Complete Logical Fallacy Reference Guide

Complete Definitions by Category

Ad Hominem (Argument To The Man)

Definition: Attacking the person instead of addressing their argument.

Examples:

• "Von Daniken's books are worthless because he is a convicted forger"
• "How can you argue for vegetarianism when you wear leather shoes?"
• "Scientists were all drunk" (dismissing entire category)
• "You're new here, aren't you?" (disrespect/status attack)
• "If you weren't so stupid you would see my point"
• "You seem very emotional" (after hogging microphone)

Valid Exception: When attack goes to credibility of argument (e.g., undermining false claim of expertise)

Related: Needling, Poisoning The Wells, Psychogenetic Fallacy

Needling

Definition: Attempting to make opponent angry without addressing argument.

Examples:

• Insulting opponent's beliefs
• Interrupting, clowning, being noisy
• Winking at audience to show disrespect
• Cutting off microphone (if you control it)

Note: Works better if you're running the show or have sympathetic moderator.

Poisoning The Wells

Definition: Discrediting sources used by opponent before they're presented.

Examples:

• "Don't listen to those biased scientists"
• "That newspaper is known for fake news"

Related: Ad Hominem variation focusing on information sources.

Psychogenetic Fallacy

Definition: If you learn psychological reason why opponent likes argument, claim they're biased so argument must be wrong.

Examples:

• "You only support that policy because you'd benefit financially"
• "Your childhood trauma makes you think that way"

Valid Use: Understanding motivation ≠ dismissing argument.

Straw Man (Fallacy Of Extension)

Definition: Attacking exaggerated or caricatured version of opponent's position.

Examples:

• "Evolution means a dog giving birth to a cat"
• "Senator Jones wants to leave us defenseless" (from: shouldn't fund one submarine)
• Comparing opponent to Hitler over minor disagreement

Inflation Of Conflict

Definition: Arguing that because scholars debate a point, their entire field is "in crisis" or doesn't exist.

Examples:

• "Historians debate whether Hitler killed 5 or 6 million Jews, therefore Holocaust didn't happen"
• "Two scientists can't agree on dates (that differ by <1%), therefore dating methods are worthless"

Note: Healthy debate ≠ fundamental uncertainty.

Argument From Adverse Consequences (Appeal To Fear)

Definition: Claiming opponent must be wrong because bad things would ensue if right.

Examples:

• "God must exist, because godless society would be lawless"
• "Defendant must be guilty, or husbands will murder wives"
• "Global warming can't raise oceans because my house is 6 inches above sea level"

Related: Wishful thinking (positive or negative consequences).

Argument By Emotive Language (Appeal To The People)

Definition: Using emotionally loaded words to sway sentiments instead of minds.

Examples:

• Using anger, spite, envy, condescension as tools
• Seeding audience with "shills" who chant/applaud
• Using emotional music or imagery in presentations
• Language that triggers rather than informs

Related: Cliche Thinking, Argument By Slogan, Argument By Poetic Language.

Argument By Personal Charm

Definition: Getting audience to cut you slack based on likability.

Note: Charm creates trust, desire to join winning team, or please speaker.

Appeal To Pity (The Galileo Argument)

Definition: "Scientists scoffed at Galileo; they scoff at me; therefore I'm right"

Examples:

• "I'm suffering enough through being an orphan" (after murdering parents)
• "They laughed at Edison; they won't give my ideas fair hearing either"

Note: Being persecuted doesn't make you right. Galileo was right AND persecuted (not right BECAUSE persecuted).

Appeal To Force

Definition: Threats or violence as argument.

Examples:

• Threat of lawsuit
• Religious threats ("You'll burn in Hell")
• Physical violence or intimidation

Argument By Vehemence

Definition: Being loud as substitute for being right.

Trial Lawyer Rule:

• If you have facts, pound on facts
• If you have law, pound on law
• If you have neither, pound on table

Related: SHOUTING IN ALL CAPS, tantrums to get reputation.

Excluded Middle (False Dichotomy, Bifurcation)

Definition: Assuming only two alternatives when more exist.

Examples:

• "Either you're with us or against us"
• "Atheism is only alternative to Fundamentalism"
• "Either traitor or loud patriot"

Related: Short Term vs. Long Term (false choice between addressing crime OR improving schools).

Reductive Fallacy (Oversimplification)

Definition: Over-simplifying complex issues.

Einstein's Rule: "Everything should be made as simple as possible, but no simpler"

Examples:

• "Taxation is theft" (political slogan)
• Reducing multi-causal problems to single cause

Related: Causal Reductionism.

Causal Reductionism (Complex Cause)

Definition: Using one cause to explain something with multiple causes.

Example: "Accident was caused by taxi parking in street" (ignoring drunk driver).

Burden Of Proof

Definition: Claiming that whatever hasn't been proved false must be true (or vice versa).

Problems:

• Arguer claims priority without backing it up
• Impatience with ambiguity
• "Absence of evidence is not evidence of absence"

Argument By Question

Definition: Asking question without snappy answer, making opponent look weak or long-winded.

Example: "How can scientists believe a living cell arose from random processes?"

Note: Usually takes longer to answer question than ask it.

Related: Rhetorical Question, Loaded Question ("Have you stopped beating your wife?").

Argument By Rhetorical Question

Definition: Asking question in way that leads to particular answer.

Examples:

• "When will we give old folks the pension they deserve?" (Answer: Right now)
• vs. "When will we be able to afford pension increase?" (Answer: Not now)

Complex Question (Tying)

Definition: Treating unrelated points as if they should be accepted/rejected together.

Example: "Do you support freedom and the right to bear arms?"

Note: Each point should be evaluated on its own merits.

Argument From Authority

Definition: "I'm an expert, so trust me"

Problems:

• Degrees and areas of expertise matter
• Expertise must be relevant to subject
• Being expert in quackery = admission of gullibility

Valid When: Authority is relevant, recent, and verifiable.

Argument From False Authority

Definition: "I'm not a doctor, but I play one on TV"

Related: Appeal to unnamed authorities ("experts agree", "they say").

Appeal To Anonymous Authority

Definition: Claiming "experts agree" without naming them.

Problem: Makes information impossible to verify; may just be spreading rumor.

Appeal To False Authority

Definition: Authority outside their area of expertise.

Example: "Physicist John Taylor found no fraud in Uri Geller's psychic feats" (Taylor not qualified to detect stage magic; later admitted being tricked).

Variations:

• Non-existent authority (made-up journals)
• Misquotes (out of context, edited, glued together)

Statement Of Conversion

Definition: "I used to believe X" (implying expertise through having explored it).

Examples:

• "I used to think that way when I was your age"
• Authors claiming they "used to be" proponents of opposite view

Problem: Doesn't demonstrate actual expertise.

Argument From Age (Wisdom of Ancients)

Definition: Very old (or very young) arguments are superior.

Examples:

• "New! Improved!" (innovation as virtue)
• "Old Fashioned" (tradition as virtue)

Related: Genetic Fallacy (things from particular origin have/lack virtue).

Not Invented Here

Definition: Ideas from elsewhere are unwelcome; "This is how we've always done it"

Note: Can work in reverse (foreign things held as superior).

Argument By Dismissal

Definition: Rejecting idea without saying why.

Examples:

• "If you don't like it, leave the country"
• "If you don't like it, live in Communist country"

Note: Usually has overtones (hopeless cause, unpatriotic, foreign ideas).

Argument To The Future

Definition: "Evidence will someday be discovered that proves me right"

Changing The Subject (Red Herring, Misdirection)

Definition: Avoiding defending claim or making good on promise.

Examples:

• Announcing tax increase (hiding larger increase elsewhere)
• Quibbling about word meanings to derail argument
• Asking opponent to "define 'is'"
• Deliberate misunderstanding
• Announcing "no question period" then not leaving

Related: Argument By Fast Talking.

Argument By Fast Talking

Definition: Moving from idea to idea quickly so audience can't think.

Psychological note: Some research suggests people must briefly believe what they hear to understand it. Rapid delivery prevents rejection.

Begging The Question (Assuming The Answer, Tautology)

Definition: Reasoning in circle; thing to be proved is used as assumption.

Examples:

• "We need death penalty to discourage crime" (assumes it discourages)
• "Stock market fell because of technical adjustment" (but is adjustment just another name for fall?)

Stolen Concept

Definition: Using what you're trying to disprove.

Examples:

• Using science to show science is wrong
• Arguing you don't exist (but existence required to make argument)

Related: Begging The Question, but about what you're trying to disprove.

Contrast: Reductio Ad Absurdum (temporarily assumes truth to show absurdity).

Bad Analogy

Definition: Claiming two situations are highly similar when they aren't.

Examples:

• "Solar system reminds me of atom, so planets must jump orbits like electrons"
• "Minds like rivers can be broad. Broad river = shallow. So broad mind = shallow."
• "We have pure food laws; why not laws against filthy movies?"

Extended Analogy

Definition: Two things both analogous to third thing, therefore analogous to each other.

Example: "You wouldn't have supported law-breaking by Martin Luther King, would you?" → "Are you saying this issue is as important as civil rights? How dare you!"

Hitler Example: "Hitler believed X; you believe X; therefore you're like Hitler" (But Hitler believed drapes should reach floor - does that make it evil?)

Argument From Spurious Similarity

Definition: Resemblance is proof of relationship.

Example: Spotting plane by noticing "little man in cockpit, just like model airplane".

Reifying

Definition: Abstract thing talked about as if concrete.

Example: "Nature abhors a vacuum"

False Cause

Definition: Assuming because two things happened, first caused second (sequence ≠ causation).

Examples:

• "Before women got vote, no nuclear weapons"
• "Every time my brother goes to game, team loses"
• "Sun goes down because we turned on street lights"

Confusing Correlation And Causation

Definition: Things that vary together must cause each other.

Examples:

• Hot chocolate sales up = street crime down (actually: cold weather = fewer people outside)
• Bigger shoe size = better handwriting (actually: child is older)

Special Pleading (Stacking The Deck)

Definition: Using arguments that support position while ignoring/disallowing arguments against.

Example: Claiming unbelievers make you unable to demonstrate abilities.

Argument By Half Truth (Suppressed Evidence)

Definition: Omitting crucial information.

Examples:

• "Prophecy" recorded after event
• Mystery books not mentioning hurricane destroyed ship

Argument By Selective Observation (Cherry Picking)

Definition: Counting hits, forgetting misses.

Examples:

• State boasts of accomplishments, silent about failures
• Casino bells announce jackpots; losses happen silently

Argument By Selective Reading

Definition: Rebut weakest argument, claim opponent made weak case overall.

Note: Overlooks strong arguments while focusing on weak ones.

Argument By Generalization

Definition: Broad conclusion from small, possibly unrepresentative sample.

Examples:

• "I know hundreds of people; none are X. So X doesn't exist."
• "We allow terminally ill to use Y, so everyone should use Y"

Argument From Small Numbers

Definition: Assuming small numbers = big numbers.

Examples:

• "I threw three sevens in a row; tonight I can't lose"
• "One-third of mice cured, one-third died, third escaped"

Fallacy Of The General Rule

Definition: Assuming general truth applies in every case.

Examples:

• "All chairs have four legs" (except rocking chairs, shooting sticks)
• Sometimes laws should be broken (ambulances breaking speed limits)

Fallacy Of Composition

Definition: Assuming whole has same simplicity as constituent parts.

Examples:

• "Car makes less pollution than bus, so cars are less of pollution problem"
• "Atoms colorless, cats made of atoms, so cats colorless"

Note: Science studies emergent properties.

Fallacy Of Division

Definition: Assuming what's true of whole is true of each part.

Example: "Humans made of atoms; humans conscious; so atoms conscious"

Slippery Slope Fallacy (Camel's Nose)

Definition: Wrong because it's next to something wrong, or could slide toward wrong.

Examples:

• "Allowing X in mild form leads to allowing X in extreme form"
• "Legalize A, more will try B"
• "If I make exception for you, I'll have to for everyone"

Moving The Goalposts (Raising The Bar)

Definition: When opponent addresses point, demand they address further point.

Example: Successfully defend gun position → must now defend knife position → must defend martial arts → etc.

Variation: Lowering bar (predicted prevention doesn't happen → claim mitigation instead).

Appeal To Complexity

Definition: If arguer doesn't understand topic, concludes nobody does, so opinions equally valid.

Argument By Prestigious Jargon

Definition: Using big words to seem expert.

Example: "Utilize" instead of "use"

Argument By Gibberish (Bafflement)

Definition: Extreme prestigious jargon; invented vocabulary.

Example: "Each autonomous individual emerges holographically within egoless ontological consciousness as non-dimensional geometric point within transcendental thought-wave matrix"

Sources: Copying style without meaning; snow job; poetic language.

Equivocation

Definition: Using word to mean one thing, then using it to mean something different.

Examples:

• "Sign said 'fine for parking', since it was fine, I parked"
• "All trees have bark; all dogs bark; so all dogs are trees"

Euphemism

Definition: Using words that sound better.

Examples:

• Lab rat wasn't killed, was "sacrificed"
• Mass murder wasn't genocide, was "ethnic cleansing"
• Death of innocents is "collateral damage"

Weasel Wording

Definition: Word changes to claim new concept rather than soften old.

Examples:

• "War" becomes "police action", "protective reaction strike"
• War Departments → Departments of Defense
• Untested medicines → "alternative medicines"

Inconsistency

Definition: Different standards for similar cases.

Example: "Declining metrics in System A = A's failure" vs. "Similar metrics in System B ≠ B's failure"

Internal Contradiction

Definition: Two contradictory claims in same argument.

Example: "I never borrowed his car, and it had that dent when I got it"

Misunderstanding Statistics (Innumeracy)

Definition: Not understanding basic statistical concepts.

Examples:

• Being astonished half of people have below-average intelligence
• Not understanding "regression to mean" (things return to normal)
• Reporting "doubled risk" without mentioning absolute increase is tiny

Affirming The Consequent

Definition: Logic reversal: "If P then Q" becomes "Q therefore P"

Examples:

• "All cats die; Socrates died; so Socrates was cat"
• "If P, we'd see Q. We see Q. So P is proven." (Actually: Q consistent with P, doesn't prove P uniquely)

Non Sequitur

Definition: Conclusion doesn't follow.

Examples:

• "Thousands saw unexplained lights. So alien life is certain."
• "Religion helps many people. So its teachings are true."
• "Bill lives in large building. So his apartment is large."

Appeal To Widespread Belief (Bandwagon, Peer Pressure)

Definition: Many people believe it, so it must be true.

Valid For: Social conventions ("good manners")

Invalid For: Facts (popular beliefs can be wrong)

Cliche Thinking

Definition: Using wise saying as if proven, with no exceptions.

Argument By Repetition (Ad Nauseam)

Definition: Say something often enough, people believe it.

Argument By Pigheadedness (Doggedness)

Definition: Refusing to accept after everyone else convinced.

Genetic Fallacy (Fallacy of Origins)

Definition: If argument has particular origin, it must be right (or wrong).

Problem: Origin doesn't determine correctness.

Argument Of The Beard

Definition: Assuming spectrum ends are same since you can travel in small steps.

Example: "Clean-shaven = big beard (since in-between exists)"

Counter: Pink existing doesn't undermine distinction between white and red.

Common Sense

Definition: Claiming "common sense" answers exist when they don't.

Problem: Common sense depends on context, knowledge, experience.

Least Plausible Hypothesis

Definition: Ignoring reasonable explanations for desired one.

Example: "Left milk out. In morning, gone. Clearly, fairies visited."

Occam's Razor: Simplest explanation is best; don't introduce new concepts (fairies) when old ones (cats) work.

Argument By Scenario

Definition: Telling story tying unrelated material, using story as proof they're related.

Hypothesis Contrary To Fact

Definition: Arguing from something that might have happened but didn't.

Reductio Ad Absurdum

Definition: Showing opponent's argument leads to absurd conclusion.

Valid When: Properly applied to show logical consequence.

Invalid When: Only showing argument doesn't apply in ALL cases.

False Compromise

Definition: If you don't understand debate, "fair" to split difference.

Problem: One side possibly wrong; could suspend judgment instead.

Example: "Some say sun rises east, some say west; truth probably in between"

Fallacy Of The Crucial Experiment

Definition: Claiming idea proved/disproved by pivotal discovery.

Problem: "Smoking gun" history is soundbite distortion.

Reality: Background first, buttressing after.

Two Wrongs Make A Right (Tu Quoque)

Definition: Answering wrongdoing charge by saying others have sinned.

Examples:

• "Okay to keep their pen since they would have taken mine"
• "They did it first" (justifying atrocities)

Pious Fraud

Definition: Fraud to accomplish good end; end justifies means.

In Debates: Shaded, distorted, or fabricated assertion by emotionally committed speaker.

Error Of Fact

Definition: Simply being wrong about facts.

Note: One error usually means more errors to find.

Argument From Personal Astonishment

Definition: "I don't see how this is possible, so it isn't"

Lies

Definition: Intentional Errors of Fact.

Contrarian Argument

Definition: Espousing something generally ill-regarded or disproven.

Motivations: Make people think, needling, external agenda, oppose conformity, ego.

Note: Being contrarian doesn't make you wrong, but if position ill-regarded for reason, defense is uphill.

Ambiguous Assertion

Definition: Statement unclear enough to leave leeway.

Failure To State

Definition: Making enough attacks/questions to never define your position.

Outdated Information

Definition: Giving old information, not latest.

Amazing Familiarity

Definition: Speaker has information there's no way to get based on their statements.

Having Your Cake (Failure To Assert)

Definition: Almost claiming something but backing out.

Meaningless Questions

Definition: Questions with no valid answer.

Example: Irresistible forces meeting immovable objects.

Disproof By Fallacy

Definition: Conclusion reached fallaciously, so incorrectly declared wrong.

Note: Different from Reductio Ad Absurdum.