Category · 55 fallacies

Informal Fallacies

An informal fallacy is an error in the content, context, or delivery of an argument rather than its logical form. The structure may look fine; the problem is with the substance — an irrelevant appeal, a loaded word, a missing piece of evidence.

That's what separates them from formal fallacies, where the flaw is in the shape of the reasoning itself. Informal fallacies are far more common in everyday argument, advertising, and debate, precisely because they can sound persuasive while quietly dodging the point.

Because they depend on meaning and context, spotting them takes a careful read rather than a diagram. The 55 below are the ones you'll meet most in the wild.

A worked example

The straw man — one of the most common informal fallacies.

The exchange

"We should fund the school's music program."

"So you think sports don't matter and we should cut the whole athletics budget?"

A straw man. The reply attacks a position the first speaker never took. Refuting an exaggerated, distorted version of the argument is easier than engaging the real one — but it proves nothing about the actual claim.

The complete list

55

Every informal fallacy in the library, each an error in the argument's content or context.

Ad HominemAttacking the person making a claim instead of the claim itself. AmbiguityExploiting a word or phrase that carries more than one meaning. AnecdotalLeaning on a personal story in place of solid evidence. Appeal to AuthorityTreating a claim as true just because an authority asserts it. Appeal to EmotionSwaying with feelings instead of offering a valid argument. Appeal to NatureArguing something is good or right because it is natural. Appeal to NoveltyAssuming something is better simply because it is new. Appeal to RidiculeMocking an argument rather than actually refuting it. Appeal to TraditionClaiming something is right because it has always been done. Argument from RepetitionRepeating a claim until it is mistaken for the truth. Argumentum ad PopulumAssuming a claim is true because many people believe it. Argumentum ex SilentioDrawing a conclusion from an absence of evidence or silence. Association FallacyJudging something by the company or group it keeps. BandwagonAdopting a belief mainly because everyone else has. Begging the QuestionAssuming the very conclusion inside the argument's premises. BulverismAssuming someone is wrong and explaining why they think it, instead of arguing. Burden of ProofDemanding others disprove a claim you never proved. Circular ReasoningSupporting a claim by restating the claim itself. Continuum FallacyRejecting a real distinction because the boundary is fuzzy. EquivocationShifting a word's meaning partway through the argument. Etymological FallacyInsisting a word must mean what it originally meant. Fallacy FallacyConcluding a claim is false because its argument was flawed. Fallacy of Composition and DivisionAssuming the parts and the whole share the same traits. Fallacy of Quoting Out of ContextDistorting meaning by stripping away the surrounding words. False Cause & False AttributionMistaking correlation, or the wrong source, for the real cause. False DilemmaPresenting only two options when more actually exist. False PremiseBuilding an argument on a starting claim that is not true. Faulty GeneralizationDrawing a broad conclusion from too few examples. Furtive FallacyAssuming outcomes were secretly caused by hidden misconduct. Gambler's FallacyBelieving past chance events change the odds of future ones. Genetic FallacyJudging a claim by its origin rather than its merit. Ignoratio ElenchiArguing a point that is beside the actual question at hand. Incomplete ComparisonClaiming something is better without saying better than what. Inflation of ConflictUsing experts' disagreement to dismiss an entire field. Kettle LogicDefending a point with several mutually inconsistent arguments. Loaded QuestionAsking a question that smuggles in an unproven assumption. Middle GroundAssuming the truth must lie between two opposing positions. Moralistic FallacyAssuming that what ought to be true morally must therefore be factually true. No True ScotsmanRedefining a group on the fly to dodge a counterexample. Personal IncredulityRejecting a claim because you find it hard to imagine. Poisoning the WellDiscrediting a source before it has a chance to speak. Projection FallacyAssuming others think and feel exactly as you do. Proof by AssertionRepeating a claim over and over as if repetition made it true. Proof by VerbosityBurying a point in words rather than supporting it. Proving Too MuchUsing reasoning that would also prove absurd conclusions. Red HerringDiverting attention with something irrelevant to the issue. ReificationTreating an abstract idea as if it were a concrete thing. Retrospective DeterminismClaiming an event was inevitable just because it happened. Shotgun ArgumentationMaking so many arguments the opponent cannot answer them all. Slippery SlopeClaiming one small step leads inevitably to extremes. Special PleadingApplying the rules to others while exempting yourself. StrawmanDistorting an argument to make it easier to knock down. Texas SharpshooterCherry-picking data to fit a pattern after the fact. Tu QuoqueDeflecting criticism by pointing to the critic's hypocrisy. Weak AnalogyComparing two things too dissimilar to support the point.

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