In The Black Swan: The Impact of the Highly Improbable, Taleb defined a black swan as “an event with the following three attributes. First, it is an outlier, as it lies outside the realm of regular expectations, because nothing in the past can convincingly point to its possibility. Second, it carries an extreme impact…. Third, in spite of its outlier status, human nature makes us concoct explanations for its occurrence after the fact, making it explainable and predictable.”

Nassim Taleb is the author of The Black Swan, Fooled By Randomness, and most recently, The Bed of Procrustes.