No True Scotsman

The No True Scotsman fallacy occurs when someone redefines a group or category in an arbitrary way to exclude counterexamples that would otherwise disprove their argument. This fallacy is a form of shifting the goalposts. When faced with a counterexample that challenges their generalization, the person making the argument simply changes the definition of the group or category to maintain their original claim.

Example 1:

Argument: "No Scotsman puts sugar in his porridge."
Counterexample: "But I’m Scottish, and I put sugar in my porridge."
Response: "Well, no true Scotsman puts sugar in his porridge."
Here, the person making the argument changes the definition of "Scotsman" in response to a counterexample to preserve the original claim. Instead of addressing the counterexample directly, they arbitrarily redefine what it means to be a "true" Scotsman.

Example 2:

Argument: "Real men don’t cry."
Counterexample: "But I’ve seen men cry."
Response: "Well, those men weren’t real men."
In this case, the definition of "real men" is being changed to exclude men who cry, just to avoid acknowledging that men can cry. Instead of addressing the claim, the speaker redefines what constitutes a "real man" to fit their argument.

Example 3:

Argument: "No good person would ever commit a crime."
Counterexample: "But I know someone who is a kind person and committed a crime."
Response: "Well, that person must not be truly good."
Here, the argument is shifting the definition of what it means to be a "good person" to exclude the counterexample, rather than dealing with the complexity of human behavior or considering that good people can still make mistakes.

Why it’s a fallacy:

The No True Scotsman fallacy is flawed because it avoids addressing counterexamples by changing the definition of the category in question. Instead of evaluating or refining the argument in light of new evidence, it dismisses it by narrowing the definition of the group or category. This creates an unfalsifiable claim—one that can never be proven wrong, because the criteria are adjusted to fit the argument. A sound argument should allow for reasonable counterexamples and engage with them directly, rather than arbitrarily excluding them.