When you're debating political or philosophical debates, you've probably come across people who accuse their opponents of having committed the "No True Scotsman Fallacy" or even have been accused themselves. In a helpful post on the Radical Classical Liberals blog, philosopher Aeon Skoble has a good explanation of why such accusations are often wrong. The supposed mistake is not always a mistake:
Suppose you meet someone, Sam, who says, "I don't like (movement / theory / group G) because he says (bad thing B)." Suppose you are a member / advocate of G and not only do you agree that B is bad, but you are also fairly certain that this is not representative of G and indeed does not match G. They tell Sam that and Sam answers some other person Bob says B and that Bob is a G. Under what conditions can we correctly say that Bob is actually not a G? In logic lessons we encounter the mistake "not a real Scot":
"No Scotsman Would Drink Vodka"
"McGregor (a Scotsman) drinks vodka."
"Well, no real Scotsman would drink vodka."
The illegal rhetorical step taken by this fallacy is to immunize a generalization against a counterexample refutation by sneaking in an ad hoc modification of the definition.
But is every scenario like the one I described an example of the "not a real Scotsman" error? Suppose Bob claims to be a Christian, but often lies and reveals and kills. When asked, he reports that he does not believe in the divinity of Jesus or in God at all. So when Sam said "I don't like Christians, this bob guy is just terrible" and you replied, "Look, Bob just isn't a Christian, so you're wrong not to like Christianity because you don't like Bob." "make no true Scottish" error? I think the answer is no. You're right; Although Bob calls himself a Christian, he is not, and Sam is wrong not only to regard Bob as a representative of Christianity but also not to like Christians on this basis.
This naturally occurs in political contexts. Sam claims to dislike libertarianism because he has read something about Bob, who also claims to be libertarian, and that it is great that the police harass racial minorities and detain them for minor offenses, or that immigration from Mexico is one bad thing is because they are mostly criminals anyway. This is a fictional example, but I've been dealing on social media with people who claim that libertarianism is bad because one man is a racist or another resists immigration. I generally answer by listing how racism (or closed borders or protectionism or what you have) is simply not part of libertarianism. Am I making the mistake of "not a real Scotsman"? I do not believe that. I think, as in the case of Bob, the non-Christian, that there has to be a way to respond to caricatures and distortions that is not wrong. As in the case of religion, Bob can simply be inaccurate in describing his policies.
I would add that being a Scotsman is an ethnic identity that may be compatible with a variety of beliefs and behaviors. In contrast, libertarianism, Christianity and other ideologies and religions are belief systems. If no belief were incompatible jokeIf you are a true libertarian or a true Christian, libertarianism and Christianity would be essentially meaningless.
There can of course be cases where a person really believes in libertarian or Christian principles but does not fulfill them. For example, a Christian could violate one or more of the Ten Commandments even if she really believes she has a moral duty to follow them. In this case, the person could be a "true Christian" in terms of their beliefs, but not in terms of their behavior.
Obviously there is room for many debates about which beliefs are incompatible with libertarianism or Christianity (as well as Judaism, Socialism, Conservatism, etc.). Some argue that you cannot be a true libertarian if you do not support the most absolutist version of the "non-aggression principle", or that you are not a true Christian if you do not support the theology of the Catholic Church or all of Pat Robertson's views. However, the fact that the boundaries of libertarianism and Christianity are controversial does not mean that there are no boundaries at all.
The presence of border gray areas does not affect the fact that there are also simple cases. For example, it should be obvious that if you are an atheist and believe that Jesus Christ does not provide a valuable insight into morality, you cannot be a true Christian. Theism and at least a substantial commitment to Christ's message are core elements of Christianity. Likewise, you cannot be a true libertarian if you support socialism, fascism, Jim Crow segregation, or ethnonationalism. All of these ideologies contradict the core libertarian commitments to universal equality of economic and personal freedom, regardless of origin or origin.
The "No True Scotsman Fallacy" is not always a mistake when applied to Scottish affairs. Being a true Scotsman (defined as a person of Scottish descent) is compatible with a variety of beliefs. But being a Scottish nationalist is not. For example, it is probably correct to say that "not a true Scottish nationalist" believes that Scotland should be robbed of any autonomy and governance that is fully controlled by the British Parliament in London.
This is true even if Scottish nationalists disagree on how much independence or autonomy is optimal for Scotland and it may not be easy to find the exact dividing line between nationalists and their opponents.
Scottish nationalism can have blurred borders. But that doesn't mean that everyone can be a Scottish nationalist, regardless of their beliefs. At least the true Scottish nationalist may enjoy "only one chance" to tell the English that "they will take our lives, but they will never take our freedom!"