Everything Is Obvious_ _Once You Know the Answer - Duncan J. Watts [69]
BLACK SWANS AND OTHER “EVENTS”
Nowhere is this problem of predicting the things that matter more acute than for what former derivatives trader and gadfly of the financial industry Nassim Taleb calls black swans, meaning events that—like the invention of the printing press, the storming of the Bastille, and the attacks on the World Trade Center—happen rarely but carry great import when they do.15 But what makes an event a black swan? This is where matters get confusing. We tend to speak about events as if they are separate and distinct, and can be assigned a level of importance in the way that we describe natural events such as earthquakes, avalanches, and storms by their magnitude or size. As it turns out, many of these natural events are characterized not by “normal” distributions, but instead by heavily skewed distributions that range over many orders of magnitude. Heights of people, for example, are roughly normally distributed: the typical U.S. male is 5 feet 9 inches, and we essentially never see adults who are 2 feet tall or 12 feet tall. Earthquakes, by contrast, along with avalanches, storms, and forest fires, display “heavy-tailed” distributions, meaning that most are relatively small and draw little attention, whereas a small number can be extremely large.
It’s tempting to think that historical events also follow a heavy-tailed distribution, where Taleb’s black swans lie far out in the tail of the distribution. But as the sociologist William Sewell explains, historical events are not merely “bigger” than others in the sense that some hurricanes are bigger than others. Rather, “events” in the historical sense acquire their significance via the transformations they trigger in wider social arrangements. To illustrate, Sewell revisits the storming of the Bastille on July 14, 1789, an event that certainly seems to satisfy Taleb’s definition of a black swan. Yet as Sewell points out, the event was not just the series of actions that happened in Paris on July 14, but rather encompassed the whole period between July 14 and July 23, during which Louis XVI struggled to control the insurrection in Paris, while the National Assembly at Versailles debated whether to condemn the violence or to embrace it as an expression of the people’s will. It was only after the king withdrew his troops from the outskirts of the city and traveled to Paris in contrition that the Assembly managed to assert itself, and the Bastille became an “event” in the historical sense. It’s hard to stop even there, in fact, because of course the only reason we care about the Bastille at all is because of what came next—the French Revolution, and its transformation of the notion of sovereignty from the divine right of a king, handed down by birth, to a power inherent in the people themselves. And that event included not only the days up until July 23, but also the subsequent repercussions, like the bizarre mass panic, often called the Great Fear, that gripped the provinces over the next week, and the famous legislative session that lasted the entire night of August 4, during which the entire social and political order of the old regime was dismantled.16
The more you want to explain about a black swan event like the storming of the Bastille, in other words, the broader you have to draw the boundaries around what you consider to be the event itself. This is true not only for political events but also for “technological black swans,” like the computer, the Internet, and the laser. For example, it might be true that the Internet was a black swan, but what does that mean? Does it mean that the invention of packet-switched networks was a black swan? Or was the black swan the growth of this original network into something much larger, eventually forming what would at first