Logical Fallacies

Errors in Logic found in Persuasive Texts

WHAT IS A FALLACY?

• A fallacy is an error in logical reasoning in an argument or a persuasive text.
• This is not the same as a “factual error.”

WHAT IS A FALLACY?

• There are different types of fallacies, and readers should be able to identify fallacies when they occur in text.

Ad Hominem

Appeal to Emotion

Appeal to Authority

Post Hoc

Hasty Generalization

Begging the Question

Exaggeration

AD HOMINEM

• Ad Hominem is when the arguer attacks the person and not the argument.
• Ad hominem literally means “against the person.”
• It can be effective, but it is fallacious.
• Similar to Name-calling in the idea where the person is attacked rather than addressing the real argument.

AD HOMINEM EXAMPLE

2008 Time Warner Cable “Puppies” Ad

AD HOMINEM ATTACK

• EXAMPLE
• Teacher: Education is important. We should spend more to improve our schools.

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• Other Person: Of course you think that. You’re a teacher.

POST HOC (CAUSE AND EFFECT)

• A Post Hoc fallacy involves attributing a cause and effect relationship without adequate evidence. (Which is similar to a hasty generalization.)
• Similar to False Cause. False cause is when someone makes the mistake of assuming that because one event occurred after another event, the first event caused the second one to occur.

POST HOC EXAMPLE

POST HOC EXAMPLE

• EXAMPLE:
• My car was running fine until Jimmy borrowed it. Now it makes a funny noise. He must have done something to it.

How is that a fallacy?

Hasty Generalization

• Another common fallacy is the Hasty Generalization. That’s when a person makes sweeping statements based on too little or biased evidence.
• Similar to Overgeneralization where the generalization is too broad. It can often be recognized by the use of words such as all, everyone, every time, anything, no one, and none.

HASTY GENERALIZATION EXAMPLE

Monty Python and the Holy Grail- “She’s a Witch” Scene

A GENERALIZATION MADE IN HASTE

• EXAMPLE
• Every swan I’ve ever seen was white.

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• Therefore, all swans must be white.

CIRCULAR REASONING

• It is also known as Begging the Question.
• A person uses Circular Reasoning when they support a statement simply by repeating it in different words.

CIRCULAR REASONING EXAMPLE

Do you see the fallacy?

THE QUESTION BEGGED

• EXAMPLE:
• My mother is always busy because she has too much to do.

If the term or idea used to support the argument is interchangeable, it is most likely a form of Circular Reasoning.

NON- SEQUITUR

• Non-sequitur occurs when the arguer reaches a conclusion that does not follow logically from the “proof” offered to support it.
• It literally means “not in sequence.”

NON SEQUITUR EXAMPLE

Direct TV: Grandson with a Dog Collar

NON SEQUITUR EXAMPLE

• EXAMPLE:
• Mrs. Lewis will make Steve the baseball team captain. He is already the captain of the volleyball team.

EITHER/OR FALLACY

• Either/Or Fallacy is a statement that suggests that there are only two choices available in a situation that really offers more than two options.

EITHER OR FALLACY EXAMPLE

EITHER OR FALLACY EXAMPLE

• EXAMPLE:
• Either I grow two inches this summer, or I’ll never make any friends at my new school.

APPEAL TO AUTHORITY

• An Appeal to Authority is one of the most common fallacies used in advertising.
• Celebrities and doctors are used as people with opinions that should be trusted.
• Just because somebody “famous” or a “doctor” has an opinion, that doesn’t make it true.

APPEAL TO AUTHORITY EXAMPLE

Dr. Dre- Dr.Pepper Ad

APPEAL TO AUTHORITY EXAMPLE

• EXAMPLE:
• Four out of five dentists who chew gum recommend Trident.

APPEAL TO POPULARITY

• Appeal to Popularity is also called the Bandwagon Fallacy, because people are encouraging you to “jump on the bandwagon.” Everybody else is doing it! All the cool kids are doing it! Don’t you want to be like everybody else?

APPEAL TO POPULARITY

How does this appeal to the general population?

APPEAL TO POPULARITY EXAMPLE

• EXAMPLE:
• Everyone else on the highway is speeding, so I can speed too. No one actually goes the speed limit.

Conclusion Quick Write

• Write about a time when you’ve seen one of these fallacies used. It can be from a commercial you’ve seen, a print ad you’ve read, or perhaps a person you know who used one of the fallacies in an argument. You can not use one of the examples given in the slide show.