Check Fallacies Online

List of Fallacies

  • Last update: 2026-08-22.

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Abstraction

Treating an abstract concept as if it were something concrete, have human-like properties, or is identical to what it merely represents.

FallacyTrigger – look for …Detail
AnthropomorphisationSpecifically human traits (emotion, intention, character) attributed to a non-human or abstract entity.MD / HTML
Pathetic fallacyHuman emotions attributed to inanimate objects, nature, or abstract systems ('the market fears', 'nature abhors') as if factual (specialized form of Anthropomorphisation).MD / HTML
ObjectificationA person – not a concept – is treated as a thing, tool, or mere function ('resources', dehumanizing language), or assumed in reasoning to behave like predictable, passive objects.MD / HTML
Ontological fallacyExistence inferred merely from a word for it, its definition, or its conceivability.MD / HTML
Semiotic fallacyA symbol, sign, model or metric is conflated with the thing it stands for.MD / HTML
Procrustean fallacyReality (data, processes, objects) is actively manipulated or forced to fit a pre-existing model, framework, or theory – rather than adapting the model to reality.MD / HTML
HypostatizationAn abstract noun (the market, society, history…) is the grammatical subject of a verb implying will, action, or blame; or an argument presupposes interests/properties independent of its members – beyond conventional shorthand (e.g., 'the company announced' → acceptable; 'the market punished investors' → flag)MD / HTML

Ambiguity

Confusion can arise if a word, phrase or position has more than one meaning and this is not made clear.

FallacyTrigger – look for …Detail
Etymological fallacyA word’s original or etymological meaning is treated as authoritative for its current use – or its modern meaning is projected back onto older usage – even though the term’s meaning has shifted over time.MD / HTML
Motte-and-bailey fallacyA strong and a weak version of a position are conflated under one term, and arguments are moved between them as if they were the same claim – e.g., retreating from an attacked strong claim to a defensible weak one without acknowledging the switch.MD / HTML
Generic generalizationAn unquantified generic statement (“Xs are Y”) is used in an argument as if it were a universal claim about every member of the class – or a universal claim is silently weakened to dodge counterexamples.MD / HTML
Syntactic ambiguityA statement is ambiguous because of an amphiboly (syntactic structure of the phrasing). This includes 'generic generalizations', but is broader because it allows for other forms of amphiboly.MD / HTML
Intensional fallacyA term is swapped for another synonym referring to the same object, even though the two terms carry different associated meanings or modes of reference (e.g., “morning star” vs. “evening star”).MD / HTML
AmbiguityA term, phrase or statement has more than one meaning and this ambiguity affects the validity of an argument – without any of the more specific sub-forms applying precisely.MD / HTML

Generalization

#TODO: Short description here

FallacyTrigger – look for …Detail
Accident fallacyA general rule (law, principle, norm) applied rigidly to a specific case where special circumstances would warrant an exception.MD / HTML
Hasty generalizationA broad or universal rule inferred from too few (or unrepresentative) instances of a class.MD / HTML
Mereological fallacyA property of a system (body, organisation, ecosystem…) attributed solely to one component – or component properties assumed to carry over unchanged to the system level, ignoring emergent interactions.MD / HTML
Naturalistic fallacyA prescriptive conclusion (what ought to be) inferred directly from a descriptive premise (what is), or vice versa – without independent justification for the normative leap.MD / HTML

Relevance

#TODO: Short description here

FallacyTrigger – look for …Detail
Fallacy-fallacyAn invalid or refuted argument for a claim is used as evidence that the claim itself is false (conflating bad reasoning with a false conclusion).MD / HTML
Appeal to authorityA claim is supported or rejected solely based on the status/expertise of the source (person, institution, “science”), rather than the evidence itself – especially when the source lacks relevant expertise, experts disagree, or the argument ignores counter-evidence.MD / HTML
Appeal to a false authorityAn argument relies on an invalid authority: someone with no relevant expertise in that specific field, an anonymous/unverifiable source (“experts say”), or a fabricated/misquoted statement from a famous person.MD / HTML
Appeal to traditionA practice or belief defended primarily because it is old, customary, or “the way things have always been done” – duration used as proof of correctness.MD / HTML
Bandwagon fallacyA position supported or rejected primarily because many people hold it, do it, or find it popular – majority size used as evidence of truth.MD / HTML
Honour by associationCredibility or acceptance granted solely through positive association with a respected person, brand, or institution – no independent evaluation of the thing itself.MD / HTML
False analogyA property of one thing is transferred to another based on their similarity in other respects, without establishing that this specific property follows from those shared features.MD / HTML
Petitio principiiThe argument's premise already assumes or restates what is supposed to be proven.MD / HTML

Ad Hominem

Attacking or undermining a person's argument by targeting the person rather than the substance of their claim

FallacyTrigger – look for…Detail
Name-callingArgument dismissed by insulting, berating or applying derogatory labels to the speaker rather than engaging with their reasoning.MD / HTML
Tu quoqueAn accusation of hypocrisy: “you do it too” – used to dismiss a valid point because the arguer doesn't practise what they preach.MD / HTML
NutpickingA group is discredited by selectively highlighting its most extreme, fringe, or absurd members as if they were representative of the whole.MD / HTML
Guilt by associationA person or group is discredited because of their associations, affiliations, or connections – not because of the argument itself.MD / HTML
Self-aggrandizementA speaker elevates themselves or their in-group with an unearned positive label to implicitly diminish the opponent's capacity or qualification.MD / HTML
Appeal to motiveA claim is dismissed by attributing an external motive (interest, bias, emotion) to the person making it – explicitly or implied – instead of addressing the substance of the argument.MD / HTML
Ad feminamArgument dismissed by referencing the speaker's female sex – via stereotypes (irrational, emotional), biological insinuations (hormones), or gendered knowledge claims.MD / HTML
Ad virumArgument dismissed by referencing the speaker's male sex – via stereotypes (privileged, aggressive), demographic identity claims, or blanket exclusion of men from a topic.MD / HTML
Ad hominemAn argument's validity is challenged or undermined by attacking the person who makes it – their character, identity, motives, associations, or behaviour – instead of addressing the substance of the claim.MD / HTML

Knowledge

#TODO: Short description here

FallacyTrigger – look for …Detail
Ecological fallacyA statistical indicator (average, rate, share) valid for a group or population as a whole is transferred to a lower level (subgroup or individual) – as if the group-level figure applied to the parts.MD / HTML

#TODO: More to come.

Rhetoric

Tactical moves that derail, deflect, or shut down a discussion by redirecting attention away from the substance of the argument.

FallacyTrigger – look for…Detail
WhataboutismA specific criticism is deflected by pointing to other groups' similar or worse actions, with the effect of blocking any resolution of the original issue.MD / HTML

Paralogisms

Unintentional thinking errors in how logical inference is applied to everyday situations – the real-world patterns behind formal fallacies. (Deliberate, rhetorical versions lean towards sophistry.)

FallacyTrigger – look for…Detail
Complement fallacyThe complement of a group or category – typically signalled via negation (eg. “not”, “no”, “never”, “none of”, “lacking”) – is used as evidence in drawing a conclusion.MD /HTML

Logic

Errors in the structure of an argument: inferences whose flaw is visible from the logical form alone, regardless of whether the individual claims happen to be true.

FallacyTrigger – look for…Detail
Denying the antecedentA conditional (“If P then Q”) is reversed: because the condition (P) failed to hold, its consequence (Q) is also denied – even though Q could have another cause. (Checkable form: “If P → Q; not-P → ∴ not-Q”).MD / HTML
Affirming the consequentA conditional (“If P then Q”) is reversed: because the consequence (Q) holds, its condition (P) is also affirmed – even though Q could have another cause. (Checkable form: “If P → Q; Q → ∴ P”).MD / HTML
Affirmative conclusion from a negative premiseIn a formal categorical inference (especially a syllogism), an affirmative conclusion (“all … are …”, “some … are …”) is inferred although at least one premise is negative (“no …”, “some … are not”).MD / HTML
Negative conclusion from affirmative premisesIn a formal categorical inference (especially a syllogism), a negative conclusion (“no …”, “some … are not”) is inferred although all premises are affirmative (“all … are …”, “some … are …”).MD / HTML
Fallacy of exclusive premisesA formal categorical inference (especially a syllogism) in which all premises are negative, yet a conclusion is still derived – which is not valid in most forms of logic. (Checkable forms: “Some C are M; All P are M → ∴ …P, C…” · “All X are M; All Y are M; All Z are M → ∴ …X, Y, Z…”).MD / HTML
Undistributed middleIn a formal categorical inference (especially a syllogism), the middle term, which connects the premises, refers only to a part of its class in all occurrences (typically as predicate of “All X are M”, or within an unqualified “Some …” statement), yet is still used as if it can connect the other terms. (Checkable form: “Some C are M; All P are M → ∴ …P, C…”.)MD / HTML
Illicit processIn a formal categorical inference (especially a syllogism), the major or minor term occurs in a distributed position (whole-class reference) in the conclusion, yet only in an undistributed position in its premise – i.e., the conclusion makes a broader claim about that class than the premise does. (Checkable form: “All P are M; All M are S → ∴ All S are P” – “S” is broader in the conclusion.)MD / HTML
Fallacies of distributionA categorical inference (especially a syllogism) in which the distribution of terms is evidently mishandled but does not clearly match either specific rule above – e.g., several distribution errors at once, or a non-standard form where the middle/major/minor roles are hard to assign (enthymemes with elided premises, multi-premise chains). Fallback entry: if the conditions for undistributed middle or illicit process are met, use those instead.MD / HTML
Ambiguous middle termThe middle term is a syllogistic form shifts meaning between premises (equivocation), therefore failing to link the two premisses. (A specific form of the four-term fallacy.)MD / HTML
Four-term fallacyA syllogism contains four distinct terms instead of exactly three – often because a term is used in two different meanings (equivocation). Count meanings, not words.MD / HTML
Circular reasoningA claim is justified by a premise that already assumes or restates the claim itself.MD / HTML
Fallacy of divisionA property of the whole is inferred to hold for its parts (or a group-level property for individual members) – as if the parts must share the whole's property, without checking whether it is emergent.MD / HTML
Fallacy of compositionA property of the parts (components, members) of a system is inferred to hold for the whole as well – as if the whole must be the sum of its parts, without checking for emergent or resultant properties.MD / HTML
Fallacies of emergenceA property is transferred between a whole and its parts (or a group and its members) as if the levels were interchangeable – without checking whether the property emerges upon combination. Umbrella/fallback: route to either fallacy of division or composition if the direction is clear.MD / HTML

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