Logical Fallacies

Casual Fallacy (Correlation ≠ Causation)

Assuming that, because two things happen together, one causes the other.

Example: “People who eat cereal every day are healthier. Therefore, cereal makes people healthy.”

• Flaw: Maybe healthy people just choose cereal more often. This doesn’t prove causation.

Confusing Necessary and Sufficient Conditions

Mixing up what’s required (necessary) vs. what guarantees (sufficient).

Example: “If someone is a surgeon, then they went to medical school. Sally went to medical school, so she must be a surgeon.”

• Flaw: Going to medical is necessary for being a surgeon, but not sufficient.

Circular Reasoning

The conclusion just restates the premise in different words.

Example: “He is the best candidate because no one is better than him.”

• Flaw: Says the same thing twice without providing evidence.

Straw Man

Misrepresenting someone’s argument to make it easier to attack.

Example:

Person A: “We should have more money for education.”

Person B: “My opponent wants to throw money at schools with no results.”

• Flaw: B distorts A’s point.

Ad Hominem

Attacking the person instead of their argument.

Example: “You can’t trust her opinion on climate change. She dropped out of college.

• Flaw: The argument ignores the issue and attacks the speaker.

False Dilemma/Dichotomy

Pretending only two options exist when others are possible.

Example: “You either support increased police funding or you’re against public safety.”

• Flaw: There could be a middle ground.

Hasty Generalization

Making a broad claim based on too little evidence.

Example: “Three kids from this school was rude. This school must have poor discipline.”

• Flaw: Generalizes from too small a sample.

Equivocation

Using a word in two different ways within the same argument.

Example: “A feather is light. What is light cannot be dark. Therefore, a feather cannot be dark.

• Flaw: “Light” changes meaning between sentences.

Composition and Division

Composition: Assuming what’s true of the parts must be true of the whole.

Division: Assuming what’s true of the whole must be true of the parts.

Example: “Each player on the team is great, so the team must be great.” (Composition)

“This cake is delicious. That must mean every ingredient is delicious.” (Division)

Appeal to Authority

Using someone’s authority as proof without actual evidence.

Example: “A famous actor says this supplement works, so it must be effective.”

• Flaw: Expertise in one area doesn’t equal truth in another.

Appeal to Popularity (Bandwagon Fallacy)

Arguing something is true because many people believe it.

Example: “Millions of people ise this app, so it must be the best.”

• Flaw: Popularity doesn’t prove quality or truth.

Temporal Fallacy (Assuming the Past Predicts the Future)

Assuming that because something happened before, it must happen again.

Example: “It has rained every July 4th, so it will rain again this year.”

• Flaw: Past trends don’t guarantee future outcomes.