Logical Fallacies: Practice

"Andrea Donnely has written several books arguing that pornography harms women. But Donnely is an ugly, bitter person, so she naturally believes pornography is bad."

Ad hominem abusive

"Gay marriages are just immoral. 70% of Americans think so!"

Ad populum

"We should abolish the death penalty. Many respected people, such as actor Guy Gorgeous, have publicly stated their opposition to it."

Appeal to false authority

"You know, Professor Smith, I really need to get an A in this class. I'd like to stop by during your office hours later to discuss my grade. I'll be in your building anyways, visiting my father. He's your dean, by the way. I'll see you later."

Appeal to force

"Active euthanasia is morally acceptable. It is a decent, ethical thing to help another human being escape suffering through death."

Begging the question

"Employees are like nails. Just as nails must be hit in the head in order to make them work, so must employees."

False analogy

"Caldwell Hall is in bad shape. Either we tear it down and put up a new building, or we continue to risk students' safety. Obviously we shouldn't risk anyone's safety, so we must tear the building down."

False dichotomy

"My roommate said her philosophy class was hard, and the one I'm in is hard, too. All philosophy classes must be hard!"

Hasty generalization

"President Jones raised taxes, and then the rate of violent crime went up. Jones is responsible for the rise in crime."

false cause

"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."

Red herring

"Animal experimentation reduces our respect for life. If we don't respect life, we are likely to be more and more tolerant of violent acts like war and murder. Soon our society will become a battlefield in which everyone constantly fears for their lives. It will be the end of civilization. To prevent this terrible consequence, we should make animal experimentation illegal right now."

Slippery Slope

"If I fail my swim test, I won't be able to graduate. If I don't graduate, I probably won't be able to get a good job, and I may very well end up doing temp work or flipping burgers for the next year."

Slippery slope

"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."

Straw Man

"I won't accept your argument, because you used to smoke when you were my age. You did it, too!"

Tu quoque

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 every day?

Jill: I never said anything about cleaning them out every day. You just want to keep all your junk forever, which is just ridiculous.

Straw Man

Guns are like hammers—they're both tools with metal parts that could be used to kill someone. And yet it would be ridiculous to restrict the purchase of hammers—so restrictions on purchasing guns are equally ridiculous.

False analogy

Senator Jill: We'll have to cut education funding this year.

Senator Bill: Why?

Senator Jill: Well, either we cut funding, or we live with a huge deficit, and we can't live with the deficit.

False dichotomy

Dave and Kenny are arguing about Stalin's reign in the Soviet Union. Dave has been

arguing that Stalin was a great leader while Kenny disagrees with him.

Kenny: I don't see how you can consider Stalin to be a great leader. He killed millions of

his own people, he crippled the Soviet economy, kept most of the people in fear and laid the foundations for the violence that is occurring in much of Eastern Europe.

Dave: Yeah, well you say that. However, I have a book at home written by a guy who

directed a movie all about Stalin. The book says that Stalin was acting in the best interest of the people. The millions that were killed were vicious enemies of the state and they had to be killed to protect the rest of the peaceful citizens. This book lays it all out.

Appeal to false authority

Interviewer: Your résumé looks impressive but I need another reference.

Bill: Jill can give me a good reference.

Interviewer: Good. But how do I know that Jill is trustworthy?

Bill: Well, I can vouch for her

Begging the question

Bill says that he likes the idea that people should work for their welfare when they can. His friends laugh at him, accuse him of being a fascist, and threaten to exclude him from their group. He decides to change his position to avoid rejection.

Ad populum

Sam is riding her bike in her home town in Maine, minding her own business. A pick-up truck comes up behind her and the driver starts beeping his horn and then tries to force her off the road. As he goes by, the driver yells, "Get on the sidewalk where you belong!" Sam sees that the truck has Ohio plates and concludes that all Ohio drivers are jerks.

Hasty generalization

The new UltraSkinny diet will make you feel great. No longer be troubled by your weight. Enjoy the admiring stares of the opposite sex. Revel in your new freedom from fat. You will know true happiness if you try our diet!

Appeal to vanity

Bill: God must exist.

Jill: How do you know?

Bill: Because the Bible says so.

Jill: Why should I believe the Bible?

Bill: Because the Bible was written by God.

Begging the question

We've got to stop them from banning pornography. Once they start banning one form of literature, they will never stop. Next thing you know, they will be burning all the books!

Slippery Slope

Sally: I played the lottery today, and I know I am going to win something.

Sara: What did you do, rig the outcome?

Sally: No, silly. I called my Super Psychic Dude at the 1-900-Fortunes number. After

consulting his magic Californian Tarot deck, he told me my lucky numbers.

Sara: And you believed him?

Sally: Certainly, he is a certified Californian Psychic Dude. I mean, like, who else would know what my lucky numbers are?

Appeal to false authority

Argument for making grad school requirements stricter: "I think there is great merit in making the requirements stricter for the graduate students. I recommend that you support it, too. After all, we are in a budget crisis and we do not want our salaries affected."

Red herring

Look, you are going to have to make up your mind. Either you decide that you can afford this car, or you decide you are going be stuck at home every day.

False dichotomy

Peter: It is immoral for people to cheat on their spouses.

Bill: But you have had several mistresses!

Tu quoque

Bill: I like classical music; I think it is of higher quality than most modern music.

Jill: That stuff is for old people. Dave: Yeah, only real losers listen to that crap. Besides, Metallica rules!

Bill: Well, I don't really like it that much. Metallica is much better.

Ad populum

I hadn't been winning any races this season. Then my girlfriend gave me a sweet Speedo, and I won my next three races. This suit must be good luck...if I keep on wearing it I can't help but win!

false cause

You know, I've begun to think that there is some merit in the Republican's tax cut plan. I suggest that you come up with something like it, because if we Democrats are going to survive as a party, we have to show that we are as tough-minded as the Republicans, since that is what the public wants.

Ad populum

Bill: Ugh, those feminists all hate men.

Joe: Really?

Bill: Yeah. I was in my philosophy class the other day and that Rachel chick gave a presentation.

Joe: Which Rachel?

Bill: You know her. She's the one that runs that feminist group over at the Women's Center. She said that men are all sexist pigs. I asked her why she believed this and she said that her last few boyfriends were real sexist pigs.

Joe: That doesn't sound like a good reason to believe that all of us are pigs.

Bill: That was what I said.

Joe: What did she say?

Bill: She said that she had seen enough of men to know we are all pigs. She obviously hates all men.

Joe: So you think all feminists are like her?

Bill: Sure. They all hate men.

Hasty Generalization

Bill purchases a new laptop and it works fine for months. He then buys and installs a new piece of software. The next time he starts up his laptop, it freezes. Bill concludes that the software must be the cause of the freeze.

false cause

You shouldn't say such things about sexual harassment! If the chair heard what you were saying, you would never receive tenure. So, you had just better learn to accept that it is simply wrong to speak out against it.

Appeal to emotion

We have to stop the tuition increase! The next thing you know, they'll be charging $80,000 a semester!

Slippery Slope

Prof. Jones: The University just cut our yearly budget by $10,000.

Prof. Brown: What are we going to do?

Prof. Jones: I think we should reduce our scheduled raises.

Prof. Brown: I can't understand why you want to take away all our money, Jones.

Straw Man

UFOs don't exist. Have you seen the people who claim to have seen them? Those people are all freaks!

Ad hominem abusive

What's the big deal about the early pioneers killing a few Indians in order to settle the West? After all, you can't make an omelet without breaking a few eggs.

False Analogy

The new PowerBlue computer gives you the power you need. If you buy one, people will envy your power. They will look up to you and wish they were just like you. You will know the true joy of power. BluePower.

Appeal to snobbery

You can never give anyone a break. If you do, they'll walk all over you.

Slippery Slope

Bill: I believe that abortion is morally wrong.

Dave: Of course you would say that, you're a priest.

Bill: What about the arguments I gave to support my position?

Dave: Those don't count. Like I said, you're a priest, so you have to say that abortion is wrong. Further, you are just a lackey to the Pope, so I can't believe what you say.

Ad Hominem abusive

If such actions were not illegal, then they would not be prohibited by the law.

Begging the question

Bill: It seems clear to me that this new music is causing the youth to become corrupt.

Joe: What do you mean?

Bill: This rap stuff is always telling the kids to kill cops, do drugs, and abuse women. That is all bad, and the kids today shouldn't be doing that sort of stuff. We ought to ban that music! You can't argue against the fact that social ills really picked up at the same time rap music got started.

false cause

Students should be allowed to look at their textbooks during examinations. After all, surgeons have X-rays to guide them during an operation; lawyers have briefs to guide them during a trial; carpenters have blueprints to guide them when they are building a house. Why, then, shouldn't students be allowed to look at their textbooks during an examination?

False analogy

Senator Williams says that we should not fund the attack submarine program. I disagree entirely. I can't understand why he wants to leave us defenseless like that.

Straw Man

Abstract art isn't really art. Those pictures and things don't represent anything.

Begging the Question

I'm not a doctor, but I play one on the hit series "Gorgeous ER Doctors with Accents." You can take it from me that when you need a fast-acting, effective, and safe pain killer there is nothing better than OwieeStopper 2000. That is my considered medical opinion.

Appeal to False Authority

I don't think a Red Ryder BB rifle would make a good present for you. They are very dangerous and you'll shoot your eye out. Now, don't you agree that you should think of another gift idea?

Appeal to fear

Cliff's assertion that Joe is innocent is not to be believed as Cliff is a criminal himself.

Tu quoque

Jane gets a rather large wart on her finger. Based on a story her father told her, she cuts a potato in half, rubs it on the wart and then buries it under the light of a full moon. Over the next month her wart shrinks and eventually vanishes. Jane writes her father to tell him how right he was about the cure.

false cause

The US shouldn't get involved militarily in other countries. Once the government sends in a few troops, it will then send in thousands to die.

Slippery slope

Bill: I believe that abortion is morally acceptable. After all, a woman should have a right to her own body.

Jane: I disagree completely. Dr. Johan Skarn says that abortion is always morally wrong, regardless of the situation. He has to be right, after all, he is a respected expert in his field.

Bill: I've never heard of Dr. Skarn. Who is he?

Jane: He's the guy that won the Nobel Prize in physics.

Appeal to False Authority

I must have caught my illness from this cat scratch. When I was at my friend's two days ago, her cat scratched me, and now I have a fever.

false cause

In order to maintain a civil debate, I will not mention my opponent's drinking problem.

ad hominem abusive