A no true Scotsman fallacy, or appeal to purity, is a fallacy which occurs when a universal (“all”, “every”, "any" etc.) claim is refuted or is given counter-evidence to and the claim is altered by going from universal to specific, and failing to give any objective criteria for the specificity rather than conceding the point or meaningfully revising the claim; it is a form of moving the goalposts. The name comes from an example made up by Anthony Flew.