Circular Reasoning / Begging the Question
the conclusion is included in the premise; there’s no proof
The Barons have a great team, so the stands are always packed, which shows how great they are.
Whatever is less dense than water will float, because such objects won't sink in water.
Accepted Middle Ground
because the position is not extreme, it must be right.
P: The diamond ring is worth less than $10,000.
P: The diamond ring is worth more than $1,000.
C: The diamond ring is worth $5,500.
Either-Or / False Choice Dilemma
eliminate logical choices in favor of an extreme view.
All ball players are either very selfish or very generous.
The diamond ring is either worth $10,000 or $1,000.
Personal Incredulity (Being a Subjectivist)
treating one’s opinion as fact or not believing something because you find it confusing.
Medicine X is supposed to cure disease Y. It didn’t work on me, so medicine X must not work at all. Patient: I can’t believe lasers can fix my nearsightedness, so I’m not going to get Lasik.”
Slippery Slope
believing that one event or action must lead to another more serious event or action.
Scientists research gene structure > manipulate animal gene structure > clone animals > manipulate human genes >
clone humans > populate the world with clones
“If you give them an inch, they’ll take a mile.”
Red Herring
going on a tangent to distract from the real issue or argument by bringing up or focusing on an irrelevant detail.
Issue: debate on implementing school uniforms.
Person A focuses on which color instead of whether they should be used or not.
False Analogy
trying to compare unrelated situations to prove a point.
guns = hammers because they can both be used as tools
If there are no laws restricting what kind of people who purchase hammers, there should
be no laws restricting what kind of people purchase guns.
Shift in Definition / Ambiguity / Equivocation
manipulating meanings of words or using words in multiple ways in the same argument
“Only man is rational. No woman is a man. Therefore, no woman is rational.”
Post Hoc (False Cause)
A causes B because A happened before B
It rained this morning; therefore, the river flooded.
Maybe there was another cause … a levee broke?
Ad Hominem (Personal Attack “at the man”)
using insults or personal, unrelated matters as a basis for argument instead of facts related to the issue
“Don’t support the mayor’s new tax proposal because he cheated on his wife.”
Non-Sequitur (False Sequence)
having details (premises) out of order, missing, or in the wrong sequence
kids getting little teacher attention > get low grades > commit more crimes > and go to jail
* There is a missing step between getting low grades and committing crime
- If A then B. (e.g., If I am in Tokyo, I am in Japan.)
- Not A. (e.g., I am not in Tokyo.)
- Therefore, not B. (e.g., Therefore, I am not in Japan.)
Straw Man
purposely rewording or misrepresent an opponent’s statement to make it seem weak or invalid
Candidate X wants to restrict criminally insane people form buying guns.
Candidate Y states, “Candidate X wants to take our guns away. Do you want that?”
Hasty Generalization
making a hurried conclusion (assumption) based on limited information
P: Tina’s Geometry class is very difficult.
P: My Algebra class is very difficult.
C: All math classes are very difficult.
Oversimplification
not allowing for complexities of an issue to influence your perception of that issue.
P: Guns are often involved in violent crimes.
C: If you eliminate guns, you eliminate most violent crime.
False Authority
referring to a person or an organization as expert to support your point when that person/org. is not credible
We should end the death penalty. Just ask musician X. Listen to what s/he says…
Half-Truth/Hidden Truth
only giving part of the story or set of facts, knowing the part left out would weaken your position
Car X gets 42 miles per gallon! (Yes, but only on paved interstates when going 55 mph.)
Biased Information/Source
relying on information that was designed to sway your opinion in a certain direction as proof of the same opinion.
I don’t like ethnicity X, so I rely on other people who don’t like ethnicity X to support
my reasoning for why I didn’t like them in the first place.
Poisoning the Well/Guilt by Association
ruining a person’s (or group’s) point based on personal associations
Person X spends time with Group Y; therefore, nothing Person X does or says is valid.
Person X was mean to me and is a cheerleader; therefore, all cheerleaders are mean.
Shifting the Burden of Proof
whoever makes a claim is responsible for proving it. Fallacy occurs when whoever claims X tries to make the opponent disprove X instead of proving it him/herself.
X: God exists.
Y: Prove it.
X: No. You have to prove God does not exist.
Tu Quoque (You’re Another One)
turning criticism back on the accuser to avoid answering the initial criticism
Parent: You lied to me about whose house you stayed at after the game last night.
Child: Well, you lied to me about there being a Santa Claus. And you lied to mom
about how you liked her new haircut but you told me you didn’t like it.
Appeal to Emotions
relying in getting someone to agree with your point based on personal feelings rather than facts.
Types:
-bandwagoning: celebrity endorsement and/or “Everyone else is doing it, so you should.”
-pity: using some perceived (or real) disadvantage to get an exception or advantage
-fear/anger: reaction to 9/11; desire for retaliation or revenge
-force/authority: because you have strength, power, age, or position doesn’t mean you’re correct
-beliefs/traditions: conservative; do it this way because that’s how it’s always been done
-progressivism: liberal; do it a new and different way because you can
Logical Fallacies QuizName______
I. Matching Definitions/Examples with Fallacies
____1. Circular Reasoning a. focus on the color of school uniforms instead of on whether to have them
(Begging the Question)b. using religious judgments to persuade someone about an argument
____2. Biasc. Because ‘x’ came first, it must have caused ‘y’ to happen
____3. Either-Or Extremesd. bad attitude bad grades crime jail time [missing steps]
(False Choice Dilemma) bad grades jail time bad attitude crime dropout [illogical order]
____4. Slippery Slopee. I thought Mr. L. was too tough of a grader, so that means he is too difficult
____5. Red Herringf. jumping to a broad judgment/conclusion about something without enough evidence
____6. False or Weak Analogyg. treating one’s personal opinion of something as though it’s fact
____7. Appeal to Beliefsh. “Because I said so” as an explanation for why you believe something
____8. Post Hoc (False Cause)i. You have two choices in life: be a winner or be a loser
____9. Ad Hominem j. citing a person or organization as an expert when it is not credible for the topic
____10. Non-Sequiturk. I should be able to own a tank or a car because I would drive them both
____11. Straw Manl. focusing on an irrelevant detail to take attention away form the real issue
____12. Hasty Generalizationm. attacking someone’s personal life instead of attacking their arguments
____13. Oversimplificationn. making something seem less complex than it really is
____14. False Authority o. not recognizing or purposely leaving out parts of opponent’s argument to make him
look weak or flawed
p. Give a kid an inch, he’ll take a mile; or, if you let one kid have an extra
day on a project, pretty soon, he’ll ask for an extra week.
II. Fill-in Fallacies.
15. ______/ This car gets 50 miles per gallon! (but only on wet roads between 45-55 miles per hour)
16. ______/ I want to sell my car for $8,000. Jim offers to buy it for $2,000, so I just decide that $5,000 must
be the right price for the car and sell it to him.
17. ______/ If Brittany Spears is allowed to endorse Mothers Against Drunk Driving, then MADD will lose all
credibility to me.
18. ______/ Person X: “You stole my phone from my locker.”
Person Y: “No, I didn’t. Prove it.”
Person X: “No. I don’t have to. Prove you didn’t steal it.”
Person Y: “I can’t prove I didn’t do something.”
19. Appeal to ______/ If you don’t take this pill, your chances of a heart attack will rise and you’ll be leaving your family
without its husband and father.
20. Appeal to ______/ My computer wouldn’t print, and I put off my project until the last day, and I’m not feeling well.
Please give me another week to do it.”
21. Appeal to Popularity is also known as ______, and can be summarized with the expression, “Everyone else is
doing it, so you should, too.”
22. ______/ An administrator counts a kid absent, calls home and says, “Jack didn’t come to school today.” Jack had come inside, but then he turned around and left, and wants to be counted present because he did “come to school”.
23. Appeal to ______/ Because I am your boss, everything I say is right.
24. Appeal to ______/ Because this is the way it’s always been done, this is how we should keep doing it.
25. Appeal to ______/ We should use a new approach because we won’t know if it’s better until we try it.
BINGO REVIEW
Logical Fallacies Worksheet
Identify the logical fallacies being used in each example.
1. Your honor, the defendant must be guilty because no one can prove his innocence.
2. Susan passed Writing 121. Joey passed Writing 121. Kory passed Writing 121. Writing 121 must be an easy class, since three out of three students I know passed it.
3. You cannot listen to Rush Limbaugh's ideas because he is a conservative. Conservative speaker's ideas are not worth listening to. Since Limbaugh is conservative, you cannot listen to his ideas.
4. We must put God back in our schools, or else American society will degenerate.
5. Alien abductions must take place because no one has found any evidence to disprove the eye-witness accounts.
6. Just answer the question yes or no. Were you still selling drugs when you came to this town?
7. You will get pregnant if you kiss a boy. I've seen Sally kiss boys three times, and now she is pregnant.
8. You can be sure of getting the best watch possible if you buy a Tempus Fugit watch, because you will be buying the world's greatest watch.
9. Friedrich Nietzche's attack on social welfare should not be taken seriously. He is said to have been a degenerate and it is a fact that he went insane.
10. Rare taste: you either have taste or you don't. (Scotch ad)
11. American citizens must raise taxes to support schools. Without more money, our schools cannot possibly do a good job.
12. Bob True is the best qualified candidate for tax assessor. I've known him eight years and he is an honorable man, a devout individual, and an outstanding father.
13. Men are all alike: selfish creatures who spend every weekend glued to a television tube.
14. The pinkos, socialistic liberals, and weirdos in that other department are naturally against my legislative reforms.
15. I interviewed the entire third floor of my dorm, and my research shows that most of the people at this university go home on weekends.
16. You may tell me that it is cruel to require students to learn Latin. But is it any less cruel to require them to enroll in physical education courses? The mental strains of mastering a dead language pale beside the rigors of athletics.
17. Bicycles are a means of transportation, and we all know that transportation is vital to American commerce. If we get rid of all the current bike lanes, there will be less bikes, hence less transportation. Getting rid of bicycle lanes would cripple American trade entirely.
18. People who think abortion should be banned have no respect for the rights of women. They treat them as nothing but baby-making machines. That's wrong. Women must have the right to choose.
19. Mel Gibson’s racist and anti-Semitic remarks are a very minor ordeal. Consider this: 24 American soldiers died in Iraq today. One person’s remarks are minor indeed compared to this tragedy.
20. The mill must be polluting the river because there has been a recent increase in bird deaths around there.
21. We should have a car wash to raise money for Senior Prom. The three classes before us have all done it!
22. Recently, I’ve been thinking that there is some merit in the Republicans’ tax-cut plan. I suggest that we come up with something like it because if we Democrats are going to survive as a party, we have got to show the people that we are as tough-minded as the Republicans, because that is what the public wants.
Section of Fiendish Difficulty. Some of the following sentences are logical fallacies, and some aren't. Which do you think constitute logical fallacies and which are logically valid?
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