no true Scotsman fallacy

== English == === Etymology === Attributed to the English philosopher Antony Flew, from his 1966 book God & Philosophy: In this ungracious move a brash generalization, such as No Scotsmen put sugar on their porridge, when faced with falsifying facts, is transformed while you wait into an impotent tautology: if ostensible Scotsmen put sugar on their porridge, then this is by itself sufficient to prove them not true Scotsmen. === Noun === no true Scotsman fallacy (plural no true Scotsman fallacies) An informal fallacy in which one attempts to defend or protect an a posteriori claim from a falsifying counterexample by covertly modifying the initial claim, especially transforming it into a tautology by saying that any counterexamples are ipso facto not valid members of the class being described. === Further reading === https://www.logicalfallacies.org/no-true-scotsman.html no true Scotsman on Wikipedia.Wikipedia