Instructor Manual

Chapter 6: Issues in argument-assessment

Instructors’ material

More scenarios for practice applying the concepts of rational persuasiveness and defeated arguments (following form of exercises in students’ section).

  1. Suppose there are 11 players in the Critical Thinking soccer team and one of them is Jaz’s sister. Jaz knows that his sister is in the soccer team. Jaz has been asleep all day. While he was asleep it was announced that each player in the team had been selected to play soccer for England. Raz has a friend, called Baz. Baz is a notorious liar and player of practical jokes. Raz knows this. Baz texts Raz and tells him:
    Evry 1 n da socca team is goin 2 play 4 Englnd. So yr sista goin 2 play 4 Englnd.
    a) Reconstruct Baz’s reasoning.
    b) Is the argument rationally persuasive for Raz? Why/Why not?
  2. Suppose the same scenario as in question 1, but this time suppose that, while Jaz was asleep it was announced that 10 players in the Critical Thinking soccer team had been selected to play for England. Jaz has a friend called Taz. Taz is extremely trustworthy and reliable. Taz texts Jaz and she tells him:
    10 of da socca team is goin 2 play 4 Englnd. So yr sista goin 2 play 4 Englnd.
    a) Applying the principle of charity, reconstruct Taz’s argument.
    b) Is this argument rationally persuasive for Jaz? Why/Why not?
    c) Think of a scenario in which the argument would be defeated for Jaz.
  3. Christy, Misty and Sissy are discussing the likely outcome of the latest series of America’s Next Top Model, which they have been following on UK TV. Christy argues that either Anya or Fatima will win because she has all the attributes that, on past form, the judges appear to be looking for and they have performed best throughout the series. All three women have watched all the episodes of the present series and have watched previous seasons as well. It is reasonable to assume that they have a good understanding. of the judges’ preferences and of the performance of this season’s participants.
    a) Reconstruct Christy’s argument.
    b) Is the argument rationally persuasive for Misty? For Sissy?  Why/Why not?
  4. Suppose the same scenario as for question 3, but suppose that Misty is not very patient and couldn’t not bear to wait until the last episode to find out who wins. The series has already ended in the US, so she looks online and finds out that, in fact, neither Anya nor Fatima wins the contest, Whitney does. Misty does not tell Christy or Sissy what she has found out.
    a) Reconstruct Christy’s argument as an inductively forceful argument.
    b) Is the argument rationally persuasive for Misty? For Sissy?  Why/Why not?


It isn’t always easy to find examples of prescriptive arguments that offer material for reinforcing understanding of the concepts of rational persuasiveness and defeated arguments. The following could work in this context:

A teacher is fired because he refused to follow his employer’s ban rule against wearing sports shoes. His employers say that teachers should not be permitted to wear clothing that children are not permitted to wear. However, the sacked teacher is a physical education teacher.

Reported in NZ Herald, 1/1/09 (my version based on the item that appears there but not quoted verbatim)

The exercise could go as follows:
a) Reconstruct the employer’s argument as a valid argument.
b) Is it sound? Why/Why not?
c) Reconstruct it as an inductively forceful argument.
d) Is it sound? Why/Why not?
e) Is the argument rationally persuasive for you? Why/Why not?

The idea is that the information that the teacher is a physical education teacher might defeat the conclusion of the inductively forceful argument – the teacher being an exception to the generalisation that ‘Usually teachers should not be permitted to wear clothing that children are not permitted to wear.’

Reconstruct the following arguments and then refute them by counterexample.

  1. The Government must continue to oppose the legalisation of drugs. Making them legal would simply create a free-for-all. Anybody could buy them anywhere. The number of drug users would go up and up.
  2. The Government should legalise recreational drugs. Making them legal would remove an entire criminal network and black market and would make drug use safer and cheaper.
  3. What this country needs at a time of high unemployment is a work-for-the-dole scheme. It would provide a better standard of living for our most needy families and we should do whatever we can to help such people.
  4. New Zealand should step back from its anti-nuclear stance. We have to do something to increase energy production and nuclear power is the best alternative. After all, most other developed countries have turned to nuclear power to meet their ever-expanding energy needs.
  5. Human cells are human life and we should preserve human life at all cost. All stem cell research should be prohibited.

Practice in writing argument commentary: any of the passages provided for reconstruction in the material for Chapter 5 would be appropriate for extending as an exercise on argument commentary.

  1. 1 Here is a passage in which several arguments for/against topless sunbathing are reported.
    Full-bodied argument slapped down
    CANBERRA  Sun-loving Australians reacted angrily yesterday to a mid-summer bit by a conservative Christian MP to ban topless sunbathing on beaches in New South Wales.
    Veteran morals campaigner the Rev Fred Nile wants to tighten existing laws covering nude sunbathing.
    Local councils can fine people for being naked on beaches not designated as nudist beaches, but none considers topless women to be naked.
    ‘The law should be clear. It must say exposure of women’s breasts will be prohibited,’ Nile said.
    Labor state government MP Paul Gibson told the Daily Telegraph that families at the beach during the summer did not want topless women.
    But scores of callers to radio talkback stations complained about the plan and Leanne Peters form the ACT Nudist Club in the capital Canberra said Australia would look like a ‘haven for prudes’ in the unlikely event that laws [were passed by ] Parliament.
    NSW Assistant Health Minister Jodi McKay said banning topless sunbathing was a sept too far for most MPs. ‘We don’t want to go down the slippery slope of banning activities like this.
    Leaders of the two major parties in the New South Wales state Parliament, where the bill will be introduced in the coming weeks, have effectively killed it by arguing that local governments should be left to decided the boundaries of decent exposure.
    NZ Herald, 31/12/08, http://nz.news.yahoo.com/a/-/mp/5237513/australians-angry-bid-ban-topless-sunbathing/
  2. Here is one espousing a pro-Christian argument:
    Have a little faith
    Finlay MacDonald thought that taking his son to church for Christmas would ‘replace one fantasy with another’ (December 21).
    Even if you do not believe yourself, please give him the opportunity to understand what the celebration of Christmas and Easter are all about and allow him to make up his own mind as to the validity of the belief.
    What you would be doing would be exposing him to the faith that has given motivation to the countless hours of selfless service to the community and has inspired some of the world’s greatest art, music and architecture. There is also the little matter of the millions of people who have found strength and comfort from that faith.
    Of course, Christianity, plus the other religions of the world, have their fundamental and fanatical adherents; they are as much a pain in the proverbial to Christians as to anyone else. Faith has been at the root of a great many injustices, wars and cruelty, but that is the fault of human beings, not the teachings of the Prince of Peace who wanted us to love one another as he loved us, and our neighbours as ourselves.
    Margaret Clark, Wellington, Sunday-Star Times, 4/1/09
  3. And one addressing child abuse:
    [ … ] Here we go again, another case of state-sponsored infanticide. How long is it going to continue? Note two pertinent facts [about the latest alleged perpetrator]: beneficiary and drugs.
    Yet again another house known to police and agencies for all the wrong reasons – wild all-night parties and other outrageous behaviour.
    So who do we blame this time, the police, or the agencies, for not removing the child? Or the government for sponsoring it by directing endless money to endless bank accounts where the beneficiary doesn’t even have to get out of bed to collect it.
    It’s high time that welfare stamps where [sic] introduced redeemable for only life’s necessities and nothing else, and if the recipients find that embarrassing, well the answer lies in their hands.
    The very minute a benefit is applied for and given it should be compulsory for the recipients to be put on a pathway of self-improvement, of re-education and just plain  life knowledge and simple parenting skills. Yes, the cost may initially be high but how much longer must we bury our young before this insanity of abuse and state-sponsored infanticide stops.
    Paul Evans-McLeod, Hamilton, Sunday-Star Times, 4/1/09
  4. This piece from the Independent is about the ethics of drinking bottled water and coke.
    http://www.independent.co.uk/opinion/commentators/johann-hari/johann-hari-my-new-year-resolution-is-to-lose-my-bottle-ndash-and-quit-coke-1219991.html, published 1/01/09, accessed 5/01/09.
  5. This piece from The Economist is about how humans are damaging the world’s oceans.
    http://www.economist.com/specialreports/displaystory.cfm?story_id=12798458, published 30/12/09, accessed 5/01/09.

 

Exercise D

Students can be asked to produce two new statements, (d) and (e), for each of the arguments given in D. One of the new statements should defeat the argument, while the other should not.

 

Exercise E

Students can be asked to produce counterexamples to the arguments given in exercise D, making use of the generalisations they have produced. Here are some example counterexamples.

 

1. (Imagine the argument being presented before 1903 when the Wright brothers made the first aeroplane flight.)

P1) Although people have tried, nobody has managed to build an aeroplane that works.
P2) If nobody has managed to build something even when people have tried, no one will ever build it.
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C) Nobody will ever build an aeroplane that works.

 

2.
P1) I enjoy murdering people with my favourite axe, Bessie.
P2) If you enjoy doing something then, even if other people say you shouldn’t do it, you should do it.
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C) I should murder people with my favourite axe, Bessie.

 

3.
P1) Ivy, who is rather clumsy and technically incompetent, is waiting to get an MRI scan in hospital. But the scanner is broken, even though it’s just been looked at by a technician (i.e. a professional scanner fixer).
P2) If something is not working, even though it has just been looked at by a professional, you should repair it yourself this time.
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C) Ivy should repair the MRI scanner herself.

 

4.
P1) If you have a car, you can easy kill or injure someone.
P2) If you can easily use something to kill or seriously injure someone, civilians shouldn't be allowed to keep that thing at home.
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C) Civilians shouldn't be allowed to keep cars at home.

 

5.
P1) Most people in group A (70-year olds) are in group B (people who have watched television).
P2) If most people in group A are also in group B, most people in group B are also in group A.
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C) Most people who have watched television are 70-year olds.

 

6.
P1) It won't take you long to push the man in front of you over the cliff, and it will help me (he's blocking my view).
P2) If it won't take you long to do something, and doing it will help someone else, you should probably do that thing.
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C) Probably, you should push the man in front of you over the cliff.

 

7.
P1) Bathsheba the bat is not a bird or an insect.
P2) If an animal isn't a bird or an insect, then it can't fly.
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C) Bathsheba the bat can't fly.

 

8.
P1) Football (soccer) was invented in England.
P2) The majority of the best players of a sport come from the country in which that sport was invented.
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C) The majority of the best football (soccer) players are English.

 

9.
P1) I like ice cream and I like mustard.
P2) If you like food A and you like food B, then you would probably like a combination of foods A and B.
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C) Probably, I would like mustard ice cream.

 

10.
P1) Most people who steal expensive cars couldn't afford to buy those cars legally.
P2) If most of the people who get something illegally could not afford to buy that thing legally, then getting that thing illegally is not immoral.
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C) Stealing expensive cars is not immoral.