1. Logical Fallacies Intro to Debate and Argumentation: Snell

2. What is a logical fallacy?
An inconsistency within your logical appeal (logos)
Lowers your credibility (ethos)

3. example #1 All Olympic runners are fast. Michael is an Olympic runner.
► Michael is fast.

4. example #2 All AHS students are smart. Pat is a AHS student.
► Pat is smart.

5. example #3 All dogs are animals. All cats are animals.
►All dogs are cats.

6. example #4 Question: How did the window get broken?
Evidence: There is a baseball on the floor.
Baseball wasn't there this a.m.
Kids were in the yard across the street.
They were playing baseball this afternoon.
They stopped playing earlier than usual.
They aren't in the yard now.
Conclusion: One of the kids broke the window with the ball and then they all ran away.

7. Example #4 continued: BUT what if…
…you have a Bears flag in your front yard?
…you live next to Mr. Thompson (aka Packers’ fan)

8. 16 Argumentative Fallacies

9. 1. Hasty Generalization or Faulty Syllogism

10. Drawing conclusion on the basis of insufficient evidence.
“Everybody agrees,” “nobody like,” “most people care”

12. 2. Faulty Use of Authority

13. misrepresenting the trustworthiness of sources
The attempt to bolster claims by citing the opinions of experts without evaluation and comparison of credentials and claims.
Taking something out of context

14. According to the doctor, I need less sodium in my diet….

16. 3. Misleading Statistics

17. A fallacy in which a very small number of particularly dramatic events are taken to outweigh a significant amount of statistical evidence.

18. The AP Japanese Exam is the most difficult exam; after all, 100 percent of Andover High School students didn’t pass it.

19. 4. Faulty Emotional Appeal

21. 5. False Analogy

22. Assuming without sufficient proof that if objects or processes are similar in some ways, then they are similar in other ways as well.
Many analogies are merely descriptive and do not offer proof of the connection between two things being compared.

24. 6. Slippery Slope

25. Predicting without justification that one step in a process will lead unavoidably to a second, generally undesirable step

27. 7. Ad Hominem

28. "Against the man"
attacking the arguer rather than the argument; discrediting an argument by trashing the person making it.
Watch for this is EVERY political debate!

31. Hilary Clinton would make a terrible president because her husband was impeached while in office.

32. 8. Post Hoc

33. "after this, therefore because of this."
The arguer infers that because one event follows another, the first event must be the cause of the second event. Proximity of events or conditions does not guarantee a causal relationship.

34. The rooster crowed, the sun came up
The rooster crowed, the sun came up. Therefore, the rooster made the sun come up.
I took a pill, I got better.
Therefore, the pill made me get better.

35. Every time Snell starts her day with a cup of coffee, she is in a better mood. To keep Snell in a good mood, we should buy her Caribou Coffee.

37. 9. Straw Man

38. Strawman
You misrepresented someone's argument to make it easier to attack.
By exaggerating, misrepresenting, or just completely fabricating someone's argument, it's much easier to present your own position as being reasonable, but this kind of dishonesty serves to undermine honest rational debate.

39. Strawman
Example: After Will said that we should put more money into health and education, Warren responded by saying that he was surprised that Will hates our country so much that he wants to leave it defenseless by cutting military spending.

41. 10. Red Herring

42. Red Herring
A diversionary tactic that avoids key issues, often by avoiding opposing arguments, rather than addressing them.

43. Red Herring
Example: The level of mercury in seafood may be unsafe, but what will fishers do to support their families?

44. 11. Ad Populum

45. "To the people”
“Everybody’s doing it”

48. 12. Begging the Claim/Question
Also Known as: Circular Reasoning, Reasoning in a Circle, Petitio Principii

49. Begging the Question is a fallacy in which the premises include the claim that the conclusion is true or (directly or indirectly) assume that the conclusion is true. This sort of "reasoning" typically has the following form:

50. Premises in which the truth of the conclusion is claimed or the truth of the conclusion is assumed (either directly or indirectly).
Claim C (the conclusion) is true.

51. This sort of "reasoning" is fallacious because simply assuming that the conclusion is true (directly or indirectly) in the premises does not constitute evidence for that conclusion. Obviously, simply assuming a claim is true does not serve as evidence for that claim. This is especially clear in particularly blatant cases: "X is true. The evidence for this claim is that X is true."

52. Some cases of question begging are fairly blatant, while others can be extremely subtle.

53. Examples of Begging the Question
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.“

54. If such actions were not illegal, then they would not be prohibited by the law."
Interviewer: "Your resume 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: "Certainly. I can vouch for her."

55. 13. Moral Equivalence

56. Compares minor misdeeds with major atrocities.
Example: The parking attendant, who gave me a ticket, is as bad as Hitler.

57. 14. Circular Argument

58. This restates the argument, rather than actually proving it.
Example: George Bush is a good communicator because he speaks effectively.
Good communicator is the same as speaking effectively, so the claim isn’t proven

59. 15. Either/or

60. This is a conclusion that oversimplifies the argument by reducing it to only two sides or choices.
Example: We can either stop using cars or destroy the earth.

61. 16. Non Sequitur

62. "it does not follow"
an argument with a conclusion that does not follow from its premises
the conclusion could be either true or false (because there is a disconnection between the premise and the conclusion), but the argument nonetheless asserts the conclusion to be true, and is thus fallacious.

63. Example:
If Bill is a human (A), then Bill is a mammal. (B)
Bill is a mammal. (B)
Therefore, Bill is a human. (A)
While the conclusion may be true, it does not follow from the premises:
Humans are mammals
Bill is a mammal
Therefore, Bill is a human