A Review of Sapiens by Yuval Harari

One-sentence summary: The history of humanity is best viewed as three revolutions: the cognitive revolution beginning 70,000 years ago characterized by the development of language; the agricultural revolution that began 12,000 years ago and led to the first permanent settlements enabled by large-scale cooperation; and the scientific revolution which commenced around 1600 when the modern ideals of humanism, liberalism and democracy were first adopted and technological progress began its exponential path.

It’s perfectly acceptable if you graduated from high school with no desire to ever pick up a history book again. The endless listing of names and dates typical of the American history curriculum is incredibly effective at driving any enthusiasm for studying the past out of students. My knowledge of history post-high school consisted of a jumbled mix of (entirely American) names and events (Betsy Ross wrote the Constitution right?). The few times I went so far as to begin a history book since then, I have felt my mind shut down at the first mention of a name-date-event combination. I enjoy books with bold ideas, those that examine trends and try to explain movements, rather than those that get mired in the endless details of who exactly did what when. Some history books seem like they are on the verge of stepping back and looking at the big picture only to zoom right back in and lose the forest in a thicket of trees. I like the sound of studying the past to learn from our mistakes, but when the past is presented in list form, it can be pretty hard to take away anything relevant. Therefore, I was excited if somewhat skeptical when I heard about Sapiens: A Brief History of Humankind, a book with an idea no less grand than the entire story of humanity, from our first upright steps on the African Savannah 2 million years ago to this very day (and even slightly into the future). The fact that the book seeks to explain central driving themes of human progress gave me hope that this would be a history book that eschewed traditional formats.

Another fault of history as it is conventionally taught is that is gives the appearance that the past is linear, with one foregone conclusion leading to another, often driven by a single character (the “Great Man” fallacy). Sapiens, written by Israeli history professor Yuval Harari, demonstrates instead that the past was full of innumerable diverging paths with never any guarantee of forward progress in one direction. It is constructive to view history through the overall trends that enable these different possibilities and to try and understand how we have changed biologically, socially, and morally during each of these periods. The choice of any dividing era of history will always be arbitrary, but Harari chooses a handy (and easily remembered) breakdown into three ages: the cognitive revolution, agricultural revolution, and scientific revolution. Harari has taken on a task with an ambitious scope, but by replacing names and dates with bold ideas, has succeeded in creating a highly readable account of how we got to this point (and where we might be heading).

The Cognitive Revolution

Our tale begins with an interesting question that few of us have likely considered: why are we, Homo sapiens, (Latin meaning “wise man”) the only still-living species in the genus Homo? (Brief note: a species is the most specific form of taxonomic classification for an organism, while genus is one step up the ladder. Organisms within the same species can mate and produce fertile offspring while species in the same genus are similar but not exact genetic matches). The genus Canis (“dog”) for example contains numerous species as diverse as domestic dogs, wolves, coyotes, and dingoes. We know for a fact that many other species of humans walked the Earth at one time, from the first Homo habilis (“handy man”) that appeared around 2.1 million years ago to Homo neanderthalensiswhich went extinct a mere 40,000 years ago (I’ll use the convention established by Harari of referring to members of the genus Homo as humans and the species sapiens as sapiens). The two plausible options for our current single species situation are interbreeding and extermination. Either sapiensthoroughly mixed with other human species to the point where they were assimilated into a single species, or our ancestors wiped the other members of the Homo genus off the Earth. As is often the case, the truth is likely somewhere between the two extremes. Recent studies have shown that modern humans in Europe and the Middle East share 1–4% of their unique human DNA with Neanderthals. It may not seem like a large amount, but it is enough to irrevocably prove that sapiens and neanderthalensis interbred to some extent. While this is intriguing in and of itself for the complex dynamics that it suggests — what would a meeting between two species of ancient humans look like? Were these inter-species relationships forbidden or encouraged? — the more interesting conundrum is that archaeological evidence suggests that sapiens was neither the smartest nor the most physically capable of the Homo genus. How then did sapiens manage to survive when all other of our brethren did not?

The best theory to explain the endurance of sapiens is that individually our species was not better adapted to survive, but collectively, sapiens was far more capable than any other Homo species. This early sapien collaboration was enabled by language, in particular, language that could explain abstract concepts not grounded in concrete reality. Abstract concepts provide the difference between saying “there is a lion over there, we should watch out right now” to “there is a lion over there, perhaps we should build a fence to protect ourselves in the future.” The fence and the future do not yet exist, but it is the ability to imagine that they do so and to take actions reflecting the possible future reality that set sapiens apart. Human’s advantage over other animals was enabled by an ability to master our environment through the creation of tools and by using resources beyond their primary value (eating a piece of fruit from a bush is extracting the primary value of the fruit; shaping a rock into an arrowhead is a secondary use of the rock) while sapiens’ advantage over other humans arose because of developments in the speech region of the brain. Improved communication capabilities allowed for planning and the spreading of beneficial innovations between individuals. Archaeological finds suggest that while some members of Homo used the same basic ax for over a million years — can you imagine a smartphone model that does not improve for millennia? — while sapiens constantly developed new iterations of tools, such spears that made it possible to attack an enemy from a distance. The cognitive enhancements were not dedicated solely to the warfare. Early sapiens also formed the first cultures and began making objects that served an aesthetic in addition to functional purpose. While none of these concepts presented in the book are groundbreaking, they are presented in a broader context that lets readers see how the details of a particular evolution feature affected the success of our species. Furthermore, it is possible to extrapolate these findings to the present day; these trends suggest that today we should promote exactly those features that made our early ancestors so capable as a collective. Laws that prohibit free communication and policies that prevent the spread of information inhibit the very advantages that allowed us to attain our privileged position as the sole representatives of Homo on the planet.

The Agricultural Revolution and Shared Myths

The tale of humanity begins to take off with the first permanent settlements near modern-day Israel and Jordan about 12,000 years ago. Contrary to popular perception of the agricultural revolution as a great step forward in average living standards, Harari paints a much darker picture calling agriculture “History’s biggest fraud.” What could possibly be negative about settling down for a life of guaranteed sustenance in a village surrounded by other humans? Well, for starters, work hours increased after the development of farming. Raising crops is unsurprisingly labor-intensive, and early farmers had 12 or more hours of back-breaking work to look forward to each day, as opposed to hunter-gatherers who could expect to spend about 4–6 hours on an average day foraging for nutrition. Even modern humans living in societies with 40-hour work weeks spend more hours supporting themselves than did hunter-gatherers. Moreover, the type of work involved with agriculture was repetitive and mentally tedious compared with the problem-solving and varied environments encountered in a hunting lifestyle. Studies of pre-historic anatomies suggests that humans living in the first permanent settlements were physically much smaller than their hunter-gatherer relatives, indicating that the quality of nutrition actually decreased after we began raising our own crops (Harari points out that it is more accurate to say that corn and wheat domesticated humans rather than the other way around because crops forced us to settle in one place). We traded a life of constant novelty (and danger) as nomadic hunter-gatherers for banality, long work hours, and poor nutrition as fledgling farmers.

If the transition to agriculture was so detrimental on an individual level, than why did humanity nearly unanimously decide to adopt this system? The answer is simple: humans traded individual life satisfaction for the well-being of the entire species. Individuals in villages had less enjoyable lifestyles, but they were able to support and raise more children because of the guarantee of at least a survival amount of sustenance. Consequently, the population of agricultural societies boomed and farming tribes were able to dominate nomadic bands through sheer numbers. Agricultural, for better or worse, became the default option for humans and allowed for the beginning of the exponential growth in population that has not slowed to this day. The ability to trade individual happiness for the good of the species was enabled by the creation of what Harari has labeled inter-subjective realities. The two conventional forms of human experience are subjective: concepts that cannot be touched such as emotions and ideas, and objective: physical realities like the objects and environment around us. Inter-subjective realities occupy a middle-space: they are creations that exist only in the human mind but enable collective action because a vast number of people believe in them. When we look at our modern world, we see we are surrounded by inter-subjective realities: religion, money, government, nations, and corporations are all shared myths. There are no gods except in the minds of humans and once enough people stop believing in a particular god, she/he will cease to exist, as evidenced by the thousands of religions throughout human history that are no longer practiced. Money is perhaps the best example of an inter-subjective reality. We don’t generally stop to think about it, but the pieces of green paper we spend so much of our waking time trying to acquire have no inherent value. They by themselves cannot satisfy our hunger, increase our happiness, or cure illness. However, they can be traded to achieve those ends because everyone in our society believes that money should have value. If all humans were to collectively stop thinking that money had any value tomorrow, then that would be the new reality. Moreover, we can exchange money for goods and services without any pieces of paper changing hands. As an illustration, consider that $60 trillion worth of transactions are conducted around the world on a yearly basis yet only $6 trillion of actual money exists. The entire system depends on the large-scale belief that the changing of numbers on a screen can represent a change in ownership of a physical object.

The idea of shared myths that enable collective action is the most important in the book. When viewing the world in this context, we can see how nearly all of our institutions are founded on one inter-subjective reality or another. Laws only have force because enough people believe in them to allow us to create police forces that enforce the rules. Government is not a fundamental constant of the universe, but rather a system where we willing subject ourselves to the control of a larger entity because we have convinced ourselves that is the proper thing to do. The critical aspect of inter-subjective realities is even though the concepts themselves have no concrete existence, they inspire action that results in the transformation of the world around us. Humans are incapable of maintaining a social circle larger than 125–150 individuals through direct communication (known as Dunbar’s number). Any group smaller than this can be compelled to action through personal relationships between members of the group. However, as human societies expanded past this number at the beginning of the agricultural revolution, inter-subjective realities came to take the place of relationships as a motivating factor for action. Two citizens in a village of 10,000 may be complete strangers, but they are willing to work together if they share the same god, just as two individuals in a large corporation today can collaborate even without a personal relationship because they believe in the purpose of the corporation. As living conditions for individual humans decreased with the adoption of farming, humanity as a whole successfully expanded and citizens were compelled to work together because they shared the same myths and stories. When we must work with a stranger, we find it easier if they share the same belief systems, such as a political alliance or nationality. Even though we may have no personal experiences together, we share a common set of myths and values that unite us and allow for productive collaboration.

The Scientific Revolution and Our New Guiding Myths

Beginning 450 years ago, the shared myths of humanity underwent a transformation. We slowly began to discard religious dogmas and an unquestioning acceptance of the order of the world in exchange for secular beliefs and inquiry. While there had been individuals who investigated the natural world and made some progress in explaining how things work in antiquity (the Greek Eratosthenes and the Persian Avicenna come to mind), the general consensus prior to the 1600s was that God — or another diety — had created the world in its present form and that there were no unanswered questions if only one looked for the answers in the word of God. It was only as individuals and gradually societies began to throw off the shackles of religious thinking and admitted that humans did in fact not know everything that progress began in fields such as biology, geology, math, and physics. The scientific revolution truly began once we started to admit our own ignorance. Much as the deeper you delve into a subject, the more you realize you don’t know about it (a phenomenon that manifests itself in the Dunning-Kruger effect), as we began to admit our ignorance in some areas, we quickly discovered that we were standing at the very edge of an unimaginably vast continent of knowledge.

The embrace of our ignorance was the dawn of the remarkable era characterized by incredible gains in our knowledge of the world. However, as Harari reminds us throughout the book, science does not just happen for the sake of knowledge. There always must be something used to justify scientific inquiry, and for the majority of the past 400 years, those forces have been imperialism and capitalism. Today we remember the great exploration fleets for their discoveries of new lands (that in reality had been inhabited for thousands of years) but the real purpose was for empires such as France, Spain, and Britain to expand their reach. Even the voyage of the HMS Beagle, the famous expedition on which Darwin conducted his research that decades later would lead to the theory of evolution by natural selection, was a surveying expedition with the intention of mapping out new territories for military advantage and expansion. The point is not to discount the knowledge gained through these expeditions, but it is to admit there was always an ulterior motive behind the discoveries. Today, science is mostly conducted under the guiding hand of capitalism. In the end, someone must pay the bills for any research, and the decision for which projects to fund often comes down to an economic potential. Again, this in no way disparages science, but we must remember that science never occurs in a vacuum and there are always interested parties behind any finding that should encourage a healthy amount of skepticism.

As in agricultural times, our society still stands on shared myths. Moreover, although in our secular society we like to think of them as much more advanced than traditional belief systems, in the end, these collective beliefs, namely humanism, liberalism, and democracy, are nothing more than modern-day instantiations of religions. Humanism, or the concept that every individual has inherent worth and dignity has become the dominant world view in developed countries. In contrast to conventional belief systems, humanism holds that individuals should derive their own ethics and values internally rather than depending on an external definition delivered by a higher being. Furthermore, humanism emphasizes the importance of rationality and evidence-based decision making. In order to live as humanists, we need to respect the differences of every individual and work to ensure the average standard of living of every human increases regardless of what tribe they are from. Humanism is best viewed as a universal religion with the only sacred object being the human or humanity as a collective. Classical Liberalism, which is distinct from the modern day political idea of liberalism in the United States, embraces the autonomy of all individuals and posits that the greatest right any human has is that of self-determination, or the ability to choose one’s path. Liberalism and humanism go hand in hand as both belief in the worth of individuals and the idea that equality should be held up as a goal for any human society. These two worldviews originated in the thinking of many 17th century philosophers such as Sir Thomas More and Francis Bacon, and, in combination with Democracy, or the idea that people should be able to determine their own government (democracy is from the Greek meaning “rule of the people”), they form the basis of our modern institutions. The takeaway from this section is not that humans today are vastly different and superior to our ancestors, but that we share the exact same tendencies which manifested themselves under different names. We need shared beliefs in order for our society to function, so we should not advocate moving away from them, but it is helpful to take a step back and realize that much of what we take for granted and think of as unchangeable rests on a foundation not of concrete but of mythical constructions of our imaginations.

What Comes Next

Harari is definitely more interested in the present/future of humanity than on the past. This can be observed in the rapidity with which he zooms over tens of thousands of years of humanity (although granted there are not that many records to draw upon from this era) in order to arrive at the present day and then delve boldly into the future. As a long-term optimist more concerned with the future than the past, I found the more modern coverage of the book fascinating. We are entering uncharted waters as the pace of social norms change not on the millennia-scale of biological evolution, but on the yearly or even monthly pace of technological advancement. Several possible outcomes for the future are presented here which are explored in depth in the sequel to Sapeins, Homo Deus: A Brief History of Tomorrow (review coming soon…). At the risk of putting words in his mouth, Harari seems to be cautiously optimism about the long-term prospects of humanity. As he points out, we have made remarkable progress in the latter half of the 21st century in reducing the rates of war, famine, and plague to historical lows, and we are now turning to even more ambitious projects such as the pursuit of machine superintelligence and vastly expanded human lifespans. Yet, we still have not answered some basic questions about ourselves. Even as we have gotten much wealthier, healthier, and live for substantially longer, the subjective happiness of humans has not increased. Although survey data does not go back much further than 100 years, people have reported about the same level of life satisfaction for over the decades. Moreover, people in wealthier countries are not generally any happier than those in developing parts of the world.

How should we view the collective progress of humans over the past two million years if all the advances have not made us one iota happier? Harari suggests that we need to spend our research efforts in the coming decades not so much on physical well-being, but on understanding the much more complex world of emotions and mental states. The reason we are not content even with objectively less suffering in our lives is that happiness = reality-expectations. When reality exceeds our expectations, we experience joy, and when our expectations were much greater than our actual experience, we are disappointed. The issue is that every time we improve our material standing, we raise our expectations which means that reality must also get better in order for us to experience emotional gains. Likewise, we view ourselves in the context of our neighbors and people in our socioeconomic class as opposed to past humans or even those in other countries living in much different circumstances. The happiness equation implies that we even though we will always be driven to improve our well-being, any improvement will not really make us satisfied. We are on a quixotic quest for the objects that we think will make us happier as we increasingly push to the side those parts of our lives — personal relationships, time spent with family, quiet times sitting and staring at the scenery — that actually have been shown to bring us lasting joy.

Harari ends the book by saying that the question we need to ask moving forward is not “What do we want?”, but “What do we want to want?” While cryptic, the message is that in the 21st century, we should concentrate on defining what makes us happy and how we can construct a society that leads to the greatest increase in happiness rather than continuing to increase wealth. Instead of judging the success of a country on its Gross National Product (the total value of all the goods and services produced by the citizens of a country) we should compare countries based on Average Citizen Happiness. I agree with Harari that the next frontier in medicine might not be physical, but mental and emotional. We have figured out the keys to a long life, but now we need to concentrate on the factors for a enjoyable life. Where I disagree with Harari is in his dire prediction for the future of humans as machine intelligence becomes superior to humans in any number of tasks. The main argument is that humans will be rendered economically useless by more capable machines in the near future. In prior technological revolutions, when we lost our physical advantage over machines, we switched to industries in which we maintained an intellectual advantage, but already algorithms that are more skilled than humans at numerous cognitive tasks are being implemented in many situations. While the concept of technological evolution leading to human irrelevance seems to be prevalent among some of the leading technology figures of our day, I am more optimistic about the ability of humans to adapt to changing situations. Sapiens demonstrates that it was human ingenuity, enabled by a unique set of biological and cognitive advances, that allowed us to shape the world to our will and this ability to solve complex problems through cooperation has us well prepared for the next set of challenges.

Recommendation

There are so many critical ideas in this book — inter-subjective realities, ignorance begets knowledge, communication as a radical innovation, how to define happiness — that reading any review or summary can never capture a majority of them. I recommend reading the entire book and then sitting quietly for a whole week to let it sink it. I finished this book brimming with subjects to talk about and was quite disappointed to realize that not everyone I encountered had also read the book. Sapiens is opinionated at times, and the last section is more aptly categorized as science fiction than history, but that is part of what differentiates it from traditional mundane history accounts. Sapiens is incredibly well-researched, but any history book, no matter how thorough, is bound to have minor errors that will only be revealed through subsequent findings. The key to avoiding being wrong when talking about the past is to focus on the larger trends, those that will be unlikely to change even as the underlying details shift. The book is readable precisely because it does not spend time examining every minute detail of historical situations. This work, along with several other history books with bold ideas (Guns, Germs, and Steel and The Better Angels of Our Nature) have finally managed to overcome the four dreadful years of history I experienced in high school and made me once again curious about the past. When I want to be put to sleep, I know that I have a stack of old history textbooks that I can rely upon, but when I want something interesting to discuss at work or the dinner table, I am confident that Sapiens will provide me with conversations for years to come.