soon after humans arrived. Those animals had evolved for millions of years without humans. They were probably unafraid of humans and easy targets. The extinctions eliminated all the large wild animals that could have otherwise been domesticated.
• In contrast, the animals of Africa and Eurasia survived into modern times because they had co-evolved with humans, as our hunting skills slowly improved. They had time to evolve a fear of humans and features that allowed them to survive in our presence.
• Diamond does point out that some people challenge the above hypothesis, termed the “overkill hypothesis” and their reasons. However he finds the overkill hypothesis compelling given that the large animals survived many droughts, Ice Ages and climate change over tens of millions of years, and then go extinct shortly after the first humans arrived. Moreover, they went extinct in every habitat, even though those habitats would be affected by climate change differently.

Spread of food production

• Eurasia’s main axis is East-West, while Africa and the Americas’ main axis is North-South.
• The climate and day length along the East-West axis is much more similar than along the North-South axis. Plants and animals are both adapted to latitude-related features of climate. As such, food production was able to spread across Eurasia quicker and more completely than it did in Africa, the Americas or Australia.
• The evidence suggests that, once a society domesticated a wild plant, the plant spread quickly to other areas and pre-empted independent domestication of that plant. So evidence that the same wild ancestor was domesticated independently in different areas suggests that the plant spread too slowly to pre-empt that independent domestication.
• There is evidence of multiple independent domestications in the Americas, which may suggest that crops spread slowly there. In contrast, Southwest Asia’s crops were mostly single domestications – they share a single mutation or they share only one arrangement of chromosomes out of multiple arrangements found in the wild ancestor.
• The Fertile Crescent founder crops spread as far south as Ethiopia but then stopped. The crops would have grown well in the South African climate but they couldn’t get past the 2,000 miles of tropical conditions between Ethiopia and South Africa.
• Similarly, climate and disease hindered the spread of the Fertile Crescent’s domesticated animals through Africa.
• Llamas, guinea pigs and potatoes were all domesticated in the highlands of the South American Andes. They would have been suited to the highlands of Mexico also but they couldn’t spread past the hot lowlands of Central America.
• Corn could not spread into eastern North Africa for thousands of years after its domestication in Mexico because of the cooler climates and shorter growing season there.
• Most of Australia is not very suitable for farming, but the southeastern and southwestern parts are. But because crops could not spread through the middle parts of Australia, farming did not reach the southern corners of Australia until European ships arrived with crops adapted to Europe’s cooler climate.
• Even along the same latitude, there could be topographic and ecological barriers to spread. For example, crop diffusion between the Southeastern and Southwestern US was very slow and selective because the intervening area was very dry. China developed food production independently because crops could not spread easily from the Fertile Crescent due to the intervening desert, Himalayas and Tibetan plateau.

Germs

• Germs have been the biggest killers of people and have therefore shaped history. Until WWII, more people in war died from infectious diseases than from battle wounds.
• Crowd infectious diseases such as smallpox, measles, and influenza played a decisive role in European conquests by decimating people on other continents. But Diamond also notes that diseases also presented an obstacle to European colonisation (e.g. malaria, yellow fever and other tropical diseases).
• Crowd infectious diseases cannot survive in small hunter-gatherer populations. This is inherent in the characteristics of crowd diseases.
• Many of our infectious diseases are closely related to diseases affecting animals we’ve domesticated, particularly ones affecting social animals that live close together. For example, measles, tuberculosis and smallpox are related to cattle diseases, the flu is related to diseases affecting pigs and ducks, while pertussis is related to diseases affecting pigs and dogs. The human diseases evolve to a point where they can directly transmit between humans.

How germs work

• Microbes evolve like other species. Evolution selects for germs most effective at spreading. Many of our symptoms of diseases are actually ways in which the germs have modified our bodies to spread further – e.g. open sores, sneezing, coughing, rabies biting frenzy. Germs don’t set out to kill their hosts. That’s just an unintended byproduct.
• Germs spread in different ways:
  • Some just wait to be transmitted passively to the next host. For example, salmonella is spread by one host being eaten by another.
  • Some hitchhike in the saliva of insects that bite hosts. Mosquitoes, fleas, lice or tsetse flies spread malaria, plague, typhus and sleeping sickness respectively.
  • Microbes can also pass from a woman to her foetus and infect babies at birth. Examples of these include syphilis, rubella and aids.
• One of our common responses to infection is to develop a fever, trying to kill the germs by heat.
• Another response is to use our immune system to kill the germs. In doing so, we gradually build up antibodies against a particular microbe. Vaccination inoculates us with a dead or weakened strain of microbe in order to stimulate our antibody production without getting us sick. But microbes can evolve, so antibodies may not protect us against new strains.
• Some people are more genetically resistant to some diseases than others. They are more likely to survive any deadly infectious disease and pass on their genes. So over time, a population repeatedly exposed to a disease will have more individual that are naturally immune to it. This makes it harder for the disease to spread in those populations.

Characteristics of epidemics

• Infectious diseases that become epidemics tend to share the following characteristics:
  1. They spread quickly and efficiently from infected people to other people nearby
  2. They are acute in that an infected person either dies quickly or recovers completely quickly.
  3. People who recover will develop antibodies against them.
  4. They tend to be restricted to humans.
• So an epidemic dies out once everyone in the population has either died or become immune to it.
• For a crowd infectious disease to sustain itself, it needs a sufficiently dense and numerous human population, so that there is a constant stream of new people (children) available to infect. Otherwise it will die out.
• Crowd infectious diseases therefore cannot sustain themselves in small hunter-gatherer societies. A small tribelet can get wiped out by a disease, so they can’t sustain such diseases to give to others. That is why European germs decimated Native Americans, rather than Native American germs decimating the Europeans.

Link between food production and crowd infectious diseases

Several reasons why the rise of food production led to crowd infectious diseases:

• Because food production sustained much higher human populations and densities, it also allowed populations to sustain crowd infectious diseases.
• Farmers tend to be sedentary and live amid their own sewage, making it easy for germs to spread from one person’s body to another’s drinking water. Whereas hunter-gatherers tended to move frequently and leave their own sewage behind.
• Farmers may also become surrounded by rats attracted to the farmers’ stored food surpluses.
• Farming also led to environmental changes that encouraged the spread of diseases. Irrigation agriculture and fish farming provide great living conditions for snails and flukes carrying diseases. Forest clearings often made ideal habitats for mosquitoes.

Germs around the world

• The Americas and Australia did not have any native crowd diseases.
• Asia, Africa, Indonesia and New Guinea did have crowd diseases such as malaria, cholera and yellow fever. They posed significant obstacles to European colonisation.
• Eurasian crowd diseases evolved out of the diseases of herd animals domesticated in Eurasia. In contrast, the few domesticated animals in the Americas (dog, duck, guinea pig, turkey and llama/alpaca) were not likely sources of crowd diseases. They don’t live in large herds, they aren’t generally kept indoors, and we don’t drink their milk.
• Far more Native Americans died from Eurasian germs than in battle. Smallpox reached Mexico in 1520 and proceeded to kill nearly half of the Aztecs. The fact that the disease didn’t seem to affect Spaniards further demoralised the Aztecs – it seemed like the Spanish were invincible. Other diseases – measles, influenza, typhus, diphtheria, malaria and mumps – spread in the Americas as well.
• Eurasian germs also decimated native peoples in Africa and Australia. Cumulative mortalities of these peoples from Eurasian germs ranged from 50% to 100%.

Why the infections were so one-sided

• Over a dozen infectious diseases from Europe reached the Americas. But, with the possible exception of syphilis, not one major deadly disease went in the other direction. Why was it so one-sided?
• Diamond suggests the main reason is because the Eurasian crowd diseases evolved from diseases of domesticated herd animals. Eurasia had many domesticated animals while the Americas only had 5 (turkey, llama/alpaca, guinea pig, Muscovy duck, and dog).
• Moreover, the 5 domesticates that the Americas had weren’t likely sources of crowd diseases. The llama was probably the most likely source, but people kept llamas in smaller herds (compared to sheep, goats and pigs) and they never had that many llamas. In addition, llamas aren’t kept indoors close with people (whereas pigs and cows were) and people don’t drink llama milk.
• However, there were germs from Asia, Africa and New Guinea that did kill many Europeans and posed a serious obstacle to colonisation.

Writing

• Writing brings power. It allows information and knowledge to spread more widely, more accurately, and in more detail than by mouth. Written accounts of early European expeditions motivated later ones by describing in detail the wealth of foreign lands and strategies.

Three writing system strategies

There are three basic strategies underlying writing systems:

• alphabets, which use a sign/letter for each sound (phoneme);
• logograms, which use a sign for each word; and
• syllabaries, which use a sign for each syllable of one consonant followed by one vowel.

Examples of languages that mostly use logograms are Chinese and Egyptian hieroglyphs. A language that mostly uses syllabaries is the Japanese hiragana and katakana systems.

A language can combine these three strategies. For example, even though English is mostly an alphabetic language, we still use logograms for certain words – e.g. numbers, $ for dollar, % for percentage.

Alphabets

Alphabets ideally provide a unique sign or letter for each basic sound of the language (phoneme). Most alphabetic languages have more phonemes than letters. Some letters may represent more than one phoneme. Languages may also combine letters to represent new phonemes. English uses 26 letters to represent 40 phonemes. A single letter represents the sounds sh and th in the Russian and Greek alphabets, respectively.

Alphabets apparently only arose once in human history. They arose around 2000 BC among speakers of Semitic languages. All alphabets since then were derived from that Semitic alphabet – mostly by blueprint copying rather than idea diffusion.

Three important innovations that improved the alphabet were:

1. Restricting letters to single consonants, rather than to pairs or trios of consonants.
2. Placing the letters in a fixed sequence and giving them easy to remember names (e.g. A, B, C).
3. Systematically providing for vowels. The Greeks were the first ones to do this in around 800 BC by using the same types of letters for vowels as the ones used for consonants.

History of writing

• Writing was developed independently at least two times in human history. It was first developed by the Sumerians (before 3000 BC) and by Mexican Indians (before 600 BC).
• Writing may also have developed independently in China (by 1300 BC) and Egypt (by 3000 BC).
  • Most scholars think that Chinese writing arose independently. There is no evidence of early writing systems in the area between the Indus Valley and China.
  • Scholars also usually assume that Egyptian hieroglyphics arose independently, but Diamond is not convinced. He notes that it appeared quite suddenly, in nearly full-blown form, around 3000 BC. Egypt also had trade contacts with nearby Sumer.

Sumerian writing

• The first Sumerian writing (termed ‘cuneiform’) were pictures of objects – e.g. a fish or bird. The texts were mostly accounting reports consisting of numerals plus a noun for visible objects.
• Gradually, the signs became more abstract and old signs were combined to produce new meanings. For example, the sign for head was combined with the one for bread to mean “eat”.
• Sumerian writing was not initially based on the sounds of the Sumerian language. Diamond suggests that perhaps the single most important step in the history of writing was the Sumerians’ introduction of phonetic representation. Initially this meant writing an abstract noun (which could not be drawn) by using the sign for a more concrete noun that could be drawn with the same phonetic pronunciation. For example, “arrow” and “life” were both pronounced ti in Sumerian. So a picture of an arrow could mean either “arrow” or “life”. To clarify whether the picture meant “arrow” or “life,” they added a silent sign called a determinative, to indicate which category of nouns it belonged to. Linguists call this the rebus principle.
• Sumerians then used the rebus principle to write many other things. But the writing never reached the level of a complete syllabary or alphabet. Some syllables didn’t have any written signs, some signs could be read in different ways, etc.

Mesoamerican writing

• Mesoamerican writing probably arose independently. There is no convincing evidence of contact between the Americas and the Eurasian societies with writing before the earliest signs of Mesoamerican writing. Moreover, the writing is completely different.
• Linguists today have still only partially deciphered most Mesoamerican scripts.
• Mayan writing uses similar principles to those used by the Sumerians. Mayan writing also consisted of both logograms and phonetic signs, and used the rebus principle.

Cherokee writing

• In 1820 in Arkansas, a Cherokee Indian named Sequoyah observed white people making use of writing.
• Sequoyah then experimented with developing a writing system for the Cherokee language. He was a blacksmith, so started by using an accounting system to help him keep track of customers’ debts.
• Sequoyah’s writing system was a syllabary. Initially he created 200 syllabic signs and gradually reduced them to 85. He had an English spelling book and used some of the letters in it to represent his sounds. For example, he used D to represent a, 4 to represent the syllable se.
• Many linguists admire Sequoyah’s syllabary because it fit the Cherokee language well and was easy to learn. The Cherokees achieved almost 100% literacy in a short time, bought a printing press, and began printing books and newspapers.

Why did writing appear so late?

• Development of writing is really difficult. Sumerian writing took at least hundreds, possibly thousands of years to develop.
• Early writing systems were not great. They were typically incomplete, ambiguous and/or complex. Furthermore, very few people were literate.
• Because of these limitations, early writing systems were mostly restricted to use in temples, records, and merchant accounts, and some propaganda.
• But because writing had such restricted uses, people did not have an incentive to improve the systems and make them simpler and clearer. Claude Levi-Strauss, an anthropologist, said that the main function of ancient writing was “to facilitate the enslavement of other human beings”.
• All places that developed or adapted writing at an early date had socially stratified societies with complex and centralised organisation. Early writing served the needs of the rulers in those societies (recordkeeping and propaganda) and users were full-time bureaucrats who didn’t need to devote their time to food production.
• Hunter-gatherer societies never developed or adopted writing because they didn’t need it, and also because they didn’t have the food surpluses needed to feed full-time scribes.
• Diamond therefore argues that food production was a necessary (but not sufficient) condition for the evolution or early adoption of writing. Societies that developed food production later might have eventually developed writing as well, or acquired it from others if they were less isolated.

Technology

The nature of invention

• Many or most inventions arise not because there is a need for it, but just through curiosity or tinkering. For such inventions, the inventor finds an application for it only after the fact because early models perform too poorly to be useful. There are also many inventions where the inventor intended one use, but people ended up using it for something else. Examples:
  • Edison’s phonograph in 1877. Edison published an article proposing 10 uses for it. Reproducing music was not on that list as Edison thought it was a frivolous use. He wanted people to use his phonograph for more “serious” office uses.
  • Nikolaus Otto’s gas engine in 1866. The engine was weak, heavy and 7 feet tall. Horses and trains were the main mode of transport and there were no problems with either. It was almost 20 years later in 1885 that engines had improved to the point that they could be useful.
• Most famous modern inventions cannot be credited to a single inventor. Inventors build on designs, prototypes and models created by other inventors.
  • Edison’s light bulb was just an improvement on many other incandescent light bulbs.
  • Before the Wright brothers invented their plane, there were already gliders and unmanned airplanes.
• It is therefore incorrect to suggest that individual genius inventors shaped the broad pattern of world history. Rather, technology develops cumulatively.
• Technology is “autocatalytic”. That is, the process of invention speeds up at a rate that increases with time, because the process catalyses itself. Two reasons:
  • Advances build on prior knowledge.
  • More technologies and materials means more things to experiment with, combine, etc. into new technologies. For example, the Phaistos disc in 1700 BC was before its time, and there were not enough other technologies to make printing particularly useful (and very few people were literate). Whereas by the time of the Gutenberg printing press in 1455 AD, inventions such as paper, the alphabet, inks, movable type and metallurgy already existed.

Success of new inventions

How readily a new invention is accepted by the same society depends on at least 4 factors:

1. Increase in economic advantage over existing technology. For example, the wheel was not as useful for Ancient Native Mexicans as we might think because they did not have domestic animals to pull their vehicles. So it did not have as much of an advantage compared to human porters. [Wheels are still useful for human power – wheelbarrows, rickshaws.]
2. Social value and prestige [of existing technologies]. For example, the Japanese continue to use its kanji writing system because of prestige, even though its own kana syllabaries are more efficient.
3. Compatibility of vested interests. Diamond points to the QWERTY keyboard as an example. The QWERTY keyboard deliberately slows down typing because typewriters at the time would jam if people typed too fast. By the time typewriters improved so that they wouldn’t jam, QWERTY keyboards were solidly entrenched. Vested interests of QWERTY typists, typing teachers, typewriter and computer salespeople and manufacturers have crushed all moves toward keyboard efficiency for over 60 years. [I think this is more an example of high switching costs than “vested interests”. I don’t think there’s a particularly organised or powerful QWERTY keyboard lobby determined to crush competing keyboards. In fact, you can use alternative keyboard layouts like DVORAK on a standard QWERTY keyboard just by installing software, so manufacturers shouldn’t care. If anything, they might be able to make more money by producing alternative keyboards and charging higher prices.]
4. The visibility of their advantages. Diamond points out that England adopted cannons enthusiastically when two English earls saw how effective they were in a battle between Arabs and Spaniards.

Why some societies are more innovative than others

Diamond then turns to consider what makes some societies more innovative than others. The development and reception of inventions has varied enormously from society to society on the same continent. They also vary over time within the same society (e.g. Islamic societies, Chinese).

Many hypotheses for these variations have been generated based on patent rights, capitalism, tolerance of diverse views, religion, etc and he thinks all of these are plausible. He argues that the diversity of independent factors behind technological innovation effectively convert variation into a random variable. The result is that, over a large enough area at any particular time, some proportion of societies is likely to be innovative.

How technology spreads

• Useful technology can spread in two ways:
  • A society may adopt or copy the invention;
  • If the society does not adopt the invention, it may find itself replaced by the society with the invention if the invention is successful useful. An example is the spread of muskets among New Zealand’s Maori tribes.
• If a society adopts or copies an invention, it may do this through blueprint copying or idea diffusion (or anywhere between these two extremes).
  • Blueprint copying refers to copying or modifying an available detailed blueprint for the technology.
  • Idea diffusion is just when someone finds out the basic idea, or even just the fact that something can be done, but they don’t know how and have to figure that out themselves. For example, writing spread to Cherokee Indians through idea diffusion. Another example is the spread of porcelain from China to Europe.

Geography affects the spread of technology

• Geographically isolated societies experienced less diffusion. For example, the Tasmanians had no contact with other societies for 10,000 years and acquired no technology from others.
• Societies that were closer to other societies experienced more technological diffusion. These societies developed faster because they had not just their own technology but other societies’. For example, medieval Islam adopted inventions from India, China and Greece.
• In particular, societies usually acquired complex inventions by borrowing, because the inventions could usually spread faster than societies could independently invent them. Some examples are the wheel and writing.
• Diamond thinks that the axis orientation affected the spread not just of food production, but also of writing, wheels and other technology. It did this indirectly as societies that were exchanging crops and livestock were more likely to exchange other technologies as well. For example, the earliest wheels were from carts that transported crops.

Food production allowed significant advances in technology

• Technology develops faster in sedentary societies than in nomadic hunter-gatherer ones. This is for two reasons:
  • nomadic societies are frequently moving, so the people will not have many possessions. You can’t carry much pottery or a large printing press with you as you move!
  • the food surpluses generated by sedentary farming societies allow some people time to do things other than produce food. They can then become specialists who invent things.
• Technology develops faster in areas with large populations, simply because there are more potential inventors.

Combining all of these various factors, it makes sense that Eurasia had a significant advantage in technological innovation. It was the largest landmass with the most people. (In 1990, it had around 6 times the population of the Americas, the next largest landmass.); it developed food production first; and it had relatively few geographical barriers to technological diffusion (its east-west axis and lack of significant ecological barriers).

Organisation of societies

• Diamond divides societies into the following stages or types: band, tribe, chiefdom and state. He caveats that the lines of demarcation are inevitably arbitrary as societies can grow out of one stage to the next.
• The long-term trend of societies has been toward large, complex societies, culminating in states. A few bands and tribes still exist today. But chiefdoms disappeared by the early 1900s because they tended to occupy prime land that states wanted.

Bands

• Bands are the smallest societies typically with between 5-80 people. Most or all of them are close relatives.
• Probably all humans lived in bands until at least 40,000 years ago. Around that time, technology for getting food improved and allowed some hunter-gatherers to settle in permanent dwellings. Most humans still lived in bands until around 11,000 years ago.
• Our closest animal relatives, gorillas, chimpanzees and bonobos, also live in bands.
• Bands lack many formal institutions such as laws and police. In small groups where everyone is related to each other, people can resolve conflicts without formal institutions.
• Anthropologists had previously idealised bands and tribes as gentle and non-violent, but this is incorrect. More extensive long-term information shows that murders are a leading cause of death in bands and tribes.
• The group jointly uses land.
• There is no economic specialisation other than that by age and sex. All people who can do so will look for food.
• Bands are often described as “egalitarian” in that there are no formalised upper and lower classes, and no formalised or hereditary leadership. Being egalitarian does not mean that all band members had equal say in group decisions. It just meant that leadership is informal and acquired through qualities such as personality, strength, intelligence and fighting skills.

Tribes

• Tribes are larger than bands, typically with hundreds rather than dozens of people.
• Usually, tribes have fixed settlements (e.g. a village or cluster of villages). But some tribes and even chiefdoms were herders that moved around.
• Tribes began to emerge around 13,000 years ago in the Fertile Crescent and later in other areas. This makes sense since a prerequisite for living in settlements is food production or an environment with abundant food resources.
• A tribe consists of more than one formally recognised kinship group (clans). But tribes are still small enough that everyone will know each other’s name and relationships.
• Land in a tribe belongs to particular clans, rather than to the whole tribe.
• Economic specialisation is minor. They won’t have a full-time bureaucracy, police force or taxes. Every able-bodied adult participates in hunting, gathering or farming. Members of a tribe cannot become disproportionately wealthy.
• Tribes still have an informal, egalitarian system of government and lack stratified social classes. Information and decision-making are both communal. Many villages will have a “big-man”, who is the most influential man of the village. But that is not a formal office. It is acquired through the big-man’s personal qualities rather than inherited.

Chiefdoms

• Chiefdoms are considerably larger than tribes, with several thousand to tens of thousands of people. They varied a lot depending on their size.
• Chiefdoms arose around 5500 BC in the Fertile Crescent and around 1000 BC in the Americas. By 1492 AD, chiefdoms were still widespread in the Americas, Polynesia and sub-Saharan Africa.
• The size of chiefdoms created potential for serious internal conflict. The solution was that one person, the chief, had a monopoly on the right to use force. Unlike a tribe’s “big-man”, a chief holds a recognised office, usually hereditary.
• The chief also made all significant decisions and had a monopoly on critical information.
• Chiefdoms did have one or two levels of bureaucrats (often lower-ranked chiefs). But these bureaucrats tended to be generalists who had many functions rather than specialists.
• In a chiefdom, society is effectively divided into hereditary chief and commoner classes.
• Chiefdoms have a redistributive economy (i.e. taxes or a precursor to them). From the commoners, chiefs would claim goods and labour. Some goods would be redistributed back to commoners but some would be retained by the chiefs or go to craftspeople.

States

• States arose around 6000 years ago in Mesopotamia, around 2000 years ago in the Americas, China, and Southeast Asia, and around 1,000 years ago in West Africa.
• Most modern states have populations exceeding 1 million.
• States have more far-reaching centralised control than chiefdoms. Early states had a hereditary leader such as a king. Leaders were similar to chiefs and exercised even greater monopoly over information, decision-making and power. Even in democracies today, Diamond notes that only a few individuals hold crucial information. They are the ones who control the flow of that information to other parts of government.
• States are organised on political and territorial lines, rather than on the kinship lines for bands, tribes and simple chiefdoms. In later states, the leaders and bureaucrats are non-hereditary and not selected on the basis of kinship.
• Redistribution or taxes in states is also more extensive.
• Economic specialisation is high. In states today, not even farmers are self-sufficient.
• States have many levels of bureaucrats.
• Conflict resolution is increasingly formalised with written laws, police, courts and judges.
• Many early states adopted slavery on a much larger scale than chiefdoms did. This is because they had more uses for slave labour, and they often had captives from war who could become slaves.
• States may also be multiethnic and multilingual (particularly empires formed by conquest of states). In contrast, bands, tribes and most chiefdoms only had one ethnic group and language.

Why bands and tribes do not work for large societies

Diamond suggests 4 reasons:

1. Conflict between unrelated strangers grows exponentially as populations increase. In small societies, two people in a conflict will be pressured by others to resolve the conflict peacefully, since many in the society will have a relationship with both of the feuding members. Whereas in larger societies, most people will only have a relationship with one of the feuding members so is more likely to egg them on rather than get them to back down.
2. Communal decision making becomes impossible.
3. A redistributive economy becomes necessary. Diamond states that large societies can only function economically if they have a redistributive economy as well as a reciprocal one. He writes: “Goods in excess of an individual’s needs must be transferred from the individual to a centralised authority, which then redistributes the goods to individuals with deficits.” [I’m not sure it’s true that this is a requirement of large societies. Diamond doesn’t really explain this point.]
4. As population density increases, the area available per person shrinks. So each person has less space in which they can find life’s necessities [and therefore has to trade with others to obtain those necessities, I think].

How and why states are formed

Other theories

Diamond attempts to explain how states are formed by first dismissing two other theories:

• Social contract theory. French philosopher Jean-Jacques Rousseau came up with the social contract theory. It is the idea that people make the rational decision to be part of a state because of the benefits that it offered. Diamond notes that this theory is not borne out by historical evidence of state formation.
• Hydraulic theory. This theory notes that any big, complex system (e.g. for irrigation) needs a centralised bureaucracy to build and maintain it. So people form states in order to get that system. [This seems quite similar to the social contract theory.] is Diamond notes that this theory is still popular with some historians and economists but again points out that it is not borne out by the evidence. Large scale irrigation systems came significantly after states emerged. Moreover, he notes that the theory only addresses the final stage of how states are formed, and not how societies moved from bands to tribes to chiefdoms.

Diamond’s explanation

Diamond first notes that food production made complex societies possible. Some hunter-gatherer societies reached the level of chiefdoms but none became states.

Food production and societal complexity feed off each other in an autocatalytic process.

• Complex societies allow for specialisation and the mobilisation of large labour forces to organise public works (e.g. irrigation systems). Both of these can intensify food production and therefore population growth.
• Food production in turn contributes to a complex society as it can generate food surpluses. Those surpluses allow economic specialisation and social stratification. Food production also permits people to become sedentary, which in turn allows them to accumulate more possessions, develop more technology and crafts, and construct public works.

There are two ways in which societies amalgamate:

• Merger under threat of external force. For example, Cherokee Indians originally had about 30 or 40 independent chiefdoms. They found they had to join up into a single confederacy when faced with increasing conflicts with white settlers. Similarly, the United States united in response to the threat of Britain.
• Conquest. Diamond refers to many examples including the Zulu, Hawaiian, Tahitian and Roman states and Aztec and Inca Empires.

Religion and ideology

• One way for elites (Diamond uses the term “kleptocrat” which I feel is a bit too strong) to gain public support and maintain power is to construct an ideology or religion to justify their authority.
• Chiefdoms typically had an ideology that supports the chief’s authority. The chief may also be a priest himself. Alternatively, he may support a separate group of priests whose job is to provide an ideological justification for the chief. This is why chiefdoms devote so much tribute to constructing temples.
• In early states, kings were often considered divine.
• Two other ways institutionalised religion and ideology benefit centralised societies are:
  • They help resolve conflicts. Unrelated people can live together more easily without killing each other if they are bonded by something other than kinship.
  • They give people a motive to sacrifice their lives for others. A society can become more effective at conquering others or resisting attacks if society members are willing to die for it. Notions of patriotism urge people to be prepared to die for their country if needed. Such sentiments are unthinkable in bands and tribes.

The decline of societies

• The book actually covers this in the Epilogue, but I think it belongs better here.
• Diamond’s coverage of this area is relatively brief. He suggests this as an area of further study and I think his points here should be taken more as possible answers rather than firm (or full) conclusions.

Fertile Crescent

• Diamond suggests the Fertile Crescent declined because of its low rainfall.
• Plant regrowth could not keep up with development and overgrazing, which led to erosion. Irrigation agriculture in an area with such low rainfall also led to salt accumulation in the land. This made the land unsuitable for agriculture.
• Today, large areas of the Fertile Crescent are desert. In contrast, much of northern and western Europe can still support intensive agriculture today, 7,000 years after food production arrived.

China

• Diamond suggests the reason China declined is because of its early unification.
• For example, in the early 1400s, China had impressive treasure fleets and led the world in maritime navigation. But the treasure fleets ended as a result of a power struggle between the eunuchs and their opponents. This backward step was not, in itself, unusual – this has happened in many other societies as a result of local politics. The difference is that China was politically unified. So one decision became irreversible (for a long period, anyway) as all shipyards ceased.
• In contrast, Europe has never come close to political unification. When Columbus wanted to sail westward, he could choose between persuading hundreds of princes in Europe to sponsor him. (He only succeeded on his fifth attempt.) When he succeeded, others followed.
• Diamond thinks the answer to China’s chronic unity and Europe’s chronic disunity is suggested again by geography:
  • Europe has a highly indented coastline, with five large peninsulas that are almost like islands. They evolved independent languages, ethnic groups and governments. China’s coastline is much smoother, with only Korea being a peninsula of note.
  • Europe also had two islands (Britain and Ireland) large enough to be politically independent and maintain their own languages. China’s two largest islands, Taiwan and Hainan, are each less than half the area of Ireland. (Japan was much more isolated geographically from the mainland than Britain was from Europe’s mainland.)
  • Europe is divided by lots of high mountains. China’s mountains are east of the Tibetan plateau and do not pose such a barrier.
  • China’s heartland is bound together from east to west by two long east-west navigable rivers (the Yangtze and Yellow Rivers). The area between the two river systems is also easily connected, eventually linked by canals. China therefore became dominated by two large core areas of high productivity (and these two areas were only weakly separated from each other). Europe’s two biggest rivers (the Rhine and Danube) are much smaller and connect much less of Europe. Europe has many scattered small core areas, none big enough to dominate the others for long. Even the Roman Empire at its peak controlled less than half of Europe.
• So geographic connectedness can positively or negatively affect the evolution of technology. Europe seemed to be in a “sweet spot” where it had enough geographic barriers to prevent political unification, but not enough to halt the spread of technology.

Examples of particular societies

In the fourth and final part of Guns, Germs and Steel, Diamond applies the general principles from the earlier parts of the book to examples from around the world.

Polynesia

• The Polynesian Islands were actually discussed in Part 1 of the book (in Chapter 2), rather than in Part 4. But the summary of that chapter fits better here.
• Eurasia had fully-fledged empires before Polynesia was event settled. Since Polynesia was colonised so late, even the oldest Polynesian societies only had about 3,000 years to develop before Europeans came.

Environmental variables

• At least six sets if environmental variables among the Polynesian islands:
  1. Island climate. Most islands near the equator have a tropical or subtropical climate. New Zealand’s climate is mostly temperate. The Chatham Islands and the southern part of New Zealand’s South Island is cold subantarctic. Rainfall varies significantly on the islands.
  2. Geological type. Some islands are just atolls or raised limestone. They have very thin soil and no permanent fresh water. Then there are volcanic islands, which are better than atolls in that they have diverse types of volcanic stones for making tools. Some volcanic islands have rich soil and permanent streams (e.g. Samoa, Hawaii). Others have rich soil but no streams (e.g. Tonga, Easter Island). New Zealand is a geologically diverse piece of continent (of Gondwanaland) with many mineral resources.
  3. Marine resources. Most of the islands have lots of accessible fish and shellfish. Easter, Pitcairn and the Marquesas are exceptions – they have rocky coasts, lack of coral reefs, and steeply dropping ocean bottoms.
  4. Area. New Zealand is the biggest of the Polynesian Islands by far. The smallest permanently inhabited island (Anuta) is only 100 acres.
  5. Terrain Fragmentation. The habitable terrain of Marquesas is fragmented by steep ridges. Other islands are not so fragmented.
  6. Isolation. Easter Island and the Chathams are remote and tiny. New Zealand, Hawaii and Marquesas are also very remote but at least their constituent islands are close enough to allow for regular contact in the same archipelago. Most other Polynesian islands were in regular contact with other islands.

Domesticated animals

• Most Polynesian islands originally had big flightless birds (e.g. moas) that had evolved in the absence of predators. These were all hunted to extinction quite quickly.
• Ancestral Polynesians brought with them three domesticated animals – chicken, pig, and dog – and domesticated no other animals within Polynesia. Many islands have all three of these, but some of the more remote ones have one or two missing. New Zealand got only dogs.

Agriculture

• Polynesian food production depended mainly on agriculture.
• At subantarctic latitudes, farming was impossible because Polynesian crops were tropical ones. People on the Chathams and the southern part of New Zealand’s South Island therefore had to revert to hunting and gathering.

Political units

• Political units ranged between a few dozen to 40,000 people (in Tonga; New Zealand had multiple political units as it was not politically unified).
• With a larger political unit, more people could be specialists not involved in food production so could have better technology. Larger political units could also have more people working to construct large-scale irrigation systems, etc for more intensive food production.

Moriori Genocide on Chatham Islands

• In 1835, a group of indigenous people of New Zealand, the Maori, travelled to the Chatham Islands. They brought guns and other weapons and killed hundreds of Moriori. In some cases they even ate them.
• The Moriori were a small, isolated group of hunter-gatherers. Their technology and weapons were simple. They had no experience with war. The Moriori had a tradition of resolving disputes peacefully and they had not wanted to fight the Maori.
• The Maori people came from a dense population of farmers, who had settled in New Zealand around 1000 AD. By this time, the Maori already had farming. They had far superior technology and weapons and were used to fighting wars with neighbouring tribes in New Zealand.
• Both the Maori and the Moriori had diverged from a common origins less than a thousand years earlier. The Moriori were originally Maori people who had left New Zealand to colonise the Chatham Islands.
• The Chatham Islands are small and remote. Farming was not viable in the Chatham Islands’ cold climate, so the Moriori reverted to hunting and gathering. Hunting and gathering did not produce large food surpluses. The Moriori could not support and feed many people who didn’t hunt and produce their own food (e.g. warriors, bureaucrats, chiefs). The Chatham Islands could only support a population of around 2,000 people.
• In contrast, New Zealand was very suitable for farming. The Maori population who remained in New Zealand increased and exceeded 100,000.
• Diamond points to this example as a brief, small-scale natural experiment that tests the impact of environments on human societies.

New Guinea and Australia

• During the Pleistocene Ice Ages, the Arafura Sea between Australia from New Guinea was dry land. The rise of the Arafura Sea around 10,000 years ago separated the two countries.
• The Native Australian and New Guinea societies were founded from Asian societies, but developed in substantial isolation from them.
• Native Australians and New Guineans also diverged genetically, physically and linguistically from each other. For a very long time, they developed isolated from each other and in very different environments.
• Some differences between the two environments:
  • New Guinea is mountainous and rugged. Australia is mostly low and flat.
  • New Guinea is one of the wettest places in the world. Australia is one of the driest.
  • New Guinea is close to the equator, so its climate varies only modestly from year to year. Australia’s climate is highly seasonal.
  • New Guinea’s soil is young and fertile because of volcanic activity and glacier movements. Australia’s soil is the oldest, most infertile and nutrient-leached soils of any continent. This is because Australia lacks volcanic activity, high mountains and glaciers.
• New Guinea posed more barriers to European colonisation than Australia did.
  • Malaria and other tropical diseases in New Guinea killed and deterred colonists. Australia did not have these diseases.
  • Its climate and environment were not suitable for European crops, which were adapted to a colder climate. Parts of Australia near the south were suitable for European crops.
  • New Guineans had some resistance to European germs by then because of their exposure to Indonesian settlers and traders. Western medicine had also improved by then and reduced smallpox and other diseases in the European populations. In contrast, Aboriginal Australians had little or no resistance.

New Guinea food production

• It’s generally acknowledged that agriculture arose independently in the New Guinea highlands around 6000 years ago.
• Farming was confined to limited areas of the highlands (between 4,000 and 9,000 feet) because of risks of drought, malaria, cloud cover etc. In the lowlands, people depended instead on hunting and gathering (including fish) and slash-and-burn agriculture.
• None of the world’s 56 largest-seeded wild grasses is native to New Guinea.accordingly, no cereal crops were domesticated in New Guinea.
• New Guinea’s staple crops, taro and sweet potato, are low in protein – even lower than white rice. Before the sweet potato arrived, the situation was even worse because the crops locally available did not grow well at New Guinea’s high altitudes. The sweet potato triggered a population explosion in the highlands.
• New Guinea had no domesticable large mammal species at all. The only domestic animals in New Guinea (pig, chicken and dog) all came from Southeast Asia through Indonesia. None of these could pull a cart.
• As a result, New Guinea highland farmers suffer from protein deficiencies (lowlanders can get protein from fish). They often ate small animals like mice, spiders, frogs to get protein. Diamond thinks that protein starvation may also be why cannibalism was common in the highlands.
• With all those limitations of food production, the population of New Guinea did not exceed 1 million until Europeans arrived.
• New Guinea’s population was also fragmented by the rugged terrain into smaller micropopulations. New Guinea has 1,000 of the world’s 6,000 languages, the highest concentration in any area of the world. Nearly half of those languages have fewer than 500 speakers.
• With such a small and fragmented population, New Guineans could not develop technology, writing and complex political systems that arose in much larger populations elsewhere.

Australia

• Compared to the other continents, Australia is by far the driest, smallest, flattest, and most infertile. Its climate is the most unpredictable and biologically it is the most impoverished. Unusually, it has an irregular nonannual cycle, the ENSO (El Nino Southern Oscillation), rather than the regular annual cycle in most other parts of the world.
• Native Australians were nomadic hunter-gatherers living in bands. They had very few domesticable native plants and no domesticable animals. Even modern plant geneticists have only been able to develop macadamia nuts from Australia’s native flora.
• We often think of Aboriginal Australians as “desert people” but they were not. They actually mostly lived in Australia’s wettest and most productive regions along the coasts. The reason they’re now in the deserts is because Europeans just killed or drove them out of the most desirable areas.
• The Aboriginal Australian population was only several hundred thousand people. But they were spread out over Australia and had limited exchanges with each other.
• The Tasmanian population of around 4,000 hunter-gatherers was particularly isolated. The Bass Strait between Tasmania and the rest of Australia was dry land in the Pleistocene Ice Ages. Around 10,000 years ago, the Strait flooded and cut off Tasmania from the rest of Australia. (Some smaller islands with populations of around 200 to 400 died out completely when sea levels rose and cut then off from Australia.)

Why did New Guinea food production and technology not spread to Australia?

• New Guineans were technologically advanced relative to Native Australians.
• But there is an island chain between New Guinea and Australia. Diamond compares the interactions between the two to the children’s game of “telephone”.
• Native Australians at Cape York would have only ever seen a very watered down version of agriculture on Muralug Island, the nearest island in that chain. And there were few or no pigs on the islands for the Australians to adopt (even if they had, they would’ve had trouble feeding them with no agriculture).

China

• China looks, at least to most laypeople, like a political, cultural and linguistic monolith. Unlike the world’s other five most populous countries, it is not a recent melting pot. China was unified politically in 221 BC and has remained so more or less since then.
• This unity is interesting because North and South Chinese are quite different genetically and physically:
  • North Chinese are most similar to Tibetans and Nepalese while South Chinese are similar to Vietnamese and Filipinos.
  • North Chinese tend to be taller, heavier, paler, with more pointed noses, and with smaller eyes that appear more “slanted”.
• Those genetic differences suggest that the North and South Chinese were historically reasonably isolated from each other.
• Diamond explains that, like other populous nations, China was also once a diverse melting pot. The difference is that it was unified much earlier.

Chinese languages

• China has 8 “big” languages and over 130 “little” ones with just a few thousand speakers. All languages fall into 4 language families.
  • Sino-Tibetan. This includes Mandarin and its relatives. Sino-Tibetan languages are distributed continuously from North to South China. In contrast, the other 3 language families have fragmented distributions.
  • Miao-Yao (aka Hmong). Miao-Yao has only 6 million speakers. It is particularly fragmented, with speakers scattered over an area from South China to Thailand. More than 100,000 Miao speaking refugees from Vietnam migrated to the US, where they are better known as Hmong.
  • Austroasiatic. There are 60 million speakers of this family. Vietnamese and Cambodian are the most widely spoken languages.
  • Tai-Kadai. There are about 50 million speakers from South China to Thailand and Myanmar. Thai and Lao are both members of this family.
• Diamond notes that all the languages currently spoken in Thailand, Myanmar, Laos, Cambodia, Vietnam and Peninsular Malaysia appear to be recent invaders from South China (and, in a few cases, Indonesia). So the original languages in those countries must now be extinct.

Food production

• China was one of the world’s first centres of plant and animal domestication.
• In fact, food production may have independently developed in China more than once. The earliest crops in China were drought-resistant species of millet in the North, and rice in the South, suggesting possibly separate domestication.
• China’s north-south axis made crop diffusion a bit slower but it was less of a barrier than in the Americas or Africa. The north-south axis covered a smaller distance in China and it wasn’t broken up by a narrow isthmus or desert.
• Moreover, China’s long east-west rivers (the Yellow and Yangtze Rivers) helped with crop (and other technological) diffusion.
• Chinese food production led to other technologies, including bronze metallurgy, writing, and various inventions. Technology predominantly spread from north to south.
• Food production also likely led to germs. European writings suggest that bubonic plague and smallpox may have arrived from China. Influenza is also likely to have come from China since pigs were domesticated early there and became very important to the Chinese.

Diffusion and unification

• States spread from North to South China during the first millennium BC. It culminated in China’s political unification under the Qin dynasty in 221 BC.
• Cultural unification also occurred over that same period as the Chinese states absorbed or were copied by the “illiterate barbarians”. Some of that spread was draconian. This spread can explain why Sino-Tibetan languages spread over most of China, and why the other language families became so fragmented.
• In turn, the people from South China spread into Southeast Asia. Modern people in Burma, Lao and Thailand are all recent offshoots of the South Chinese. There are very few hunter-gatherers of Southeast Asia remaining – the Semang Negritos (Malay), Andaman Islanders and Veddoid Negritos (Sri Lanka). These populations suggest that Southeast Asia’s native populations may have been dark-skinned and curly haired (like New Guineans) rather than light-skinned and straight haired (like Chinese and modern Southeast Asians).
• Korea and Japan were heavily influenced by China. Korea and Japan adopted rice, bronze metallurgy and writing from China. They also received West Asian wheat and barley through China. But their geographic isolation meant that, unlike the Southeast Asians, they did not lose their languages or physical and genetic distinctness.

Austronesian expansion

• The Austronesian expansion was among the biggest population movements of the last 6,000 years. One prong of it became the Polynesians.
• Austronesians originated from mainland China. They colonised and replaced the original inhabitants of Indonesia, but were only able to occupy a narrow strip of New Guinea lowlands. They were not able to displace the New Guinea highlands people at all.
• The people of most Indonesian islands and the Philippines have similar genes and appearance to South Chinese. Their languages are also quite homogenous – though there are many languages, they are closely related and fall within the same language sub-subfamily (Western Malayo-Polynesian) of the wider Austronesian language family.
• Humans have occupied at least western Indonesia for a million years, so you’d expect them to evolve some more diversity in that time. You also might expect them to have dark skin like other tropical peoples. One has to pass Indonesia to reach New Guinea and Australia 40,000 years ago, so you’d expect Indonesians to look like Aboriginal Australians and New Guineans. But Indonesians and Filipinos today have light skin.
• All these facts strongly suggest that the original populations of Indonesia and the Philippines were replaced relatively recently by South Chinese or Southeast Asians – too recently for the colonists to evolve dark skins and greater language or genetic diversity.
• Diamond points out that societies founded by the same Austronesian peoples (from Taiwan) developed very differently depending on their environments. Within 1000 years, Austronesians on the Chatham Islands had reverted to hunting and gathering while Austronesians in Hawaii had developed intensive food production and built a protostate.

Origins in Taiwan

• Taiwan’s indigenous people comprise only 2% of the current Taiwanese population. Over the last thousand years (and particularly after 1945) many mainland Chinese have settled in Taiwan.
• Diamond thinks that all the Austronesian expansion originated from Taiwan – first to Indonesia and the Philippines, and then further abroad to Polynesia and even Madagascar. He cites two broad strands of evidence – linguist and archaeological evidence.
  • Linguistic evidence.
    • The Austronesian language consists of 959 languages divided into 4 subfamilies. The Malayo-Polynesian subfamily is by far the largest, accounting for 945 of the 959 languages. The other 3 subfamilies are all confined to Taiwan.
    • The concentration of 3 of the 4 Austronesian subfamilies in Taiwan suggests that those languages were spoken for the longest time on Taiwan, as they’ve had more time to diverge from each other and become separate subfamilies. All the other Austronesian languages stemmed from a population expansion out of Taiwan.
    • By comparing modern Taiwanese, Philippine, Indonesian and Polynesian languages, we can reconstruct a “Proto-Austronesian language”. Diamond finds that the reconstructed language has words for “pig”, “dog” and “rice”, suggesting that these all featured in Proto-Austronesian culture. The reconstructed language also have words consistent with a maritime economy, such as “outrigger canoe”, “sail”.
    • You can use the same technique to reconstruct “Proto-Malayo-Polynesian”, the language Austronesians spoke after emigrating from Taiwan. This language contains words for tropical crops like taro, breadfruit, bananas, yams and coconuts. But the Proto-Austronesian language does not contain such words, so it suggests those crops were adopted after the emigration from Taiwan.
  • Archaeological evidence.
    • Beginning around 4000 BC, polished stone tools and distinctive pottery from South China appeared on Taiwan and on the opposite coast of the South China mainland. There is also evidence of rice and millet in Taiwan at later sites.
    • This same “package” of pottery, stone tools and domesticates appeared around 3000 BC in the Philippines, around 2500 BC on some Indonesian islands , around 2000 BC on the Indonesian islands of Java and Sumatra, and around 1600 BC in the New Guinea region.

Austronesians in New Guinea

• Austronesians appeared to reach New Guinea but failed to penetrate the island’s interior. However, there is evidence that Austronesians and New Guineans traded, intermarried and acquired each other’s languages for several thousand years on the North New Guinea coast and islands.
• Why did the Austronesians manage to overtake the native populations of Indonesia and the Philippines, but not New Guinea?
  • Before Austronesians arrived, most of Indonesia was thinly occupied by hunter-gatherers without even polished stone tools.
  • New Guineans had developed food production thousands of years ago. They already had polished stone tools and were competent seafarers.
  • New Guineans were also at least as resistant to tropical diseases as Austronesians. [What about crowd infectious diseases like influenza? The New Guineans did not have any domesticated animals other than the pig, chicken and dog from Southeast Asia. Perhaps they had already developed resistance to these diseases by the time the Austronesians arrived?]
• Diamond points out that these two different outcomes illustrate the importance of food production, which is ultimately driven by geographical features.

The Americas

• Humans first arrived in the Americas sometime between 14,000 and 35,000 years ago through Alaska. Either way, of the habitable continents, the Americas have the shortest human histories.
• When Columbus arrived in 1492, the native Indian population exceeded 1 million.
• European diseases spread in the Americas far in advance of the Europeans themselves. Germs alone largely wiped out some of the most advanced native American societies around the US Southeast and Mississippi River system.

Food production

• As noted earlier, the Americas had only one large domesticable mammal (the llama/alpaca). People couldn’t use llamas for milk, transport, war, or pulling ploughs.
• Once Europeans introduced suitable domestic animals, the native Americans readily adopted them. Native Americans became renowned for their mastery of horses and sometimes cattle and sheepherding.
• The eastern US’s founder crops were 4 plants domesticated between 2500-1500 BC. (Diamond notes there is controversy over when food production started in the Americas.) The 4 crops were pretty crap and only amounted to minor dietary supplements. Between 500-200 BC, another 3 crops were added. While those 7 crops were highly nutritious, they had other major disadvantages. Some had tiny seeds, could cause hayfever, skin irritation, or smelled really bad. Even modern plant breeders have had little success in exploiting North American wild plants.
• Corn first arrived from Mexico around 200 AD but did not grow well in the US’s colder climate. Also, corn is low in protein so it was not as valuable nutritionally as wheat or barley. A better variety of corn arrived around 900 AD and beans arrived around 1100 AD. At this time, farming grew significantly and triggered a population boom.
• By 1492, agriculture was widespread in the Americas. But hunter-gatherers still occupied a larger fraction of the area than in Eurasia.

Technological diffusion

• The Americas are more geographically fragmented than Eurasia. In addition to its North-South axis, it was broken up by areas unsuitable for food production or dense populations.
• The Americas’ geographic fragmentation is also reflected in its languages. All but a few Eurasian languages fall into about a dozen language families. In contrast, most linguists consider that, apart from two groupings (Eskimo-Aleut and Na-Dene around the Arctic and Alaska), Native American languages can only be grouped into a hundred or more language groups or isolated languages.

Defeat of Atahuallpa at Cajamarca

• This example is in Chapter 3 (in Part 1) of the book, rather than in Chapter 4.
• In 1532, not long after Columbus “discovered” the Americas, the Spanish conquistador Francisco Pizarro encountered the Inca emperor Atahuallpa in Cajamarca (a Peruvian town).
• Atahuallpa was the monarch of the largest and most advanced state in the Americas. The Incas revered him as a sun-god. At Cajamarca, he commanded around 80,000 Indian soldiers.
• But even though he was hopelessly outnumbered, Pizarro managed to capture Atahuallpa quickly with only a 62 cavalry and 106 foot soldiers. The Spanish killed thousands of Indian soldiers without a single casualty.
• There were many other examples of similar encounters where a few dozen European horsemen defeated thousands of Native Americans.
• Part of the reason for Pizarro’s success was that the Spanish steel swords, helmets, chain-mail armour, guns* and horses were simply superior. The Incan soldiers only had stone, bronze or wooden clubs, maces, slingshots and quilted armour. Horses and guns were also unknown to the Incans at the time. (It should be noted that guns played only a minor role at Cajamarca. Guns at that time were difficult to load and fire and Pizarro only had a few guns. But they did have a large psychological impact.)
• Another reason was that Atahuallpa had just won a civil war that had left the Incans divided and vulnerable, and Pizarro was able to exploit those divisions. The civil war in turn had been precipitated by a smallpox epidemic that the Spanish had brought to Panama and Colombia. The Incan emperor, Huayna Capc, as well as his heir had both been killed. Atahuallpa had had just defeated his half-brother to get the throne.
• Turning to less proximate causes of Pizarro’s victory, Diamond points to European maritime technology, the centralised political organisation that allowed Spain to finance, build, staff and equip the ships, and the writing that informed Pizarro of Columbus and Cortes’s voyages. (The Americas did have writing at this time but it was much more limited than in Eurasia.)
• Diamond points out that writing provided the motivation to journey to the Americas, the sailing directions to do so. It also gave Pizarro information about what he could expect there (even if it was not direct knowledge about the Incans, but about Cortes’ exploits against the Mexicans). In contrast, Atahuallapa had very little information about the Spaniards or their military power. What information he did have was received by word of mouth from an envoy who had seen Pizarro’s force for two days while they were at their most disorganised. Furthermore, he had not even heard or read of similar threats to anyone else at any other point previously in history.

Africa

• Humans have lived in Africa for around 7 million years, far longer than anywhere else. But in terms of food production, Eurasia had the the head start and advantages over Africa.
• Africa is very diverse, owing to its geography and long prehistory. One quarter of the world’s languages are spoken only in Africa, more than in any other continent.
• While Africa today is mostly black, up until a few thousand years ago, Africa had 5 of the world’s 6 major divisions of humanity: blacks, whites, Pygmies, Khoisan and Asians. (The sixth group is Aboriginal Australians.)
  • Blacks traditionally occupied west Africa’s coastal zone, as well as East Africa – north to Sudan and south to South Africa.
  • Whites are those in Africa’s north coastal zone and northern Sahara. They are not blue-eyed blond-haired whites, but they have lighter skin and straighter hair than “blacks”. Examples include Egyptians, Libyans, and Moroccans.
  • Pygmies are hunter-gatherers without crops or livestock. Like blacks, Pygmies have dark skins and tightly curled hair. But there are differences particularly in their much smaller size. Their skin colour is also more reddish, and they have more facial and body hair and prominent foreheads, eyes and teeth. There are about 200,000 Pygmies today, mostly scattered through the Central African rainforest.
  • Khoisan consisted of small-sized hunter-gatherers (San) and larger herders (Khoi). The Khoisan were formerly distributed over much of southern Africa. There are very few Khoi now as European colonists (or their germs) killed many of them. Others interbred with Europeans to produce the “Colored” and “Baster” populations in South Africa. There are also few San but a small number have remained in groups in Namibian desert areas. The Khoisan look quite different from blacks. Their skins are yellowish, their hair is tightly coiled and the women tend to accumulate fat in their buttocks (steatopygia).
  • Asians, like those in Southeast Asia, are found in Madagascar (along with blacks). The language spoken in Madagascar is Austronesian and very similar to that spoken in Borneo in Indonesia. There were already Austronesians in Madagascar when Europeans first arrived in 1500. Archaeological evidence suggests that Austronesians reached Madagascar by at least 800 AD, possibly earlier.
• Africa’s 1500 languages fall into just 5 families:
  • Afro-asiatic, which whites and blacks speak.
  • Nilo-Saharan and Niger-Congo, which blacks speak.
  • Khoisan, which the Khoisan speak.
  • Austronesian, which the Indonesians speak. [This is what the book says, but surely he means Madagascans?]
• The Pygmies are the only group which don’t really have a distinct language. Each group of Pygmies speak the same language as their neighbouring black farmers, with some differences.
• Diamond thinks that because the Pygmies and their language are currently so scattered, suggests that they used to be widespread until black farmers displaced them.
• He also thinks the same happened with the fragmented distribution of Nilo-Saharan languages and, to a greater extent, the Khoisan. The Khoisan language is unique in that it uses clicks as consonants (e.g. in !Kung, exclamation mark represents a click).
• All the Niger-Congo languages below the equator belong to the Bantu language subfamily. The other 176 Niger-Congo subfamilies are all in West Africa. The closest ones to Bantu are in a tiny area of Cameroon and part of eastern Nigeria. This indicates that the Bantu people, who are now all over Africa, originated from the Cameroon/Nigeria region.
• Food production and technology spread slowly through Africa due to its north-south axis and difficulties crossing the equatorial region.
  • Horses reached Egypt around 1800 BC but could not cross the Sahara for thousands for years.
  • Livestock reached the northern part of the Serengeti around 3000 BC but could not cross it for more than 2000 years.
  • Pottery was in Sudan and the Sahara around 8000 BC but did not reach the Cape until around 1 AD.

Food production

• The earliest evidence of food production in Africa comes from the Sahara. Between about 9000 and 4000 BC, the Sahara was more humid and had lakes and game. Saharan pastoralism precedes the earliest known date of around 5200 BC for food production arriving from Egypt (the Southwest Asian crops and livestock).
• Food production also arose in West Africa and Ethiopia.
• In the 1400s, when Europeans first reached sub-Saharan Africa, Africans were growing 5 sets of crops.
  • The first set were North African crops, all domesticated in the Fertile Crescent.
  • The next two sets’ wild ancestors occur just south of the Sahara. They are adapted to summer rains (Sahel rains fall in summer rather than in winter) and less seasonal variation in day length. The second set’s ancestors were probably domesticated in the Sahel region. They include sorghum and pearl millet, now staples in much of sub-Saharan Africa. The third set’s wild ancestors were probably domesticated in Ethiopia and are still mostly grown there.
  • The fourth set’s wild ancestors are in the wet climate of West Africa. Some are still confined to that region but others, such as African yams, have spread to other areas.
  • The last set originated in Southeast Asia. They include bananas, Asian yams, taro and Asian rice. Some of these were already widespread in sub-Saharan Africa by the 1400s.
• All of the native African crops (i.e. all but the Southeast Asian set) originated above the equator. The wild plants of southern Africa were just unsuitable for domestication. That gives us a hint as to why the Niger-Congo speakers from north of the equator were able to displace the Pygmies from around the equator and the Khoisan from below the equator.
• The only animal we know for sure was domesticated in Africa is the guinea fowl. There are also wild ancestors of cattle, donkeys, pigs, dogs and cats in North Africa but it’s unclear if they were imported from Southwest Asia or independently domesticated.

Bantu expansion

• In Zambia, north of where the Khoisans are now, archaeologists have founds skulls that bear a possible resemblance to the modern Khoisan’s.
• The expansion of ancestral Bantu farmers may have begun as early as 3000 BC.
• By then, the linguistic evidence indicates that Bantu already had cattle and wet-climate crops such as yams, but they didn’t have metal. They still did a lot of fishing, hunting and gathering. The Bantu’s wet-climate crops allowed them to farm in wet areas of East Africa unsuitable for earlier inhabitants.
• When they reached East Africa, the Bantu began to acquire sorghum and millet and iron. They also reacquired cattle as their cows from the tsetse-free Sahel zone died when crossing the equatorial forest.
• The acquisition of iron gave the Bantus an advantage over all other peoples in subequatorial Africa at the time. The Khoisan were still hunter-gatherers and did not have iron or crops. Within a few centuries, the Bantu farmers had colonised up to the east coast of South Africa.
• The Bantu people did not overrun all of the Khoisan. Some survived in southern African areas unsuitable for agriculture.
• The southernmost Bantu people, the Xhosa, stopped short of South Africa’s Cape Town. The Cape’s Mediterranean climate (winter rains) made it unsuitable for the Bantu’s crops. A consequence of this was that Dutch settlers at the Cape in 1652 only had to fight the sparse Khoisan herders, rather than a dense population of Bantu farmers with steel. They then had a secure base at the Cape to make further inroads. Later, when the Dutch fought the Xhosa with the advantage of a secure base at the Cape, it took them 9 wars and 175 years to subdue the Xhosa. If the Bantu had colonised the Cape before the Dutch, perhaps they might have prevented Dutch colonisation entirely.

Japan

Japan’s geography and climate

• During the Ice Ages, land bridges connected Japan with the Asian continent. Stone tools show there were humans in Japan as early as 500,000 years ago, long before there were boats.
• 13,000 years ago the sea levels rose, converting Japan into an archipelago.
• The natural resources in Japan were abundant, allowing its local population to remain hunter-gatherers without being nomadic:
  • Japan’s high rainfall makes it the wettest temperate country in the world. So its plants and forests were very productive.
  • The lakes, rivers, and seas in and around Japan were also incredibly productive, full of fish and other seafood.
  • Most of Japan’s land area consists of mountains unsuitable for farming, but the farmland it does have is very productive.
• Japan may look geographically similar to Britain but it is larger and more distant from the Asian mainland. Diamond thinks this is why Japan is more distinctive culturally from its East Asian neighbours than Britain is from its European neighbours.

The origins of most modern Japanese

• Most Japanese are genetically and physically similar to other East Asians, particularly Koreans. Culturally and biologically they are homogenous, except for a very different people called the Ainu on Japan’s Hokkaido island.
  • The Ainu are genetically related to other East Asians including the Japanese, Koreans and Okinawans.
  • When Japan annexed Hokkaido in 1869, the Japanese made deliberate efforts to expunge Ainu language and culture. The Ainu language is now virtually extinct and there are probably no purebred Ainu people left.
• However, what is puzzling is that the Japanese language is not closely related to any East Asian mainland language.
• There are 4 conflicting theories of the origins of modern Japanese:
  1. The Japanese gradually evolved from ancient Ice Age people who occupied Japan long before 20,0000 BC. This is the most popular theory in Japan.
  2. The Japanese descended from horse-riding central Asian nomads who passed through Korea to Japan in around 300 AD (but are not themselves Koreans). This theory is also popular in Japan.
  3. The Japanese descended from Koreans who immigrated to Japan around 400 BC. This theory is popular among Western Archaeologists and Koreans.
  4. The Japanese are descended from people from a mix of the other 3 theories.
• Diamond thinks the evidence suggests that the Ainu descended from the original hunter-gatherers in Japan, whereas the modern Japanese are the more recent arrivals from Korea. The main problem with this theory is the distinctive Japanese language (see explanation below).
• There is a lot of archaeological evidence for exchanges between Japan and Korea in the period 300-700 AD. The Japanese like to say this means they conquered Korea while Korea like to say they conquered Japan.
• As of 712 AD, the people inhabiting Japan were at last unquestionably Japanese (as we know them today). Their language was also unquestionably ancestral to modern Japanese.

Japan’s early history (pre-400 BC)

• The earliest written information about Japan comes from China. They called the Japanese the “Wa”, consisting of over 100 little states that constantly fought each other.

Pottery

• 12,700 years ago, around the same time that sea levels rose and made Japan an archipelago, Japan invented pottery.
• Pottery was quite revolutionary:
  • It allowed people to boil, steam or simmer food and thereby access food sources they previously couldn’t.
  • People could also feed soft boiled foods to small children, so they could wean kids earlier and thus shorten birth intervals.
  • Pottery triggered a population boom. Japan’s population grew from a few thousand to around 250,000.
• These were the first signs of pottery in the world:
  • When the Japanese invented pottery, they were still hunter-gatherers.
  • This is unusual because hunter-gatherers are typically nomadic. Pottery is generally found in sedentary societies (you can’t own much pottery if you have to move around all the time). In the Fertile Crescent, it was only around 1000 years after farming that pottery arose. But because the Japanese environment was so productive, they could be sedentary hunter-gatherers.
• Pottery started in Kyushu, the southernmost Japanese island. It spread north, along with the spread of trees rich in nuts. This suggested the increase in food availability permitted sedentary living and therefore pottery. The style of pottery was fairly uniform across Japan.

Jomon lifestyle

• Jomon is the name of the style of that early Japanese pottery. That name also applies to the early Japanese people who made it.
• The Jomon hunter-gatherers were possibly the densest populations of hunter-gatherers ever. However, they did not have much technology:
  • It’s not clear if they had agriculture at all – if they did, it was not much.
  • They had no domestic animals other than dogs and possibly pigs.
  • They also had no metal tools, writing or weaving.
• There were signs of Jomon trade with Korea, Russia and Okinawa. There were surprisingly few direct imports from China but that was because China and the Jomon were not in direct contact, only indirectly through Korea.
• Interestingly, the Jomon peoples’ contact with other societies did not seem to influence it much for 10,000 years.
  • Korea had agriculture including rice since 2,200 BC and metal since 1,000 BC. You’d think this might lead to Japan also adopting agriculture and metal being – either through voluntary adoption or invasion.
  • But the Tsushima Strait actually separated poor farmers in Korea from rich hunter-gatherers in Japan rather than the other way around. Japan’s climate was so productive that their hunter-gatherers were actually relatively rich. And rice was domesticated in southern China and spread slowly to Korea, because the Korean climate was a lot cooler. So early Korean farming could not compete with Jomon hunting and gathering.

The Yayoi lifestyle (from 400 BC)

• In around 400 BC, a new lifestyle (and possibly people), called the Yayoi lifestyle appeared.
  • The Yayoi lifestyle first appeared in Kyushu, immediately across the Tsushima Strait from South Korea.
  • It involved iron tools and full-scale agriculture with irrigated rice fields, canals, dams, banks, etc, 27 new crops and domesticated pigs.
  • There were also many Korean elements such as bronze objects, weaving, glass beads, Korean styles of tools and houses.
  • Evidence for war also arose – arrowheads, defensive moats, etc.
  • The Yayoi lifestyle triggered an immediate population explosion.
• The Yayoi lifestyle quickly spread from Kyushu to Shikoku and Honshu. But in cooler areas in the north, elements of the Jomon lifestyle remained and we see a mixed Yayoi/Jomon culture. In those places, rice farming was less productive and Jomon hunter-gatherers were densest.
• Japanese culture experienced far more change in the 700-year Yayoi era than in the 10,000 years before that. What happened in 400 BC?
  • The first theory (the one that Japanese like) says the Jomon hunter-gatherers gradually evolved into the modern Japanese by adopting technology from Korea.
  • The second theory is that Koreans migrated to Japan and diluted the genes of the Jomon people (only around 75,000 at the time). There is debate over how much immigration there was – some say a few thousand, others several million.
• Diamond finds the second theory more plausible:
  • In similar transitions elsewhere in the world, farming did not usually spread by hunter-gatherers adopting farming but by farmers outbreeding and/or killing hunter-gatherers. Korean farmers in 400 BC would have enjoyed a huge advantage over the Jomon people as they already had iron tools and intensive agriculture.
  • Yayoi and Jomon skeletons are also quite different. The Jomon skeletons are more like the Ainu people while the Yayoi skeletons are more like the modern Japanese.

Language issue

• The Japanese language does not seem related to any other language in the world.
• It is probably most closely related to Korean, but even then they are very different, sharing only about 15% of their basic vocabulary. That low percentage suggests that if the Japanese and Koreans were related, they diverged over 5000 years ago. But their biology suggests a much more recent arrival. So why are the Japanese and Korean languages so different?
• Diamond’s hypothesis is that the Jomon’s language was not actually similar to the modern Ainu language and that the Yayoi’s language was not similar to modern Korean.
• During the 10,000 Jomon years, they would have evolved linguistic diversity. We know that they were never unified politically and they had diverse pottery styles and subsistence techniques.
• Many Japanese place names in the north include Ainu words (e.g. for “river” or “cape”) but these words don’t appear further south. This suggests that the Yayoi people may have adopted local Jomon place names, but Ainu was only the Jomon language in the north, and there was a different language in the south.
• The Jomon language may have had a common ancestor with Austronesian language family. The Japanese language shows some influence of Austronesian languages in the shared preference for “open syllables” (consonant followed by a vowel).
• Korea consisted of three kingdoms before it became unified politically in 676 AD. Each kingdom had a different language. The modern Korean language is derived from the Silla kingdom, but another kingdom was the one that had close contact with Japan. So the Yayoi language may have been from that other kingdom.

Responses to (possible) criticisms (in epilogue)

• Diamond defends himself against people who might call him a “geographic determinist”. That label, he notes, seems to have unpleasant connotations that suggest human creativity counts for nothing. But all human societies contain inventive people – it’s just that same environments had more favourable conditions for development and inventions than others.
• Diamond recognises that compressing 13,000 years of history on all continents into a 400-page book inevitably results in some oversimplification. But one compensating benefit, he argues, is that comparing different regions over a long time period yields insights that a detailed shorter-term study of a single society cannot.
• Circumstances change, and past primacy is no guarantee of future primacy. Is it possible the factors Diamond identifies may no longer be relevant today? After all, the Internet and air freight has greatly facilitated the spread of ideas and technologies.
  • But Diamond thinks that the rules are still the same. The nations rising to power today are ones that link back to the Fertile Crescent or China in some way (including nations populated by emigrants from Eurasia). The prospects of dominance of sub-Saharan Africans, Aboriginal Australians and Native Americans remain dim.
• Diamond recognises that his analysis leaves unanswered many important questions about cultural and individual idiosyncrasies.
  • For example, was there anything about India’s environment that predisposed it toward a socioeconomic caste system? Or was there anything about the Chinese environment predisposing toward Confucian philosophy and cultural conservatism?
  • What about idiosyncratic individuals? To what extent did people like Hitler, Alexander the Great, Augustus, Buddha, Chris, Lenin, etc really “change” events? Or were they just in the right place at the right time? Diamond contrasts Thomas Carlyle’s “Great Men” theory with Otto von Bismarck’s deterministic view.
• Diamond accepts that cultural and individual idiosyncrasies could be wildcards that make history inexplicable in terms of environmental forces. But it remains an open question how much of an impact idiosyncratic individuals truly have in the long run.

Epilogue: the future of human history as a science

• Most historians do not think of themselves as scientists and receive little scientific training.
• Many people think that history is just a random mass of facts – e.g. “History is just one damn fact after another”.
• But Diamond argues that history is a science:
  • Science just means “knowledge” (from the Latin word scientia).
  • Among the natural sciences, astronomy, climatology, ecology, evolutionary biology, geology and palaeontology all involve the study of history but are all regarded as sciences.
• To gain knowledge, you should use whatever method is most appropriate to the particular field. For most historical science, you’ll have to use observation, comparison and natural experiments rather than lab experiments.
• In chemistry and physics, the test for whether you understand a system is whether you can predict its future behaviour. But human societies are extremely complex and involve many independent variables that may affect each other. So even if you understand or can explain something after the fact, that does not necessarily translate into predictability:
  • Historians can make some predictions based on statistical trends. But individual cases will have their own unique features. For example, Diamond can predict with a high degree of accuracy that, of the 1,000 babies born at a particular medical centre, between 480 to 520 of them will be boys. But he has no way to know in advance whether his next two children will be boys. Predictions in history are therefore most feasible over large spatial scales and long time periods, where the impacts of small-scale events are averaged out (in other words noise is reduced).
  • There are also long chains of causation that separate final effects from ultimate causes lying outside that field of science. For example, dinosaurs became extinct because of asteroids, but the field of astronomy is very remote from palaeontology.
• In short, Diamond acknowledges the difficulties in understanding human history compared to understanding other fields of science involving fewer independent variables. But he points out that people generally regard the histories of dinosaurs, nebulas and glaciers as “science”. Diamond hopes that the study of human history can also be pursued more scientifically.
• Some suggested extensions of Diamond’s work are:
  • To quantify further and establish more convincingly the four sets of intercontinental differences he has identified. For example, working out how many big mammals were disqualified for domestication by each factor on each continent, particularly in Africa.
  • Use smaller geographic scales and shorter time scales. For example, why did European societies, rather than societies in the Fertile Crescent, China or India, end up taking the lead in technology?

2017 Afterword – Rich and Poor Countries

• One of the central questions in economics concerns is understanding why some countries are rich while others are poor? The answer to that question has enormous policy implications. If we knew the answer, perhaps we could help poorer countries become rich.
• Economists tend to credit good institutions for rich countries being rich. Human institutions are things like laws, codes of behaviour, principles of governance.
• Three examples commonly cited are (1) South Korea vs North Korea; (2) West Germany vs East Germany; and (3) Hispaniola and the Dominican Republic. Diamond accepts that these comparisons provide “compelling evidence” that institutions can produce big differences in national wealth, even when geography is largely the same.
• However, Diamond thinks it is an overgeneralisation to then claim that institutions are the sole or major explanatory factor. Two reasons:
  • Geographic factors are still important. Tropical and landlocked countries (taking into account navigable rivers) tend to be poorer. These effects can sometimes override institutions.
    • Tropical countries. Tropical infectious diseases and parasites affect humans, animals and plants. Also, tropical locations tend to have less fertile soils.
      • For example, Africa has 48 countries – 10 in temperate zones in the north and south, 38 in the tropical middle. 37 of the 38 tropical countries are poorer than any of the 10 temperate countries.
      • The 3 countries in South America’s south temperate zone (Argentina, Chile and Uruguay) are richer than any of its 9 tropical countries.
    • Landlocked countries. Transport overland is about 7 times more expensive than transport by sea or river.
      • In Africa, within each of the temperate/tropical sets, coastal countries are about 50% richer than the landlocked ones.
      • Bolivia is South America’s poorest country, and is the only one that’s landlocked.
  • It doesn’t explain why some countries have good institutions while others don’t. Good institutions are just a proximate cause – not an ultimate cause. It’s not like good institutions randomly drop out of the sky onto some lucky countries.
• Diamond suggests that good institutions evolved out of complex institutions.
  • At the end of the last Ice Age, all humans were hunter-gatherers and had relatively simple political, economic and social institutions.
  • Institutions such as money, rule by kings, market economy and taxes are complex institutions that can make a society richer. Not all complex institutions are good, but a society without complex institutions can’t have good complex institutions.
  • The ultimate cause of complex institutions is agriculture, which led to densely populated sedentary societies. Because some countries had agriculture for longer, they also had complex institutions for longer.
  • Countries with a long history of agriculture and state governments have higher incomes per capita on average. The effect is large and accounts for half of the explained variance.

Other Interesting Points

• It was not until the beginning of the early 20th century that Europe’s urban populations became self-sustaining. Before then, people in cities kept dying due to diseases in unsanitary conditions. The urban population was only maintained through healthy peasants constantly migrating to the city.
• When syphilis was first recorded in Europe in 1495, it covered people’s entire bodies in pustules, caused flesh to fall off people’s faces, and led to death within a few months. By 1546, the disease evolved to what it’s like today. It’s much slower to develop, the symptoms are not as bad, and it only causes death after many years. So it keeps people alive for longer, so that it can spread more.
• During the Ice Ages, sea levels were higher. Some shallow bodies of water today were dry land back then – e.g. Bering Strait separating Alaska and Russia, English Channel.
• Wild almonds contain enough cyanide to kill us.
• A swollen belly is characteristic of a high-bulk but low-protein diet.
• Frisian is the Germanic language most closely related to English. Frisian is spoken by a tiny coastal area of Holland and western Germany. Hence you can easily deduce that English arose in northwestern Europe and spread from there.
• It was only around WWII that Emperor Hirohito finally told the Japanese people he was not of divine descent.
• Archaeology in Japan is very well funded and attracts a lot of public attention because they believe that ancient sites are those of the modern Japanese themselves.
• Otto von Bismarck had said that “The statesman’s task is to hear God’s footsteps marching through history, and to try to catch on to His coattails as He marches past.”
• Zambia on paper seems to have a lot of advantages compared to even the Netherlands. But the average income in the Netherlands is 33 times higher than that in Zambia.
  • Zambia generates all of its own energy by hydroelectric dams, with even a surplus to sell to other countries. In contrast, the Netherlands has to buy its oil and gas.
  • Zambia is very rich in minerals, particularly copper. The Netherlands is not.
  • The climate in Zambia is warm, and farmers can grow several crops per year. In the Netherlands, farmers can only grow one crop.
  • Zambia is peaceful, stable and democratic. It has never had a civil war, nor any war with its neighbours. Unlike the Netherlands, Zambia has never been invaded by a neighbour.

Radiocarbon dating

Radiocarbon dating is estimating the date of something by looking at its carbon 14/carbon 12 ratio. Plants take up atmospheric carbon, which has a known and approximately constant ratio of carbon 14 to carbon 12. Once a plant or animal dies, its carbon 14 content slowly decays into carbon 12.

There are a number of problems with radiocarbon dating. The two mentioned in the book are:

• Until the 1980s, radiocarbon dating required relatively large amounts of carbon, more than the amount found in small seeds or bones. Scientists would instead date materials nearby at the same site that they thought were “associated with” the food remains. They often used charcoal from a nearby fire, but the fire may not actually have been associated with the food remains at all. The radiocarbon dating techniques today bypass this problem and allow radiocarbon dating of a single small seed or bone.
• The carbon 14/carbon 12 ratio in the atmosphere actually fluctuates slightly over time. This fluctuation can result in errors if you assume a constant ratio. To correct for this error, scientists use the growth rings of old trees. So you can count up the rings to get an absolute calendar date, and then analyse a wood sample for its carbon 14/carbon 12 ratio. A “calibrated” radiocarbon date is one that has undergone this correction. The book uses calibrated radiocarbon dates. Calibrated dates can be up to 2,000 years earlier than an uncalibrated date (and possibly even more).

My Thoughts

I really enjoyed this book. It contained lots of things I hadn’t thought about before. Examples include the east-west axis of a continent makes the spread of plants and animals easier than a north-south one, or how you can use linguistics to trace prehistoric human migrations. It had never occurred to me that pottery could be such a groundbreaking invention. It makes sense once Diamond explains it, but I had simply never thought about it before.

That said, I didn’t find Guns, Germs and Steel to be a particularly easy read. It’s very dense and Diamond uses plenty of facts and examples. His writing style is clear and convincing, but Diamond also uses plenty of words and concepts I wasn’t familiar with. There are lots of asides where he explains the scientific methods used to understand how things unfolded in the past (e.g. radiocarbon dating, or how they work out where something was first domesticated). I haven’t studied biology since I was 15 – and even then it was a limited part of our broader “Science” curriculum. I also found that referring to maps/Google while reading was helpful as my knowledge of geography is not as great as I’d like it to be.

Guns, Germs and Steel is certainly an ambitious, transdisciplinary book. As a layperson in all the fields discussed in the book, it’s difficult to assess how accurate the facts were and how solid Diamond’s arguments were. But he did seem to provide appropriate caveats, particularly when summarising complex things into a table or map. He does not overstate his conclusions, either. For example, Diamond states in the epilogue that the book just puts forward some “partial answers plus a research agenda for the future”, rather than a “fully developed theory” (I’m not sure if this was also in earlier versions).

There are quite a few criticisms of Guns, Germs and Steel. I have summarised what I have found of those criticisms and written up some thoughts in a separate post here. Diamond has also responded to some complaints that his book promotes “geographical determinism” on his website.

There were some parts I did not find entirely convincing but they were, on the whole, quite minor. Many times he’d offer up “at least” x reasons for something, but some of the reasons were much more developed or well-argued than others. Overall, Guns, Germs and Steel did make me want to learn more and seek out competing views, which can only be a good thing.

Some have criticised the book for being a bit repetitive. This was certainly true particularly towards the end – many parts of the chapter about the Americas’ disadvantages had already been covered previously and could have been shortened. It’s also true that the key takeaways from this book could be summarised in a much shorter form, as I have done so above. But I liked the care Diamond took in explaining his reasoning each step of the way, and I think it added greatly to the book’s persuasiveness.

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If you enjoyed this summary of Guns, Germs and Steel, you may also want to check out:

• Book Summary: Sapiens: A Brief History of Humankind by Yuval Noah Harari
• Sapiens vs Guns, Germs and Steel
• Book Summary: The 48 Laws of Power by Robert Greene