Linear Modeling and Logic Unit
4.6 Logical Fallacies
Appeal to authority: argues that something is true because an expert says it is, but the person in question is not a legitimate authority on the subject
Appeal to consequence: concludes a belief to be true or false based on whether the premise leads to desirable or undesirable consequences
Appeal to ignorance: uses lack of knowledge about the truth of a proposition to conclude the opposite
Appeal to popularity: the fact that large numbers of people believe or act some way is used inappropriately as evidence that the belief or action is correct
Circular reasoning: the premise and conclusion both say essentially the same thing
Correlation implies causation: presumes that a real or perceived relationship between things means that one is the cause of the other
False cause: the fact that one event came before another is incorrectly taken as evidence that the first event caused the second event
Hasty Generalization: a conclusion is drawn from an inadequate number of cases or cases that have not been sufficiently analyzed
Limited Choice: forces a conclusion by artificially limiting the available options
Personal Attack: attacks the opponent’s character or personal traits in an attempt to undermine the argument
Straw man: misrepresents someone’s argument to make it easier to attack
Appeal to Emotion: uses emotional appeals, such as pity, fear, and joy, instead of relevant facts and logic to support a claim.
Slippery Slope: a course of action is rejected because, with little or no evidence, one insists that it will lead to a chain reaction resulting in an undesirable end or ends.
- Identify if each statement or argument includes a logical fallacy or not:
- You should turn to channel 6. It's the most watched channel this year.
Fallacy
- You should turn to the ESPN channel. There’s an exciting game on right now.
No fallacy
- For the fallacy, what’s wrong with the logic?
The problem is arguing that you should do something just because everyone else is. (Appeal to Popularity)
- What makes the other statement/argument reasonable?
It makes sense to want to watch a sports event because it’s entertaining and exciting.
- You should turn to channel 6. It's the most watched channel this year.
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Identify if each statement or argument includes a logical fallacy or not:
- Please contribute to the National Park Foundation. National parks have been called America’s Best Idea, but they are expensive to maintain.
No fallacy
- Well, it's time for a decision. Will you contribute $20 to our environmental fund, or are you on the side of environmental destruction?
Fallacy
- For the fallacy, what’s wrong with the logic?
Not contributing to the environmental fund does not necessarily mean you want environmental destruction. There could be another reason such as you choose to donate to another fund or help the environment in another way. (Limited Choice)_
- What makes the other statement/argument reasonable?
It’s a supportable fact that national parks are expensive to maintain.
- Please contribute to the National Park Foundation. National parks have been called America’s Best Idea, but they are expensive to maintain.
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Identify if each statement or argument includes a logical fallacy or not:
- Nobody has ever proved to me there's a God, so I know there is no God.
Fallacy
- Nobody has ever proved to me there’s a God, but I believe God exists.
No fallacy
- For the fallacy, what’s wrong with the logic?
Just because you lack knowledge of the truth of something does not necessarily mean it’s not true. (Appeal to Ignorance)
- What makes the other statement/argument reasonable?
Beliefs are sometimes based on faith rather than tangible proof.
- Nobody has ever proved to me there's a God, so I know there is no God.
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Identify if each statement or argument includes a logical fallacy or not:
- [The speaker knows he is talking to an aggrieved person whose house is worth much more than $100,000.] You had a great job and didn't deserve to lose it. I wish I could help somehow. I do have one idea. Now your family needs financial security even more. You need cash. You could sell your house and downsize to an apartment that would cost you less per month.
No fallacy
- [The speaker knows he is talking to an aggrieved person whose house is worth much more than $100,000.] You had a great job and didn't deserve to lose it. I wish I could help somehow. I do have one idea. Now your family needs financial security even more. You need cash. I can help you. Here is a check for $100,000. Just sign this standard sales agreement, and we can skip the realtors and all the headaches they would create at this critical time in your life.
Fallacy
- For the fallacy, what’s wrong with the logic?
The speaker is playing on the emotions of the person who just lost his job and trying to make money off them by offering them an unfair price for the house. (Appeal to Emotion)
- What makes the other statement/argument reasonable?
The speaker is offering an idea that could help the person save expenses. The speaker is not trying to scam the person.
Identify which statements or arguments include a logical fallacy. Give a reason to support your answer.
- [The speaker knows he is talking to an aggrieved person whose house is worth much more than $100,000.] You had a great job and didn't deserve to lose it. I wish I could help somehow. I do have one idea. Now your family needs financial security even more. You need cash. You could sell your house and downsize to an apartment that would cost you less per month.
- That can't be Senator Smith there in the videotape going into her apartment. If it were, he'd be a liar about not knowing her. He's not the kind of man who would lie. He's a member of my congregation.
Fallacy (Appeal to Consequence). The speaker doesn’t like the consequence of Senator Smith being a liar, so the speaker refuses to believe that Senator Smith is the man in the video.
- That can’t be Congressman Jones there in the videotape going into her apartment. If it were, he’d have grown a foot taller since I saw him last month.
Reasonable argument based on the Congressman’s height.
- The email scandal is a story, and therefore reporters need to keep talking about it because it’s a story.
Fallacy (Circular Reasoning) The premise and conclusion of the argument both state that the email scandal is a story.
- (A debate before the city council):
Opponent: Because of the killing and suffering of Native Americans that followed Columbus's discovery of America, the City of Berkeley should declare that Columbus Day will no longer be observed in our city.
Speaker: This is ridiculous, fellow members of the city council. It's not true that everybody who ever came to America from another country somehow oppressed the Native Americans. I say we should continue to observe Columbus Day, and vote down this resolution that will make the City of Berkeley the laughing stock of the nation.
Fallacy (Straw Man) The speaker turns around the opponent’s statement to claim that the opponent is saying everyone who immigrated to America oppressed the Indians.
- (A debate before the city council):
Speaker: We need to fund the new Dean of Students position at the middle school to help manage students with disciplinary problems in the classroom.
Opponent: It is more important that we spend that money to fund more Student Resource Officers in the building to protect all students from weapons.
Reasonable argument. Each side has a different opinion on how best to spend the money in the school budget.
- You shouldn’t procrastinate when it comes to completing your homework assignments and projects. If you wait until the last minute you won’t have time to ask questions in the tutoring center or your instructor’s office. Then you’ll have to miss some problems or leave them blank. That would affect both your grade and your learning.
Reasonable argument. The speaker is stating realistic ramifications of procrastinating on homework.
- More and more people are buying sports utility vehicles. It is time you bought one, too.
Fallacy (Appeal to Popularity) The speaker is arguing that you should buy an SUV just because lots of other people are buying them.
- More and more people are buying sports utility vehicles. Trucks and SUV’s accounted for 63% of U.S. vehicle sales in 2016. The Honda CR-V was the bestselling SUV in the U.S. last year, with sales up 3% to 357,335.
Reasonable. The speaker uses factual data to support the claim that the number of people buying SUV’s is increasing.
- The toddler screams: Buy me this book! Or else don’t care if I learn to read or not!
Fallacy (Limited Choice) There may be many other reasons why a parent chooses not to buy the toddler a certain book.
- A pollster asks you this question about your job: "Would you say your employer is drunk on the job about (a) once a week, (b) twice a week, or (c) more times per week?
Fallacy (Limited Choice) The option “not at all” needs to be one of the choices.
- The auto accident rate rises with the increased use of windshield wipers. The use of wipers causes auto accidents.
Fallacy (Correlation Implies Causation) It’s not actually the use of wipers that’s the problem. The problem is probably the weather conditions that necessitate the use of wipers.
- My psychic adviser says to expect bad things when Mars is aligned with Jupiter. Tomorrow Mars will be aligned with Jupiter. So, if a dog were to bite me tomorrow, it would be because of the alignment of Mars with Jupiter.
Fallacy (False Cause)
- I've met two people in Nicaragua so far, and they were both nice to me. The citizens of Nicaragua are very kind.
Fallacy (Hasty Generalization)
- We can’t allow people to bring beverages into the conference room. If we do, soon they’ll be bringing in snacks and then meals. Pretty soon we’ll have a full-blown restaurant in here! I’d have to hire wait staff and a chef! We could get shut down for a health code violation! Somebody could even choke and die! Do you want that on your conscience?
Fallacy (Slippery Slope)