No True Scotsman

Real unicorns have curves!

No True Scotsman (NTS) refers to a logical fallacy that occurs when a debater makes a generalization of a group that requires observational evidence to support it. When confronted with evidence that instead clearly falsifies their claim, the debater fallaciously switches their claim from requiring evidence to being a definitional statement. For example, it's common for one to argue that "all members of [my religion] are fundamentally good", but when provided a clearly falsifying counter-example, to simply discard the counter-example as "not true [my-religion]-people by definition".

NTS is most commonly used to avoid having to back down from falsified universal claims like "all group members are X" to "most group members are X". One may think of it as a form of inverted cherry picking, where one rejects unfavourable group members by defining them out of the group in an ad hoc fashion. The NTS fallacy paves the path to other logical fallacies, such as letting the "best" member of a group represent it. Thanks to these remarkable qualities, the NTS fallacy has proved a vital tool in the promotion of denialism.

A common misconception is to confuse the NTS with an Pre-emptively defining a group to be entirely composed of "good" or "bad" properties before a counterexample is offered is commonly mistaken as an example of the NTS, though cannot satisfy the criteria Antony Flew set out when coining the fallacy, since even if a debater starts with an incongruent or strange definition, they make it so there is no possibility of offering a successful counter-example by definition. It is, however, almost ubiquitous for the redefined group in a NTS to use an incongruent definition, which leads to the confusion.

Origin
The coining of the term is attributed to professor Antony Flew, who gave an example of a Scotsman who, in his 1975 book Thinking About Thinking, wrote;

Imagine Hamish McDonald, a Scotsman, sitting down with his Glasgow Morning Herald and seeing an article about how the "Brighton Sex Maniac Strikes Again". Hamish is shocked and declares that "No Scotsman would do such a thing". The next day he sits down to read his Glasgow Morning Herald again; and, this time, finds an article about an Aberdeen man whose brutal actions make the Brighton sex maniac seem almost gentlemanly. This fact shows that Hamish was wrong in his opinion, but is he going to admit this? Not likely. This time he says: "No true Scotsman would do such a thing".

Thus, when McDonald is confronted with evidence of a Scotsman doing similar acts, his response is that "no true Scotsman would do such a thing". This denies membership in the group "Scotsman" to the criminal on the basis that the commission of a heinous crime is evidence for him not having been a Scotsman (or at least a "true" Scotsman) in the first place. McDonald has therefore fallaciously moved from making a claim that could be either true or false according to the evidence (that Scotsmen are not criminals) to a definitional claim (that Scotsmen are definitionally not criminals) that could not even in principle be false if the definition is accepted.

This reasoning is clearly fallacious since it was only after the empirical evidence became antithetical to Hamish's case that he discarded the evidence in favor of appealing to definition, thus making Hamish's reasoning ad hoc. Furthermore, "Scotsman" has a clearly established definition — a native of Scotland — which is strong evidence that Hamish's differing definition has been modified ad-hoc, since it is unlikely that he would continue to use this narrow definition in most other contexts rather than the clearly established one.

Form
P1: All elements of set X have quality Y. P2: Element X1 contained within group X does not have quality Y. C: Element X1 is not a member of set X; all true X have quality Y.

In practice, application of the NTS fallacy is (usually) far more subtle than this, but the line of thinking always boils down to a denialistic attitude towards counterexamples.

Retroactive use
When used in the past tense, NTS can also be used to retroactively disqualify group membership based on future wrongdoing. In this scenario, the axiom becomes "having done something bad just proves how you never really were a member of this group in the first place", a statement as comfortably shallow and devoid of meaning as answering a question regarding which sports team you're rooting for in a game as "the team that wins".

Improper accusation
Accusations of committing the No True Scotsman are often levelled when terms like "true", "real", or "authentic" are included in otherwise reliable generalizations. However, it is important to recognize that the inclusion of this rhetoric does not necessarily mean the fallacy has been committed. Generalizations like "no true bachelor is married" or "no real theist can be an atheist" are examples which may not commit the fallacy (they are safe insofar as they are identical to the statements "no bachelor is married" and "no theist can be an atheist", where the words "true/real" do not change an earlier meaning since there would exist no possible counter-example to improperly exclude).

One can demonstrate they have not fallaciously modified their generalization if the terms included are clear and widely-understood, since this makes it easy to tell if the terms are being applied consistently across contexts and therefore are not being changed ad-hoc (one criterion for committing the No True Scotsman). However, be extremely wary in assuming that you can therefore use a strange or disputed definition to prove the fallacy has been committed. ''A clear and widely-understood definition DOES itself show the fallacy HAS NOT been committed. ''

A strange or disputed definition DOES NOT itself mean the fallacy HAS been committed.

It is in principle possible for one to use a strange or disputed definition in a consistent manner across all contexts, which would not commit the No True Scotsman (although doing so probably presents other problems, like using words in ways no one else would, perhaps even in an attempt to cause confusion or vagueness). While seeing the word "true" put next to a strange definition which just so happens to exclude a counter-example that would refute your own preferred language is absolutely suspicious, more digging is required for you to verify that a fallacious redefinition has actually occurred. It is possible that your interlocutor is consistently just using innocent language you personally happen to be unfamiliar with or not prefer.

There is also the slippery matter of demarcation; for the Scotland example, a town right on the border between Scotland and England might or might not count as "Scottish" culturally, even if it's clearly on one side of the border or the other. So long as the speaker acknowledges the case as a situation that is either ambiguous or a border case, it's more likely a case of moving the goalposts than No True Scotsman.

In religion
No man can ever be opposed to Christianity who knows what it really is. With respect to religion, the fallacy is well used, often even overused. Religious apologists will repeatedly try to use NTS to distance themselves from more extreme or fundamentalist groups (and vice versa), but this does not prevent such extremists from actually being religious &mdash; they themselves would certainly argue otherwise. Moderate Muslim leaders, for example, are well known for declaring Islamic extremists as "not true Muslims" as Islam is a "Religion of Peace".

Similarly, moderate Christians, such as those in Europe, are sometimes aghast when viewing their fundamentalist counterparts in the United States, immediately declaring them "not True Christians™", even though they believe in the same God and get their belief system from the same book. Many of these statements claiming that the extremists are not true believers are often used as a reaction against Guilt by Association. The NTS fallacy can likewise occur when believers modify the definition of "the divine" to mean any and all good fortune on their behalf, definitionally excluding that which goes awry.

The NTS fallacy can also run the other way when it comes to extremism. Extremists will make a religious statement, and when someone points out that there are many believers who don't believe the extremist's viewpoint, the moderates are deemed not to be true believers (i.e., Christians who support gay marriage or accept evolution as fact are not "real Christians" or Muslims who support women's rights are not "real Muslims"). Modern pagans do it all the time, perhaps even more than other religions, due to the fact that there is no agreed-on orthodoxy for the whole group, with some well-established practices in one setting being considered unpalatable in others. Silver Ravenwolf, one of the best-selling "leaders" of neopagans, has done this with multiple ancient, well-established practices.

It's a tricky business, as being a member of a religious group, to the minds of those involved, encompasses adhering to a certain standard of behavior. For example, charity can certainly be called an essentially Christian ethic, considering the emphasis that Jesus placed on it. The man himself would most definitely disavow the greedy and "What's mine is mine" mindset of many right-wingers who call themselves Christians. However, strictly speaking, a Christian is defined as "one who professes belief in the teachings of Jesus Christ"; there's no rule saying they have to do it right.

In atheism
Atheists can also be guilty of the fallacy, such as an atheist claiming that "true atheists" don't believe in ghosts or UFOs, although the non-ad-hoc definition they would otherwise use for "atheist" refers only to the disbelief of gods, and under that original definition, it would be possible for an atheist to have belief in other supernatural or non-scientific phenomena. Some (particularly the New Atheists) are known to share the same argument as the religious extremists that religious moderates aren’t true members of their religion, though from the angle of trying to say that a "true" religious person must be an extremist, and as such, those who aren’t extremists are practicing their religion incorrectly and don’t really believe it (or else they’d be extremists and ignore their moral objections because God demands it).

In fact, there are probably more atheists who use this argument to attack religion than there are fundies who use it to justify themselves.

In politics
Argentina was then under the rule of these neo-Nazi generals, and I was sent La Prensa from Buenos Aires, the big newspaper in Argentina−there was a big article saying, "You can't read this guy's linguistics because it's Marxist and subversive." The same week I got an article from Izvestia in the Soviet Union which said, "You can't read this guy's linguistics because he's idealist and counter-revolutionary." I thought that was pretty nice.

Language-users can use NTS to uphold positive, neutral, or negative stereotypes by portraying people who do not conform to them as exceptions. For example, note the claim that feminists, being "well-educated and having strong opinions about gender issues", do not speak for "typical" women. NTS also commonly occurs as a form of name-calling (e.g. "Real men eat meat", "Real Americans don't question the existence of God", "Real artists don't use a computer", etc.)

Phrases such as "un-American", "un-Christian", "un-Islamic", or "inhuman" are widely used in politics and media to distance oneself from a subject, defining them as outside the bounds of what the speaker regards as truly "American", "Christian", "Muslim", or "human" behaviour. Such phrases strongly suggest NTS is in use, since the use, for example, of "un-American" to describe specific political activities by some American citizens implies some special definition of "American" beyond mere nationality.

In recent years with the advent of the Tea Party Movement circa 2009, the label "Republican in name only" (RINO) has come into more prominence from people who want to disassociate from certain fellow supporters of the Grand Old Party. The trouble with this phrase is that it is not useful at all — its use tends to be a replacement for "Republican I don't agree with, despite being in the same party". People who use this phrase tend to throw it even if there is only one issue the supposed RINO doesn't toe the party line on, such as being pro-choice. The term of art Cuckservative has similarly been used for otherwise conservative persons who believe that racial and gender inequality persists in the United States. This also exists on the other side of the Great U.S. Political Divide as well, but having terms that identify subgroups like Blue Dog Democrat is far less damning and more useful.

Speaking of feminists, multiple feminists claim that TERFs are not real feminists due to their transphobic beliefs and because not only do they refuse to support trans women's rights, but they also campaign against trans women. TERFs are still to be considered as at least partial feminists since they still support cis women's rights — that, and the acronym includes "Feminist."

Another recent example that has become common on social media is when someone posits a somewhat politically conservative ill-considered idea, is called a boomer, but turns out to be younger, resulting in the reply "boomer is a mindset". However, this fallacy is not limited to the right side of politics: for instance, a common meme among radical leftists is that the Soviet Union wasn't "a real attempt to achieve socialism", even though it was clearly the objective of the state to own the means of production, just as is dictated by Marx. You can decry the crimes of the Soviet Union (like the Holodomor) without resorting to fallacies to deny that it was actually a socialist regime (even if it was a very poor attempt at socialism).

In autism
This separation between real autistics and people who are "just quirky," "just awkward," or "almost too high-functioning to count" is a mental dance that non-autistics have to do whenever they're confronted with a three-dimensional autistic human being in the flesh. Otherwise everything they've ever thought, everything they've ever been told about us, starts to seem a little monstrous.

The No True Scotsman fallacy may be used to dismiss autistic advocates who dare to point out that groups like Autism Speaks are doing more harm than good to the demographic they represent. When they say "I'm autistic and X is harmful to us," detractors reply "You're not autistic, because..."
 * "real autistics can't speak for themselves/use social media/stand up to me."
 * "real autistics live lives of constant suffering and sadness."
 * "real autistics hate themselves and want a cure for autism so they can stop being burdens."

Then, the anti-autism advocates claim that the person is simply "too high-functioning" to understand the horrible constant suffering of the "low-functioning" people, and thus their entire argument is invalid. This might lead to an autistic person feeling pressured to describe their impairments in detail to prove their autism, even though this could harm the autistic person socially or professionally.

Never mind the fact that you don't have to be autistic at all to recognize that a lot of so-called "autism advocacy" and "autism organizations" are downright horrible to autistic people.

And if an autistic person with obvious impairments protests against ableism, they may say that the person either (a) is too stupid to know better, or (b) is either faking disability or being used as a puppet via facilitated communication.

In any case, the only "true" autistics are apparently the ones who are willing to shut up and be grateful for whatever attention/abuse that non-autistic people are willing to bestow upon them.

In vaccines
See also.

Inverse Scotsman
All the above being said, one should be wary of an "inverse Scotsman": Taking an (usually extreme) example of a self-proclaimed "Scotsman" as typical of the class. To provide one example, "I don't like Christians, because Bob says he's a Christian, and he lies, murders, and steals" would probably not be very sound, since in the context of Christianity, Bob is probably not very good at being a Christian (what with all the lying, murdering, and stealing). Further, if the objection also includes "Bob also argued against the divinity of Jesus Christ", that would probably add a great deal of validity to the "Bob's not actually a Christian" claim.

Such is particularly necessary in political science, where the problem of self-proclaimed "Socialists", "Libertarians", "Conservatives", and so on who aren't actually all that whatever they claim to be can be particularly acute.

Of course, this leads to the same problem as how to define nutpicking, namely, how many people must hold an extreme opinion for it to become representative of their whole group (and cease to be nutpicking)? In many cases, different people will draw the line differently based entirely on their own political or religious biases, such that those strongly opposed to a certain belief may speciously accuse more moderate debaters of invoking No True Scotsman on a belief they don’t even hold.