No True Scotsman

Description:

The argument defends an assertion by disallowing, by definition, all counterexamples, emphasizing that we are only talking about true examples of whatever population is under consideration.

Comments:

The fallacy takes its name from the colorful example (paraphrased below) that Anthony Flew originally invented to illustrate it.

Examples:

"No true Scotsman puts brown sugar on his porridge. The fact that Angus MacGregor puts brown sugar on his porridge just proves that he's no true Scotsman!"

"Liberals are a bunch of latte-sucking elitist pseudo-intellectuals from New England. Of course, Hubert Humphrey was from South Dakota, so I'm not talking about him."

Discussion:

Political parties and other interest groups need to have principles, and a person who claims to be a member of that party or group, while denying the central principles that define the group, is surely mistaken or confused. For example, one could hardly be an atheist while believing that Vishnu is the deity responsible for sustaining and supporting the universe. It is reasonable to demand some standards of behavior or belief, and there is no fallacy in saying that no true atheist worships Vishnu.

The No True Scotsman fallacy mimics this demand for standards, but it attempts to create (by definition) membership criteria that are not the defining criteria that we normally expect (or that are actually in force). For example, membership in the Republican Party requires only that one register as a Republican on a voter registration form. The attempt to say that no true Republican would ever increase taxes (as George H. W. Bush did), is to impose a definitional criterion that does not actually exist. While Democrats also sometimes ostracize one of their own by claiming that they are not true Democrats, this practice has become so common in the Republican Party that it now features its own widely recognized term: RINO (Republican in Name Only).

The No True Scotsman fallacy is used in two ways. It can be used to try to enforce conformity and orthodoxy within a particular group, and it can also be used by people outside the group to "define" the group in negative ways. When the fallacy is used in the second of these ways it can bear a strong resemblance to the Straw Man fallacy, i.e. creating a misrepresentation of an opponent's view. The fallacy also bears some resemblance to the fallacy of Equivocation, since the term at issue--"Scotsman" for example--shifts its meaning: a Scotsman is a member of a particular geographic or ethnic group, vs. a Scotsman is a member of that group who doesn't put brown sugar on his porridge. Despite these similarities, I have classified the No True Scotsman fallacy as an Inductive circularity, since it seems to me that the central error in the fallacy is the use of mere stipulation to disallow observable counterexamples that would otherwise refute the arguer's generalization about a population.

Source: Anthony Flew, Thinking About Thinking, 1975.

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