Book Review: The Black Swan

I.

Writing a review of The Black Swan is a nerve-wracking experience.

First, because it forces me to reveal I am about ten years behind the times in my reading habits.

But second, because its author Nassim Nicholas Taleb is infamous for angry Twitter rants against people who misunderstand his work. Much better men than I have read and reviewed Black Swan, messed it up, and ended up the victim of Taleb’s acerbic tongue.

One might ask: what’s the worst that could happen? A famous intellectual yells at me on Twitter for a few minutes? Isn’t that normal these days? Sure, occasionally Taleb will go further and write an entire enraged Medium article about some particularly egregious flub, but only occasionally. And even that isn’t so bad, is it?

But such an argument betrays the following underlying view:

 It assumes that events can always be mapped onto a bell curve, with a peak at the average and dropping off quickly as one moves towards extremes. Most reviews of Black Swan will get an angry Twitter rant. A few will get only a snarky Facebook post or an entire enraged Medium article. By the time we get to real extremes in either directions – a mere passive-aggressive Reddit comment, or a dramatic violent assault – the probabilities are so low that they can safely be ignored.

Some distributions really do follow a bell curve. The classic example is height. The average person is about 5’7. The likelihood of anyone being a different height drops off dramatically with distance from the mean. Only about one in a million people should be taller than 7 feet; only one in a billion should be as tall as 7’5. Nobody is order-of-magnitude differences in height from anyone else. Taleb calls the world of bell curves and minor differences Mediocristan. If Taleb’s reaction to bad reviews dwells alongside height in Mediocristan, I am safe; nothing an order-of-magnitude difference from an angry Twitter rant is likely to happen in entire lifetimes of misinterpreting his work.

But other distributions are nothing like a bell curve. Taleb cites power-law distributions as an example, and calls their world Extremistan. Wealth inequality lives in Extremistan. If wealth followed a bell curve around the median household income of $57,000, and a standard deviation scaled the same way as height, then a rich person earning $70,000 would be as remarkable as a tall person hitting 7 feet. Someone who earned $76,000 would be the same kind of prodigy of nature as the 7’6 Yao Ming. Instead, people earning $70,000 are dirt-common, some people earn millions, and the occasional tycoon can make hundreds of millions of dollars per year. In Mediocristan, the extremes don’t matter; in Extremistan, sometimes only the extremes matter. If you have a room full of 99 average-height people plus Yao Ming, Yao only has 1.3% of the total height in the room. If you have a room full of 99 average-income people plus Jeff Bezos, Bezos has 99.99% of the total wealth.