No true Scotsman

Actually overheard in a London pub last week..

First man: "gutted that we lost the independence vote"
Second man: "aye, no true Scotsman would have voted no"

This logical fallacy is a very common form of rhetoric that people use to justify a behaviour (or lack of) by appealing to an unfalsifiable and abstract property of something. When it comes to a uniform way of thinking, "True Scotsmen" don't exist of course, the distribution of opinion on most topics in any sufficiently large group of kilted men will vary according to much more mundane factors. It's the intellectual equivalent of putting your fingers in your ears and shouting "la la la", a childish way of closing down unwanted debate.

I've heard many other forms of this fallacy, here are some topical examples just from last week.

First Indian: "How can India spend millions on a mission to Mars when so many Indians still live below the poverty line"
Second Indian: "No true Indian would question this great achievement"

First Muslim: "I see ISIS have committed another atrocity on YouTube"
Second Muslim: "yes I saw that too; no true Muslim would do such things"

First woman: "Shocking about those poor babies in Cork"
Second woman: "I know, no true Christian could treat children that way"