What is the no true Scotsman fallacy in simple terms?

It is moving the goalposts on who belongs to a group. Someone says all members behave a certain way; shown one who doesn’t, they declare that person was never a real member. The original claim survives only by being emptied of content.

Who came up with the no true Scotsman fallacy?

The British philosopher Antony Flew described it in his 1966 book God & Philosophy and developed it further in Thinking About Thinking in 1975. His best-known illustration involves a claim that no Scotsman puts sugar on his porridge.

What is an example of no true Scotsman reasoning?

“Good managers never lose their temper.” “Ours shouted at the whole team yesterday.” “Then he isn’t a good manager.” The reply protects the claim instead of testing it, so no example could ever count against it.

Is redefining a term always a no true Scotsman?

No. If a group has an agreed definition, such as a professional qualification or a membership rule, pointing out that someone does not meet it is fair. The fallacy is inventing or tightening a definition only after a counter-example turns up, purely to dismiss it.

No true Scotsman fallacy

Also called appeal to purity · Logical fallacy · Definition & framing

The no true Scotsman fallacy is shielding a generalisation from a counter-example by redefining the group so that the counter-example no longer counts. “No real fan would leave early” survives only by excluding every fan who does.

By the ReadGlobe Editors · Reviewed 2026-10-24

Why does the no true Scotsman fallacy persuade?

People attach their identity to groups, and admitting that a member behaved badly, or simply differently, can feel like conceding something about themselves. Redefining the group ends that discomfort without giving up the original claim. It persuades because the new definition is never announced; it slips in after the fact, so listeners may not notice the goalposts have moved. The name comes from the philosopher Antony Flew, who described the move in God & Philosophy (1966) and returned to it in Thinking About Thinking (1975), illustrating it with Scotsmen and sugar on their porridge.

Examples of the no true Scotsman fallacy

“No real runner uses a treadmill.” “My club captain does.” “Then she isn’t a real runner.”
A company boasts that its staff always put customers first, and treats every rude employee who comes to light as “not really one of us”.
A home cook insists no genuine chef would touch a microwave, then disqualifies each well-known chef shown using one.
“Nobody who truly loves dogs would ever buy from a breeder.”

How do you spot it and respond?

Ask for the definition up front: what exactly makes someone a “true” member of this group, and was that test applied before the awkward case appeared?
Notice when a claim can no longer be shown wrong by any conceivable case. At that point it has stopped telling you anything about the world.
Allow that some definitions are legitimate. If a group has clear criteria set in advance, applying them is not a fallacy.

Frequently asked

What is the no true Scotsman fallacy in simple terms?: It is moving the goalposts on who belongs to a group. Someone says all members behave a certain way; shown one who doesn’t, they declare that person was never a real member. The original claim survives only by being emptied of content.
Who came up with the no true Scotsman fallacy?: The British philosopher Antony Flew described it in his 1966 book God & Philosophy and developed it further in Thinking About Thinking in 1975. His best-known illustration involves a claim that no Scotsman puts sugar on his porridge.
What is an example of no true Scotsman reasoning?: “Good managers never lose their temper.” “Ours shouted at the whole team yesterday.” “Then he isn’t a good manager.” The reply protects the claim instead of testing it, so no example could ever count against it.
Is redefining a term always a no true Scotsman?: No. If a group has an agreed definition, such as a professional qualification or a membership rule, pointing out that someone does not meet it is fair. The fallacy is inventing or tightening a definition only after a counter-example turns up, purely to dismiss it.

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ReadGlobe. (2026). No true Scotsman fallacy. https://readglobe.com/fallacy/no-true-scotsman/

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"No true Scotsman fallacy." ReadGlobe, 24 Oct. 2026, readglobe.com/fallacy/no-true-scotsman/.

Editorial synthesis © ReadGlobe 2026, drawing on the Internet Encyclopedia of Philosophy and the Stanford Encyclopedia of Philosophy entries on fallacies and the logic and critical-thinking literature they cite. · Last reviewed 2026-10-24.