How Thinking Goes Wrong Twenty-five Fallacies That Lead Us to Believe Weird Things

Transcription

1 How Thinking Goes Wrong Twenty-five Fallacies That Lead Us to Believe Weird Things From Chapter 3 of Why people believe weird things by Michael Shermer 1

2 Announcement Starting next week, class will meet from 1-1:50pm. We will not go past 1:50pm. Location is unchanged. You can always use the 12:30-1:00pm for team meetings. 2

3 Team Competition Name that logical fallacy Teams get 20 seconds to identify the logical fallacy in each case. Write your answers on a piece of paper. Keep your own score. There are 11 cases. 3

4 1. Looking for judgement day The science of astronomy states that the speed of planet Mars has been decreasing in its course toward the eastern direction in the few past weeks to the level we notice the waver between the east and the west and on Wednesday the 30 th of July (2004?) the planet movement stopped going toward the eastern direction. Then in the months of August and September Mars changed its course in the opposite direction to the West and that until the end of September which means the sun will rise now from the west on Mars!! And this weird phenomena of the opposite movement called Retrograde motion most scientists state that all the planets will go through the same once at least and our planet Earth is one of them. Planet Earth will move in the opposite direction some day and the sun will rise from the west!! 4

5 2. The O Reilly Factor TV personality Bill O Reilly claims that the fact that the tides go in, tides go out, never a missed communication is proof that there is a god. More here: link 5

6 3. Nightlights and nearsightedness Children who go to bed with a night light on in their room are significantly more likely to be nearsighted when they get older. Nightlights cause eye strain and eventual nearsightedness. (CNN 1999) 6

7 4. Smoking and cancer My friend had an uncle who had a cousin who knew a guy who knew another guy that smoked 11 packs of cigarettes per day and lived to be 106 years old. Therefore, cigarettes don t cause cancer. 7

8 5. Presidential quotes "Some say that if you're Muslim you can't be free." -George W. Bush "I reject the view that... says government has no role in laying the foundation for our common prosperity." -Barack Obama 8

9 6. Philosophy of philosophy "My roommate said her philosophy class was hard, and the one I'm in is hard, too. All philosophy classes must be hard!" 9

10 7. Acupuncture for dogs My dog was in pain and the vet gave him acupuncture. He s doing much better now. You should get acupuncture for your dog, too. It really works. 10

11 8. Climate change We either live with the possibility that global warming might affect our world or else we destroy our economy by adopting policies to avoid it. 11

12 9. Acupuncture We know acupuncture works because it s been used for more than 3000 years. If it didn t work, it would have been abandoned by now. 12

13 10. UFOs visited Earth "Von Daniken's books about ancient astronauts visiting the are worthless because he is a convicted forger and embezzler." 13

14 11. Blood type and behavior In Japan, "What's your type?" is much more than small talk; it can be a paramount question in everything from matchmaking to getting a job. By type, the Japanese mean blood type, and no amount of scientific debunking can kill a widely held notion that blood tells all. In the year just ended, four of Japan's top 10 best-sellers were about how blood type determines personality, according to Japan's largest book distributor, Tohan Co. The books' publisher, Bungeisha, says the series _ one each for types B, O, A, and AB _ has combined sales of well over 5 million copies. Taku Kabeya, chief editor at Bungeisha, thinks the appeal comes from having one's self-image confirmed; readers discover the definition of their blood type and "It's like 'Yes, that's me!'" -link 14

15 1. Looking for judgement day The science of astronomy states that the speed of planet Mars has been decreasing in its course toward the eastern direction in the few past weeks to the level we notice the waver between the east and the west and on Wednesday the 30 th of July (2004?) the planet movement stopped going toward the eastern direction. Then in the months of August and September Mars changed its course in the opposite direction to the West and that until the end of September which means the sun will rise now from the west on Mars!! And this weird phenomena of the opposite movement called Retrograde motion most scientists state that all the planets will go through the same once at least and our planet Earth is one of them. Planet Earth will move in the opposite direction some day and the sun will rise from the west!! Scientific language does not make science. 15

16 2. The O Reilly Factor TV personality Bill O Reilly claims that the fact that the tides go in, tides go out, never a missed communication is proof that there is a god. More here: link Unexplained is not inexplicable. (In this case, we have good explanations ) The religious aspect is also referred to as the God of the gaps argument. 16

17 3. Nightlights and nearsightedness Children who go to bed with a night light on in their room are significantly more likely to be nearsighted when they get older. Nightlights cause eye strain and eventual nearsightedness. (CNN 1999) After the fact reasoning. Also known as: correlation does not necessarily mean causation. 17

18 4. Smoking and cancer My friend had an uncle who had a cousin who knew a guy who knew another guy that smoked 11 packs of cigarettes per day and lived to be 106 years old. Therefore, cigarettes don t cause cancer. Anecdotes do not make a science. (could also argue that this is: rumors do not equal reality.) 18

19 5. Presidential quotes "Some say that if you're Muslim you can't be free." -George W. Bush "I reject the view that... says government has no role in laying the foundation for our common prosperity." -Barack Obama Emotive words and false analogies Also known as a straw man. 19

20 6. Philosophy of philosophy "My roommate said her philosophy class was hard, and the one I'm in is hard, too. All philosophy classes must be hard!" Hasty generalization 20

21 7. Acupuncture for dogs My dog was in pain and the vet gave him acupuncture. He s doing much better now. You should get acupuncture for your dog, too. It really works. Anecdotes do not make science 21

22 8. Climate change We either live with the possibility that global warming might affect our world or else we destroy our economy by adopting policies to avoid it. Either-Or Also known as False dichotomy. 22

23 9. Acupuncture We know acupuncture works because it s been used for more than 3000 years. If it didn t work, it would have been abandoned by now. Ad populum (not in Shermer) Anecdotes do not make science Heresy does not equal correctness Bold statements do not make claims true. 23

24 10. UFOs visited Earth "Von Daniken's books about ancient astronauts visiting the are worthless because he is a convicted forger and embezzler." Ad hominem (attack the individual and not the case) 24

25 11. Blood type and behavior In Japan, "What's your type?" is much more than small talk; it can be a paramount question in everything from matchmaking to getting a job. By type, the Japanese mean blood type, and no amount of scientific debunking can kill a widely held notion that blood tells all. In the year just ended, four of Japan's top 10 best-sellers were about how blood type determines personality, according to Japan's largest book distributor, Tohan Co. The books' publisher, Bungeisha, says the series _ one each for types B, O, A, and AB _ has combined sales of well over 5 million copies. Taku Kabeya, chief editor at Bungeisha, thinks the appeal comes from having one's self-image confirmed; readers discover the definition of their blood type and "It's like 'Yes, that's me!'" -link Anecdotes (also known as cherry-picking) Coincidence Rationalized failures 25

26 Problems in Scientific Thinking 1. Theory influences observations 2. The observer changes the observed 3. Equipment constructs results 26

27 Problems in Pseudoscientific Thinking 4. Anecdotes do not make a science 5. Scientific language does not make a science 6. Bold statements do not make claims true 7. Heresy does not equal correctness 8. Burden of proof 9. Rumors do not equal reality 10. Unexplained is not inexplicable 11. Failures are rationalized Link ( 12. After-the-fact reasoning (post hoc, ergo propter hoc) Correlation does not mean causation 13. Coincidence 14. Representativeness 27

28 Logical Problems in Thinking 15. Emotive words and false analogies 16. Ad Ignoratiam If you cannot disprove a claim, it must be true 17. Ad Hominem and Tu Quoque 18. Hasty Generalization 19. Overreliance on Authorities 20. Either-Or 21. Circular reasoning 22. Reductio ad Absurdum and the Slippery Slope 28

29 Psychological Problems in Thinking 23. Effort inadequacies and the need for certainty, control and simplicity 24. Problem-solving inadequacies 25. Ideological immunity, or the Planck problem. 29

30 Get together with your team Team exercise See if you can come up with examples for each of these types of fallacies. (They don t have to be applied to science.) Team 1 Anecdotes do not make science (or fact) Ad hominem Team 2 Heresy does not equal correctness Overreliance on authorities Team 3 Unexplained is not inexplicable Either or Team 4 After the fact reasoning Slippery slope 30