Fallacies

The third slideshow for an ethics course.

Transcript

1. Fallacies bad arguments that might look good George Matthews CC 2016 Creative Commons, attribution.
2. classifying fallacies
3. classifying fallacies 1. fallacies of relevance Make use of irrelevant information.
4. classifying fallacies 1. fallacies of relevance Make use of irrelevant information. 2. fallacies of ambiguity Rest on the multiple or confusing meanings.
5. classifying fallacies 1. fallacies of relevance Make use of irrelevant information. 2. fallacies of ambiguity Rest on the multiple or confusing meanings. 3. fallacies of presumption Make unwarranted and unstated assumptions.
6. fallacies of relevance
7. fallacies of relevance appeal to authority Experts say that drinking a glass of milk a day is the best way to lose weight. Thus it is a good idea to drink a glass of milk a day.
8. fallacies of relevance appeal to authority Experts say that drinking a glass of milk a day is the best way to lose weight. Thus it is a good idea to drink a glass of milk a day. It is always a bad idea to trust someone just because they have the status of an expert. The experts might be right, but then don’t we need to see their evidence?
9. fallacies of relevance
10. fallacies of relevance ad hominem Ms. X says that animals deserve rights. But we don’t have to listen to her since she is wearing leather shoes.
11. fallacies of relevance ad hominem Ms. X says that animals deserve rights. But we don’t have to listen to her since she is wearing leather shoes. Ad hominem means “against the person” in Latin. This is a fallacy because it ignores what is being said and focuses on who is saying it.
12. fallacies of relevance
13. fallacies of relevance popular appeal The death penalty is supported by a majority of people. Therefore it is a justified punishment.
14. fallacies of relevance popular appeal The death penalty is supported by a majority of people. Therefore it is a justified punishment. Once again there is an irrelevant appeal made here to something that has no bearing on the truth of the conclusion. Just because many people believe something does not by itself mean that they are correct.
15. fallacies of relevance
16. fallacies of relevance appeal to force Either my work is good enough for me to pass this course or you are a dead man.
17. fallacies of relevance appeal to force Either my work is good enough for me to pass this course or you are a dead man. Yes, threats may get people to do what you want them to do, but they fail to provide reasons to believe what you are saying.
18. fallacies of relevance
19. fallacies of relevance appeal to consequences If evolution is true, then we are all related to apes. But this is something I really don’t like to admit. So evolution must be false.
20. fallacies of relevance appeal to consequences If evolution is true, then we are all related to apes. But this is something I really don’t like to admit. So evolution must be false. Remember that the merely uncomfortable consequences of a theory do not make that theory false. Truth or falsity depends on evidence that directly bears on the case.
21. fallacies of relevance
22. fallacies of relevance naturalistic fallacy Women alone are capable of getting pregnant and having babies. Therefore us men should not be responsible for changing diapers.
23. fallacies of relevance naturalistic fallacy Women alone are capable of getting pregnant and having babies. Therefore us men should not be responsible for changing diapers. The premise is about the facts of human nature and is clearly true. But the conclusion is about something very different – the question of social roles which are up to us to create as we see fit. Hence appealing to nature here is irrelevant.
24. fallacies of relevance
25. fallacies of relevance red herring That guy claims that animals have rights. Well he should consider doing something more to protect humans. After all, there are plenty of people who are in need of protection from tyranny and abuse.
26. fallacies of relevance red herring That guy claims that animals have rights. Well he should consider doing something more to protect humans. After all, there are plenty of people who are in need of protection from tyranny and abuse. This fallacy gets its name from a tactic used to throw off bloodhounds – wipe a (reddish colored) piece of smoked fish across the trail and toss it into the bushes nearby. Changing the subject is not arguing fairly.
27. fallacies of relevance
28. fallacies of relevance weak analogy Asking me to pay taxes is like asking me to let you steal money directly from by banking account, and that’s just not right!
29. fallacies of relevance weak analogy Asking me to pay taxes is like asking me to let you steal money directly from by banking account, and that’s just not right! We should be careful with our use of analogies, especially when one of the terms has very strong emotional content. A weak analogy is one where relevant differences between two analogous things are ignored.
30. fallacies of ambiguity
31. fallacies of ambiguity equivocation If you can think whatever you want, you are really free. People in jail can think whatever they want. So they should stop whining about wanting to be free.
32. fallacies of ambiguity equivocation If you can think whatever you want, you are really free. People in jail can think whatever they want. So they should stop whining about wanting to be free. Note the change in meanings of the word “free” here. To equivocate is to confuse multiple different meanings of a word with each other.
33. fallacies of ambiguity
34. fallacies of ambiguity straw person By asking for us to withdraw our troops from that country those hippies are saying we shouldn’t ever defend ourselves from attack!
35. fallacies of ambiguity straw person By asking for us to withdraw our troops from that country those hippies are saying we shouldn’t ever defend ourselves from attack! We should always be careful to avoid creating a caricature of any position we oppose. Such a view might be easy to knock down but if we are after the truth, misrepresenting other viewpoints does not get us any closer to it.
36. fallacies of presumption
37. fallacies of presumption mere assertion There are simply no grounds for believing that global warming is caused by humans.
38. fallacies of presumption mere assertion There are simply no grounds for believing that global warming is caused by humans. Is there even a reason given here?
39. fallacies of presumption
40. fallacies of presumption begging the question You should be a Christian. After all, the Bible says that you will go to Hell if you are not a Christian.
41. fallacies of presumption begging the question You should be a Christian. After all, the Bible says that you will go to Hell if you are not a Christian. We beg the question whenever we assume in the premises of our argument the very question we are claiming to prove. This is also known as “preaching to those already converted.”
42. fallacies of presumption
43. fallacies of presumption appeal to ignorance Nobody has ever proven that the death penalty deters crime. It is most likely not even possible to prove this. Thus it does not deter crime.
44. fallacies of presumption appeal to ignorance Nobody has ever proven that the death penalty deters crime. It is most likely not even possible to prove this. Thus it does not deter crime. To quote from Dick Cheney – “lack of evidence is not evidence of a lack.” Just because we do not know something does not mean we are entitled to conclude that it is false.
45. fallacies of presumption
46. fallacies of presumption false dilemma Either you agree with me that Donald Trump would be a great president or you are a communist. Since you do not agree with me, you are clearly a communist.
47. fallacies of presumption false dilemma Either you agree with me that Donald Trump would be a great president or you are a communist. Since you do not agree with me, you are clearly a communist. In spite of its popularity in political campaigns this argument strategy clearly doesn’t work – how many other possibilities are just not mentioned? Another name for this fallacy is the “black or white fallacy.”
48. fallacies of presumption
49. fallacies of presumption hasty generalization Most people are against raising taxes to fund public transportation. After all 95 percent of my friends are.
50. fallacies of presumption hasty generalization Most people are against raising taxes to fund public transportation. After all 95 percent of my friends are. It is possible to legitimately generalize from a sampling of data from a larger set, but only if your sample is large enough and free of biases.
51. fallacies of presumption
52. fallacies of presumption slippery slope If we legalize physician assisted suicide or euthanasia, anyone over 60 had better watch their backs.
53. fallacies of presumption slippery slope If we legalize physician assisted suicide or euthanasia, anyone over 60 had better watch their backs. This fallacy involves arguing against something relatively uncontroversial by highlighting a possible, but highly improbable, and highly undesirable consequence. What is the mechanism that would propel us down the slippery slope? Often it is not spelled out.
54. fallacies of presumption
55. fallacies of presumption false cause Two days ago I had a bad cold. Then I drank a bottle of whiskey. Thus whiskey must cure colds.
56. fallacies of presumption false cause Two days ago I had a bad cold. Then I drank a bottle of whiskey. Thus whiskey must cure colds. This fallacy confuses correlation with causation and is especially popular among peddlers of remedies for a disease that has no cure – the common cold. It is also known by the fancy Latin name: post hoc, ergo propter hoc, which translates as “after which, therefore because of which.”
57. fallacies of presumption
58. fallacies of presumption circular reasoning He definitely did it, since he has a guilty look on his face. And it is clear that it is a guilty look, since he is the one who did it.
59. fallacies of presumption circular reasoning He definitely did it, since he has a guilty look on his face. And it is clear that it is a guilty look, since he is the one who did it. Which is the premise here and which is the conclusion? Both and neither since the first leads to the second which leads to the first. Round and round we go.
61. For more examples of fallacies, check out the links below. Or pick up any newspaper.
62. For more examples of fallacies, check out the links below. Or pick up any newspaper. ! logicalfallacies.info
63. For more examples of fallacies, check out the links below. Or pick up any newspaper. ! logicalfallacies.info http://www.logicalfallacies.info
64. For more examples of fallacies, check out the links below. Or pick up any newspaper. ! logicalfallacies.info http://www.logicalfallacies.info ! Thou shalt not commit logical fallacies
65. For more examples of fallacies, check out the links below. Or pick up any newspaper. ! logicalfallacies.info http://www.logicalfallacies.info ! Thou shalt not commit logical fallacies https://yourlogicalfallacyis.com
66. For more examples of fallacies, check out the links below. Or pick up any newspaper. ! logicalfallacies.info http://www.logicalfallacies.info ! Thou shalt not commit logical fallacies https://yourlogicalfallacyis.com ! Rhetological Fallacies
67. For more examples of fallacies, check out the links below. Or pick up any newspaper. ! logicalfallacies.info http://www.logicalfallacies.info ! Thou shalt not commit logical fallacies https://yourlogicalfallacyis.com ! Rhetological Fallacies http://www.informationisbeautiful.net/ visualizations/rhetological-fallacies