In his book The Black Swan, Nassim Taleb describes a “Black Swan” as an unexpected event caused by some unanticipated variable that has a disproportionate impact on things. Taleb cites J.K. Rowling, Christianity, and 9/11 as Black Swans.

Black Swan events only happen under certain circumstances. The example from the book is say you have a thousand people, and that the average weight amongst them is 135 pounds. Now add the heaviest person in the world to this group – a guy who weighs 1...