As my readers know, one of my personal bêtes noires is the complete ignorance of most of the people who charge others with committing a material fallacy of the fact that a material fallacy is, in fact, a material fallacy, rather than a formal fallacy. If a material fallacy were a fallacy by virtue of its form alone, it wouldn’t be a material fallacy, but a formal one.
What I call the All True Scotsman fallacy occurs when someone mistakenly attempts to use the No True Scotsman fallacy, a material fallacy, as a formal fallacy. The All True Scotsman fallacy looks like this:
- Any statement of the form “X is not a true Y” is a No True Scotsman fallacy.
- Therefore, all Xs are true Ys, always and necessarily, for any values of X and Y.
More concretely, this takes the form of saying that since any denial that anyone ever is a true Scotsman is a “No True Scotsman” fallacy, it follows that everyone always is necessarily a Scotsman, no matter what. There are literally no circumstances under which any person could fail to be a Scotsman.
It is logically impossible for anyone not to be a Scotsman.