Though black swans aren’t as rare as once thought, their symbolism is that of transformative occurrences, like 9/11. Photo: CC BY: JoshBerglund19

 

 

Why call big surprises black swans?
It goes back to the 2nd-century Roman poet Juvenal, who said that some events are “as rare a bird as a black swan.” In reality, black swans aren’t so rare, but Europeans once believed there was no such thing because they had never seen one. Their certainty evaporated when early European explorers of Australia came upon swans whose feathers were black. The term has recently come into vogue thanks to Nassim Nicholas Taleb’s book The Black Swan: The Impact of the Highly Improbable, which became a surprise best seller after the 2008 financial crisis. As defined by Taleb, a black swan is not just an unprecedented event but one with a large, widespread impact. “A small number of black swans,” Taleb writes, “explain almost everything in our world.”