Logical Fallacies

advertisement

21 LOGICAL FALLACIES

English III

What is a logical fallacy?

Error in reasoning that undermines the logic of an argument

Can be illegitimate arguments or irrelevant points

Usually lack evidence to support evidence to support claims

1. Ad Hominem

Literally means “against the man”

Attacks the person creating the argument

Diverts from the actual validity of an argument

Ex. Bob’s idea is wrong because he does not like cats. People who hate cats are horrible.

2. Ambiguity

As a feature of language, ambiguity occurs when a word or phrase has more than one meaning.

Example:

The warrant officer sent city police out at 11:38 a.m. to kick kids off the roof of a downtown furniture store.

3. Appeal to Ignorance

A proposition is true simply on the basis that it has not been proven false or that it is false simply because it has not been proven true.

Example:

Since the class has no questions concerning the topics discussed in class, the class is ready for a test.

4. Appeal to Pity

When a person substitutes a claim intended to create pity for evidence in an argument.

Example:

Haley: "He'd be a terrible coach for the team."

Shayna: "He had his heart set on the job, and it would break if he didn't get it."

Haley: "I guess he'll do an adequate job."

5. Bandwagon

Bases argument around what the majority believe

The majority’s opinion must be correct; thus, a person should believe in the majority

Ex. Ninety percent of people prefer Apple computers to IBMs; thus Apple computers are better than IBM computers.

6. Begging the Question

Using the conclusion as a premise to prove the conclusion. (redundancy)

Example:

I was late because I didn't get there in time.

Example

You want to know why I failed the test? I failed the test because I didn't pass it.

7. Circular argumentation

Also known as “begging the question”

Assumes what it tries to prove

Writer or speaker uses no actual proof to support their claims

Ex. Bill Clinton is a good orator because he speaks effectively.

8. Either/or Fallacy

Writer or speaker implies there are only two choices

Creates a simple outcome to a complex problem

Usually uses very strong generalizations

Either you can stay in here or go outside and freeze to death.

9. Faulty Authority

When a person in question is not a legitimate authority on the subject.

Example:

I’m not a doctor, but I play one on TV.

10. Genetic Fallacy

Idea, person, or product is untrustworthy due to racial, geographic, or ethnic origin.

Ex 1. That car must have failing brakes because it was made in Japan!

Ex 2. All of these Chinese products cannot be any good. They were probably made using cheap

Chinese labor.

11. Guilt by Association

A fallacy in which a person rejects a claim simply because it is pointed out that people she dislikes accept the claim.

Example:

Social security is a state funded old-age pension.

Nazis supported state funded old-age pensions.

Therefore, social security is bad.

12. Hasty Generalization

Known as “Dicto Simpliciter”

Uses faulty inductive reasoning

Bases reasoning on insufficient or biased evidence

Usually not an accurate statement

Ex. Fifty percent of women trying to get their license failed. Thus women are bad at driving. But, this sample was taken from two women.

13. Moral Equivalence

Compares harmless actions with atrocious behavior

Unfair and inaccurate comparison

Ex. That parking attendant who gave me a ticket is as bad as Hitler.

14. Non Sequitur

Literally means “It does not follow”

Any argument that does not follow from previous statements

Speaker may leave out a step in her argument

Conclusion may be completely unrelated

Ex. Ralph Wiggum: Martin Luther King had a dream.

Dreams are where Elmo and Toy Story had a party and

I was invited. Yay! My turn is over!

Principal Skinner: One of your best, Ralphie.

("The Color Yellow," The Simpsons)

15. Oversimplification

Ignoring the complicated issues behind an argument.

Very often only one possible cause for a current situation is addressed rather than addressing the multiple causes that often gives rise to the problem.

Example: If Joe would just stop smoking, he could avoid a heart attack.

16. Post Hoc

Writer or speaker assumes a false relationship between two events simply because one event happened before another.

No actual correlation between the two events is established

Ex. A black cat crossed my path. Later, I took Mr.

Boesch’s lit term quiz and failed. The cat must have caused me to fail.

17. Red Herring

Attempts to change the subject

Use to divert argument from the real issues

Usually changes the subject to something completely irrelevant

Ex. We admit healthcare important, but the issue at hand here is childhood obesity.

18. Scare Tactic

Creating fear in people, which does not constitute evidence for a claim.

Example:

Because of the possibility of a terrorist hijacking or a mechanical failure, flying on a plane is too dangerous and should be avoided altogether.

19. Slippery Slope

Argues one action will lead to an array of others with undesirable consequence

Chain of events cannot be stopped in the middle

Ex. Once the debt ceiling is increased once, slowly it will frequently raised until the U.S. is bankrupt.

20. Card Stacking

Uses deliberate deception (bias) to manipulate an argument.

Speaker or writer lists examples to only support their argument.

Ignores examples that disprove one’s point.

Ex. Obviously the U.S. and Mexico should have a trade agreement since it would lead to lower prices, improve U.S. and Mexican relations, and facilitate cultural exchange.

21. Straw Man Argument

Attempts to water down an opposing argument

Committed when a person simply ignores a person's actual position and substitutes a distorted, exaggerated or misrepresented version of that position.

Ex. Speaker A. We should give children Pop Tarts after school everyday.

Speaker B. But that is not healthy for our kids!

Speaker A. Do you want our children to starve to death?

I ate five candy bars and got an A on my test. I should eat five candy bars before every test because I will get an A if I do it.

Post Hoc

The level of mercury in seafood may be unsafe, but what will fishers do to support their families?

Red Herring/ Appeal to pity

He is a misogynist; thus he hates women.

Circular argumentation

People who don't support the proposed state minimum wage increase hate the poor; therefore they are idiots.

Ad hominem/ Oversimplification

If we ban Hummers because they are bad for the environment eventually the government will ban all cars, so we should not ban Hummers.

Slippery Slope

I drank bottled water and now I am sick, so the water must have made me sick.

Post Hoc

We can either stop using cars or destroy the earth.

Either/or Fallacy

Green Peace's strategies aren't effective because they are all dirty, lazy hippies.

Ad Hominem

Everyone else is going out and getting drunk, so you should too.

Bandwagon

Works Cited

"Logical Fallacies." http://owl.english.purdue.edu.

N.p., n.d. Web. 07 Nov. 2012.

Wheeler, L. Kip. "Logical Fallacies

Handlist." Web.cn.edu. N.p., n.d. Web. 7 Nov. 2012

Download