Book review: The Black Swan: the impact of the highly improbable (Part II)


This is the second of a three-part review. Read the first part here.

A big part of the book is about explaining rare events after the fact. Taleb talks about the September 11th attacks as being a sort of prototypical example. On September 10th, such an attack would have been considered unimaginable. Now, we pretty much consider future attacks to be inevitable without great preventative measure. So, we defend against something very close to exactly the same sort of attack, not realizing that the next big thing will be of a different form.

Indeed, suppose a politician had sponsored and passed a bill, going into effect on September 10th, 2001, making sure that cockpits of commercial aircrafts be locked during flight. That would have stopped the September 11th attacks. But then, no one would have realized what a disaster had been averted. Instead, the bill would look completely frivolous, and the politician would probably be seen by history as supporting thoroughly useless legislation. Our heroes are those who fix disasters; those who prevent them from happening to begin with are forgotten.

What Taleb doesn’t discuss, however, is that we have to give the impression that we’re trying to deal with predictable things. It would be almost as easy for a future airline attack to occur now as it was in 2001 if we didn’t put any security measures in place. Our preparation influences the sorts of freakish events that can occur, so saying that we should not bother with preparing for the types of things that have already occurred isn’t sensible.

So, what happens is that we see instances of success while sometimes being blind to related aspects of failures. Here’s my favorite story about this sort of thing:

Suppose that my priorities were to change all of a sudden and I decided that I wanted to make a lot of money in a very short amount of time. Having little knowledge in the dark arts of get-rich-quick schemata, I’d try to find a list of a bunch of people who became much richer in a very short amount of time. Then, I’d interview each person on the list to find out what sorts of tricks they used.

The following day, I’ll buy a lottery ticket.

Oops. So, that didn’t quite work as expected. And it didn’t work because we measured the wrong quantity. I really should have tried to figure out which activities regularly make people who try it rich, rather than just looking at the success stories while ignoring the failures. The problem is that the failures are more difficult to locate. It wouldn’t be interesting to collect a list of people who didn’t get rich quickly, because that consists of nearly everyone, and interviewing all (or many) of them would be thoroughly useless. So, we interview only the successes (survivor bias), but we need to keep in mind that we may get a heavily distorted story by doing so.

Similarly, we look for explanations for many other events after the fact; sometimes, this leads to us giving explanations that are not wholly accurate due to survivor bias. Taleb says that one of his biggest gripes about our education system is that we are so strongly discouraged from saying “I don’t know.” For example, we might ask why the Black Death pandemic in Europe in the mid-14th century “only” killed 30% or so of the European population (rather than, say 90% or 100%). We’re then “supposed” to give some answer about the nature of the bacteria causing the disease, explaining why some people didn’t get it or survived with it, or something like that.

But perhaps that’s a silly answer. Is it a better answer to say “Well, if everyone (or, at least enough of our ancestors) had died as a result of Black Death, we wouldn’t be having this conversation.” We might believe that the result is essentially random, and there’s no good reason why some people should have survived, but the fact that people did is a prerequisite for asking the question in the first place.

Similarly, some people like to invoke the anthropic principle as evidence for a god. The argument goes that, since certain constants in the universe have to be very finely tuned in order to support life forms as we know them, someone must have set them up that way. But this is only because we are asking the wrong question, and perhaps there isn’t really any question we should be asking in its place. We shouldn’t be asking why constants are set up the way they are, since we couldn’t even be having this discussion if they weren’t.

A friend pointed out a great response to the anthropic argument for a god: just ask why the constants weren’t set up so that a wider range of them be friendly for our existence. But no one ever asks that, because it doesn’t help to further anyone’s agenda. (Thanks, Nathan!)

(To be continued, once more…)

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About Simon

Hi. I'm Simon Rubinstein-Salzedo. I'm a mathematics postdoc at Dartmouth College. I'm also a musician; I play piano and cello, and I also sometimes compose music and study musicology. I also like to play chess and write calligraphy. This blog is a catalogue of some of my thoughts. I write them down so that I understand them better. But sometimes other people find them interesting as well, so I happily share them with my small corner of the world.
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2 Responses to Book review: The Black Swan: the impact of the highly improbable (Part II)

  1. Pingback: Road Map to Your Highly Success in Affiliate Marketing Business Review Affiliate of the Month | Affiliate Marketing Strategy

  2. Pingback: Book review: The Black Swan: the impact of the highly improbable (Part III) | Quasi-Coherent

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