The term black swan was a Latin expression, “a good person is as rare as a black swan” (“rara avis in terris nigroque simillima cygno”). It was a common expression in 16th century London as a statement that describes impossibility, deriving from the old world presumption that ‘all swans must be white’, because all historical records of swans reported that they had white feathers. Thus, the black swan is often cited in philosophical discussions of the improbable. Aristotle’s Prior Analytics most likely is the original reference that makes use of example syllogisms involving the predicates “white”, “black”, and “swan.” More specifically Aristotle uses the white swan as an example of necessary relations and the black swan as improbable. This example may be used to demonstrate either deductive or inductive reasoning; however, neither form of reasoning is infallible since in inductive reasoning premises of an argument may support a conclusion, but does not ensure it, and, similarly, in deductive reasoning an argument is dependent on the truth of its premises. That is, a false premise may lead to a false result and inconclusive premises also will yield an inconclusive conclusion. The limits of the argument behind “all swans are white” is exposed—it merely is based on the limits of experience (e.g., that every swan one has seen, heard, or read about is white). Hume’s attack against induction and causation is based primarily on the limits of everyday experience and so too, the limitations of scientific knowledge.*
Had these philosophers lived in Australia, this discussion may have been quite different, or at least, different examples may have been used to illustrate the point. Black swans are common place and can be found in briny shallow water and lakes around Australia
A good person is as common as a black swan!
Thanks Ailsa, I’m hoping to embrace a bit of minimalism now that the Festive Season is over.