Like Malcolm Gladwell s Tipping Point , Nassim Taleb s Black Swan threatens to become a permanent part of the lexicon. In this best-selling book, he makes the argument that evolution has prepared us to over-emphasize continuous, Gaussian relationships because they occur much more frequently than do rare but momentous, unpredictable events. Until the discovery of Australia, it was believed in Europe that all swans were white, and this conclusion was "confirmed" by every sighting of such a bird. But the first sighting of a black swan invalidated previous understanding of the nature of the animal. Talib's "Black Swans" are things like the spread of the Internet, the rise of Islamic fundamentalism, the market crashes of 1929 or 1987, the collapse of the Soviet Union, and 9/11. In science, they could be paradigm shifts, in the Kuhn s Structure of Scientific Revolutions . They can have positive or negative effects (often both), but one cannot prepare for them in detail because they have very small probabilities but huge consequences. Since they aren't predictable, Taleb doesn't tell us how to predict them, but he provides advice about how to position yourself to survive or even benefit from their occurrence. Remember the Boy Scout motto.
Nassim Nicholas Taleb