Logical fallacies

Logical Fallacies

Common errors in reasoning that undermine the logic of your argument

Slippery Slope

If A happens than B, C, D... X, Y, Z will happen

Hasty Generalization

A conclusion based on insufficient or biased evidence

post hoc ergo propter hoc

If A occurs after B then B must have caused A
Correlation=causation

Genetic fallacy

the origins of a person, idea, institute, or theory determine its character, nature, or worth

Begging the Claim

The conclusion that the writer should prove is validated within the claim.

Circular Argument

Restates the argument instead of proving it

Either/or

oversimplifies the argument by reducing it to only two sides or choices

Ad hominem

An attack on the person rather than on the opponent's ideas.

ad populum/bandwagon

an appeal that presents what most people, or a group of people think, in order to persuade one to think the same way

Red herring

a diversionary tactic that avoids the key issues, often by avoiding opposing arguments rather than addressing them

Straw man

It oversimplifies an opponents argument and then attacks that hollow argument

Moral Equivalence

Comparing minor misdeeds with major atrocities, implying they are the same

Tu Quoque

When someone avoids the argument and attacks the other person, "No you are!"

Equivocation

Writer shifts the meaning of a word that then shifts the argument

reductio ad absurdum

Showing someone the inevitable conclusion of a thought in order to make it look ridiculous

No True Scotsman

Shifting the goalpost or definition so that no example is acceptable

Middle-Ground Fallacy

Presenting two extremes and assuming that a compromise is the correct course of action

Texas Sharpshooter Fallacy

Finding a pattern where none exists, or changing the conclusion to fit the evidence

The Fallacy Fallacy

Tossing out someone's argument because it contains a fallacy

Ex: Slippery Slope

If you don't take honors courses, you won't get into a good college.

Ex: Hasty Generalization

Jack met a few people with red hair in his life, but he thought they were all mean. Jack now believes all redheads are mean and no longer associates with them.

Ex: post hoc ergo propter hoc

Crime rates increased after people started playing video games, so video games are responsible for the increased crime rates.

Ex: genetic fallacy

I can't believe anything my doctor says about my health issues, he is overweight himself!

Ex: Begging the claim

Water bottles are bad for the environment because they're bad for nature

Ex: Circular argument

You must obey the law, because it's illegal to break the law.

Ex: either/or

You either support praying in public schools or you're an atheist

Ex: Ad Hominem

Steve thinks Earth is flat, so who knows what other crazy stuff he believes?

Ex: ad populum/bandwagon

Everyone drives over the speed limit, so it should not be against the law.

Ex: Red herring

Why are you pulling me over for speeding? Shouldn't you be out catching the real criminals? Someone could be robbing a bank as we speak!

Ex: straw man

A Democrat politician says he wants to spend more money on the social safety net. His Republican opponents call him a communist.

Ex: Moral Equivalence

Cars kill people just like guns. Therefore, if we ban either one of them, we should ban the other too

Ex: Tu Quoque

Parent: "You have to clean your room, it's too messy." Child: "But your room is messy too, so why should I listen to you?"

Ex: Equivocation

Noisy children are a real headache. Two aspirin will make a headache go away. Therefore, two aspirin will make noisy children go away.

Ex: reductio ad absurdum

If you were the unhappiest person in the world then you would probably die from sadness. You are still here so you cannot be that unhappy.

Ex: No True Scotsman

John doesn't drink alcohol. No real man avoids alcohol. John isn't a real man.

Ex: middle ground fallacy

Joe says the sky is pink and Liz says the sky is blue, so they should really just compromise and say the sky is purple.

Ex: Texas Sharpshooter fallacy

A recent study showed that the top 10 countries where Italian soda is most commonly consumed are also countries that have some of the lowest rankings in reported cases of depression. Therefore Italian soda makes people happy

Ex: fallacy fallacy

Jenna thinks we should do yoga before work because it is natural and is said to relax you. Miles thinks we should also smoke pot before work for the same reasons