The Black Swan: The Impact of the Highly Improbable Paperback – January 1, 2008

The polemicist Simon Foucher warned that, “we are dogma-prone from our mother’s wombs.” Nassim Nicholas Taleb’s philosophical work, The Black Swan, is truly a masterpiece that addresses this problem. At one point in the book, Taleb asserts that “the ultimate test of whether you like an author is if you’ve reread him”. Considering the fact that I’ve now read this book twice, it’s fair to say that I greatly admire Taleb’s work. Now on to the review.***In “Part 1″, there is an interesting anecdote, that sets the tone for the rest of the book, about Umberto Eco’s library. Eco is a highly respected semiotician, essayist, philosopher, literary critic, and novelist. And he owns a library that reportedly contains over 30,000 books. He isn’t, however, known for being boastful about it. When guests come over to his house he usually gets one of two reactions. The vast majority of guests, according to Taleb, respond with something similar to the following “Wow! Signore professore dottore Eco, what a library you have! How many of these books have you read?” And then there are the people who get the point: “A large personal library is not an ego-boosting appendage, but a research tool.” The point of this story emphasizes a critical theme throughout the book, i.e., we overemphasize what we think we know and downplay how ignorant we really are. An antilibrary (representing things we don’t know) is more valuable to us than are the books we’ve already read (or things we already know).Early on we also learn that Taleb classifies himself as a skeptical empiricist. And, you may be wondering, what exactly is a skeptical empiricist? “Let us call an antischolar — someone who focuses on the unread books, and makes an attempt not to treat his knowledge as a treasure, or even a possession, or even a self-esteem enhancement device — a skeptical empiricist.”For further clarification, empiricism is a theory of knowledge, which asserts that knowledge can only be ascertained exclusively via sensory experience. And skepticism, it’s important to note, comes in many different varieties. Taleb traces his skepticism back to its roots in the Pyrrhonian tradition. However, he is also fond of “Sextus the (Alas) Empirical” (better known as Sextus Empiricus) and David Hume. Taleb, however, is not entirely devoted to promoting rampant philosophical skepticism. He simply wants to be “a practitioner whose principal aim is to not be a sucker in things that matter, period.”Largely, then, this book is about epistemology, also known as the study of human knowledge. What can we truly know? And what are the limits of human knowledge? I think Taleb focuses one of the fundamental problems of philosophy, which the German Philosopher, Immanuel Kant, also wrote extensively about (although from a different perspective), i.e., what are the limits of our reason? Kant realized that examining human reason is inherently problematic, namely because when humans try to examine metaphysical or even epistemological issues we can never do so outside the bounds of our own reasoning ability. We’re suckers, blinded to reality, because we are trapped in our own human minds!Throughout the book, Taleb picks on the great thinker of antiquity, Plato. Taleb, however, also gives the impression that he is quite fond of the great philosopher too, despite his shortcomings. What Taleb calls Platonicity is the obsessive focus on the pure and well-defined aspects of reality, while ignoring the messier parts and less tractable structure that exist in reality. Perhaps an example of Platonicity might help clear up this distinction. A Platonified economist, for example, thinks that he can accurately model something as complex as the macroeconomy. Using foolish assumptions, the Platonified economist tries to assume conditions of reality (that don’t really exist) in order to fit her model rather than accepting that reality is far messier than the model. One who is a Platonic thinker, then, could also be classified as a nerd. Nerds, according to Taleb, believe that what cannot be Platonized and formally studied doesn’t exist, or isn’t worth considering.One interesting example of Platonicity provided in the book pertains to breast milk. At one point in time, Platonified scientists believed that they had created a formula for a mother’s “milk” that was perfectly identical to a mother’s real milk. Alas, they could then manufacture this milk in a laboratory and make financial gains from it! Despite what appeared to be an identical chemical composition, there was empirical evidence showing increases in various cancers and other health problems in children who drank this fake-milk. Was this a coincidence? Perhaps. But it also could be that the Platonified scientific formula for milk was missing some crucial element of the milk that we cannot see!Platoncitity can further be generalized as follows, “it is our tendency to mistake the map for the territory, to focus on well and pure defined “forms,” whether objects, like triangles, or social notions, like utopias (societies built according to some blueprint of what “makes sense”), even nationalities. “ In other words, a Platonified nerd is someone who visits New York City, but has with a map of San Francisco with them, and yet still thinks that their incorrect map will somehow help them. Taleb believes that we have a built-in tendency to trust our maps, even when they’re for the wrong location. Furthermore, we fail to realize that no map is often better than the wrong map.The trouble is, according to Taleb, that we encourage nerd knowledge over other forms of knowledge, especially in academia. Nerds focus on what fits in the box, even if the most important things in life fall outside the box. The nerd simply neglects the antilibrary.At one point in history it was considered “knowledge” that all swans are white. This was stated as a scientific fact because no black swans had ever been observed. However, this line of reasoning presents an interesting philosophical problem, i.e., “The Problem of Induction“. And the great philosopher, David Hume, wrote in great detail about this problem, although he wasn’t the first to do so.In order to further understand this problem let’s consider the following classic inference that led to the problem: All swans we have seen are white, and therefore all swans are white. The problem is that even the observation of a billion white swans does not make that statement unequivocally true. This is because black swans may exist, we just haven’t observed one yet. We have obviously since discovered that black swans do indeed exist. What can we learn here? An over reliance on our observations can lead us astray.Still confused? Then, let’s consider what we can we learn from a turkey, which hopefully provides further clarification. The uberphilsopher Bertrand Russell illustrated this turkey example quite well.Consider a turkey that is fed every day. Every single feeding will firm up the bird’s belief that it is the general rule of life to be fed every day by friendly members of the human race “looking out for its best interests,” as a politician would say. On the afternoon of the Wednesday before Thanksgiving it will incur a revision of belief.Taleb, then, states, “The turkey problem can be generalized to any situation where the same hand that feeds you can be the one that wrings your neck.” Probably the most important point to note from the turkey is that our perceived knowledge from learning backwards may not just be worthless, but rather, it may actually be creating negative value by blinding us to future events with dire consequences.As such, it’s certainly important to note that a series of corroborative facts is not necessarily evidence. But where does that leave us in terms of how we can know things? Well, Taleb further argues that we can know things that are wrong, but not necessarily correct (think Karl Popper’s falsifiability). This he calls negative empiricism. The sight of one black swan, then, can certify that not all swans are white, but the observation of a trillion white swans doesn’t give us any certifiable claims.Strangely, however, we humans have a tendency to ignore the possibility of silent evidence and look to confirm our theories, rather than challenge them.One of the central tenets of the book is the distinction between “Mediocristan” and “Extremistan”, which are terms for different types of domains.. When you’re dealing with a domain that’s in Mediocristan, then your data will fit a Gaussian distribution (a bell curve). In Extremistan, however, you’re not dealing with data that is normally distributed. A single observation in Extremistan can have an incredible impact on the total. Think of the following example. If we took the average height of a million humans and then, say, added the tallest person in the world to the sample, the average wouldn’t be affected in a significant way. Height is normally distributed. Now imagine we did the same thing with wealth. Adding the richest person in the world to a sample of a million people would greatly affect the average. The distribution of height, then, falls within the domain of Mediocristan and things like wealth in Extremistan.One of Taleb’s main points is that we often try to use the model that works in Mediocristan in Extremistan. Taleb states, however, that almost all social matters belong to Extremistan and that the casino is the only human venture where probabilities are known and almost computable. But even casinos aren’t immune to Extremistan — think about it.Another interesting concept from the book is the “toxicity of knowledge.” Too much information can be toxic especially when it inflates the confidence in an “expert” prediction. More information is not always better; more is sometimes better, but not always. And we often blindly listen to experts in fields where there can be no experts.If you follow Taleb’s argument, then reading the newspaper may actually decrease, rather than increase, your knowledge of the world. The Black Swan, however, will not only increase your understanding of the world, but it will make you wiser as well. For that reason, I can assure you that I will be rereading this book yet again at some point in the future.

Taleb's romp through the land of what we do not know, what we cannot know, and how we deceive ourselves into thinking we know so very much more than we actually do is both fun and insightful. He takes observations that he made as a trader and uses them as a launching platform into the many pitfalls and traps we fall into in considering any problem.I bought this book with Mandelbrot's Behavior of Markets, and for the same purpose. I wanted to get a strong intuitive understanding of the consequences of the difference between the actual behavior (power-law) and the assumed behavior (Gaussian) of markets. I wanted to know what the power-law relationships were, so that I could build my own statistical models. And I wanted an analysis of real data showing that, in fact, markets in question do follow power-law relationships. Were I to rate this book solely on its ability to deliver on these expectations, I would have to give it two stars; for this book has nothing to do with the actual empirical facts. It is, instead, a highly rhetorical appeal to us to use empirical facts in making decisions about the market while it nevertheless manages to completely dodge the task of presenting any real market data.The inquiry here is much broader. Taleb is painstaking, almost encyclopedic, in his enumeration of ways in which our understanding of information breaks down. He draws on ideas from Greek, Roman, Arab, French, and English thinkers spanning more than two millennia. He also draws from the fine work of contemporaries Kahneman and Tversky which demonstrates how - when guessing about things - we all systematically underestimate our probability of being wrong by about a factor of twenty. He asserts that people with MBA's and those running large financial institutions do so a great deal more than, say, taxicab drivers and trash collectors.He visits physical models which prove that we cannot know much about the physical world, such as the three-body problem. The point is that when even physical systems that can be described very exactly in mathematical equations cannot be predicted with arbitrary accuracy, what's the hope of predicting things for which we don't even know the variables or the math one might use in describing them? Here he misses some opportunities by needlessly scoffing at the uncertainty principle, and by failing to include comments by one towering physicist of the twentieth century, probably Von Karman*, about how no physical phenomenon seemed spookier - i.e. more difficult to describe accurately using mathematics - than turbulent flow in fluids. This is an unfortunate omission since Mandelbrot actually uses the term "turbulence" to describe the fluctuations in market prices of goods and securities.One reaction to Taleb's arguments about how little we can ultimately know and on what shaky ground our beliefs lie is to stand, like a deer in the headlights, waiting for better information. Taleb argues that this is a mistake. It might be a bit better to proceed, looking for evidence that would prove one's course of action wrong, then modify one's model of reality and repeat the process. Doing this has the advantage that one can learn quite quickly about how any problem is bounded, and get some sense for the shape of the space inside. He quotes Warren Buffet: it is a great deal better to be approximately right than it is to be precisely wrong. And when choosing among things to believe, he advises us to rank beliefs not by their implausibility but by the harm they might cause. Although there are robust methods that draw on both judgments, this is generally very sound advice.The book is highly irreverent. In financial circles it is seen as blasphemous, not just because it flies in the face of conventional wisdom, but because the author has so much fun demolishing revered ideas. Anyone who can take it seriously and follow its advice ought to be much better at evaluating information and making decisions. This quality gives you a much better chance of becoming rich and famous like Taleb - though as Taleb might explain, there is still a vanishingly small chance of this happening. The down side is that following Taleb's advice is likely to make one a great deal less promotable (especially in financial firms) because - according to Taleb - reaching high levels of a company depends almost exclusively on making others believe you know things about which you are actually completely clueless; and only sociopaths and very self-deluded people do this convincingly.This suggests that one would read the book for the sole joy of knowing that you're the only person in the room who is sane enough to understand how little you actually know about pretty much anything.Good Reading---*Taleb makes great use of footnotes, and I recommend reading them all. Some of the best material in the book is in them. Van Karman is most famous, perhaps, for his role in adjudicating what to do after the collapse of the Tacoma Narrows bridge - arguably a Black Swan event. One day not long after this long suspension bridge was erected, it began twisting and oscillating in a 50 MPH wind. Some minutes later it collapsed. Von Karman was called in to evaluate what happened. He told the town council that the vortex shedding frequency of the bridge in a 50 MPH wind happened to closely match the natural vibrational frequency of the bridge. The bridge had gone into harmonic oscillation which created stresses that were much higher than those created by static loads for which it was designed, and this was why it failed. Although it is to avoid collapsing bridges via harmonic oscillation that British soldiers fell out of step when crossing bridges over several centuries prior, the town council had never heard of anything like this happening before. They declared "It was a very well-built bridge" and therefore "we shall build it exactly as it was before." To which Von Karman replied "If you build it exactly as it was before, it shall collapse exactly as it did before." To their credit, they had the bridge re-designed.