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Logical Fallacies

Common logical fallacies with definitions and examples

25 cards · philosophy

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Cards (25)

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Ad HominemAttacking the person instead of the argument
Example: "What does he know about healthcare? He's not even a doctor." Focus on the claim, not the speaker.
Straw ManMisrepresenting an argument to make it easier to attack
"You want to defund the police? So you want total anarchy?"
False DilemmaPresenting two options as the only possibilities
Example: "You're either with us or against us." Consider other viable options.
Hasty GeneralizationDrawing a broad conclusion from too little evidence
Example: "My two neighbors are rude; this city is unfriendly." Look for larger samples.
Appeal to AuthorityTreating a non-expert or irrelevant authority as decisive evidence
Example: "A famous actor says this diet works, so it must." Citing qualified experts in their field can be valid; the fallacy is relying on non-experts or irrelevant authorities.
Slippery SlopeClaiming one step will inevitably lead to extreme outcomes
Example: "If we legalize marijuana, soon all hard drugs will be legal." The chain is asserted as inevitable without support.
BandwagonArguing a claim is true because many believe it
Example: "Everyone's investing in it; it can't be risky." Popularity isn't proof.
Red HerringIntroducing an irrelevant topic to distract
Example: "Why worry about tax reform when the roads have potholes?" Stay on the claim.
Begging the QuestionAssuming the conclusion in the premises
Also called circular reasoning. Example: "This book is immoral because immoral books are those that corrupt readers, and this book corrupts readers." The conclusion is presupposed.
Post Hoc Ergo Propter HocAssuming earlier event caused a later one
"I wore my lucky socks, and we won; the socks did it."
Appeal to EmotionUsing emotion as a substitute for relevant evidence
Example: "Think of the children; pass this law now." Emotion may supplement sound arguments but cannot replace evidence.
False AnalogyDrawing a conclusion from an analogy that ignores critical differences
Example: "Running a country is like running a business, so it should be managed by a CEO." Relevant differences weaken the comparison.
No True ScotsmanRedefining a group to exclude counterexamples
Example: "No true gamer uses easy mode; he isn't a real gamer." The definition shifts to dismiss counterexamples.
Shifting the Burden of ProofImproperly shifting the proof obligation to the doubter
Example: "Homeopathy works—prove it doesn’t." The claimant bears the burden.
Appeal to IgnoranceClaiming truth because it hasn't been disproven
"No one has proved aliens aren't here, so they are."
Cherry PickingSelecting only favorable evidence while ignoring the rest
"This one study supports me; ignore the meta-analyses."
Genetic FallacyJudging a claim by its origin instead of its merits
Example: "That idea started on social media, so it must be wrong." Evaluate the claim, not its source.
EquivocationUsing a key term in two different senses
"Feathers are light; light can't be dark; feathers aren't dark."
Loaded QuestionAsking a question that presupposes a disputed claim
Example: "Have you stopped cheating?" Any answer seems to admit guilt.
Appeal to TraditionArguing something is true because it’s longstanding
"We’ve always done it this way, so it’s best." Age alone isn’t evidence.
CompositionInferring the whole has a property because parts do
"Each player is a star, so the team will be great."
Gambler's FallacyBelieving past random events affect future ones
"It’s come up red five times; black is due." Independent events don’t self-correct.
Affirming the ConsequentIf P then Q; Q, therefore P
"If it rains, streets are wet; streets are wet, so it rained."
Denying the AntecedentIf P then Q; not P, therefore not Q
Example: "If it is a cat, it is a mammal; it is not a cat; therefore it is not a mammal."
False EquivalenceTreating unlike things as equal by ignoring key differences
Logical fallacy that flattens relevant differences. Example: "He missed a deadline; she committed fraud—both are equally unprofessional."