MMH Logical Fallacy Guide

Ad Hominem (Argument To The Man)

Attacking the person instead of addressing their argument.

• "Von Daniken's books are worthless because he is a convicted forger"
• "How can you argue for vegetarianism when you wear leather shoes?"
• "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"

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

Related: Needling · Poisoning The Wells · Psychogenetic Fallacy

Needling

Attempting to make opponent angry without addressing argument.

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

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

Poisoning The Wells

Discrediting sources used by opponent before they're presented.

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

Psychogenetic Fallacy

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

• "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)

Attacking exaggerated or caricatured version of opponent's position.

• "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

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

• "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"

Healthy debate ≠ fundamental uncertainty.

Argument From Adverse Consequences (Appeal To Fear)

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

• "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"

Argument By Emotive Language (Appeal To The People)

Using emotionally loaded words to sway sentiments instead of minds.

• Using anger, spite, envy, condescension as rhetorical tools
• Seeding audience with "shills" who chant/applaud
• Language that triggers rather than informs

Related: Cliche Thinking · Argument By Slogan · Argument By Poetic Language

Argument By Personal Charm

Getting audience to cut you slack based on likability. Charm creates trust, desire to join the winning team, or please the speaker.

Appeal To Pity (The Galileo Argument)

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

• "They laughed at Edison; they won't give my ideas fair hearing either"

Being persecuted doesn't make you right. Galileo was right AND persecuted — not right BECAUSE persecuted.

Appeal To Force

Threats or violence as argument.

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

Argument By Vehemence

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 the table.

Excluded Middle (False Dichotomy, Bifurcation)

Assuming only two alternatives when more exist.

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

Reductive Fallacy (Oversimplification)

Over-simplifying complex issues.

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

• "Taxation is theft" (political slogan reducing multi-causal reality)

Causal Reductionism (Complex Cause)

Using one cause to explain something with multiple causes.

• "Accident was caused by taxi parking in street" (ignoring drunk driver)

Burden Of Proof

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

"Absence of evidence is not evidence of absence."

Argument By Question

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

It usually takes longer to answer a question than to ask it.

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

Argument By Rhetorical Question

Asking a question in a way that leads to a particular answer.

• "When will we give old folks the pension they deserve?" → Answer implied: Right now
• "When will we be able to afford a pension increase?" → Answer implied: Not now

Complex Question (Tying)

Treating unrelated points as if they should be accepted or rejected together.

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

Each point should be evaluated on its own merits.

Argument From Authority

"I'm an expert, so trust me." Expertise must be relevant, recent, and verifiable.

Appeal To Anonymous Authority

Claiming "experts agree" without naming them — makes information impossible to verify.

Appeal To False Authority

Authority cited outside their area of expertise.

• Physicist endorsing psychic claims — physics credentials don't qualify one to detect stage magic.

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

Statement Of Conversion

"I used to believe X" — implying expertise through having explored the opposite view.

Doesn't demonstrate actual expertise — only prior belief.

Argument From Age (Wisdom of Ancients)

Claiming very old (or very new) arguments are superior simply by virtue of their age.

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

Not Invented Here

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

Can work in reverse — foreign things held as superior.

Argument By Dismissal

Rejecting an idea without saying why.

• "If you don't like it, leave the country"
• "If you don't like it, go live in a communist country"

Argument To The Future

"Evidence will someday be discovered that proves me right."

Changing The Subject (Red Herring, Misdirection)

Avoiding defending a claim by shifting the topic.

• Quibbling about word meanings to derail argument
• Deliberate misunderstanding
• Announcing "no question period" then not leaving

Argument By Fast Talking

Moving from idea to idea quickly so the audience can't think critically.

Research suggests people must briefly believe what they hear to understand it — rapid delivery prevents rejection.

Begging The Question (Assuming The Answer, Tautology)

Reasoning in a circle — the thing to be proved is used as an assumption.

• "We need the death penalty to discourage crime" (assumes it discourages)
• "The stock market fell because of a technical adjustment" (adjustment = another name for fall)

Stolen Concept

Using what you're trying to disprove.

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

Bad Analogy

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

• "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."

Extended Analogy

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

Hitler believed drapes should reach the floor. Does believing that make it evil?

Reifying

Treating an abstract thing as if it were concrete.

• "Nature abhors a vacuum"

False Cause

Assuming because two things happened, the first caused the second. Sequence ≠ causation.

• "Before women got the vote, there were no nuclear weapons"
• "Sun goes down because we turned on the street lights"

Confusing Correlation And Causation

Things that vary together must cause each other.

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

Special Pleading (Stacking The Deck)

Using arguments that support your position while ignoring or disallowing arguments against.

Argument By Half Truth (Suppressed Evidence)

Omitting crucial information.

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

Argument By Selective Observation (Cherry Picking)

Counting hits, forgetting misses.

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

Argument By Selective Reading

Rebut weakest argument, claim opponent made a weak case overall. Overlooks strong arguments while focusing on weak ones.

Argument By Generalization

Broad conclusion from small, possibly unrepresentative sample.

• "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

Assuming small-sample results represent large-scale reality.

• "I threw three sevens in a row; tonight I can't lose"

Fallacy Of The General Rule

Assuming a general truth applies in every case.

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

Fallacy Of Composition

Assuming the whole has the same properties as its constituent parts.

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

Science studies emergent properties — the whole behaves differently than its parts.

Fallacy Of Division

Assuming what's true of the whole is true of each part.

• "Humans are made of atoms; humans are conscious; so atoms are conscious"

Slippery Slope Fallacy (Camel's Nose)

Wrong because it's adjacent to something wrong, or could slide toward something wrong.

• "Allowing X in mild form leads to allowing X in extreme form"
• "If I make exception for you, I'll have to for everyone"

Moving The Goalposts (Raising The Bar)

When opponent addresses your point, demand they address a further point.

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

Variation: Lowering the bar — predicted prevention doesn't happen → claim mitigation instead.

Appeal To Complexity

If arguer doesn't understand the topic, concludes nobody does — therefore all opinions are equally valid.

Argument By Prestigious Jargon

Using unnecessarily complex language to appear expert.

• "Utilize" instead of "use"

Argument By Gibberish (Bafflement)

Extreme prestigious jargon; invented vocabulary designed to obscure rather than illuminate.

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

Equivocation

Using a word to mean one thing, then shifting its meaning mid-argument.

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

Euphemism

Using words that sound better to obscure the reality of what's being described.

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

Weasel Wording

Word changes to claim a new concept rather than soften an old one.

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

Inconsistency

Applying different standards to similar cases.

• Declining metrics in System A = A's failure. Similar metrics in System B ≠ B's failure.

Internal Contradiction

Two contradictory claims made within the same argument.

• "I never borrowed his car, and it had that dent when I got it."

Misunderstanding Statistics (Innumeracy)

Failing to understand basic statistical concepts.

• Being astonished that half of people have below-average intelligence
• Not understanding "regression to the mean"
• Reporting "doubled risk" without mentioning the absolute increase is tiny

Affirming The Consequent

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

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

Non Sequitur

Conclusion doesn't follow from the premises.

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

Appeal To Widespread Belief (Bandwagon, Peer Pressure)

Many people believe it, so it must be true.

Valid for social conventions ("good manners"). Invalid for facts — popular beliefs can be wrong.

Argument By Repetition (Ad Nauseam)

Say something often enough and people believe it, regardless of its truth.

Genetic Fallacy (Fallacy of Origins)

If an argument has a particular origin, it must be right (or wrong) on that basis alone.

Origin doesn't determine correctness.

Least Plausible Hypothesis

Ignoring reasonable explanations in favor of a desired one.

• "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.

Reductio Ad Absurdum

Showing opponent's argument leads to an absurd conclusion.

Valid when properly applied to show logical consequence. Invalid when only showing argument doesn't apply in ALL cases.

False Compromise

If you don't understand a debate, splitting the difference seems "fair."

• "Some say sun rises in the east, some say west; truth is probably in the middle."

Two Wrongs Make A Right (Tu Quoque)

Answering a wrongdoing charge by pointing out that others have sinned.

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

Contrarian Argument

Espousing something generally ill-regarded or disproven for its own sake.

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

Ambiguous Assertion

A statement unclear enough to leave leeway in interpretation or deniability.

Failure To State

Making enough attacks and questions to never have to define your own position.

Outdated Information

Giving old information rather than the latest — often used deliberately to mislead.

Having Your Cake (Failure To Assert)

Almost claiming something but backing out — getting rhetorical benefit without commitment.

Error Of Fact

Simply being wrong about facts.

One error usually means more errors to find.

Argument From Personal Astonishment

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

Cliche Thinking

Using a wise saying as if proven, with no exceptions or examination.

Pious Fraud

Fraud committed to accomplish a good end — the end justifies the means.

In debates: shaded, distorted, or fabricated assertions by emotionally committed speakers.

Hypothesis Contrary To Fact

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

Disproof By Fallacy

A conclusion reached fallaciously, so incorrectly declared wrong.

Different from Reductio Ad Absurdum — the conclusion may still be correct despite the flawed reasoning.

Argument By Scenario

Telling a story tying unrelated material together, then using the story as proof they're related.

Fallacy Of The Crucial Experiment

Claiming an idea was proved or disproved by a single pivotal discovery.

The "smoking gun" history is a soundbite distortion. Background comes first; buttressing follows.

Argument Of The Beard

Assuming spectrum ends are the same since you can travel between them in small steps.

• "Clean-shaven = full beard (since all in-between states exist)"

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

Meaningless Questions

Questions with no valid answer — posed to confuse or waste time.

• What happens when an irresistible force meets an immovable object?

Common Sense

Claiming "common sense" answers exist when they don't — or when the questioner's "common sense" is actually cultural assumption.

Common sense depends on context, knowledge, and experience.

Amazing Familiarity

Speaker claims knowledge there is no way to have based on their stated position or access.

Argument By Pigheadedness (Doggedness)

Refusing to accept a conclusion after everyone else has been convinced — not on new evidence, but on stubbornness alone.