What is "just-so story"

n. (context anthropology social sciences literature English) A story that cannot be proven or disproven, used as an explanation of a current state of affairs.

In science and philosophy, a just-so story, also called an ad hoc fallacy, is an unverifiable and unfalsifiable narrative explanation for a cultural practice, a biological trait, or behavior of humans or other animals. The pejorative nature of the expression 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).

This phrase was popularized by the publication in 1902 of Rudyard Kipling's Just So Stories, containing fictional and deliberately fanciful tales for children, in which the stories pretend to explain animal characteristics, such as the origin of the spots on the leopard.

This phrase has been used to criticize evolutionary explanations of traits that have been proposed to be adaptations, particularly in the evolution–creation debates and in debates regarding research methods in sociobiology and evolutionary psychology.