Language Matters | How the black swan metaphor evolved, and why it shouldn’t be confused with a grey rhino
- For centuries a black swan was a metaphor for something thought impossible, such as an ‘honest lawyer’. The discovery of black swans in Australia changed that
- Its meaning changed, and changed again to mean an extreme, unexpected event that becomes explicable. A grey rhino, though, is an entirely different beast
Once upon a time, in a western land, there were no black swans.
Such an understanding about the world formed the basis of commentary such as that of 2nd century Roman poet Juvenal in his Satire VI, writing about a good wife: Rara avis in terris nigroque simillima cygno, “A rare bird on this earth, like nothing so much as a black swan”.
At the time, black swans were believed not to exist, since all records of swans documented them as having white feathers.
The expression “black swan” – in Latin, several European languages, and in English from the 16th century, based on the classical Latin niger cygnus – thus referred to something impossible, non-existent, which defied belief. (Also borrowed into English was rara avis “rare bird”, also for that which is unusual, exceptional or rarely encountered.)
References from the 16th to 18th centuries can be found to “husbands without faults (if such black swans there be)”, or “an honest lawyer”.
