LOGICAL FALLACIES Common Mistakes in Weak Arguments Moody AP Language and Composition.

LOGICAL FALLACIES

Common Mistakes in Weak Arguments

MoodyAP Language and Composition

Introduction

Ad HominemHasty GeneralizationFalse DilemmaBegging the QuestionPost HocFalse Analogy

Definition

Logical fallacies are flaws in reasoning that lead to faulty, illogical statements. They are unreasonable argumentative tactics named for what has gone wrong during the reasoning process.

Most logical fallacies masquerade as reasonable statements, but they are in fact attempts to manipulate readers by reaching their emotions instead of their intellects.

Ad Hominem

Latin for to the manDirectly attacks someone’s appearance, personal habits, or character rather than focusing on the merit of the issue at hand. The implication is that if something is wrong with this person, whatever he/she says must be wrong.

How can you say he’s a good musician when he’s been in and out of rehab for three years?

Ad Hominem – Making it Personal

Sara is divorced, so whatever relationship advice she gives you can’t be good.

It is the suggestions, not the person who makes them that deserve attention. Sara’s marital status has nothing to do with the quality of her advice. Isn’t it also possible that Sara could be married and give awful advice?

If my husband forgot to wash his dish, I would move out too. You did the right thing, Carol.

Hasty Generalization

A hasty generalization is a conclusion based on insufficient or unrepresentative evidence.

Stereotyping and Sexism are forms of this fallacy.

Take, for example common dumb blonde jokes:

Q: What do you call a blonde skeleton in the closet?

A: Last year's hide-and-go-seek winner.

Example of a Generalization

The only redheads I know are rude.

Therefore, all redheads must have bad

manners.

If the speaker only knows two redheads, then he has insufficient evidence to make the general claim about all people with that hair color.

Either – Or / False Dilemma

A false dilemma asserts that a complex situation can have only two possible outcomes and that one of the options is necessary or preferable.

Either go to college or forget about making money.

This falsely implies that a college education is a pre-requisite for financial success.

Was it her college education that made Britney tons of money?

Begging the Question

This is a kind of circular argument where the support only restates the claim.

Wrestling is dangerous because it is unsafe.

Jogging is fun because it is enjoyable.

Unsafe means the same thing as dangerous and fun means the same thing as enjoyable. This makes the reasoning circular.

Post Hoc Fallacy

Short for post hoc, ergo propter hoc, which means after this, therefore caused by this.

This fallacy assumes that just because Bhappened after A, it must have been causedby A.

Politicians love this one.

Post Hoc Example

Since Florida Governor Bush took office, unemployment of minorities in the state has decreased by seven percent. Governor Bush should be applauded for reducing unemployment among minorities.

Before we pat the governor on the back, the speaker

must show that Bush’s policies are responsible for the decrease in unemployment. It is not enough to show the decrease came after his election.

False Analogy

An analogy points out similarities in things that are otherwise different. A false analogy claims comparison when differences outweigh similarities. Essentially, it’s comparing apples and oranges!

False Analogy Example

If we can put a man on the moon, why

can’t we find the cure for the common

cold?

While both things being compared here are related to science, there are more differences than similarities between space and biological advancements.

Band Wagon (Argumentum ad populum)

A claim that an idea should be accepted because a large number of people favor it or believe it to be true. The popularity of an idea has no bearing on its validity.Most people believe the Earth is flat, therefore, it is flat.

Bandwagon Examples

In a court of law, the jury vote by majority; therefore they will always make the correct decision

Many people buy extended warranties, therefore it is wise to buy them.

Nine out of ten of my constituents oppose the bill, therefore it is a bad idea.

Everyone's doing it.

Non Sequitur (Does Not Follow)

A conclusion that does not follow logically from preceding statements or that is based on irrelevant data.

– Mary loves children, so will make an excellent school teacher.

– I hear the rain falling outside my window; therefore, the sun is not shining.

Non Sequitur

In a non sequitur, the conclusion can be either true or false, but the argument is fallacious because there is a disconnection between the premise and the conclusion. Almost all formal fallacies are special cases of non sequitur. Advertising is espedcially adept at the non sequitur in its appeals to pathos....

Non Sequitur appeal to pathos (Fear Tactic)

“The streets of our country are in turmoil, the universities are filled with students rebelling and rioting. Communists are seeking to destroy our country. Russia is threatening us with her might, and the Republic is in danger. Yes, danger from within and from without! We need law and order. Without it, our nation can not survive!”

--Adoph Hitler, 1932

The non sequitur in advertising

The non sequitur is possibly the most commonly used logical fallacy in advertising. Advertisers use strong appeals to our emotions to sell there products.– If I buy that new Snazzydoo, I’ll be more

popular.– If I drink that superhighsugarandcaffeine soft

drink, I’ll have more fun!– If I don’t wear that brand, I’ll be less popular.

Straw Man (a form of non sequitur)

Definition: One way of making our own arguments stronger is to anticipate and respond in advance to the arguments that an opponent might make. The arguer sets up a wimpy version of the opponent’s position and tries to score point by knocking it down

Straw Man Example

Example: Bill and Jill are arguing about cleaning out their closets: Jill: "We should clean out the closets. They are getting a bit messy." Bill: "Why, we just went through those closets last year. Do we have to clean them out everyday?" Jill: "I never said anything about cleaning them out every day. You just want too keep all your junk forever, which is just ridiculous."

Straw Man Example

A: Sunny days are good.

B: If all days were sunny, we'd never have rain, and without rain, we'd have famine and death.

In this case, B falsely frames A's claim to imply that A believes only sunny days are good, and B argues against that assertion. A actually asserts that sunny days are good and, in fact, says nothing about rainy days.

Straw Man Example

C: We should give children ice cream after every school day.

D: That would be rather bad for their health.

C: Do you want our children to starve?

Person C says that children should be given ice cream after every school day. D replies to that statement assuming that children would be getting this in addition to their regular meals, and states that this would be unhealthy. Person C replies with the unreasonable suggestion that if children were not given ice cream, they would starve. Person C does this because it is harder for Person D to argue that children should starve than to argue that children should not be unhealthy.

The Red Herring (another form of non-sequitur)

Partway through an argument, the arguer goes off on a tangent, raising a side issue that distracts the audience from what's really at stake. Often, the arguer never returns to the original issue.

It a point that purposely mislead or distracts from the main point.

Red Herring Example• Example: "Grading this exam on a curve would be the most

fair thing to do. After all, classes go more smoothly when the students and the professor are getting along well." Let's try our premise-conclusion outlining to see what's wrong with this argument:– Premise: Classes go more smoothly when the students

and the professor are getting along well.– Conclusion: Grading this exam on a curve would be the

most fair thing to do.

• When we lay it out this way, it's pretty obvious that the arguer went off on a tangent--the fact that something helps people get along doesn't necessarily make it more fair; fairness and justice sometimes require us to do things that cause conflict. But the audience may feel like the issue of teachers and students agreeing is important and be distracted from the fact that the arguer has not given any evidence as to why a curve would be fair.

Red Herring

I am qualified to be President because my husband is Bill Clinton.

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Summary

Ad HominemHasty GeneralizationFalse DilemmaBegging the QuestionPost HocFalse AnalogyBand WagonStraw Man

Sources Used

Troyka, Lynn Quitman. Quick Access. New

Jersey: Prentice Hall, 2001.