Logical Fallacies

1. Logical Fallacies

2. What is a Fallacy? A fallacy is an error in reasoning or a flawed argument. A fallacy is an "argument" in which the premises (reasons) given for the conclusion do not provide the needed degree of support. Fallacies may be created unintentionally, or they may be created intentionally in order to deceive other people.

3. Prevalence of Fallacies Fallacies are all around you… Advertisements in magazines, on T.V., on billboards all contain fallacies. Politicians use fallacies to persuade you.

4. Types of Fallacies

5. Ad Hominem (Personal Attack) • Appeal to Tradition • False Analogy • False Authority • False Cause (Post Hoc) • False Dilemma (Either/Or Fallacy) • Hasty Generalization • Appeal to Fear • Slippery Slope • Straw Man

6. Ad Hominem or Personal Attack Ad Hominem (“against the person”) attacks a person’s character and not the person’s issue or reasoning. The major difficulty with labeling a piece of reasoning as an ad hominem fallacy is deciding whether the personal attack is relevant. Example: Why should we think a candidate who recently divorced will keep her campaign promises?

7. Appeal to Tradition Occurs when it is assumed that something is better or correct simply because it is older, traditional, or "always has been done." This sort of "reasoning" has the following form: 1. X is old or traditional 2. Therefore X is correct or better. Example: Of course this mode of government is the best. We have had this government for over 200 years and no one has talked about changing it in all that time. So, it has got to be good.

8. False Analogy An inaccurate, inappropriate, or misleading comparison between two things. Example: 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.

9. False Authority When the person in question is not a legitimate authority on the subject. The most blatant examples of misplaced appeals to authority appear in advertising “testimonials.” Example: We are urged to drive an automobile of a given make because a famous golfer or tennis player affirms its superiority.

10. False Cause False Cause (or Post Hoc) - a fallacy with the following form: 1. A occurs before B. 2. Therefore A is the cause of B. False Cause wrongly assumes a cause and effect relationship. Example: A year after the release of the violent shoot-’em-up video game Annihilator, incidents of school violence tripled—surely not a coincidence. Example: It’s Friday the 13th. Mistakes happen on this day!

11. False Dilemma or Either/Or Reduces complicated issues to only two possible courses of action. Example: The patent office can either approve my generator design immediately or say goodbye forever to affordable energy.

12. Hasty Generalization Draws conclusions from scanty evidence. Example: I wouldn’t eat at that restaurant. When I ate there once, my entree was undercooked. Example: I’ve met two people in Nicaragua so far, and they were both nice to me. So, all people I will meet in Nicaragua will be nice to me.

13. Appeal to Fear or Scare Tactics An attempt to frighten people into agreeing with the arguer by threatening them or predicting unrealistically dire consequences. Example: "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."

14. Slippery Slope Suggests that one thing will lead to another, often times with disastrous results. Example: If you get a B in high school, you won’t get into the college of your choice, and therefore will never have a meaningful career.

15. Straw Man Oversimplifies an opponent's viewpoint and then attacks that hollow argument. Example: People who don't support the proposed state minimum wage increase hate the poor.

16. Bill and Jill are arguing about cleaning out their closets: Jill: "We should clean out the closets. They are getting a bit messy." Bill: "Why? We just went through those closets three months ago.” Jill: “You just want to keep all your junk forever, which is just ridiculous."

17. Identify the fallacy: 1. A husband comforts his wife. The wife is near tears. Husband: Stop worrying. Please…calm down! Wife: You just don't understand! She's only 13. If she goes to the movies with a boy this weekend, she'll be married in four years; she'll never go to college. She'll be driving kids to kindergarten before she's 20! a. False dilemma - either/or b. Straw man c. Slippery slope

18. Identify the fallacy: 2. One guy sits eating. His friend walks in limping. GUY: (to limping friend) What happened to you? FRIEND: I just twisted my ankle on the curb! GUY: I knew it! You walked under that ladder this morning. Bad luck! Here! throw some salt over your shoulder! a. Ad hominem (attacking the person) b. Hasty generalization c. Post hoc..(false cause)

19. Identify the fallacy: 3. Businessman speaks on the phone. BUSINESSMAN: The English in this application letter is terrible. Citizens should stop providing tax money to the state college if it graduates students like this! a. False authority b. Hasty generalization c. Ad hominem

20. Identify the fallacy: 4. Two friends getting coffee during a break. QUESTIONER: So! Who is your choice for Mayor? FRIEND: I would never vote for Jones! QUESTIONER: Why? FRIEND: He has a big car, a big house. He's probably a rich snob; he won't understand the average guy. a. False cause b. False analogy c. Ad hominem (attacking the person)

21. LOGICAL FALLACIES PRACTICE • INSTRUCTIONS: • In groups, explain a scenario in which each of the 10 logical fallacies may be used. Then, a group member will present a scenario to the class to see if they can identify which one is being used.