1 - It's good to hear from Onenski!
2 - I agree with most everything Don and Onenski have written.
3 - I want to emphasize the underlined part of the wikipedia entry:
QuoteNo true Scotsman or appeal to purity is an informal fallacy in which one modifies a prior claim in response to a counterexample by asserting the counterexample is excluded by definition. Rather than admitting error or providing evidence to disprove the counterexample, the original claim is changed by using a non-substantive modifier such as "true", "pure", "genuine", "authentic", "real", or other similar terms.
As I see it, it's important to see that the "no true Scotsman fallacy" does not mean that the thrust of the position being taken is not statistically true. All this "fallacy" is saying is that if you want to be precise about your assertion, you should explain and be prepared to prove - more than just asserting it to be true - why the counterexample being thrown in your face is an exception to the generalization.
Just because your uncle Angus puts sugar on his porridge does not prove that as a cultural generalization, 99% of Scotsmen do not put sugar on their porridge. The only thing that the "fallacy" says is that if someone can point to an exception, then the "rule" is not true 100% of the time, and so if one wants to be precisely accurate, what needs to say is "the great majority of Scotsmen do not put sugar on their porridge."
BOTH can be true at the same time: (1) your uncle DOES put sugar on his porridge, and (2) 99% of Scotsmen do not. There is no conflict between those two positions, but to say "No true Scotsman" or "No Scotsman" puts sugar on his porridge is overbroad.
Some cases call for precision more than do others, and asserting the Scotsman fallacy can sometimes be ridiculous itself when everyone knows that the person is stating a generalization rather than really meaning that there are no exceptions. However it's always good to be precise when issues are complex, such as when Onenski wrote:
It’s possible that Epicurus also thought that we all act in pursuit of pleasure (i.e., hedonistically), and if we acknowledged this, we’d avoid many mistakes and sufferings by directly seeking what brings us the most long-term pleasure.
I commonly say that myself, and I think it's sometimes or even often true. But I think it's important to remember that in the letter to Menoeceus Epicurus said specifically that time is not only or overriding factor, thus "long-term" is not quite right. It's "the greatest pleasure" which might or might not necessarily be the "long-term" choice.
[126] ... And just as with food he does not seek simply the larger share and nothing else, but rather the most pleasant, so he seeks to enjoy not the longest period of time, but the most pleasant.
So precision is generally a good idea. No true Epicurean would want to be less than clear!