3 Lesser-Known Logical Fallacies
These commonly overlooked fallacies can distort discussions and decisions.
Posted December 1, 2025 | Reviewed by Gary Drevitch
Logical fallacies are flaws in reasoning. They are often called informal fallacies. It's becoming more common for people to call out these fallacies by name. You often hear accusations of people engaging in “ad hominem,” “appeal to nature,” and “straw man” thinking, for example. Some logical fallacies, however, are prevalent and yet rarely discussed. Here are three of them.
You commit the appeal to stone when you dismiss a claim as absurd without giving any reason or evidence. It can show up as “That’s nonsense,” “Be serious,” or “That’s obviously false.” Often, people say these things because they don’t want to engage in a debate. That’s fine, and not necessarily a fallacy: We don’t owe everyone who makes a claim a full discussion. But we shouldn’t pretend these statements are rebuttals; they’re just conversation enders.
This fallacy also often appears as “You’re being pedantic,” “You’re splitting hairs,” or “You’re arguing semantics.” Sometimes a person does get stuck on irrelevant details; but at other times, those “hairs” are crucial details to address. For example, take this statement: “Plate tectonics is just a theory. I have my own theories.” This is a logical fallacy called equivocation . Someone might reply, “In science, ‘theory’ means a well-supported explanation.” If the first person brushes this off by saying, “Don’t be pedantic,” they’ve committed a second logical fallacy: the appeal to stone.
2. Fallacy of Composition
You commit the fallacy of composition when you assume that what’s true of each part must be true of the whole. Properties don’t always scale; when pieces combine, totals can cross limits — for example, from light to heavy — or interact with each other.
Here are more examples:
To avoid this fallacy, consider:
The converse is also a fallacy: the fallacy of division . You commit this fallacy when you assume that what’s true of the whole must be true of each part. For example: “This cake is delicious, so every ingredient must be delicious,” or “The company is thriving, so every department must be doing great.”
3. Historian’s Fallacy
“They should’ve seen this coming.”
You commit the historian’s fallacy when you judge a past decision as obviously wrong using information that wasn’t available at the time. It confuses hindsight with what was knowable then. This fallacy stems from hindsight bias : After we learn an outcome, it feels like it was predictable all along.
Although the name suggests it’s about judgments of historical figures, it’s more common with recent events. People often say someone “made a bad call” simply because things turned out poorly, even if they acted rationally with the information they had. For example, scientific guidance often changes as data improves. A later update doesn’t mean the earlier decision was careless; it means evidence changed.
Learn about 17 other logical fallacies here.
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Stephanie Simoes, M.A., is the founder of Critikid, a critical thinking site for kids and teens.
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This article is part of the Bringwise Psychology Journal — daily insights on human behavior, mental health, and personal growth.