The Black Swan

| Sun May 3, 2009 6:28 PM EDT

I finished The Black Swan over the weekend, and although a full review at this late date is kind of pointless, it's an odd enough book to deserve a few notes.

First, the tone: it's intensely annoying.  The problem is that Nassim Nicholas Taleb basically sounds like a crank.  His prose has all the usual markers: everyone else is an idiot (this includes philosophers, economists, historians, journalists, and pretty much all social scientists, among others); he's the only one who truly understands the world as it is; there's a monocausal explanation for this almost universal lack of understanding in others; and there's a tiny cast of other unappreciated geniuses who do get it (Benoit Mandelbrot, Karl Popper, G.L.S. Shackle, Daniel Kahneman, etc.).  It's all sort of Unabomber-like, though with a better sense of humor.

But of course, that's just an esthetic judgment.  What about the content?  Well, here's the funny thing: once I got past the tone I didn't really have a problem with most of it.  Taleb talks about confirmation bias and the narrative fallacy.  Survivor bias and the anthropic principle.  He writes about how humans are hardwired to be bad at estimating risks in the modern world.  He explains how network effects can create large inequalities out of small differences and how randomness is responsible for more of our success than we think.  As it happens, this is all stuff I was already pretty familiar with, which made the book annoying and a bit tedious, but that's obviously not Taleb's fault.

Unfortunately, I'm not sure how effective the book would be even for someone who found this stuff new and interesting.  Taleb tends to flit from subject to subject without ever really explaining anything fully enough to make sense, and in the end it's not quite clear what case he wants to make.  Generally speaking, he wants to persuade us that we know less than we think and that forecasting the future is a mug's game because history is primarily governed by huge, unpredictable events that come out of nowhere (black swans).  But this is sort of a banal point: scholars have been arguing about the importance of contingent events vs. broad historical trends forever, and the difficulty of predicting technological breakthroughs is well-trod ground.  Worse, Taleb doesn't add much to what's already been said about it.  Just the opposite, in fact.  In one chapter he cherry picks some inventions here and there to help make his case, but even using his own hand-picked examples he's not very convincing.  We all know that penicillin was discovered by accident, but the computer?  Taleb seems to think it sprang out of nowhere, but that's sure not how I remember it.  It was a big invention and a huge discontinuity, but it was hardly unpredictable and hardly an accident.

The last few chapters are a diatribe against statisticians who are over-devoted to Gaussian distributions, and I don't have the chops to know if he has a point there.  The statisticians I've come across all seem to be keenly aware that there are lots of different kinds of distributions in the world, but maybe that's all shuck and jive.  Maybe they talk a good game and then end up modeling the world using bell curves anyway.  And in the financial world, for which he reserves his primary scorn, I know even less.  Taleb says they obstinately continue to use Gaussian models that flatly don't work and hide known risks, and he probably has a good point.  Certainly recent events are on his side, and Wall Street's almost cultlike reliance on VaR and CAPM and portfolio theory and the Gaussian copula seems to have played a big role in its current collapse.  But who knows?  Maybe it was actually just a gigantic housing bubble and this other stuff is a minor sideshow.  I don't know for sure, and Taleb doesn't provide enough evidence one way or the other for me to make up my mind.

In the end, he doesn't have much advice for us.  He insists that Mandelbrot provides a better mathematical basis for financial modeling, but never tells us how.  He insists that the world is mostly governed by a small number of big events, but never seriously grapples with the arguments for or against.  He insists that he's used his sensitivity toward black swan events as a practical guide to his own trading and investing strategy, but then he sums it up with this: "As I said, if my portfolio is exposed to a market crash, the odds of which I can't compute, all I have to do is buy insurance...."  Really?  That didn't work out so well recently, did it?

(On the other hand, the rest of that sentence reads: "....or get out and invest the amounts I am not willing to ever lose in less risky securities."  That's basically a way of saying that investors should limit their leverage, and he's certainly right about that.)

So I'm not sure what to think.  Taleb makes plenty of good, if rambling, points about the limitations of human nature, but his concrete advice is pretty prosaic.  Stay open to lots of experiences.  Embrace empiricism and let the data lead you without pretending it says things it doesn't.  Keep the possibility of massive losses in mind and don't invest money you can't afford to lose.  If you are going to take risks, invest in things like startup companies, where the risks are plain and open.  I don't really have any argument with most of that, but I'm not sure any of it is really all that remarkable either.

Did I miss the point?  Maybe.  To be honest, I'm really not sure.