This is a logical fallacy I see referred to off and on in Great debates. What is it exactly?
From the context I gather it has something to do with the illegitimate exclusion of contradictory examples as in:
A: All Scotsmen drink.
B: Angus McFeely has never touched a drop in his life.
A: Then he is not a true Scotsman.
But I’m not sure about this. Could I get some help please?