A just-so story, also called the Ad hoc fallacy, is a term used in
academic anthropology, biological sciences, and social sciences. It
describes an unverifiable and unfalsifiable narrative explanation for
a cultural practice or a biological trait or behavior of humans or
other animals. The use of the term is an implicit criticism that
reminds the hearer of the essentially fictional and unprovable nature
of such an explanation. Such tales are common in folklore and
mythology (where they are known as etiological myths -- see etiology).
The phrase was popularized by the publication in 1902 of Just So
Stories by Rudyard Kipling, which are fictional and deliberately
fanciful tales for children which pretend to explain animal
characteristics such as the spots of a leopard (e.g., "How the Leopard
Got His Spots").
http://en.wikipedia.org/wiki/Just-so_story
http://en.wikipedia.org/wiki/Just_So_Stories
http://www.boop.org/jan/justso/