Tuesday, April 7, 2015


Histories come in different flavors in accord with the tastes of their authors. Some are detailed chronologies of events while others gossip about the private lives of key actors. Still others concern themselves with grand themes and broad analyses; any book titled Sapiens: A Brief History of Humankind scarcely can be anything but one of these. Published in 2014,Yuval Noah Harari’s book begins when at least six species of humans co-existed on earth, discusses factors that may have led to the emergence of a sole survivor (Homo Sapiens), provides a global overview of prehistory and history, and ends with speculations about whether future bioengineering (or just plain engineering) will lead to our replacement by a new species of human, transhuman, or nonhuman. That’s a lot of territory to trek in 428 pages counting footnotes, but Harari still pauses here and there long enough to make some interesting arguments. Even the ones with which I disagree are valuable as thoughts to ponder.

Two themes in particular run through the book. First, Harari argues that the critical difference between Sapiens and other humans, including the equally big brained Neanderthals, was the ability to form social networks larger than 150 individuals. 150 is the limit below which modern people are able to maintain easy familiarity; above a group size of 150 we begin to lose track of names and relationships, which is to say that we can regard some of the members as strangers. There is no evidence any hominid other than Sapiens ever formed larger groups. Sapiens hunter-gatherer bands tend to split once they reach this size, but Sapiens did find a way to achieve larger associations. Harari credits a cognitive revolution by which Sapiens was able to create social fictions and believe in them: common origin stories, common mythologies, common religions, and the like allowed people to expand the definition of “us” to form tribes, alliances, and trading networks. These allowed us to accept commonality and kinship with people we didn't know personally. This was a killer app against a more fractured “them.” Such fictions continue to underlie modern societies. The fictions can be purely ideological; Harari cites the classical liberal idea of natural human rights and the socialist idea of human equality as examples. Just because an idea is fiction doesn’t mean it isn’t useful. Quite the contrary. But, he argues, it still is fiction. Money is a shared fiction; money is valuable only because people believe it is; when they cease to believe it (and this happens with some frequency) a currency will crash. Nations, too, are fictions that exist by consensual belief.

His second argument is that determinist theories of history are pleasing but wrong. Random events and the whims of individuals can have vast long-term consequences: “the better you know a particular historical period, the harder it becomes to explain why things happened one way and not another.” Humankind, he says, forms a second order chaotic system. A first order chaotic system is one that is not affected by predictions – e.g. the weather. A second order chaotic system is one in which predictions change the outcome; a respected investment firm that makes a prediction about a commodity price, for example, will affect the price by that very prediction. So, whatever current trends might seem to be, things easily can take unexpected turns. In the 1990s, for example, many folks argued the world was moving inexorably toward secular capitalist liberal democracy (remember “the end of history”?); nowadays that looks doubtful.

That human myths are flexible and arbitrary is not a new idea. Nietzsche in Beyond Good and Evil and elsewhere remarked that prevailing ethical systems have no inherent truth but were invented to keep the current elite in power while rival ethical systems are invented by those who want to transfer power from the current elite to themselves. (This simple and, in retrospect, obvious argument unsettled my ideological confidence when I was young.) Myths nonetheless are enormously effective tools for social organization, and Harari may be onto something when he points to Sapiens’ capacity for them as a key advantage as opposed to just a capacity for language per se (of the practical “a lion is over there” variety), which we possibly shared with other human species.

Harari doesn’t convince in every chapter and even some of his “facts” are debatable, but his book is an intriguing read. Besides, anything that can prod folks to question their own mythological certainties in our world of clashing true-believers is welcome. Recommended.

pity this busy monster, manunkind - e.e. cummings



  1. Sounds like an interesting book, and I had to go over to Amazon to investigate it further. Seems there plenty of ideas that he talks about to think about (and blow your mind). It's hard for me to imagine early man 2,000 years ago no less earlier, and that we evolved from chimpanzees. I don't feel alone however in trying to wrap my head around that concept.

    The idea of imagined or abstract concepts to form societies is a strange one too: religion, money, nations. It would be nice if humans could bio-engineer a way to get along better, maintain order, and prevent annihilation. I'm not sure how that would happen or work out, but it probably wouldn't be without some sort of coup/resistance. Unless you could secretly slip it by or into our cultures & others as well.

    I was watching a BBC nature program called The Planet (I believe), it was one that dealt with the ocean, and how was wowed at how symbiotically different species work together thru nature. Humans seem to separate ourselves away from the other species. I wonder how he came up with the 150 number as a network for groups? I assume from research, but seems awfully pat (granted I'm sure he using using it more to make a point). One of the scenes in the Ocean series, however, show a school of dolphins and how they'd work together to corral a bunch of fish together in order to eat them. I thought that was an amazing bit of nature.

    Thanks for the review, sounded plenty food for thought.

    1. I’m glad the review struck your fancy about the book enough to look it up on Amazon. I don’t buy into everything Harari has to say, but he does make a pretty good case on some of his big points.

      150 is a number I’ve encountered before in this context. Anthropologists generally agree that 100-150 is the common maximum group size of hunter-gatherer bands. (A 20-50 range as a subdivision of 150, also recurs, but the bigger number is the key one.) In a larger population it’s hard for members to keep track of each other’s personal details – we’re not wired to handle much more. When bands get bigger they split in two. There is a correlation in primate species between cortex development and the size of the close social groups they can maintain. Evolutionary psychologist Robin Dunbar did the math on this and came up with 148.3 for humans. He then looked at 21 surviving hunter-gatherer groups in various environments and found the average population to be 148.4. People in more advanced societies recreate those group sizes. The average Christmas card list is 154. Armies commonly have units about this size, e.g. the Roman centuries or US Army companies. While people may have hundreds of facebook “friends” they rarely interact regularly with more than 150 of them. Dunbar refers to the (independently reached) sociological principle that groups larger than 150-200 need a central authority to maintain order and cohesion, while smaller groups often can get by with informal controls (i.e. peer pressure). This is one reason small towns typically are safe. In her book “I See Rude People” Amy Alkon notes that you can’t very well hold up the local liquor store when the owner knows your mother.

      It may well be that in order to get ourselves to care about more than our particular 150 group – something we are not pre-wired to do – we need some mythological help

  2. Ok, I'll buy that premise. :)

    To override that 150 premise might make a good SF story or novel--something chemical or bio-mechanical, chemical that can be worn or something akin to a brainwashing process like in A Clockwork Orange.