I picked up Yuval Noah Harari’s Sapiens (find in a library) because of my academic interest in early social complexity and specifically how we humans became the complex social creatures embedded in networks that we are today.

Ostensibly a “history” book (Harari’s PhD at Oxford was in history), Sapiens unexpectedly turned out to be much more than a history book full of names, dates, and places. Instead, Harari focuses on what I can best describe as large-scale shifts in the population (both form and quantity) of the Earth, and, of critical importance, the origins of these shifts.

While Harari doesn’t specifically bring a complexity science perspective to Sapiens, he is erudite and obviously exposed to a broad range of ideas and academic disciplines in addition to history. Biological anthropology, archaeology, cognitive psychology, environmental science, and economics are all very well represented.

Harari doesn’t pull any punches and relies heavily on research and science throughout the book. He discusses both sides of issues and notes if evidence is scant and debate continues, for example, in the competing hypotheses regarding what happened to Homo neanderthalensis, commonly known as Neanderthals. This question appears to have been answered in recent years by DNA evidence, though some “how” questions still remain.

The book is heavy at just over 400 pages, but Harari’s style drew me in from the start: The book opens with a two-page “Timeline of History,” in which he starts at 13.5 billion years ago goes through the Industrial Revolution and ends, interestingly, at “the Future.”

To give an example of his style:

13.5 billion years ago: Matter and energy appear. Beginning of physics. Atoms and molecules appear. Beginning of chemistry.

3.8 billion years ago: Emergence of organisms. Beginning of biology.

[…]

500 years ago: The Scientific Revolution. Humankind admits its ignorance and begins to acquire unprecedented power.

I know of no other author who’d pen “Beginning of physics” and “Beginning of biology” in this manner.

Harari is both concise and a contrarian, and I love a contrarian thinker.

Moreover, he gets complexity and the means by which large-scale cascades and changes can occur as the result of many small interactions (“tipping points,” to borrow Malcolm Gladwell’s book title).

In one of my favorite passages, Harari invokes chaos theory in explaining why history can’t be explained deterministically nor can the future be predicted. He writes on page 240:

So many forces are at work and their interactions are so complex that extremely small variations in the strength of the forces and the way they interact produce huge differences in outcomes.

He continues, explaining that exacerbating the problem of predicting the future is the fact that history is a Level Two chaotic system. A Level One chaotic system, like the weather, does not react to predictions made about it. A Level Two chaotic system, on the other hand, reacts to predictions made about it. Example: stock marketscog.

Harari also talks about the spread of ideas over networks: culture (the idea of “memetics”) and nationalism. [Robert Axelrod’s model The Dissemination of Culture uses agent-based modeling to explain the process of cultural dissemination.]

Perhaps the most helpful idea in Sapiens is Harari’s discussion of how we evolved to become Homo sapiens from our chimpanzee forbears and, importantly, what differentiated the Sapiens species from our closest relatives (i.e., the now extinct other members of genus Homo: Homo rudolfensis, Homo erectus, Homo neaderthalensis, Homo denisova, Homo floresiensis, Homo ergaster, Homo soloensis and, quite possibly, others which have simply not been discovered in the archaeological signatures to date). This section of the book, the Cognitive Revolution, tackles the implausibility of the Sapiens catapulting from “an animal of no significance” to the very top of the food chain and spreading like wildfire across an entire planet. Rich with discussions of extant research in psychology and genetics, Harari argues that the collective ability of Sapiens to create shared mental models and myths very likely explains the successes that simply could not be achieved without collective action on such a massive scale. This idea is key for both cognitive and social psychologists seeking to understand how individual cognition results in the emergence of behaviors at the aggregate level of groups, and sometimes enormous groups.

For those looking for a quick exposure to Harari and his ideas, while I heartily recommend reading Sapiens, Harari’s 2015 TED talk nicely covers his take on the role of shared mental models (or “stories”) in the Cognitive Revolution of Homo sapiens:

I’d be remiss if I stopped here, since Harari goes on to discuss the transition of Sapiens from hunter-gatherer bands to agricultural pastoralists during the Agricultural Revolution and then, provocatively, the surprisingly very few forces that have managed to unite mankind into what is increasingly one single global society on planet Earth: money (and, importantly, trust in what money represents), empires, and religions. Harari does not shy away from frank discussion of religion, including humanism.

Finally, Harari covers the Scientific Revolution and how a fundamental shift in our thinking – namely, that despite what empires or religions might profess to know, Sapiens in fact, were ignorant of many things that science could answer – that ultimately spurred so much progress in what is truly the blink of an eye in the very long history of Homo sapiens.

The combination of history, science, and critical interpretation made Sapiens (find in a library) a thoroughly enjoyable read.