LOGIC 3 (Material Fallacies)

3 Kinds of Material Fallacies

1. AMBIGUITY — “What do you mean?”

   Meaning/language is messed up

2. RELEVANCE — “How does that prove your point? (

   The reason doesn't actually prove the conclusion

3. PRESUMPTION — “Why are you assuming that?”

   The argument assumes something doubtful

   
   

A kind of fallacy that happens because the meaning, grammar, parts/whole, emphasis, or consistency is messed up.

E A C D A I

FALLACIES OF AMBIGUITY

• Equivocation

• Amphiboly

• Composition

• Division

• Accent

• Inconsistency

A fallacy where one important word changes meaning during the argument.

“I have the right to marry. Therefore, it is right to marry several times.”

First right = legal entitlement.
Second right = morally correct.

Fallacy of EQUIVOCATION = WORD CHANGES - SEMANTIC

EQUIVOCATION = SAME WORD, DIFFERENT MEANING

Ask: “Did the word change meaning?”

If YES → Equivocation

The sentence structure allows multiple interpretations.

Usually caused by:

• misplaced comma

• unclear pronoun

• confusing grammar

“If BBM wins the presidential election against Robredo, he will continue the Gobyerno Tapat, Angat Buhay Lahat.”

Fallacy of AMPHIBOLY = SENTENCE/GRAMMAR IS UNCLEAR

EQUIVOCATION = WORD confusion
AMPHIBOLY = SENTENCE confusion

Something is true of the parts, so you assume it's true of the whole.

Every player on the team is excellent.
Therefore, the team must be excellent.

Fallacy of COMPOSITION = PART → WHOLE

You took: PARTS → WHOLE

COMPOSITION = Combine the parts

Something is true of the whole, so you assume it is true of every part.

“Since DPWH was on the list of the top 10 corrupt government agencies, it follows that all DPWH workers are also corrupt.”

Fallacy of DIVISION = WHOLE → PART

You emphasize a different part of the statement—or remove something from its original context—and suddenly the meaning changes.

Example: “NO PARKING ON BOTH SIDES.”

Person: “I only parked on ONE side!”

The emphasis on BOTH versus ONE changes how the statement is interpreted.

Fallacy of ACCENT = EMPHASIS/CONTEXT CHANGES

ACCENT = STRESS

Ask: “Was something emphasized or taken out of context?”

YES → Accent.

Two claims cannot both be true in the same sense at the same time.

Example:

Juan is older than Pedro.
Pedro is older than Juan.

Fallacy of INCONSISTENCY = CONTRADICTION

A kind of fallacy that gives you something that may be emotionally relevant, socially relevant, or psychologically convincing—

but logically, it doesn't prove the conclusion.

“Does this actually prove the conclusion?”

FALLACIES OF RELEVANCE

MEMORY WORD: DISTRACTION

“Agree with me, or else.”

Example: “Support this policy or you'll lose your job.”

They're not proving the policy is good.

They're threatening you.

APPEAL TO FORCE = THREAT

FORCE = “DO IT OR ELSE.”

Very similar to force, but focus on fear.

“Take this product, or you'll get sick.”

The argument essentially says:

“Believe X because you're scared of Y.”

APPEAL TO FEAR = SCARY CONSEQUENCE

Appeal to Force → someone threatens/coerces you.

Appeal to Fear → you are persuaded through fear of something bad.

“Please give me a passing grade because if I fail, my scholarship might be affected.”

Does the situation deserve sympathy? Maybe.

Does it prove that you deserve to pass? No.

APPEAL TO PITY = FEEL SORRY FOR ME

PITY = “FEEL BAD FOR ME, THEREFORE I'M RIGHT.”

Instead of answering the argument: “Your argument is wrong.”

You attack: “YOU are bad.”

Example: “Don't believe Pedro's testimony. He's a bad person.”

The person's character doesn't automatically make the claim false.

ABUSIVE AD HOMINEM = ATTACK THE PERSON

ABUSIVE = INSULT

Instead of: “He's bad, therefore he's wrong.”

You say: “He's good/respected/religious; therefore, he's right.”

Example: “You should believe him because he's a respected priest.”

NON-ABUSIVE AD HOMINEM = PRAISE THE PERSON

ABUSIVE = BAD PERSON → WRONG

NON-ABUSIVE = GOOD PERSON → RIGHT

You attack someone's argument because of their position, circumstances, occupation, interests, status, etc.

Example:

“Of course the politician supports that law—he's a politician.”

Instead of asking: “Is his argument actually good?”

You're saying: “His circumstances make his argument unreliable.”

CIRCUMSTANTIAL AD HOMINEM = LOOK AT THEIR SITUATION

CIRCUMSTANTIAL = “LOOK WHO YOU ARE / WHERE YOU STAND.”

Someone points out your mistake.

You respond: “YOU DO IT TOO!”

Example:

A: “Smoking is unhealthy.”
B: “You smoke too!”

Did that prove smoking is healthy? No

TU QUOQUE = “YOU TOO!”

TU QUOQUE = HYPOCRISY

Remember the childish argument:

“You can't tell me not to do it because YOU did it!”

You attack someone's reputation before they even get to make their case.

Example: “Don't listen to anything that politician says. He's corrupt.”

You've already contaminated the audience's perception.

POISONING THE WELL = DESTROY THEIR REPUTATION FIRST

POISON THE WELL BEFORE THEY DRINK

Attack the person beforehand → Poisoning the Well

Also called Bandwagon.

“Millions of people use this product, so it must be the best.”

MANY PEOPLE ≠ TRUTH

Think: “Everyone says it!”

APPEAL TO NUMBERS/MASSES = EVERYONE BELIEVES IT

“You can't prove it's false, therefore it's true.”

OR:

“You can't prove it's true, therefore it's false.”

Example: “Nobody has proven that aliens don't exist. Therefore, aliens exist.”

The absence of proof is being treated as proof.

APPEAL TO IGNORANCE = NO PROOF OTHERWISE

IGNORANCE = “YOU CAN'T DISPROVE ME!”

Authority itself isn't automatically bad.

The problem is: The person isn't an authority on THIS subject.

Example: “Michael V. says this medicine works, therefore it works.”

He's famous. But being a celebrity doesn't make him a medical expert.

INAPPROPRIATE AUTHORITY = FAMOUS PERSON SAID IT

AUTHORITY ≠ EXPERTISE

Ask: “Is this person actually qualified in this subject?”

If NO → Inappropriate Authority

Kind of fallacy where the argument goes wrong because it assumes something that hasn't been properly established.

D B C C S S

FALLACIES OF PRESUMPTION

MEMORY WORD: ASSUMPTION

• Dichotomy

• Begging the Question

• Complex Question

• Cause

• Straw Man

• Slippery Slope

This is the: “Either A or B!” fallacy.

when there are actually: A, B, C, D, E...

Example: “Either you support the government or you hate the country.”

Those aren't necessarily the only options.

FALSE DICHOTOMY = ONLY TWO OPTIONS

This one sounds complicated until you realize: THE CONCLUSION IS ALREADY HIDING IN THE PREMISE.

Example:

“Texting in class is wrong because it is morally wrong.”

You asked: “Why is it wrong?”

Answer: “Because it's wrong.”

You've gone in a circle.

BEGGING THE QUESTION = CIRCULAR

Think: 🔵 → conclusion → premise → conclusion → 🔵

This is the famous: “Have you stopped cheating?”

If you answer: “Yes.”

You're admitting you cheated before.

If you answer: “No.”

You're also admitting you cheat.

You're trapped.

COMPLEX QUESTION = TRAPPED QUESTION

COMPLEX QUESTION = NO SAFE ANSWER

The question secretly contains an assumption.

Something happened after something else.

You conclude: A happened first → therefore A caused B.

Example:

“I got wet in the rain and then got sick. Therefore, getting wet caused my sickness.”

Temporal sequence ≠ causation.

FALSE CAUSE = AFTER ≠ BECAUSE

FALSE CAUSE = “AFTER DOESN'T MEAN BECAUSE.”

Your opponent says: 🧑 “We should reduce homework.”

You respond: 🧑 “So you want students to stop studying altogether!”

Wait. That's not what they said.

You created a weaker, distorted version of their position and attacked that instead.

STRAW MAN = CHANGE THEIR ARGUMENT

STRAW MAN = TWIST THE ARGUMENT

Think: REAL ARGUMENT → TWIST → FAKE ARGUMENT → ATTACK

You claim:

A will cause B
B will cause C
C will cause D
...
therefore A will eventually cause Z.

The problem? You're assuming that the chain must continue.

Example: “If students are allowed to use phones during breaks, eventually they'll use phones during class, then they'll stop studying, then they'll fail, then society will collapse.”

SLIPPERY SLOPE = ONE STEP → DISASTER

SLIPPERY SLOPE = “IF WE ALLOW THIS, EVERYTHING WILL GO WRONG!”