No true Scotsman orappeal to purity is aninformal fallacy in which one modifies a prior claim in response to acounterexample by asserting the counterexample is excluded by definition.[1][2][3] Rather than admitting error or providing evidence to disprove the counterexample, the original claim is changed by using a non-substantive modifier such as "true", "pure", "genuine", "authentic", "real", or other similar terms.[4][2]
PhilosopherBradley Dowden explains the fallacy as an "ad hoc rescue" of a refuted generalization attempt.[1] The following is a simplified rendition of the fallacy:[5]
Person A: "NoScotsman puts sugar on hisporridge."
Person B: "But my uncle Angus is a Scotsman and he puts sugar on his porridge."
Person A: "But notrue Scotsman puts sugar on his porridge."
The "no true Scotsman" fallacy is committed when the arguer satisfies the following conditions:[3][4][6]
An appeal to purity is commonly associated with protecting a preferred group. Scottish national pride may be at stake if someone regularly considered to be Scottish commits a heinous crime. To protect people of Scottish heritage from a possible accusation ofguilt by association, one may use this fallacy to deny that the group is associated with this undesirable member or action. "Notrue Scotsman would do something so undesirable"; i.e., the people who would do such a thing aretautologically (definitionally) excluded from being part of our group such that they cannot serve as a counterexample to the group's good nature.[4]
The description of the fallacy in this form is attributed to the English philosopherAntony Flew, who wrote, in his 1966 bookGod & Philosophy,
In this ungracious move a brash generalization, such asNo 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 nottrue Scotsmen.
In his 1975 bookThinking About Thinking, Flew wrote:[4]
Imagine some Scottish chauvinist settled down one Sunday morning with his customary copy ofThe News of the World. He reads the story under the headline, "Sidcup Sex Maniac Strikes Again". Our reader is, as he confidently expected, agreeably shocked: "No Scot would do such a thing!" Yet the very next Sunday he finds in that same favourite source a report of the even more scandalous on-goings of Mr Angus McSporran inAberdeen. This clearly constitutes a counter example, which definitively falsifies the universal proposition originally put forward. ('Falsifies' here is, of course, simply the opposite of 'verifies'; and it therefore means 'shows to be false'.) Allowing that this is indeed such a counter example, he ought to withdraw; retreating perhaps to a rather weaker claim about most or some. But even an imaginary Scot is, like the rest of us, human; and none of us always does what we ought to do. So what he is in fact saying is: "No true Scotsman would do such a thing!"
David P. Goldman, writing under his pseudonym "Spengler", compared distinguishing between "mature" democracies, whichnever start wars, and "emerging democracies", which may start them, with the "no true Scotsman" fallacy. Spengler alleges that political scientists have attempted to save the "US academic dogma" that democracies never start wars against other democracies from counterexamples by declaring any democracy which does indeed start a war against another democracy to be flawed, thus maintaining that notrue and mature democracy starts a war against a fellow democracy.[5]
political-science professors... Jack Mansfield and Ed Snyder distinguish between 'mature democracies', which never, never start wars ('hardly ever', as the captain of thePinafore sang), and 'emerging democracies', which start them all the time, in fact far more frequently than do dictatorships
