Black Swans and Evolution

Nassim Taleb argues that financial reform should take a page from nature and add redundancy to protect against "black swans," his name for unexpected, very rare events.

Let me summarise my ideas of how Mother Nature deals with the Black Swan. First, she likes redundancies. Look at the human body. We have two eyes, two lungs, two kidneys, even two brains (with the possible exception of company executives) - and each has more capacity than is needed ordinarily. So redundan cy equals insurance, and the apparent inefficiencies are associated with the costs of maintain ing these spare parts and the energy needed to keep them around in spite of their idleness.

Let's be careful. Some of those extra parts are not redundant; the "two brains" are different parts of the same brain and one is not a perfect substitute for the other. Our "extra eye" is not idle; two eyes allow depth perception and losing one is more than losing some insurance (though it's far better than losing both).

But it's more than that: a black swan is a very rare event. If losing an eye or a kidney is a black swan (and I think it is), then it is unlikely to happen before someone reaches maturity or even in their lifetime. And redundancy's costly. Energy devoted to a second, idle, organ is energy not devoted to keeping the body alive. Exactly how much this is, I admit, I don't know. But anything more than one redundant organ is very rare across across all animal species despite that all organisms exist in very different environments and places in the food chain.

It's more likely that these pairs are evolutionary hold-overs from a common ancestor who faced either a black swan kind of problem but the extra organ was very cheap to grow and maintain (unlikely as "black swan" again implies there's time, on average, to reproduce and pass on your genes) or the problem was more common than a black swan (though is still not "common") and the organ was less cheap to grow and maintain.

Despite it all I agree that some redundancy in the financial market is a good thing and to be sure, we already have some of that (competition between banks, credit unions, etc) and much of what he suggests I support. But a riskless world is not optimal and I wouldn't go so far as to ban complex financial products.