The Black Swan

PROLOGUE

ON THE PLUMAGE OF BIRDS

Before the discovery of Australia, people in the old world were convinced that all swans were white, an unassailable belief as it seemed completely confirmed by empirical evidence. The sighting of the first black swan might have been an interesting surprise for a few ornithologists (and others extremely concerned with the coloring of birds), but that is not where the significance of the story lies. It illustrates a severe limitation to our learning from observations or experience and the fragility of our knowledge. One single observation can invalidate a general statement derived from millennia of confirmatory sightings of millions of white swans. All you need is one single (and, I am told, quite ugly) black bird.*

I push one step beyond this philosophical-logical question into an empirical reality, and one that has obsessed me since childhood. What we call here a Black Swan (and capitalize it) is 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.

I stop and summarize the triplet: rarity, extreme impact, and retrospective (though not prospective) predictability.* A small number of Black Swans explain almost everything in our world, from the success of ideas and religions, to the dynamics of historical events, to elements of our own personal lives. Ever since we left the Pleistocene, some ten millennia ago, the effect of these Black Swans has been increasing. It started accelerating during the industrial revolution, as the world started getting more complicated, while ordinary events, the ones we study and discuss and try to predict from reading the newspapers, have become

Nassim Nicholas Taleb

Praise for Nassim Nicholas Taleb
 
The most prophetic voice of all. GQ
 
Praise for The Black Swan
 
[A book] that altered modern thinking. The Times (London)
 
A masterpiece. Chris Anderson, editor in chief of Wired, author of The Long Tail
 
Idiosyncratically brilliant. Niall Ferguson, Los Angeles Times
 
The Black Swan changed my view of how the world works. Daniel Kahneman, Nobel laureate
 
[Taleb writes] in a style that owes as much to Stephen Colbert as it does to Michel de Montaigne. . . . We eagerly romp with him through the follies of confirmation bias [and] narrative fallacy. The Wall Street Journal
 
Hugely enjoyable compelling . . . easy to dip into. Financial Times
 
Engaging . . . The Black Swan has appealing cheek and admirable ambition. The New York Times Book Review