Intro to Logic. Lisa Duffy. November Week 1. (Suggested use: November 1-9) Monday

Transcription

1 Intro to Logic Lisa Duffy November Week 1 (Suggested use: November 1-9) Monday Please turn to a blank page in your Logic notebook and copy the following statements: 1. You should buy me lunch. My mechanic said so. 2. Use this homeschool curriculum. The weatherman on channel 10 says it s the best. 3. Elect Simms to the US Senate! Five famous actors say he s the best. Each of these examples uses the same type of bad reasoning. Based on your experience and background knowledge, try to find the faulty logic in each example. What do you notice about the evidence or justification (or the lack of evidence or justification) presented in each example? What just doesn t sound right to you? Jot down a few notes about the bad reasoning you think these examples have in common. Don t worry if you re not sure! Just study each example and look for reasoning that doesn t make sense to you. It s a great idea to talk this over with others, if you d like. We ll discuss the faulty reasoning used in each of these statements in the next session.

2 Tuesday Read the explanation below of the informal fallacy used in yesterday s examples. In each example, instead of backing up the statement or claim with reasons to support it, the speaker indicates that someone else supports his position. The mechanic, the weatherman, and the actors are specialists in their fields. They may be considered authorities in their area of expertise. However, the mechanic, the weatherman, and the actors are not authorities on whether someone should by you lunch, use a certain curriculum, or elect Simms. Each of these statements is an example of the informal fallacy known as Appeal to Faulty Authority. The individual may be an authority in their own field, but that doesn t make them an authority in the matter being discussed. At the top of the notebook page on which you wrote the examples on Monday, please write the title Appeal to Faulty Authority. Under the examples you copied yesterday, write the definition of Appeal to Faulty Authority in your own words. Read the following examples. Jot down the letter of each example that you believe contains the informal fallacy Appeal to Faulty Authority. 1. Elect Mr. Boss. My hairdresser says he s the best! 2. Homeschooling is bad for children. The Vice President said so. 3. Exercise is important to health. The Doctor s Association says so. 4. Jope track shoes are the best! The Olympic swim team endorses them. Double-check your conclusions with the answers below. Then, copy those examples that contain the week s fallacy into your notebook.

3 Answers for Tuesday s exercise: Tuesday s examples that contain the informal fallacy Appeal to Faulty Authority: a, b, d. Example c is an appeal to appropriate authority. We expect doctors to be able to give informed advice about matters of health.

4 Wednesday It s time to find your own examples of this week s informal fallacy, Appeal to Faulty Authority, and record them in your notebook. Like Snob Appeal, Appeal to Faulty Authority is common in advertising. It is frequently used in other types of persuasive communication as well.

5 Thursday It s quiz day! Some of the examples below contain the informal fallacy Appeal to Faulty Authority. Others may be examples of other informal fallacies we ve covered, or may not include an informal fallacy. Please read each example and note which, if any, of the informal fallacies we ve covered is contained in each. Then check your responses with the answers that appear below the quiz. You should be developing a keen ability to spot these types of bad reasoning and faulty logic! 1. You should definitely buy this certificate giving you part ownership of the Brooklyn Bridge. The 2012 World Champion Surfer is planning to buy one! 2. You can t make us pay rent! The President of the National Garden Society is against making tenants pay rent. 3. More moms buy Pop-Happy than any other brand! Buy some today! 4. Can I please go to the game, Dad? If I don t go, I might never get invited to anything ever again! I might grow up to be a social misfit and never be able to get a job or do anything constructive. You wouldn t want to live with that guilt, would you? 5. We cannot elect him! He used to be a plumber! 6. World-renowned chefs endorse the A-Plus Underground Irrigation System. Have it installed at your home today. 7. Visit No-More Hair Salon today! Nobody ever goes there anymore, and the owners will have to go out of business if things don t pick up. They were really hoping to make it big. Don t let their dreams go down the drain. 8. Nine out of ten Americans bank with Bucks Bank. Shouldn t you? 9. We can t support the school nutrition bill he s proposed! He s a school employee! 10. Why should you vote in favor of the school nutrition bill? I ll tell you why. My mother and my two aunts were all national award-winning school principals, and they re all voting for it. That s all you need to know!

6 Answers to Logic Quiz: The following examples employ the informal fallacy Appeal to Faulty Authority: 1, 2, 6, 10. Instead of giving evidence, reasons, or facts to support the claim in these statements, the writer or speaker tells us that other people, who are known or respected for something else, agree with his position. Example 3 demonstrates the Appeal to the People fallacy. According to this bad reasoning, everybody (or practically everybody) else is doing it, so shouldn t you? Example 4 is the informal fallacy Appeal to Fear. You wouldn t want to live with that guilt, would you Dad? Do you see the Appeal to Pity in this example, too? The question at the end is clearly an Appeal to Fear, but the speaker is trying to get Dad to feel a bit of pity, too. Number 5 is an example of the Ad Hominem fallacy. Instead of giving any legitimate reasons why the candidate shouldn t be elected, we re just told he used to be a plumber. This is tricky, because we re not being told he is a cheater or a liar, but we aren t being told anything about his lack of qualifications, either. Accusing someone of being a plumber just sounds ridiculous, because being a plumber isn t a character flaw. Even though the speaker in this example chose a ridiculous personal attack against the candidate, it s still a personal attack, since it tells us nothing about whether we should vote for the candidate. Statement 7 is a classic example of Appeal to Pity. Instead of giving us any good reasons to visit the hair salon, we re supposed to feel sorry for the owners because nobody gets their hair done at their salon. There just might be a very good reason for that! Example 8 is another example of the Appeal to the People fallacy. You know this one. Number 9 is a little different from the school nutrition bill proposed in last week s quiz, but it still suffers from the same type of bad reasoning: the Ad Hominem fallacy. The fact that the bill is proposed by a school employee doesn t tell us anything at all about the merits of the bill. It might be worth supporting, or it might not. We need information about the bill itself, not an attack against the person who proposed it. Example 10 does not tell us all we need to know about the nutrition bill. It doesn t tell us anything we need to know about the bill. All we know is that the speaker s mother and aunts were school principals and are voting for it. The mom and aunts may be authorities on running schools, but that wouldn t necessarily make them authorities on nutrition bills. We need to know more! Give us some reasons why the bill is a good idea!