30th
These black swans are not theoretical - they live on a pond at the Alabama Shakespeare Festival grounds in Montgomery, AL.
Black swan theory
From Wikipedia, the free encyclopedia
In Nassim Nicholas Taleb’s definition, a black swan is a large-impact, hard-to-predict, and rare event beyond the realm of normal expectations. Taleb regards many scientific discoveries as black swans—”undirected” and unpredicted. The September 11, 2001 attacks are often referred to as a Black Swan event. [1]
The term black swan comes from the ancient Western conception that all swans were white. In that context, a black swan was a metaphor for something that could not exist. The 17th Century discovery of black swans in Australia metamorphosed the term to connote that the perceived impossibility actually came to pass.
Taleb notes that John Stuart Mill first used the black swan narrative to discuss falsification.