The term black swan was a Latin expression — its oldest reference is in the poet Juvenal expression that "a good person is as rare as a black swan" ("rara avis in terris nigroque simillima cycno", 6.165). 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 an oft cited reference 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.- Wikipedia, "The Black Swan (Taleb book)"