I'm looking for the name for a particular logical fallacy that I think of variously as the "philosopher's fallacy" or the "annoying middle school kid fallacy", based on the particular informal contexts where one is most likely to encounter it. A more specific name might be the "fallacy of underwhelming exception".
It's sort of like the reverse of the fallacy of accident.
Where the argumentative fallacy of accident takes a broadly accurate generalization and misapplies it in a specific context where it becomes invalid, the fallacy I have in mind seeks to cast doubt on a broadly accurate generalization by nitpicking a particular instance where it fails.
I also see it as being the flip side to the "overwhelming exception" fallacy: instead of a 'generalization' that's overwhelmed by so many caveats it ends up lacking any generality, it's a purported refutation of a generalization, but one that's so underwhelming that it actually underlines the reliability of the original generalization (hence "underwhelming exception"). Here are some instances:

Teacher: "You shouldn't talk during class."
Annoying middle school kid: "But what if there's a murderer behind one of our classmates, and we need to warn them? It'd be okay to talk during class then, right?”


Regular person: "It's wrong to murder toddlers."
Annoying, slightly older middle school kid: "But what if, like, you could see the future, and you saw in the future that the toddler was going to grow up to be, like, Adolf Hitler times a million? It seems like sometimes, like in a situation like that, you might have to murder toddlers. Why would you say it’s not okay? Why do you hate Jews so much?"

These can come up in social justice-type discussions, as well:

Sociologist: "Mainstream media outlets often manipulate the public via appeals to sexuality."
SJW: "Um, you're erasing asexuals, and hemicorporectomy survivors. Are you saying we don’t need to take them into account in sociology? Why would you write off entire groups of people as irrelevant and unimportant? Sounds acephobic and ableist, but okay....”

But almost any discipline in philosophy worth its salt is structured around one or two paradigmatic instances of this fallacy. An obvious one is the trolley problem in moral philosophy:

Regular person: "It's wrong to deliberately kill innocent people."
Philosopher: "But what if there's 100 innocent people tied to a trolley track, and a single innocent person on a side track, and you can save the 100 people by switching tracks, at the cost of killing the one person? It'd be wrong not to kill the one person, right?"

Or take the classic JTB account of knowledge in epistemology:

Regular person: "Knowledge is justified true belief."
Gettier: "But what if I intend to watch the 1998 NBA Finals live, but I accidentally watch the 1997 NBA Finals where the Bulls beat the Jazz 4-2 on VHS, and meanwhile the Bulls really do beat the Jazz 4-2 in the 1998 Finals?
I believe that the Bulls are the '98 NBA Champions, and it's true, and I've justified my belief by watching the Bulls win, but my justification was accidentally bad, so do I really know that the Bulls won in '98?"

What is the name for this kind of informal fallacy, where a picayune, innately hypothetical, farfetched, or just plain impossible counterexample is implied to severely undermine, or outright disprove, a widely valid generalization?

  • Your examples sound like instances of secundum quid ("accident fallacy") itself, the fallacy is exactly in ignoring (unsaid) qualifications implied by context and common sense. Does not really apply to philosophy (or, similarly, science), whose purpose is, in part, to spell out and put precise boundaries on what is commonly left unsaid. That Newton's theory had "exceptions" was a valid reason to probe its boundaries, and the same with Gettier or the trolley. The same informal figures may or may not be fallacious depending on context of their use.
    – Conifold
    Jan 21, 2021 at 11:49
  • @Conifold OK, so in your interpretation, it’s actually Person 1 in those examples who is committing a fallacy, of hasty generalization? But in these instances, Person 1 is supposed to be perfectly well aware that they are stating a general rule which may have some minor exceptions. Person 2 is highlighting the minor or theoretical exception triumphantly, as if to cast doubt on every application of the general rule. With the exception, perhaps, of some tautologies in formal logic, there is absolutely no general rule with which one could not play this game, so the exception underwhelms. Jan 21, 2021 at 13:35
  • JTB isn't a "general rule of thumb", it's meant to be a conceptual analysis of the concept of knowledge. With general rules of thumb, exceptions can prove the rule. But conceptual analyses cannot withstand even far-fetched exceptions, because it shows that something has been left out of the analysis, which was supposed to be complete and closed. Jan 21, 2021 at 17:48
  • As for the trolley problem, your gloss is not how moral philosophers think about the trolley problem. If you read the actual literature, the trolley problem consists of the question of why it seems right to kill one to save five in that case, when in other structurally similar cases it seems wrong to kill one to save five. It actually presents a pretty deep question about our moral reasoning, and isn't the kind of game that you've strawmanned it as (I'd recommend reading the original articles by Thomson, Foot, etc., that spawned that literature). Jan 21, 2021 at 17:51
  • It is Person's 2 highlighting of exceptions to undermine the rule that is fallacious in many such contexts. Because the rule was (implicitly) qualified to have the exceptions in the first place, and person 2 is ignoring the qualifications.
    – Conifold
    Jan 21, 2021 at 19:00

1 Answer 1


It sounds like you're talking about "the exception proves the rule". This isn't really a fallacy, because pointing out exceptions to purportedly universal rules isn't a flaw of logical reasoning. I think it's important to distinguish between types of general claims here. Some general rules are not meant to universally applicable, but rather function as a general heuristic. The student in your example seemed to be pretending through willful ignorance as if their teacher's statement was the former kind of claim rather than the latter.

However, when we're talking about the internal logic of systems, particularly within fields like mathematics or philosophy, pointing out exceptions that contradict general rules does oftentimes threaten to undermine or call into question the legitimacy of systems that presuppose these general rules.

  • Let me be clearer about the rhetorical fallacy that is being committed. It should be understood that the goal of Person 2 in each of the above statements is not to add qualifications to the generalization, or acknowledge instances where it does not apply for the sake of accuracy, a la “exception proves the rule”. Rather, it is to discredit or belittle the generalization by implying that it is useless, fundamentally and irremediably flawed, and perhaps (as in #3) even laced with callous bigotry, because of a minor, rare, improbable, or purely hypothetical exceptional case. Jan 22, 2021 at 14:32

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