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 black bird.
Did you know that until Australia was discovered there was a phrase that "all swans are white".
In that context, a black swan was a metaphor something that could not exist.
The discovery of Australia - and the discovery of a large black waterbird breeing in the sout of Australia, the black swan - meant that perceived impossibilities actually come to pass.
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Nassim Nicholas Taleb, a professor in marketing at the London Business School, has popularised the phrase "black swan" in describing a large impact, hard to predict and rare event beyong the realm of normal expectations.
To be considered a black swan, Taleb sets three criteria
- it is an outlier, as it lies outside the realm of regular expectations, because nothing in the past can convincingly point to its possibility.
- it carries an extreme impact.
- in spite of its outlier status, human nature makes us concoct explanations for its occurrence after the fact, making it explainable and predictable.
In Taleb's definition many scientific discoveries are black swans— undirected and unpredicted. Events such as the September 11, 2001 attacks on the United States also fall within the definition.
Taleb's contribution to risk literature is that he challenges the theory that it is possible to draw general conclusions (about risk) from specific observations.
His claim is that almost all consequential events in history come from the unexpected—while humans convince themselves that these events are explainable in hindsight.
One problem identified by Taleb is the the assumption that the unexpected can be predicted by extrapolating from variations in statistics based on past observations.
He argues that many events are simply without precedent, undercutting the basis of this sort of reasoning altogether.
The first chapter of Taleb's book The Black Swan - The Theory of the Highly Improbable can be found:
(Thanks to Todd for bringing my attention to the concept).
1 comments:
Tom, thanks for the reference. Interestingly enough I'm from Perth - the Black Swan is on our flag and I'd never heard of a white swan for the early years of my life. There are a lot of things that can be drawn from this - one man's continuity is another man's discontinuity etc. This is something which we're exploring deeply in the resilient futures network and hopefully something which will be of interest to your readers.
http://www.resilientfutures.org/feed/
Thanks,
Todd
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