https://medium.com/bull-market/violent-warfare-is-on-the-wane-right-99223faa45e6

Violent warfare is on the wane, right?

Many optimists think so. But a close look at the statistics suggests that the idea just doesn’t add up

by Mark Buchanan on May 17, 2015

A spate of recent and not so recent books have suggested that “everything is getting better,” that the world is getting more peaceful, more civilized, and less violent. Some of these claims stand up. In his book The Better Angels of Our Nature, psychologist Steven Pinker made the case that everything from slavery and torture to violent personal crime and cruelty to animals has decreased in modern times. He presented masses of evidence. Such trends, it would certainly seem, are highly unlikely to be reversed.

Pinker also suggested — as have others, including historian Niall Ferguson — that something big has changed about violent warfare since 1945 as well. Here too, the world seems to have become much more peaceful, as if war is becoming a thing of the past.

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Nassim Taleb criticized Pinker’s arguments a few years ago, arguing that Pinker didn’t take proper account of the statistical nature of war as a historical phenomenon, specifically as a time series of events characterized by fat tails. Such processes naturally have long periods of quiescence, which get ripped apart by tumultuous upheavals, and they lure the mind into mistaken interpretations. Pinker responded, clarifying his view, and the quotes above come from that response . Pinker acknowledged the logical possibility of Taleb’s view, but suggested that Taleb had “no evidence that is true, or even plausible.”

That has now changed. Just today, Taleb, writing with another mathematician, Pasquale Cirillo, has released a detailed analysis of the statistics of violent warfare going back some 2000 years, with an emphasis on the properties of the tails of the distribution — the likelihood of the most extreme events. I’ve written a short Bloomberg piece on the new paper, and wanted to offer a few more technical details here. The analysis, I think, goes a long way to making clear why we are so ill-prepared to think clearly about processes governed by fat tails, and so prone to falling into interpretive error. Moreover, it strongly suggests that hopes of a future with significantly less war are NOT supported by anything in the recent trend of conflict infrequency. The optimists are fooling themselves.

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One final thing, and maybe this is most important. Cirillo and Taleb make a strong argument that the quantity that one should study and try to estimate from the statistics is the tail exponent ? (see point 5 above). This is certainly not easy to estimate, and it takes a lot of data to get even a crude estimate, but working with ? is a much better way of getting at the true mean of the process than working with the sample mean over various periods. Looking at past events, and estimating the average number over any period, is simply a bad way to go about thinking about any process of this kind. The sample mean is NOT a mathematically sound estimate of the true mean of the process. For more on this, see Taleb’s comments at the top of the 3rd page of his earlier criticism of Pinker’s argument.

And that, I think, is pretty good reason to believe that all talk of the dwindling likelihood of wars based on recent past experience is mostly based on illusion and people telling themselves convincing but probably unfounded stories. Sure it looks as if things are getting more peaceful. But, looking at the mathematics, that’s exactly what we should expect to see, even if we’re most likely due for a much more violent future.