Avi Tuschman is an evolutionary anthropologist and the author of “Our Political Nature: The Evolutionary Origins of What Divides Us.”

A Brief History of Humankind

By Yuval Noah Harari

Harper. 443 pp. $29.99

Yuval Noah Harari is an emerging rock-star lecturer at the nexus of history and science. In a recent talk at Google on “Silicon Prophets,” he stunned the audience by convincing them that the most interesting place in the world today in religious terms is Silicon Valley and that “techno-religions” will replace liberalism’s cult of the individual as big data overwhelmingly surpasses the predictive power of our feelings and intuitions.

Harari’s thinking is amplified in his new book, which has quickly become an international bestseller. “Sapiens” takes readers on a sweeping tour of the history of our species. The author structures this ambitious journey around three momentous events that have irrevocably shaped the destiny of humankind: the Cognitive Revolution, the Agricultural Revolution and the Scientific Revolution.

‘Sapiens: A Brief History of Humankind’ by Yuval Noah Harari (Harper)

The Cognitive Revolution arose from the evolution of the massive human brain. Harari ponders the considerable energy cost of maintaining such an expensive thinking organ and the concomitant atrophy of our physical strength compared with other primates’. He correctly points out that it’s not entirely obvious what first spurred the development of our species’s extraordinary intelligence.

On the origins of language, however, Harari is more certain: It evolved as a way for social animals to gossip about other people’s reputations. In addition, language allows people to communicate about abstract concepts such as religion. And religion, in turn, bonds people together and permits cooperation among much larger populations than chimpanzee troops can sustain.

Our hunter-gatherer ancestors were not always cooperative, though. Harari stays well-balanced by citing the high level of violence among prehistoric populations and present-day foragers such as the Aché of Paraguay. He also admonishes readers not to take the romanticized view that our ancestors lived in harmony with nature, because we have been, since our earliest days, “the deadliest species in the annals of biology.” Within only 2,000 years of humanity’s arrival in the New World, indigenous peoples drove to extinction 84 of the Americas’ 107 genera of large mammals — all before the invention of the wheel, writing or iron tools.

Next, Harari walks readers through the Agricultural Revolution. About 10,000 years ago, our ancestors began to spend nearly all their time domesticating a few plant and animal species. Like Michael Pollan, Harari argues that these plants manipulated people into dramatically expanding their habitats and multiplying their genes. In return, these species did the same for sapiens, although monoculture produced unhealthy diets, sedentarism and farm animals spawned more infectious diseases, and most people had to engage in back-breaking labor at the bottom of a steeply hierarchical social pyramid. Thus, Harari wittily describes the Agricultural Revolution as “history’s biggest fraud.”

With pith and awe, the author defines the Scientific Revolution as the point in history when “humankind admits its ignorance and begins to acquire unprecedented power.” This scientific progress, he asserts, was fueled by the twin forces of imperialism and capitalism. Rather than conquering only neighboring territories as did imperialists past, Europeans broke with convention by setting out for distant shores to conquer uncharted land and gain knowledge. The British, for example, not only surveyed the natural resources of India but also “took the trouble to collect information about rare Indian spiders, to catalogue colorful butterflies, to trace the ancient origins of extinct Indian languages, and to dig up forgotten ruins.”

Harari recounts, with more wonder than moralization, how the “military-industrial-scientific complex and technological wizardry” led to a period of European dominance, followed by the globalization of science and its power. He puts into perspective the truly awesome feats that humans have accomplished over the 500 years since the Scientific Revolution, such as discovering microorganisms, splitting the atom and landing on the moon.

Harari then muses on where our species is headed. He considers genetic engineering, artificial intelligence and the possibility of the “singularity,” when technology may intimately integrate with or overtake us. This clear-sighted section foresees a future that will surely challenge our notion of humanity. In an especially insightful moment, the author wonders whether the story of Frankenstein, and its moral that natural humans are obviously superior to any cyborg, may be simply a comforting myth.

Throughout the book, Harari’s formidable intellect sheds light on the biggest breakthroughs in the human story. Yet numerous parts of “Sapiens” reflect an inner conflict between the author’s freethinking scientific mind and a fuzzier worldview hobbled by political correctness. On the one hand, he champions cultural relativism by arguing that “history declared its independence from biology” at the time of the prehistoric Cognitive Revolution. On the other hand, he asserts that human behavior is governed by genes and biochemical algorithms.

This confusion resurfaces numerous times in “Sapiens.” For instance, Harari insists at multiple points that social hierarchies and moral emotions (such as the idea of fairness) exist only in the human imagination. Here he ignores much primatological research on rank, as well as the fact that various forms of altruism analogous to our own also exist among apes and monkeys. And he concedes elsewhere that ability may play some small role in human hierarchies.

Harari also claims that our mental abilities have not changed at all over the past 30,000 years. And yet he speculates elsewhere that the much more recent rise of agriculture and industry opened up new “niches for imbeciles” by allowing people to rely on the skills of specialists to survive, instead of forcing them to be multitalented generalists, as in earlier hunter-gather societies.

Harari believes that religion emerges from a belief in supernatural agency combined with arbitrary rules, but he sees little connection with biology. Much like some of the new-atheist science writers, he disregards how individual differences in religious practice significantly affect fertility rates and reproductive patterns. For those of us taking evolutionary approaches to the social sciences, Harari underestimates how intimately our genes and physiology influence our moral emotions. His cultural relativism also leaves him unable to explain why gender inequality has changed substantially over the course of human history, even though the important phenomenon has predictable causes.

Perhaps the most thought-provoking aspect of “Sapiens” is the author’s questioning of whether historical revolutions have any implication for human happiness. The answer, Harari proposes, is that the evolutionary success of our species, along with the technological powers we’ve gained, has brought much individual suffering. A case in point is the Agricultural Revolution, which kept many more people alive under much worse conditions. And the Scientific Revolution has arguably given a Chinese factory worker today a harder life than his hunter-gatherer ancestors had. Like evolutionary fitness, Harari concludes, history’s successful revolutions disregard the well-being of individuals.

By suggesting that history may be at odds with individual happiness, Harari is the intellectual heir to T.H. Huxley, who in his 1893 book, “Evolution and Ethics,” pitted a humanist morality against an evolutionary struggle for existence. The cruelness and kindness of evolution and history, in truth, could fill four encyclopedias. Still, Harari’s book is important reading for serious-minded, self-reflective sapiens.