Sapiens: A Brief History of Humankind

Who are we?  A common question, but seldom asked from the standpoint of Homo sapiens. Yuval Harari provides some fresh answers, drawing on an array of academic disciplines, including biology, anthropology, archaeology, paleontology, psychology, and sociology. The book has created quite a buzz, having been read by the likes of Bill Gates, Mark Zuckerburg, and Barrack Obama. 

Born in 1976, Harari received his PhD at Oxford and currently teaches history at Hebrew University in Jerusalem.  He’s unusually curious about everything and not afraid to step outside his academic niche.  He pushes the envelope of what a historian can and can’t do, by digging deep into fields far beyond his purview. How did humans evolve from apes into creatures with a large brain, then develop language, culture, role divisions, and empires?  Where do fire, cooking, language, and cooperation fit in?  How did the Sapiens brain get to be so large?  All questions so big, nobody expects perfect answers. No single academic program could cover a tenth of this material. It often comes down to enlightened speculation, at which Harari happens to be a master.

Harari starts off the book with a bang, as in the Big Bang: 13.5 billions years ago, time and space were born. 300,000 years later came atoms. 3.8 billion years later came living organisms. 70,000 years ago, Homo sapiens arrived on the scene. Roughly 20,000 years later came what Harari and others call the “Cognitive Revolution,” and it’s this topic that puts Harari’s book on the map, in my opinion. Here he paints the story of Homo sapiens as they emerged from just another mammal struggling to survive, to masters of their environment. He builds his story in ways not possible 20 or even 10 years ago, drawing on new scientific evidence informed by imagination and common sense.  For example, the knowledge that modern human DNA can be up to 3% or so from Neanderthal was only first published in 2010. It’s left to the imagination, just how the two species came to procreate, however limited and short-lived.

Thankfully, Harari explains things in layman’s terms. Homo is a genus. A genus can include many varieties. The genus for the cat family, Panthera, includes lions, tigers, jaguars, and pussy cats. Our human genus of Homo first branched off the Great Ape family tree about 2.5 million years ago, beginning with Australopithecus. Harari reserves the word “human” for all living members of the genus Homo, which is currently down to one member (us). Our last living human relative was the dwarf-like humans in the Flores Island of Indonesia, who died 12,000 years ago. Before that were Neanderthals (30,000 years ago), and Homo denisova in Siberia (50,000 years ago).

Harari envisions the possibility that Homo sapiens may one day evolve into a new species, not by the slow hand of natural selection, but by genetic engineering. Species, of course, is defined as an animal population able to produce fertile offspring. Hence, horses and donkeys are not the same species since they are not sexually attracted to each other and can’t produce fertile offspring. Midway through the book, it becomes clear that Harari is very cynical about the human tendency to harm, enslave, and oppress one another. As scientific knowledge grows, there may come a day when humanity will be faced with a choice of allowing science to improve upon the species, by lengthening lifespan, eliminating certain diseases, or possibly modifying the aggressive tendencies. (More to come on the future of Homo.)

Harari pays close very attention to cranial anatomy and brain size. Humans have very large brains, but these brains have not come without a price. Our brain accounts for 2-3 percent of body weight yet consume 25% of our energy, compared to 8% for other apes. At the same time our brains grew in size, we walked more upright, our muscles atrophied, and our hands became adept at tool making.  What was driving all this? Harari speculates that fire was a big catalyst. Some humans used fire as long as 800,000 years ago, and by 300,000 years ago, our Homo sapiens ancestors were using fire on a daily basis, as were Homo erectus and Neanderthal. Suddenly, equipped with fire, humans were truly different from all the other animals. Now humans could heat themselves at night, cook their food, or burn down entire forests. Today's technology gives humans an astronomically higher leverage over nature.  

Cooking! While apes spent five hours per day chewing, early humans spent one hour. Cooked food required less energy to digest, allowing for a much shorter digestive tract. That surplus energy was directed to the brain. In Harari’s explanation, fire is integral to human evolution. Absent fire, modern humans would not have been possible. Cooking not only freed up energy for brain development, it also encouraged role divisions, underscoring the idea that human evolution was greatly accelerated by the process of socialization within tribal groups.

Stadel lion man
Stadel lion man, circa 35,000-40,000 years ago

The Cognitive Revolution began in Africa and was carried forth in migrations, such as the second great migration out of Africa. Once again they visited the Middle East, this time succeeding at driving out the Neanderthals. Many things were invented around this time, such as needles, boats, bows and arrow, oil lamps, and new kinds of art more refined than previous art. The Stadel lion-man, an ivory figurine from 35,000 to 40,000 years ago found in Germany, has been called the oldest known Homo sapiens artwork, showing that humans were interested religion and imaginative beings.  Imagination and language were indeed the gateways through with sapiens advanced, leaving the rest of the animal kingdom behind. 

Harari examines several theories of language development. Human language evolved within bands of maybe 50 individuals, according to one theory.  Monkeys could communicate messages such as “Danger, a lion is nearby!”.   But sapiens could say something like, “This morning by the bend in the river a lion was stalking a herd of buffalo,” or gossip about what other tribe members were doing.  Early language evolved into fantastic mythology tales about beings things that demanded fear and respect. From mythology came the ability of some humans to motivate entire tribes in the pursuit of common interests. This new, collective imagination helped humans live cooperatively, in much larger groups than before. 

Harari has some bad news for the anti-collectivists in the world today: Humans rule the world today only because of our ability to cooperate within groups. As a species, we are inherently cooperative, not the opposite.  Neanderthals were individualists.  Modern humans were able to accomplish great things only because of their shared myths and collectivism. 

Harari also has bad news for those who think the Agricultural Revolution of 12,000 years ago was all to the upside. Ever the contrarian, Harari throws shade on the idea that agricultural villages were superior to hunter-gatherer society. He believes our behavior patterns were largely formed long before the Agriculture Revolution. Humans have only been farming for 12,000, but were hunting and gathering for several million years before that, to the first homo, Australopithecus. That helps explain when people stumble upon high caloric food, they tend to binge on it, for example, because that opportunity may not come again. Harari speculates that Hunter-gatherers had to be on their toes at all times and must have led interesting, adventurous lives compared to farmers, who were stuck in one place and did not enjoy the same healthy variety of food. 

Also, farming introduced something completely new to human development: targets of attack. Surplus grain could become the envy of a neighboring tribe, tempting an attack.  Strongmen could demand taxes in the form of crops, or build empires using slave labor. While hunter-gatherers had natural limits on their growth, farmers had far fewer natural restrictions. Under farming, population could mushroom out of control. However, while I find the notion that hunter-gatherers had a better life than farmers to be interesting, I’m not sure I buy it. We simply have no way to gauge the hardship of hunter-gatherers, nor the degree of comfort experienced by farmers, knowing their grain reserves were full or their pigs getting fatter.

In any case, Harari challenges you throughout the entire book with his provocative, contrarian ideas, dismissing so many of our dear and cherished notions as sacred cows. He takes on subjects that are generally not part of polite society’s table talk: What to do about surplus unskilled humans, or the coming end of Homo sapiens, or the possible need to improve the species by manipulating the human genome, or the coming merger between living and digital forms of intelligence, into something known as “cyborgs.” 

For my taste, Harari seems ever too willing to shock the present day sensibilities, ever too willing to make a bold step forward into the Brave New World of Aldous Huxley and beyond.  No doubt, the future will be presented with some very difficult questions.  Fortunately, we do not have to decide today what future generations will have to decide for themselves. We would probably make the wrong decision anyway.