Some authors make you change how you think about something highly important, such as Darwin on the subject of evolution. Some, like Adam Smith or David Hume, make you change how you think about human nature, and consequently their manner of thinking seeps into all departments of your mind. Nicholas Taleb makes you change how you think about what you know, and thus makes you change your mind more fundamentally than all of them.
You have probably heard of “The Black Swan”, a book by a Lebanese-born New York market trader and philosopher of knowledge named Nassim Nicholas Taleb. Maybe you have not had time to read him yet. Let me help you to make the decision to do so.
A black swan, in Taleb’s definition, is an event which has three characteristics:
- it is an outlier, “as it lies outside the realm of regular expectations, because nothing in the past can convincingly point to its possibility.”
- it carries extreme impact;
- despite its outlier status, human nature makes us concoct explanations for its occurrence after the fact, making it explainable and predictable.
Taleb, who is an Orthodox Christian from Lebanon’s elite, is at war with a vast category of higher-order fools, particularly in the area of finance. They are higher-order fools because they are measuring risk by means of intellectual tools that, by their very operation, rule out black swans.
Think of the most dramatic recent example: the attacks on the twin towers on September 11, 2001. I think most of you who witnessed it would have felt like me: this isn’t happening, this can’t be happening, O Lord, we are in a science-fiction universe! (It also illustrates that a black swan to the rest of us is not a black swan to the people who planned it).
Taleb is NOT saying that better predictive abilities will rule out black swans. He is arguing that, in a world far more affected by black swans than we care to believe, it is imperative that our mental tools accommodate their reality. And this, he says, is precisely what business schools and most statistical methods taught in universities fail to do.
The world, he says, is divided into events that come from Mediocristan, and those that come from Extremistan. In Mediocristan, the domain of the Gaussian bell curve of probability, outliers can have very little impact on the statistical norm. Put a hundred people in a line-up and weigh them. Measure their height. Measure their life-spans. Average height, weight and life-span will not depart significantly, that is to say, by orders of magnitude, from some average, even if you compare lard-asses to Laotian hill people, or smokers to alpine hill-dwellers. Even if you compare the average intelligence of 100 people to the average intelligence of Nobel-prize winners.
Then take wealth. Put Bill Gates in a line-up with 100 other people. The combined wealth of the other 99 will hardly be more than Bill Gates’ interest income in a day. Wealth distribution partakes of Extremistan. So does most of the forces and things that make the world as it is.
Taleb is not talking about the kind of risk that occurs inside casinos (the ludic fallacy, he calls it). Nothing that happens inside of a casino partakes of Black Swan-ness, else casinos would go broke as often as Lehman Brothers, Barings, and Wall Street crashes.
Nothing that you know will be the source of a Black Swan. Take for example, the elm tree that hovered over my country house. It started to die, so that progressively larger branches were falling off it. I had it cut down, to avoid the disaster of a 150-year old elm crushing my house. No Black Swan there. The course of events was foreseen and prevented. Most of what you insure against partakes of Mediocristan. Indeed, excluding risks coming from Extremistan is precisely what insurers try to do.
The essence of the Black Swan is that no recurrence of events, no matter for how long, rules out the catastrophe. Put a few dots in a line. Put as many dots as you like and make a projection through their mean. If the dots derive from data subject to the rules of Mediocristan, you may have a valid trend. But if the dots derive from data obeying the mathematics of Extremistan, no matter for how long the data is derived, the trend line is just so much bullshit and self-deception. If a turkey lives a thousand days, it has every reason to believe its kindly feeder will feed it on day 1001. But on day thousand and one, it is killed. For the turkey (but not for us), its slaughter is an event from Extremistan.
Or as he says, you cannot foresee the event, but you can make yourself more robust against the consequences of unforeseen events. Society can stop putting blind people in charge of driving school buses.
Taleb frustrates those who want easy answers because his book asserts that the unpredictable lies in a domain of ignorance so deep that it cannot be computed, ever. It lies beyond the bell curves of Gauss, or even the mathematics of his friend, the late, the regretted Benoit Mandelbrot, whose mathematics inform us that Grey Swans are possible. (Mandelbrot has also written that the stock market obeys rules of risk that are far from those of the bell curve).
He writes:
“I am going to be blunt. Before The Black Swan (and associated papers) most of the epistemology and decision theory was, to an actor in the real world, just sterile mind games and foreplay. Almost all the history of thought is about what we know,or think we know. The Black Swan is the very first attempt (that I know of) in the history of thought to provide a map of where we get hurt by what we don’t know, to set systematic limits to the fragility of knowledge – and to provide exact locations where these maps no longer work.”
I have not conveyed the pleasure of reading Taleb. He is deeply and vastly well-read. He cites thinkers I had never heard of, as well as plenty that I have. He demolishes the reputations of learned fools with elegance and total intellectual clarity. His attacks on economists and finance professors for their systemic blindness to Black Swan phenomena are fierce, joyous, merciless.
“Research shows that academics are overrepresented in the systematizing, Black-Swan-blind category….I haven’t seen any formal direct test of Black Swan foolishness and the systematizing mind, except for a calculation George Martin and I made in 1998, in which we found evidence that all the finance and quantitative economics professors from major universities whom we tracked and who got involved in hedge fund trading ended up making bets against Black Swans, exposing themselves to blow-ups. The best-known such academics were, once again, the “Nobel”-crowned Myron Scholes and Robert C. Merton, whom God created so that I could illustrate my point about Black Swan blindness”.
“Normally, such people exit the gene pool; academic tenure holds them a bit longer.”
Most of all, he confirms you in the conviction that we are living in a Black Swan universe. Why does the stock market crash every eight or ten years on average, rather than the 780 odd years predicted by Gaussian bell curve distributions? Why do small bands of outliers create world-shaking religions? Seize states and plunge us into world wars? Invent devices that destroy previous industrial empires?
Taleb is the foe of the tidy-minded. He is the enemy of hubris. Reading his book will change how you think. It will compactify everything you know into a small quadrant, everything you might know into another, and keep your mind open to the need to fortify yourself against the consequences of things going badly wrong. A large amount of debt , for example, is not a Black Swan except to the turkeys who hold it.
Ages ago, in another universe, I read a beautiful illustration of what Taleb was talking about in, of all places, Carlos Castaneda. You may recall from your distant hippie past that Carlos Castaneda claimed to have been under the personal tutelage of a Mexican Indian shaman, who was called Don Juan Matus. Castaneda’s teachings are to Don Juan as Plato was to Socrates; he writes as the foolish scribe who never understood what the Master was talking about.
Don Juan insisted upon the division of the world into the tonal, and the nagual, which we would pronounce “nahual”. The tonal is the domain of the known and the knowable, and the nagual, the unknowable. One day, stirred by his students’ incessant questioning on this point, Don Juan organizes his apprentices to go on a picnic. They gather everything for this journey: plates, cutlery, baskets, even chairs and table. They drive for hours and then begin a hike up into the beautiful arid mountains of the Sierra Nevada, through the chapparal. They climb for hours and eventually find themselves on a flat look-out facing another, equally beautiful range of parallel mountains many miles away across the plain. The range is lit by the rosy afternoon glow of the sun. The view is magnificent: the space, the sky, the silence, the distant eagles, the clouds beginning to be lit from underneath by the setting sun. The table is set, as if it were at a banquet, knives forks and spoons in order, the tablecloth below, the chairs arranged. The scene is perfect in every way.
Then Don Juan says: “You have asked me about the tonal and the nagual: the known, the unknown and the unknowable. This, he says, pointing to the nicely arranged table, is the tonal, the domain of the known. And underneath the table is also the tonal, the domain of the unknown. And this, he says, with a gesture embracing all that surrounds them, the sky, mountains, the earth: this is the nagual.”
We owe to Nassim Taleb the first mathematical and philosophic discussion of the limits of the tonal , the knowable, in the western tradition. For that we can be grateful. His book is a deeply personal pleasure. Read it for that reason, if for no other. And do not be distracted by my likening its lesson to an anecdote in Castaneda. Taleb has produced a serious, learned, and delightful mind-changer. He dwells in the world of finance, and has brought deep learning to the problem of risk (the known unknowns) and uncertainty (the unknown unknowns). Mainly, he would say, it is the consequences of the latter which we need to fortify against, and we cannot do this until we acknowledge that this domain is powerful and ever-present.