Course Notes - PHL137

Phl137 - Critical Thinking Contents 1

2

Introduction ................................................................................................................................................. 5 1.1

The Art Of Critical Thinking.................................................................................................................. 5

1.2

Exercises In Critical Thinking................................................................................................................ 5

1.3

What Are Arguments? ......................................................................................................................... 7

1.4

Identifying Arguments And Their Components ................................................................................... 8

1.5

Explanations Vs Arguments ............................................................................................................... 10

Standardisation.......................................................................................................................................... 14 2.1

Propositions ....................................................................................................................................... 14

2.1.1 2.2

3

Standardisation.................................................................................................................................. 16

2.2.1

Linked and convergent premises............................................................................................... 17

2.2.2

Paraphrasing implicit premises and conclusions ....................................................................... 18

2.3

Subarguments.................................................................................................................................... 19

2.4

Checking Your Standardisation.......................................................................................................... 23

Counter Arguments ................................................................................................................................... 27 3.1

Arguments And Counterarguments .................................................................................................. 27

3.2

Noting Direct Responses ................................................................................................................... 29

3.3

Counterconsiderations ...................................................................................................................... 31

3.4

Validity And Invalidity: Introduction.................................................................................................. 32

3.5

Necessary And Sufficient Conditions ................................................................................................. 33

3.6

Common Forms Of Conditional Proposition ..................................................................................... 34

3.6.1

"All/ Every / Any Fs are Gs" ...................................................................................................... 34

3.6.2

"Only Fs are Gs"- ........................................................................................................................ 34

3.6.3

"If A then B" ............................................................................................................................... 35

3.6.4

A Only if B (Only A if B) .............................................................................................................. 35

3.7

Checking Necessary And Sufficient Conditions ................................................................................. 36

3.7.1

Paraphrasing .............................................................................................................................. 36

3.7.2

Diagrams .................................................................................................................................... 37

3.7.3

Ambiguity................................................................................................................................... 38

3.8 4

Asserted propositions ................................................................................................................ 14

Counterexamples............................................................................................................................... 39

Conditional Arguments .............................................................................................................................. 41 4.1

Valid Conditional Argument Forms ................................................................................................... 41

4.1.1

Affirming the sufficient condition ............................................................................................. 41

4.1.2

Denying the necessary condition .............................................................................................. 42

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4.2

Invalid Conditional Argument Forms................................................................................................. 43

4.2.1

Affirming the necessary condition ............................................................................................ 43

4.2.2

Denying the sufficient condition ............................................................................................... 44

4.3

Examples ............................................................................................................................................ 45

4.4

Using Diagrams To Check Your Answers ........................................................................................... 47

4.5

Validity (Deductive Validity) .............................................................................................................. 48

4.6

Deductive And Inductive Arguments................................................................................................. 50

4.6.1 4.7 5

Deductive and inductive arguments: summary ........................................................................ 51

A Note On Types Of Reasoning.......................................................................................................... 52

Inductive arguments.................................................................................................................................. 53 5.1

Overview............................................................................................................................................ 53

5.2

Inductive Generalisations .................................................................................................................. 53

5.2.1

Components Of An Inductive Generalisation ............................................................................ 54

5.2.2

Evaluation Of Inductive Generalisations ................................................................................... 55

5.3

Statistical Generalisations ................................................................................................................. 56

5.3.1

Evaluating Statistical Generalisations........................................................................................ 56

5.3.2

Evaluating Samples .................................................................................................................... 57

5.3.3

Evaluating Statistical Research Methods................................................................................... 60

5.3.4

What was tested? What questions were asked? ...................................................................... 62

5.3.5

Do The Statistical Results Justify The Conclusion? .................................................................... 63

5.3.6

Example: .................................................................................................................................... 64

5.3.7

Statistical Syllogisms .................................................................................................................. 66

5.4

Inference To The Best Explanation .................................................................................................... 67

5.4.1 5.5

Inference To The Best Explanation In Scientific Reasoning ....................................................... 68

Causal Arguments .............................................................................................................................. 69

5.5.1

Correlations ............................................................................................................................... 69

5.5.2

When Can A Cause Be Inferred From A Correlation? ................................................................ 72

5.5.3

Is The Causal Explanation The Best Explanation?...................................................................... 72

5.5.4

What Makes One Explanation Better Than Another? ............................................................... 74

5.5.5

Is The Causal Conclusion Accurate? .......................................................................................... 75

5.5.6

Discussion exercise .................................................................................................................... 75

5.6

Analogical Reasoning ......................................................................................................................... 76

5.6.1

Simple Inductive Analogical Arguments .................................................................................... 76

5.6.2

Components Of An Argument From Analogy ............................................................................ 77

5.6.3

Evaluating Arguments From Analogy ........................................................................................ 78

5.6.4

Uses Of Analogical Reasoning.................................................................................................... 79

5.6.5

When Is A Single Analogue A Sufficient Sample? ...................................................................... 80

5.6.6

Other Examples Of Analogical Reasoning.................................................................................. 84

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6

Clarifying arguments.................................................................................................................................. 88 6.1

Introduction ....................................................................................................................................... 88

6.2

Summarising An Argument................................................................................................................ 89

6.2.1 6.3

Emotional charge ....................................................................................................................... 93

6.3.2

Euphemism ................................................................................................................................ 93

6.3.3

Loaded terms ............................................................................................................................. 94

6.3.4

Suggestions of certainty or doubt ............................................................................................. 94

6.3.5

The appropriateness of rhetoric in a context ............................................................................ 95

6.3.6

EXERCISE - emotionally charged language ................................................................................ 96

Text For Analysis ................................................................................................................................ 96

6.4.1

Summary of Text........................................................................................................................ 96

6.4.2

Summary.................................................................................................................................... 97

6.4.3

Uses of language........................................................................................................................ 97

Broad standardisation ............................................................................................................................... 99 7.1

Close Standardisation And Broad Standardisation............................................................................ 99

7.2

Text For Analysis .............................................................................................................................. 100

7.2.1

Standardisation........................................................................................................................ 100

7.2.2

Subpremises ............................................................................................................................ 102

7.3

8

Persuasive Language And Other Rhetorical Devices ......................................................................... 92

6.3.1

6.4

7

Examples .................................................................................................................................... 90

The Acceptability Of Premises ......................................................................................................... 105

7.3.1

Common knowledge ................................................................................................................ 105

7.3.2

The importance of common knowledge in constructing a broad standardisation ................. 106

Evaluating inferences .............................................................................................................................. 108 8.1

Introduction ..................................................................................................................................... 108

8.2

Suppressed Assumptions................................................................................................................. 108

8.3

Fallacies Overview ........................................................................................................................... 111

8.4

Fallacies Of Clarity ........................................................................................................................... 112

8.4.1

Ambiguity................................................................................................................................. 112

8.4.2

The Fallacy Of Equivocation..................................................................................................... 113

8.4.3

Vagueness ................................................................................................................................ 114

8.5

Fallacies Of Vacuity .......................................................................................................................... 116

8.5.1

Question-Begging Arguments.................................................................................................. 116

8.5.2

Circular Arguments .................................................................................................................. 116

8.6

Fallacies Of Relevance ..................................................................................................................... 116

8.6.1

Straw Person Fallacy ................................................................................................................ 117

8.6.2

Appeals To Authority ............................................................................................................... 117

8.6.3

Appeals To Tradition................................................................................................................ 118

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8.6.4 8.7 9

Ad Hominem Arguments ......................................................................................................... 119

Evaluation ........................................................................................................................................ 120

Sample text evaluation ............................................................................................................................ 127 Notes on writing your text evaluation..................................................................................................... 127

10

Conclusion ........................................................................................................................................... 131

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1 INTRODUCTION Welcome to PHL 137, Critical Thinking, and welcome to the course website. This website will be an important resource for this unit. It provides the course notes, as well as exercises, self tests and communication facilities. Information about the website including advice on the use of the online resources available for this unit are to be found in "How to use this website" from the homepage.

1.1 The Art Of Critical Thinking We all engage in reasoning everyday. We engage in reasoning whenever we argue with each other, evaluate what we read and hear, and consider the evidence for and against views or ideas. So it is not something that’s foreign or alien. But reasoning is something that you can get better at doing. It is a skill or an art. Like any skill, it requires a bit of knowledge and practice. Lots and lots of practice. Our aim in this course is to teach you the fundamentals of good reasoning. We will illustrate these fundamentals by looking at reasoning from newspapers, journals, advertisements, textbooks, and some philosophical works. By the end of the course you will know the difference between good reasoning and bad reasoning. You will be able to detect fallacies and bad reasoning in others. You will become more clearheaded and logical in your own thinking. The skills you acquire through doing this course will stand you in good stead whatever course you take at Macquarie and whatever career your pursue afterwards. Even though reasoning is something we all do, it can be quite difficult at times to do correctly. We are all prone to making mistakes in reasoning. Indeed, there is an entire branch of psychology which is dedicated to examining the common patterns of illogical and fallacious thinking. To illustrate the difficulty of correct reasoning I want to consider two reasoning tasks that have been much discussed by psychologists. The two tasks show how easy it is to fall into the traps of fallacious reasoning.

1.2 Exercises In Critical Thinking The card selection task You are presented with four cards as below. One half of each card is masked. The other half is blank or has a circle. Your job is to work out which of the masked cards you need to see in order to answer the follow question decisively: FOR THESE CARDS, IS IT TRUE THAT IF THERE IS A CIRCLE ON THE LEFT THERE IS A CIRCLE ON THE RIGHT? You have only one opportunity to make this decision. You must not assume that you can inspect the cards one at a time. Name those cards which it is absolutely essential to see -- ie that you absolutely must see to answer the question.

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Before you read any further, pause to consider what you think is the right answer. What do most people say? The most common answer is that you should see cards (a) and (c); the next most common answer is that you need only see (a). The correct answer: The correct answer is: you must see (a) and (d). Let’s consider each card in turn. You must see (a) because if the right-hand side of (a) has no circle, the conditional is shown to be false. You need not see (b) because it has no circle on the left-land side and so whatever is hidden on the right-hand side has no bearing on the truth of the conditional. You need not see (c) because what is hidden on the left-hand side does not bear decisively on the truth of the conditional, does not have the potential to decisively show the truth or falsity of the conditional. You must see (d) because if the left-hand side of (d) has a circle, the conditional is shown to be false. The original experiment by the British psychologist Peter Wason is described in the article: Wason, P. C. (1968). Reasoning about a rule. Quarterly Journal of Experimental Psychology, 20, 273-281. For a good review of the theoretical psychological discussions see: Oaksford, M., & Chater, N. (1994). A rational analysis of the selection task as optimal data selection. Psychological Review, 101, 608-631. The Monty Hall problem This problem is named after the presenter on the American TV show Let’s Make a Deal. On the table are three identical boxes, each with a lid and also a neat pile of ten dollar bills. This game is to be repeated many times. Let’s say I’m running the show.

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Here are the rules of the game. First, you leave the room and while you are out, I put a ten dollar bill in one of the boxes. I then close the boxes. I know in which box the money is, but you don’t. Now I invite you back into the room. Each game is divided into two distinct phases. In the first, by doing no more than pointing, you indicate your choice among the three boxes, which remain closed. As you have made your choice, I open another box, one of the two remaining boxes. That box will be empty - remember that I know in which box the ten dollar bill is. Having seen one empty box (the one I just opened), you now face two closed boxes, one of which must contain the ten dollar bill. Now comes the second phase. I now offer you the chance to stay with your first choice, or to switch your choice to the other closed box, the one you failed to choose the first time round. After this second phase, whatever is in the box you have chosen is what you win. This game can be repeated countless times, and each time, if your second choice is right, you win ten dollars. You leave the room and the game starts all over again. Now the question is: As a general rule, are you better off sticking to your first choice or switching? Does it make any difference? Before you read any further, pause to answer these questions. The correct answer: A common thought is that in the second phase of the game the probability of choosing the box with the ten dollar bill is 50/50 and so there is no reason to switch. But this is wrong: it pays as a general rule to switch. To see this suppose that your original choice was the right one. Then when I open the box, for you to switch will certainly penalise you. If, on the other hand, your first choice was an empty box, you will certainly gain by switching. How often do you think your first choice will be correct (and thus penalising you if you switch)? One in three times. And how often will you choose an empty box (and thus be necessarily better off switching)? Two times out of three. So it pays as a general rule to switch boxes in the second phase.

This problem has been so much discussed that there are a number of websites devoted to it. This website, for example, has a simulator so you can see what would happen if you were to play this game 100 or 1000 times: http://www.grand-illusions.com/simulator/montysim.htm

1.3 What Are Arguments? Our aim in this course is to learn how to analyse and evaluate arguments. It is necessary, before we can engage in such analysis, to have a clear idea of what an argument is, and how passages containing arguments can be identified. Consider the following passages: (3a) There are some grey shapes under the water. There must be some dolphins there. (3b) Either the butler or the gardener committed the murder. The gardener has a good alibi. So the butler must have done it.

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Each of these passages contains an argument. What distinguishes an argument from other kinds of discourse is that an argument attempts to convince its audience of some point, by citing reasons for believing it. Argument (3a) aims to convince you that there are dolphins under the water. Argument (3b) attempts to convince you that the butler did it. The word "argument" is used in ordinary language to mean a variety of things, but in the sense we are interested in , an "argument" involves a process of reasoning, or inference, and the attempt by one person to convince another or others of some claim by providing evidence, or reasons for believing it. Whether the argument is written or spoken, the person or people who put the argument forward will be referred to as the "author of the argument" or simply the "arguer". The person or people the arguer is attempting to convince will be referred to as the "audience".

1.4 Identifying Arguments And Their Components You can identify a passage as containing an argument, if the purpose of that passage is to convince you of some claim, by providing reasons to believe it. Identifying an argument Does the passage attempt to convince an audience of some claim, by providing reasons for believing it? If so, it the passage an argument.

Premises and conclusions Any argument will contain premises, and a conclusion. The best way to identify the premises and conclusion of an argument is to ask yourself what the author of the argument is trying to convince you of: What does the author want you to believe? The point about which the argument is trying to convince you is the conclusion. The reasons or pieces of evidence the author offers to convince you of that conclusion are the premises. Indicator words In identifying arguments, and drawing out their structure, look out for "indicator words." These are words and phrases which often appear in arguments, which function as cues to alert you to the presence of an argument in a passage, and to help identify its premises and conclusion. Conclusions, for example, will often be signalled by words such as "therefore" and "so", while premises will often be introduced by words such as "because" or "since". Premises are often indicated by:

Conclusions are often indicated by:

for, since, because, on the grounds that

thus, therefore, so, hence

In the following arguments, the conclusions are underlined. Note the occurrence of premise and conclusion indicators, and confirm that the rest of the passage does appear to be intended to support the conclusion, and give reasons for believing it: (4a) Acid rain is caused by burning of unclean fuel such as brown coal. Therefore the use of brown coal endangers forests. (4b) You needn't worry about the dangers of nuclear energy, because much stricter safety precautions have been implemented since the Chernobyl disaster.

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(4c) Open fireplaces are very inefficient. It follows that their popularity is aesthetic, rather than practical. Also look out for words such as "should" and "must". These will frequently occur in conclusions, since they are used to persuade or convince the audience that some action is required. For example: (4d) Eventually, the world's oil will run out. Governments must invest more heavily in finding alternate fuel sources. (4e) The use of leaded petrol should be banned. The use of leaded petrol is harmful to the environment, and any car can be converted to run on unleaded petrol. These are hints, rather than rules. Not every occurrence of these words will indicate a premise or conclusion. Once you think you have found the conclusion, always reread the passage to confirm that reasons or evidence are given to support that conclusion. Identifying arguments without premise or conclusion indicators Not all arguments contain premise or conclusion indicators. These arguments can still be recognised by thinking about the relationship between different parts of the passage. If the passage involves an attempt to persuade you to accept some claim, and gives reasons or evidence to persuade you, then it is an argument. The following examples are arguments which do not contain any argument indicators. Their conclusions are underlined. To confirm that the underlined part is the conclusion, try reading the argument back, by reading the rest of the passage first, then "therefore", and then the conclusion. This should sound like a reasonable argument. (4f) CFCs, which were a significant contributor to the greenhouse effect, have been banned. The progress of global warming is likely to be slower than it otherwise would have been. (4g) This refrigerator does not produce CFCs. CFCs were banned some years ago, and this is a new fridge. (4h) This fly spray advertises itself as CFC free, but that claim, though true, is completely spurious now - No sprays contain CFCs! In each case, note that there are premises given to convince you of the conclusion. If there is not a point in the passage which for which the other points offer support, then it is probably not an argument. Examples Do the following passages contain arguments? If so, what is the conclusion? (i) If asylum seekers are returned to their home countries, many of them will be punished - they may be jailed, or even killed. But if we allow everyone who arrives here illegally to stay, then we will set a precedent which will result in more and more people coming here - even those who may not have pressing reasons to leave their own countries. And if we allow illegal immigrants to stay, then we will be disadvantaging those who are trying to immigrate through the proper channels. (i) is not an argument. There is not one point which is supported by other points in the passage (ii) Both the major parties have promised tax cuts, in one form or another, if they win the next federal election. But surveys have shown that most Australians would be willing to sacrifice tax cuts to allow better funding for essential government services such as health and education. This just shows that neither side of parliament understands the wishes and priorities of the Australian public. (ii) is an argument. Its conclusion is "Neither side of parliament understands the wishes and priorities of the Australian public". We are given reasons to believe this : both parties are planning to offer tax cuts, but tax cuts are not a priority for the Australian people.

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(iii) There has been a significant outcry about the courts handing down lenient sentences to serious offenders, and the state Government has now acted to promote tougher sentences for serious crimes. But there are concerns that such intervention runs the risk of jeopardising the independence of the judiciary. (iii) is not an argument. There is not one point which is supported by other points in the passage.

1.5 Explanations Vs Arguments It is easy to confuse arguments with explanations, because they use many of the same indicator words. The difference between an argument and an explanation is best understood in terms of how the rest of the passage relates to the main point:

An argument makes a claim and gives reasons for you to believe it, while an explanation gives you reasons why a particular claim is true. To work out whether something is an argument or an explanation, begin by identifying the main point of the passage, and the claim which is being made in that main point: If the rest of the passage tries to convince you THAT the claim is true, it is probably an argument. If the rest of the passage tells you WHY the claim is true, it is probably an explanation. 

Consider, for example, the following sentences: (5a) Queen Elizabeth the First died in 1603, because she was old. (5b) Queen Elizabeth the First died in 1603. It says so in this history book. The main point in each sentence is that Queen Elizabeth the First died in 1603. In each case, this is "backed up" in some sense by what follows. But while (5a) is best understood as an explanation (is aim is to tell you why Queen Elizabeth I died when she did), (5b) is best understood as an argument, since it offers evidence which might convince you that it is true that she died in 1603. What about these sentences? (5c) The volcano must have erupted because there is new lava on its slopes. (5d) The volcano erupted because there was a build-up of magma along a fissure. The first sentence gives reasons to convince you that the volcano has erupted, so it is an argument. The second sentence gives the causes of the eruption, so it is an explanation. Other tests for arguments and explanations Which are you more inclined to believe - the main point, or the rest of the passage? The point of an argument is to try to convince you of something, by showing you that it follows from things you already believe. For that reason, the premises of an argument should be at least as likely to be believed as the conclusion. There is no point in trying to convince you of something you don't believe by showing that it follows from other things that you don't believe. If the main point of the passage is something which is

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unlikely to be believed unless reasons are given, then, it is probably an argument, intended to convince you by providing such reasons. An explanation, however, will not try to convince you of its main point, so very often the main point is something the reader or audience is already likely to accept. The author will assume that the main point is accepted, and go on to describe its causes. So: If the main point is less likely to be believed than the rest of the passage, it is probably an argument. If the main point is something which the audience is already likely to believe, it is probably an explanation.

Which of the following is an argument, and which is an explanation? (5e) The Blue Mountains appear blue because of a mist produced by the eucalypt forests. (5f) Sydney's urban sprawl is unlikely to slow down much in the near future and a lot of people already commute from the Blue Mountains to the city, so within twenty years the blue mountains will be considered part of the Sydney metropolitan area. (5e) is an explanation, because it makes a point which an audience would be likely to accept, "the Blue Mountains appear blue", and explains why that it the case. It suggests a cause of this phenomenon. (5f) is an argument, because it makes a relatively surprising claim, that within twenty years the Blue Mountains wll be considered part of the Sydney metropolitan area, and gives reasons to believe that claim. Applying the Principle of Charity Sometimes it still won't be clear whether a passage is an argument or an explanation. Perhaps it looks as though it could be interpreted either way. The Principle of Charity says that when you interpret a passage, you should try to be fair to the author's intentions, and you should interpret the passage in the way that makes the most sense. So, if a passage would make a good explanation but a bad argument, you should assume that it is meant to be an explanation. If it would be better interpreted as an argument, interpret it as an argument. For example, the sentence: (5g) Alfred must have had a car accident because he was talking on his mobile phone. would make a reasonable explanation of why Alfred crashed -- the fact that he was talking on his mobile is a cause of the crash. It would, however, make a poor argument, as the fact that Alfred had been talking on his phone would not convince anyone that he had a car accident. The fact that he was talking on the phone does not provide any evidence that he had an accident. So, applying the principle of charity, we would assume the person who asserted the sentence above meant this to be an explanation. By contrast: (5h) Alfred must have had a car accident, because the front of his car is badly dented. would not explain why he crashed. The evidence about the state of the front of Alfred's car could, however, be used as evidence to convince someone that Alfred had had an accident. So by the principle of charity, we should interpret this as an argument.

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Argument and explanation? Some passages you come across will have elements of both. Once you decide what the main point is, however, there should only be one way to interpret the passage. For example: (5i) Alfred had a car accident because he was talking on his mobile phone. So using a mobile phone while driving can be dangerous. As we saw above, the first sentence is an explanation. But here, the main point is the second sentence. The first sentence, which reports the cause of Alfred's accident, is given as evidence to convince you that "using a mobile phone while driving can be dangerous". So the passage is an argument. It is also possible for an explanation to be given as a premise in an argument. If someone is trying to convince you of a rather unbelievable claim, then the fact that there could be an explanation might help make the claim more plausible, and therefore make the argument more convincing. For example: (5j) The CIA faked Elvis' death. People still keep seeing him in hamburger shops, and that wouldn't happen if he were dead. A possible explanation for the CIA's action is that they wanted him to go undercover to investigate money laundering in Las Vegas casinos. The final sentence suggests an explanation for the CIA's action in faking Elvis' death, but the point of the passage as a whole is to convince you that they did. The fact that there is an explanation for why the CIA might want to fake Elvis' death is meant to make the rather outlandish conclusion more acceptable. So the passage is an argument, the suggested explanation is supposed to make you more willing to accept the conclusion, so it functions as a premise in the argument. In summary, then: Tests for arguments vs explanations 1. If the passage gives evidence for the main point, it's probably an argument. If it lists causes of the main point, then it's probably an explanation. 2. If you are not already inclined to believe the main point, it's probably an argument. If you are already inclined to believe the main point, it's probably an explanation. 3. By the principle of charity, you should interpret a passage so it makes the most sense. So if it makes a good argument but a weak explanation, treat it as an argument, and if it makes a weak argument but a good explanation, treat it as an explanation.

Examples For each of the following passages determine whether it is an argument or an explanation or neither. (i) The pilot was forced to make an emergency landing in the Atlantic, because both the plane's engines had malfunctioned. Cases like this should lead aviation officials to reconsider the use of twin engine aeroplanes for long flights across water. This passage contains an explanation - the first sentence explains why the pilot was forced to make an emergency landing in the Atlantic, but this is used as a reason to convince the audience that aviation officials should reconsider the use of twin engine aeroplanes for long flights across water. So the passage overall is an argument, since it provides evidence to convince its audience of its main point.

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(ii) Guarana is a highly concentrated source of caffeine, and caffeine can be harmful to children, so confectionary and drinks containing guarana are labelled with warnings stating that they should not be consumed by children under 15. This passage is best understood as an explanation of why these products are labelled with warnings. It would be inaccurate to consider this as an argument, because the facts that guarana is a concentrated source of caffeine and caffeine can be harmful to children would not convince you that they have warning labels. SELF TEST AND EXERCISES At the top of this page, in the action menu, you will notice a link to a "Self test". This is a short set of multiple choice questions to test your understanding of the material covered in these notes. There will be a self test available for each week's course notes. Try these questions now, and read over the notes again if there's anything you don't know. At this point it is also a good idea to try your hand at the exercises in "Week 1" of the Exercises section on the course website. After you have tried each question, you will be given an explanation of the correct answer. SKILLS FOR WEEK 1 You should be able to: Identify whether a passage contains an argument, an explanation or neither. Recognise the premises and conclusions of an argument, with or without indicator words.

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2 STANDARDISATION (Week2) To allow the clear analysis of arguments, we will be adopting a method of representing their structure known as standardisation. Standardisation requires us first to identify the premises and conclusion of an argument, and then to give a clear, unambiguous representation of its form. Before we can begin to construct standardisations, it is necessary to have a clearer understanding of the components of an argument. We must begin by identifying the premises and conclusion -- but what sort of things are they? How do we decide what to include as part of a given premise? How do we know what is essential and inessential?

2.1 Propositions In order to determine the structure of an argument we need to be able to identify the propositions out of which the argument is composed. A proposition is the content or meaning of a sentence. It is the kind of thing which is capable of being true or false. (not be confused with premise) Propositions can be simple or complex. A simple proposition is one which expresses one and only one complete thought . For example, the sentence expresses a simple proposition: (1a) John Howard is the PM of Australia. On the other hand, the following sentence: (1b) Although the PM is the government leader, he can be voted out of power by the people, which is a safeguard against tyranny.is a complex proposition, since it contains several simple propositions: The PM is the government leader. The PM can be voted out of power by the people. The fact that a PM can be voted out of power is a safeguard against tyranny.

2.1.1 Asserted propositions However, note that the simple propositions contained in a sentence may not all be asserted by the speaker of the sentence. When someone asserts a proposition, they are presenting that proposition as true. For example, consider the sentences: (1c) If it rains tomorrow, the match will be cancelled. (1d) Either it will rain tomorrow or the match will be cancelled. These sentences involve the simple propositions: It will rain tomorrow. The match will be cancelled but in neither case is the speaker presenting these propositions as true. The speaker is not claiming either that it will definitely rain tomorrow, nor that the match will definitely be cancelled. In the sentences (1c) and (1d) above, the speaker is asserting a complex proposition, which claims that a certain relationship holds between the simple propositions. The simple propositions themselves are not asserted.

To work out whether a proposition is asserted, ask yourself: Is the speaker presenting this proposition as true?

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If not, it is not being asserted Look out for sentence forms such as "either... or..." and "If... then ...". These will contain propositions which are not separately asserted. Examples What are the simple proposition contained in the following sentences? What are the propositions asserted? (i) Society is best served by educated people, so cutting spending on education is wrong. A: There are two simple propositions: "Society is best served by educated people" and "Cutting spending on education is wrong". Both are asserted, since the speaker is claiming that both these things are true. (ii) If you turn left at the corner, you will see the garage. A: There are two simple propositions "You will turn left" and "You will see the garage", but the speaker is not claiming that these propositions individually are true. The only proposition asserted is the complex one: "If you turn left at the corner, you will see the garage". (iii) Either the new PM will live in Canberra or, if she is of John Howard's mind, she will live in Sydney. A: There are three simple propositions: "The new PM will live in Canberra", "The new PM is of John Howard's mind" and "She will live in Sydney". The only proposition asserted is the complex one: "Either the new PM will live in Canberra, or, if she is of John Howard's mind, she will live in Sydney".

The premises of an argument and its conclusion will each be a simple or complex proposition which is asserted. In analysing the structure of the argument, then, we do not need to isolate every simple proposition which is contained in the argument. We need to identify the propositions which are asserted. For example, consider the argument: (1e) Either university funding will be increased or class sizes will continue to grow, and university funding will not be increased. Therefore class sizes will continue to grow. The premises here are contained in the first sentence. In this sentence two separate propositions are asserted: Either university funding will be increased or class sizes will continue to grow. University funding will not be increased. These should be treated as two separate premises, but should not be broken down any further. Although the first premise contains two separate propositions: "University funding will be increased" and "Class sizes will continue to grow, " these are not both asserted, so they cannot be treated as separate premises. The three propositions asserted in the argument, then, are: 1. Either university funding will be increased or class sizes will continue to grow. 2. University funding will not be increased. 3. Class sizes will continue to grow. The first two are premises, the third is the conclusion. What propositions are asserted in the following argument?

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(1f) Unfortunately, we won't be able to stop the flooding. We could only stop the flooding if we had a way of damming the river, but, when you really think about it, there is no way we can dam the river. When looking for propositions, we are just looking for the factual content of what is being asserted. Identifying the premises will therefore sometimes involve leaving out inessential features of the argument. The three propositions asserted in this argument are: We won't be able to stop the flooding. We could only stop the flooding if we had a way of damming the river. There is no way we can dam the river. In this case, the first proposition is the conclusion, and the other two are given as premises in support of that conclusion.

2.2 Standardisation It will help us understand the structure of an argument if we can represent it in a standardised form. A standardisation of an argument identifies the premises and conclusion of the argument, while disregarding all its inessential features. It also identifies the evidential relationship between premises and conclusion by a conventional representation. We will be using one method for representing standardised arguments in this course. (It is, with a few slight variations, that developed in the book Thinking Clearly by LeBlanc.) Many other texts use a pictorial method of standardisation, but the numerical method has the advantage of making the structure of an argument unambiguous in text form, without requiring a diagram. We will, however, sometimes use diagrams as an additional aid. Consider the following argument: (2a) Anyone who had any sense would agree that capital punishment is wrong. It should be obvious that it unjustly exacts a punishment that is disproportionate to whatever crime has been committed. It's also just plain obvious how it brutalises a society that practices it. There's a lot of excess verbiage in this argument. Stripped down to its essentials, the argument asserts three propositions: Capital punishment is wrong. Capital punishment unjustly exacts a disproportionate punishment. It brutalises a society that practices it. First, we need to identify the premises and conclusion. To identify the conclusion, think about what the argument is supposed to convince you of. In this case, the conclusion of the argument is "captial punishment is wrong." The other propositions are given as premises: they are reasons supposed to convince you of the conclusion. To standardise the argument, we number the premises consecutively and put a C next to the conclusion, which is listed after the premises. 1: Capital punishment unjustly exacts a disproportionate punishment. 2: It brutalises a society that practices it. C: Capital punishment is wrong. The structure of this argument could also be represented pictorially:

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Now let's consider another example: (2b) The book will not be published. It is too long, and it is too dull, and the people it is written about would undoubtedly sue if it ever went to print. This author of the argument intends to convince you that the book will not be published. The argument has three premises supporting its conclusion, and would be standardised as: 1: The book is too long. 2: The book is too dull. 3: The people the book is written about would undoubtedly sue if it ever went to print. C: The book will not be published.

2.2.1 Linked and convergent premises In the arguments we have considered so far, the premises been convergent, which means that they independently support the conclusion. But sometimes the premises must work together to support a conclusion. Such premises are said to be linked. If two premises are linked, they are interdependent and work together to support the conclusion. If two premises are convergent, they work independently of one another to support the conclusion. To see the difference consider the following arguments: Argument 2c: with convergent premises I'm not going to lend you the money. If I lent you money you wouldn't return it, and anyway, I'm broke. This is standardised as: 1. If I lent you money you wouldn't return it. 2. I'm broke. C. I'm not going to lend you the money. Argument 2d: with linked premises: God must exist because the world shows signs of design and we know that a designed object can't exist without a designer. This is standardised as:

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1. The world shows signs of design. 2. A designed object cannot exist without a designer. C. A designer God must exist. In argument (2c), the premises are convergent, since they offer independent support for the conclusion. Premise 1 on its own would support the conclusion, and premise 2 on its own would support the conclusion. There are two separate inferences or lines of argument in support of the conclusion. In argument (2d), however, the premises are linked, since they must be taken together to support the conclusion. Neither premise on its own would provide a reason to believe the conclusion. There is only one inference made in support of the conclusion, from the two premises jointly. While the numbering system of representing standardised arguments does not bring out the difference, the pictorial system does. The difference between the types of argument can be represented thus:

An argument can also have a combination of linked and convergent premises. For example: (2e) Jones is likely to vote for the National Party, since he is a farmer, and the Nationals are known for putting farmers' interests first. Besides, he told me that he would vote for the Nationals

1: Jones is a farmer. 2: The National Party is known for putting farmers' interests first. 3: Jones told me that he was going to vote for the Nationals. C: Jones is likely to vote for the National Party. In this argument, premise 1 and 2 would have to be linked, since they are interdependent (neither 1 nor 2 would give us a reason to believe C without the other), but premise 3 offers an independent piece of evidence for the conclusion. This could be represented by the following diagram:

2.2.2 Paraphrasing implicit premises and conclusions

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It is important to remember that the premises and conclusion of an argument should always express propositions. If they are not in an appropriate form in the original argument, they will need to be paraphrased. Consider the following argument: (2f) Well, somebody broke the vase, and your son Billy is the only person who has been near it. So who do you think did it? The conclusion here is stated as a rhetorical question, instead of a proposition. (Note that a question cannot be a proposition, since it is not the sort of thing which can be true or false). The proposition which is implicitly being concluded, however, is clear. The argument could be standardised as: 1: Somebody broke the vase. 2: Your son Billy is the only person who has been near it. C: Your son Billy broke the vase. Paraphrasing can sometimes also be helpful when the premises or conclusions are given as propositions, but are stated in the argument in a way that is unclear out of context. For example, how would you standardise the following argument? (2g) You're only allowed to enter if you know the secret handshake. But you don't. So that's that. Strictly speaking, we do have three propositions asserted here, but rather than standardising the argument as 1: You're only allowed to enter if you know the secret handshake. 2: You don't. C: That's that. It would be much clearer to paraphrase, to get the following standardisation: 1: You're only allowed to enter if you know the secret handshake. 2: You don't know the secret handshake. C: You're not allowed to enter. Always try to standardise the argument so that the meaning of the constituent propositions is clear.

2.3 Subarguments The arguments we have seen so far have been fairly simple, because all their premises, whether linked or convergent, provided support for a single conclusion. In many arguments, premises are given not only to support the main conclusion, but to provide support for other premises. An argument the conclusion of which is not the main conclusion is a subargument. Consider the following argument: (3a) Jones is the only suspect without an alibi. Therefore, Jones is the bank robber. This is a simple argument, which has the form:

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1 Jones is the only suspect without an alibi. C Jones is the bank robber. Now consider the following slightly more complicated argument: (3a-i) Jones is the only suspect without an alibi, since all the other suspects were at the Queen's garden party. Therefore, Jones is the bank robber. We now have a new premise "All the other suspects were at the Queen's garden party" to include in the standardisation. But what is its relationship to the existing premise 1? Is it linked? Convergent? In fact, it is neither. The relationship between the new premise and premise 1 is suggested by the occurrence of the premise indicator "since". What follows a premise indicator is often a premise or reason for what precedes it, which suggests that the new premise is a premise in support of 1, or a reason to convince you of the truth of 1: The arguer tells us that all the other suspects were at the garden party, to convince us that they all have alibis. In this argument, premise 1 functions as a premise, but also as the conclusion of a subargument. (The premises and conclusions in subarguments are sometimes referred to as subpremises and subconclusions, when it is important to distinguish them from those of the main argument, which can be referred to as the main premises, and main conclusion.) In a numerical standardisation, the convention is that main premises will be given the numbers 1, 2, 3 and so on. The number assigned to a subpremise will begin with the number of the premise it supports, followed by a full stop, and a number of its own, to distinguish it from other subpremises supporting the same premise: For example: Premises supporting 1, will be 1.1, 1.2, 1.3 ... Premises supporting 2 will be 2.1, 2.2, 2.3 ... In the argument [1b], then, the new premise can be numbered 1.1, to indicate that it is a subpremise supporting 1. Just as numbered premises are listed above the conclusion in the standardisation of an argument, so we now list any subpremise above the premise it supports. The standardisation of the argument now looks like this: 1.1

All of the other suspects were at the Queen's garden party

1:

Jones is the only suspect without an alibi

C:

Jones is the bank robber.

Levels of premises Subpremises may, in turn, be supported by further subpremises. In the previous argument, for example, further evidence might be given to convince you of the truth of 1.1. For example if a premise were included asserting that "The police have photographs of the other suspects taken at the Queen's garden party", the role of that new premise would be to convince you that 1.1 ("All of the other suspects were at the Queen's garden party") is true. That new premise, then, would be 1.1.1. 1.1.1

The police have photographs of the other suspects taken at the Queen's garden party

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1.1

All of the other suspects were at the Queen's garden party

1:

Jones is the only suspect without an alibi

C:

Jones is the bank robber.

A series of premises or subpremises will be said to be on the same level if they directly support the same conclusion. In the argument standardised above, each of the premises has a different level. There is, of course, no limit to the number of levels of subpremises which may occur in an argument. Wherever a premise occurs, its premise number is determined by what it is a premise in support of. If it is in support of a premise numbered X, however complex X is, then it should be called X.1 or X.2 or X.3 .... We will consider a few more premises, in a longer version of this argument. (3a-ii) Jones is the only suspect without an alibi, since all the other suspects were at the Queen's garden party. The police have photographs of the other suspects at the Queen's garden party, and besides, the Queen says they were there, and she wouldn't lie. Anyway, Jones confessed. Therefore, Jones is the bank robber. So far, we have the standardisation: 1.1.1

The police have photographs of the other suspects taken at the Queen's garden party

1.1

All of the other suspects were at the Queen's garden party

1:

Jones is the only suspect without an alibi

C:

Jones is the bank robber.

and we now have three more pieces of information to include: The Queen says the other suspects were at the garden party. The Queen wouldn't lie. Jones confessed. To decide on the role of each of these statements, look back to the argument as we have standardised it so far, and ask whether any of the new statements give us reason to believe any of the premises already occuring in the standardisation. No evidence is given to support 1.1.1 ( we are given no reason to believe that the police have the photos described), but what about 1.1? Are we given new reasons to believe that all of the other suspects were at the Queen's garden party? In fact we are given two linked reasons: The Queen says they were there, and she wouldn't lie. The number "1.1.1" has already been used, so these premises will be "1.1.2" and "1.1.3". Note that these two new premises must be linked to each other, because we are to believe the other suspects were there because the Queen said they were AND she wouldn't have been lying. The other statement we have not yet added, "Jones confessed", is a main premise, since it is given as a reason to believe the main conclusion, that Jones is the bank robber. The number "1" has already been assigned to a premise in this argument, so this premise will be assigned the number "2". Since 2 offers and independent reason to believe the conclusion, premises 1 and 2 are convergent. Finally then, the argument is standardised as follows:

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1.1.1

The police have photographs of the other suspects taken at the Queen's garden party

1.1.2

The Queen says the other suspects were at the garden party

1.1.3

The Queen wouldn't lie.

1.1

All of the other suspects were at the Queen's garden party

1:

Jones is the only suspect without an alibi

2:

Jones confessed.

C:

Jones is the bank robber.

(Note: Within a level, it does not matter how the premises are numbered. So for example in the standardisation above we have premises 1.1.1, 1.1.2 and 1.1.3. It would not matter if you swapped these numbers around, as all these numbers indicate is that these are three premises in support of 1.1.) This structure of the argument could be represented pictorially as follows:

The argument standardised above is relatively complicated, but the method described above is a good way to approach complex arguments. Find the conclusion first, and identify any premises which seem to directly support that conclusion. Then look at each of those main premises, and decide whether any evidence or reasons are given in support of each of them, gradually building up the standardisation as a whole. We will go through this process with another example. As you are reading through arguments, prior to standardising them, it can be helpful to mark with brackets the different propositions which are asserted, which you expect will be the premises and conclusion: (3b) [Australia should adopt more stringent quarantine standards], because [if we fail to make our quarantine standards stricter, Australia could fall victim to foot and mouth disease], and [this would have a devastating effect on our economy]. [Foot and mouth disease can ruin a nation's meat industry] -- [a huge proportion of England's livestock had to be destroyed due to the disease] -- and [the meat trade is vital to Australia's economy]. The conclusion here is that Australia should adopt more stringent quarantine standards - that is what the author of the argument is trying to convince the reader should be done. Find the main premises by asking what reasons are given to convince you of the truth of the conclusion. In this argument, the main premises are the two which are mentioned immediately after the conclusion: Why should we adopt stricter quarantine standards? Because [1] if we fail to do so then Australia could fall victim to foot and mouth, and [2] foot and mouth would have a devastating effect on Australia's economy.

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Having decided that these two are main premises, we have three premises left to deal with: Foot and mouth disease can ruin a nation's meat industry A huge proportion of England's livestock had to be destroyed due to foot and mouth. The meat trade is vital to Australia's economy. Are any of these further main premises supporting the conclusion? Do any of them support 1? Or 2? We are not given any evidence to believe 1, since we are given no reason to believe that if we fail to make our standards stricter, Australia could fall victim to foot and mouth: we are told nothing about the laxity of our quarantine standards, or the transmissibility of the disease, for example. We are, however, given evidence in support of premise 2, "Foot and mouth would have a devastating effect on Australia's economy." The reasons we are given to believe this are that the meat trade is vital to our economy, and that foot and mouth can ruin a nation's meat industry. The inference we have here as a subargument, then, is: 2.1 Foot and mouth disease can ruin a nation's meat industry 2.2 The meat industry is vital to Australia's economy 2 Foot and mouth would have a devastating effect on Australia's economy. The last thing we have to decide on is the role of the premise "A huge proportion of England's livestock had to be destroyed due to foot and mouth". The purpose of this premise is to give evidence for the claim made in premise 2.1, that foot and mouth disease can ruin a nation's meat industry. The final premise, therefore, will be 2.1.1. The standardisation we end up with, then, is: 1 If we fail to make our standards stricter, Australia could fall victim to foot and mouth disease 2.1.1 A huge proportion of England's livestock had to be destroyed due to foot and mouth 2.1 Foot and mouth disease can ruin a nation's meat industry 2.2 The meat trade is vital to Australia's economy. 2

Foot and mouth disease would have a devastating effect on our economy

C Australia should adopt more stringent quarantine standards.

2.4 Checking Your Standardisation The more complex an argument gets, the easier it is to make a mistake in the standardisation. For that reason, it is important to check your standardisation after you have constructed it, to make sure that the inferences you have represented by your numbering correspond to the inferences which were being made in the original argument. Once you have constructed a standardisation, the numbering identifies which premises are meant to support which conclusion, so you should be able to read these inferences back and have them make sense. More importantly, you should have them correspond to the inferences with which you began. In argument [2] above, for example, 2.1.1 is the only premise we have which supports 2.1. We should therefore be able to read this inference back as "2.1.1, therefore 2.1", that is: A huge proportion of England's livestock had to be destroyed due to foot and mouth, therefore foot and mouth disease can ruin a nation's meat industry.

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This does seem to correspond to one of the inferences made in the argument. We have two premises in support of 2 -- 2.1 and 2.2. So we should be able to read this inference back as "2.1 and 2.2, therefore 2"; that is: Foot and mouth disease can ruin a nation's meat industry, and the meat trade is vital to Australia's economy. Therefore, foot and mouth disease would have a devastating effect on our economy. This, too, sounds like an accurate representation of the inference which has been made. If there are mistakes in the standardisation, however, this is often the easiest way to pick them up. If, for example, we had mistakenly assigned the premise "The meat trade is vital to Australia's economy" the number 2.1.1, instead of 2.2, then when we came to read back the alleged inference "2.1.1, therefore 2.1", the inference would be: The meat trade is vital to Australia's economy, therefore foot and mouth disease can ruin a nation's meat industry. This inference does not make much sense, and is not one which was intended by the original argument. The fact that the meat trade is important to Australia's economy does not give us reason to believe anything about the effects of foot and mouth on the meat industry. So this indicates that an error has been made. Reading an argument from a standardisation: The Monty Hall problem revisited (Note that this argument is more complicated: it is here to provide practice in reading an argument back from a standardisation). Standardisation can be used to help clarify complex reasoning. Recall the problem you saw in the first lecture:

On the table are three identical boxes, each with a lid and also a neat pile of ten dollar bills. This game is to be repeated many times. Let’s say I’m running the show. Here are the rules of the game. First, you leave the room and while you are out, I put a ten dollar bill in one of the boxes. I then close the boxes. I know in which box the money is, but you don’t. Now I invite you back into the room. Each game is divided into two distinct phases. In the first, by doing no more than pointing, you indicate your choice among the three boxes, which remain closed. As you have made your choice, I open another box, one of the two remaining boxes. That box will be empty - remember that I know in which box the ten dollar bill is. Having seen one empty box (the one I just opened), you now face two closed boxes, one of which must contain the ten dollar bill. Now comes the second phase. I now offer you the chance to stay with your first choice, or to switch your choice to the other closed box, the one you failed to choose the first time round. In the first lecture, you saw the reasoning which shows that you maximise your chances of winning by switching in phase 2, but despite the argument given, many people find the conclusion difficult to accept,

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and claim that there must be something wrong with the argument. By using standardisation, we can present the argument in a precise form, so that it is clear what is being argued. Once we have a standardisation of the argument, if you still want to dispute the conclusion, you will now need to find fault with one of the premises, or one of the inferences presented in the standardisation -which won't be easy to do! Here is one way -- although not the only way -- that the argument can be standardised: 1.1.1

In phase 1, you choose from 3 boxes: two empty boxes and one with the money

1.1

There is a 2 in 3 chance that your original choice was an empty box

1.2.1.1.1 In phase 1, you choose from 3 boxes: two empty boxes and one with the money 1.2.1.1.2 After phase 1, the host will open an empty box which you didn't choose. 1.2.1.1 For phase 2 there are 2 closed boxes left: the box you chose and another box - one of which contains the money 1.2.1

In phase 2, either the money is in the box you chose, or the other box

1.2.2 You can stay with your original choice or switch to the other box, and you win the contents of the box you choose. 1.2

You will win by switching if and only if your original choice was an empty box.

1:

There is a 2 in 3 chance you will win by switching

C:

You can double your chance of winnning by switching

Don't be offput by the numbers appearing in this standardisation. They should really make things clearer, as they disambiguate the structure of the argument, and show how each inference works. Remember that numbers such as "1.2.1.1.1" and "1.2.1.1.2" just indicate that these are the first and second premises in support of 1.2.1.1. Note that one of the premises ("In phase 1, you choose from 3 boxes, 2 empty boxes and one with the money") has been repeated. This premise seems to offer support for two other premises in the argument. To indicate this, it appears with the number 1.1.1 (when it is used to support 1.1) and 1.2.1.1.1 (when it is used to support 1.2.1.1). To read this standardisation back, try reading the premises in the order suggested by the numbering: [1.1.1] therefore [1.1] [1.2.1.1.1] and [1.2.1.1.2], therefore [1.2.1.1] [1.2.1.1] therefore [1.2.1] [1.2.1] and [1.2.2], therefore [1.2] [1.1] and [1.2], therefore [1] [1] therefore [C] Check that each of these sounds like a good inference. This argument is quite complex, but its standardisation suggests two reasons that this is a useful procedure. If an argument is complex, it is useful to break it up into its different subarguments, firstly so that you can see precisely what is being claimed and inferred and decide whether you think it is a good argument, and secondly so that you can present the inferences in a clear and unambiguous way to convince others.

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SKILLS FOR WEEK 2 You should be able to: Standardise arguments with or without subarguments work out whether the premises of an argument are linked or convergent Check a complex standardised argument by reading it back

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3 COUNTER ARGUMENTS (Week 3)

3.1 Arguments And Counterarguments A counterargument is an argument which responds to another argument, presenting an opposing viewpoint. Often you will find a passage which contains two arguments: one which is reported, and another which criticises it. In such a passage, the argument which is just reported is the target argument, the argument opposing the target argument is the counterargument. (1a) Some people have argued that [it is unreasonable for employers to monitor the use of the internet by their employees], since [it is an invasion of privacy]. But [employers have a right to know what their employees are doing on company time], since [they are paying these employees to do their jobs]. [Employers may also be held liable if employees download or transmit illegal or offensive material using company equipment]. [Employers are entitled to protect themselves against such liability], and [they must therefore be permitted to monitor internet usage to avoid potential legal action]. The target argument here is the argument introduced by the phrase "Some people have argued that ...". Target arguments will very often be signalled in this way, by being attributed to some particular source. The conclusion of the target argument above is "It is unreasonable for employers to monitor the use of the internet by their employees." (Note that it would be wrong to have as the conclusion: "Some people have argued that it is unreasonable for employers to monitor the use of the internet by their employees." If this were the conclusion, then this would be what the rest of the argument was trying to convince you of — but the argument is not trying to convince you that that is what some people have argued.) When a target argument is attributed to a particular source, that source will not be mentioned in the premises or conclusion of your standardistion. It is, however, a good idea to note in brackets at the beginning of your standardisation, the person or group to whom the target argument is attributed. That way, when you are evaluating the arguments, you will know whose argument has been countered. There is only one premise in the target argument, so it is standardised as follows: 1 For employers to monitor employees' internet usage is an invasion of their privacy. C It is unreasonable for employers to monitor employees' internet usage. As is often the case, the conclusion of the counterargument is not explicitly stated. But as is also usually the case, the intention of the counterargument is to oppose the conclusion of the target argument. So the intended conclusion is something like: C It is not unreasonable for employers to monitor employees' internet usage In making explicit a conclusion which is not explicit in the original argument, you should again apply the principle of charity. Don't make the conclusion any stronger than it has to be. So in this case, we would choose something like the conclusion above, rather than "Employers should monitor employees' internet use" or "It is good for employers to monitor their employees' internet use". The person presenting the

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counterargument might not be intending to argue for anything as strong as these. All that is being argued, is that (contrary to the conclusion of the target argument), it is not unreasonable for employers to act in this way. Looking at the argument, it is clear that there are two separate lines of reasoning being given in support of the conclusion. The first line of reasoning is: "[employers have a right to know what their employees are doing on company time], since [they are paying these employees to do their jobs]. " This consists of two premises, and the relationship between them is indicated by the premise indicator "since". Two of the premises, then, will be: 1.1

Employers are paying these employees to do their jobs.

1

Employers have a right to know what their employees are doing on company time.

The other main line of reasoning is contained in the rest of the argument, and contains three individual premises: "[Employers may also be held liable if employees download or transmit illegal or offensive material using company equipment]. [They are entitled to protect themselves against this], and [they must therefore be permitted to monitor internet usage to avoid potential legal action]." "Therefore", a conclusion indicator, occurs in the last sentence, which suggests that "Employers are entitled to protect themselves against this [being held liable...]" is a premise in support of "Employers must be permitted to monitor internet usage to avoid potential legal action", which will be a main premise. Where does the other premise ("Employers may be held liable if employees download or transmit illegal or offensive material using company equipment") fit in? It needs to be linked to "Employers are entitled to protect themselves against this [being held liable...]" to support "Employers must be permitted to monitor internet usage to avoid potential legal action" : We are to believe that employers should be allowed to monitor employees' internet use because they can be held liable for such use and they are entitled to protect themselves against liability. The second part of the argument, then would be: 2.1

Employers may be held liable if employees download or transmit illegal or offensive material

using company equipment 2.2

Employers are entitled to protect themselves against this [being held liable...]

2

Employers must be permitted to monitor internet usage to avoid potential legal action

The final standardisation of this argument and counterargument, then, is: Target argument ("some people") 1 For employers to monitor employees' internet usage is an invasion of their privacy. C It is unreasonable for employers to monitor employees' internet usage. Counterargument: 1.1

Employers are paying employees to do their jobs.

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1

Employers have a right to know what their employees are doing on company time.

2.1

Employers may be held liable if employees download or transmit illegal or offensive material

using company equipment 2.2

Employers are entitled to protect themselves against this [being held liable...]

2

Employers must be permitted to monitor internet usage to avoid potential legal action

C

It is not unreasonable for employers to monitor employees' internet usage.

3.2 Noting Direct Responses The premises of the counterargument above do not directly address the claim that the monitoring of employees' internet access is an invasion of privacy, but instead gives reason to think that the action is still reasonable because other considerations outweigh the employees' privacy in this context. Often, however, counterarguments specifically address some or all of the premises of the target argument. When this occurs, it is a good idea to keep track of which premises have been refuted or addressed, to see how successful the counterargument is in opposing the target argument. To mark such direct responses, we will adopt a new piece of notation. If a premise of the counterargument is given as a direct response to premise 1 of the target argument, for example, we will note this by writing [X1] next to the premise of the counterargument. ([X2] will mark a direct response to premise 2 of the target argument, [X1.1] marks a direct response to premise 1.1 of the target argument, and so on]. (2a) Some lobby groups think [it is justifiable to keep illegal immigrants in detention centres], because [they have deliberately committed a criminal offence], and because [their imprisonment acts as a deterrent to others]. But [often those who arrive in Australia are innocent of any deliberate wrongdoing], since [illegal immigration is organised by people-smuggling syndicates]. [These syndicates mislead the immigrants into thinking that they are doing nothing wrong]. And [there is no real deterrent effect], since [that would only work if the the potential illegal immigrants were informed about what will happen to them in Australia], but [they often do not know that they will be detained]. [Imprisonment, therefore, cannot be justified]. Target argument: ("some lobby groups") 1 Illegal immigrants have deliberately committed a criminal offence 2 The imprisonment of illegal immigrants acts as a deterrent to others. C The imprisonment of illegal immigrants in detention centres is justifiable. Counterargument: 1.1 Illegal immigration is organised by people-smuggling syndicates 1.2 People-smuggling syndicates mislead the immigrants into thinking that they are doing nothing wrong. 1

Often those who arrive in Australia are innocent of any deliberate wrongdoing.

[X1]

2.1 Deterrence would only work if the potential illegal immigrants were informed about what will happen to them in Australia. 2.2 Often they do not know they will be detained. 2

There is no real deterrent effect.

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C

The imprisonment of illegal immigrants in detention cannot be justified.

In this counterargument, the two premises of the target argument have been directly addressed. This has been noted in the standardisation of the counterargument with the references "[X1]" and "[X2]". By noting these as you go along, when you come back to evaluate the argument, it is easier to see if there are some points which were made in the target argument which have not been addressed, and it will make it easier to evaluate the success of the counterargument as a refutation of the target argument. Which premises have been addressed is also something to keep in mind when constructing your own counterarguments. If you make it clear that you are addressing each of your opponent's points, this will strengthen your counterargument. Example: (2b) The Australian Home Birth Collective argues that [women should be discouraged from giving birth in hospital], on the grounds that [birth is a natural process], and because [women managed to give birth in the past, before hospitals and medical intervention]. But [the fact that something is natural, is not normally thought of as a reason to shun the benefits of medical science which could make it easier]. [Cancer is natural too], but [we do not think in that situation that nature should be left to take its course]. And [in earlier times, to which this group so nostalgically refers, before medical assistance was available, the mortality rate during childbirth for women and babies was tragically high]. So [women should really be encouraged to give birth in hospital]. Target argument:("The Australian Home Birth Collective") 1 Birth is a natural process. 2 Women managed to give birth in the past, before hospitals and medical intervention. C Women should be discouraged from giving birth in hospital Counterargument: 1.1 Cancer is natural, too 1.2 We do not think when people have cancer that nature should be left to take its course 1 The fact that something is natural is not normally thought of as a reason to shun the benefits of medical science which could make it easier. [ X1] 2 In earlier times, before medical assistance was available, mortality rates for women and babies during childbirth were tragically high [X2] C Women should be encouraged to give birth in hospital. It is important to note that a counterargument can be good without responding to each of its target argument's premises, and often strong counterarguments will criticise the strength of the argument itself, rather than debating any of the specific points made. The reason making a note of any direct responses can be useful, however, is that it gets you into the habit of thinking about how the counterargument responds to the target argument, and whether its response is successful. We will look more at how to evaluate the success of counterarguments later in the course.

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3.3 Counterconsiderations When you are giving an argument, it is often a good idea to show that you have thought about possible objections, and that you can respond to them. By including counter considerations ,and responses to them, an argument is fortified against potential criticisms. For example, in the argument: (3a) A well constructed vegetarian diet can supply the body with all the nutrients it needs. While it is true that red meat is the best source of iron, iron is also found in green vegetables and legumes. Vegetables are also the best source of all essential vitamins. An anticipated objection -- that meat is the best source of iron --is acknowledged, so that the arguer can respond to that possible objection before it is made. When a counterconsideration is given in an argument you are standardising, list it with the argument, with the reference [cc] instead of a premise number (in an argument with more than one counterconsideration, they may be numbered [cc1], [cc2] etc - but make sure that what you have isn't actually a target argument to which a counterargument is being given). As was the case with counterarguments, any response to a particular counterconsideration can be noted in the standardisation. [cc] Red meat is the best source of iron 1 Iron is also found in green vegetables and legumes [Xcc] 2

Vegetables are also the best source of all essential vitamins.

C A well constructed vegetarian diet can supply the body with all the nutrients it needs. The reference [Xcc] next to premise 1 indicates that it is addressing the counterconsideration [cc]. To identify counterconsiderations, look out for propositions which seem to count against the conclusion, but which are not offered as part of a separate argument. Counterconsiderations are often signalled by words such as "although", "despite the fact that... ", or "while it is true that....". Identify the argument and counterargument in the following passage, and look out for any counterconsiderations: (3b) A group of self-proclaimed defenders of Earth have argued that although there is no uncontroversial proof of alien visitation, aliens must visit earth, because many people believe they have been abducted, and because there are crop circles throughout England. They argue that we should, therefore, put an emergency plan into place to cope with an extra-terrestrial attack. But anyone with a tractor can make a crop circle, and although many people believe they have been abducted, none of the alleged abductees have ever come up with any evidence of their abduction. So we have no reason to believe that there are aliens visiting earth. It would therefore be pointless to worry about being attacked by aliens. This argument could be standardised as follows. Target argument ("self-proclaimed defenders of Earth"): [cc] There is no uncontroversial proof of alien visitation 1.1: Many people believe they have been abducted 1.2: There are crop circles throughout England 1: Aliens visit earth C: We should put an emergency plan into place to cope with an extra-terrestrial attack. Counterargument:

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1.1: Anyone with a tractor can make a crop circle [X1.2] 1.2: None of the alleged abductees have come up with any evidence of their abduction [X1.1] 1: We have no reason to believe that there are aliens visiting earth. C: It would be pointless to worry about being attacked by aliens Note that in the original passage, premise 1.2 of the counterargument is introduced by the phrase "Although many people believe they have been abducted...". This does not need to be included in the standardisation as a counterconsideration, because it is just restating a premise from the target argument (1.1), and signalling that a point is being made in response to that premise. We do not need to include this again, because it has already been noted in the standardisation of the counterargument that premise 1.2 is being made as a response to the target argument's premise 1.1.

3.4 Validity And Invalidity: Introduction Valid Definition: if the premises are all true, the conclusion must also be true. Validity is a matter of its structure, not its content. Invalid: Possible for their premises to be true and their conclusions false. So far, we have been concerned with the structure of arguments, and the representation of that structure using standardisation. Now that you are confident about identifying the structure of arguments, we are able to begin to evaluate arguments, and to analyse what makes an argument good or bad. In some cases, determining the exact structure of the argument is a very important part of its evaluation. For example, consider the argument: (1a) 1 If echidnas are monotremes, then they are marsupials. 2 Echidnas are monotremes. C Echidnas are marsupials. Even if you don't know whether the premises and conclusion of the argument are true or false, there is something about the structure of the argument which makes it importantly different from some of the arguments we have seen so far. This argument is valid, which means that if the premises are all true, the conclusion must also be true. Without knowing anything about monotremes and marsupials, you should be able to see that if it is true that if echidnas are monotremes, then they are marsupials and it is true that echidnas are monotremes, then it must also be true that echidnas are marsupials. The validity of the argument is a matter of its structure, rather than its actual content. This structure it has in common with many other arguments which will also be valid, for example: (1b) 1 If you have paid your fee, you may enter. 2 You have paid your fee. C You may enter. Other, superficially similar arguments lack this feature, for example:

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(1c) 1 If possums are monotremes, then possums are marsupials 2 Possums are marsupials, C Therefore possums are monotremes. (1d) 1 If Elvis' death was faked by the CIA, then most people would believe that Elvis was dead. 2 Most people do believe that Elvis is dead. C Elvis' death was faked by the CIA These arguments are invalid. It would be possible for their premises to be true and their conclusions false. To establish some general rules about when arguments such as these are valid or invalid, it will be necessary to look more closely at the structure of the propositions occurring in them.

3.5 Necessary And Sufficient Conditions An important kind of proposition occurring in arguments is the conditional statement, a statement which asserts that one thing is necessary for another, or that one thing is sufficient for another. Some common forms of conditional statements are those involving "All" or "only" and those involving "If... then...". Necessary For example: Sufficient

"All humans are mortal"

tells us that if something is a human, that is sufficient to guarantee that it must be mortal. "Only valid arguments are good" tells us that it is necessary for an argument to be valid, in order for it to be good. "If the candidate wins the election, she will be happy" tells us that the candidate winning the election is sufficient to ensure her happiness.

In each of these formulations, two conditions are related, a necessary condition and a sufficient condition. The necessary condition is so called because (if the statement is true) it must hold in order for the other condition to hold. The sufficient condition is so called because (if the statement is true) if it holds, then that is enough to guarantee that the other condition will also hold. Every conditional statement will have both a necessary and a sufficient condition. If A is a necessary condition for B, then B is a sufficient condition for A. For example, according to the conditional statement: All medical students did well in the HSC A person's being a medical student is sufficient to ensure that he or she must have done well in the HSC, and doing well in the HSC is necessary for being a medical student.

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3.6 Common Forms Of Conditional Proposition For our purposes, a conditional statement will be any statement which relates a necessary and sufficient condition. These are some of the most common kinds of conditional statements: Are G

3.6.1 "All/ Every / Any Fs are Gs"

All F Sentences using "all" and "only" state general necessary and sufficient conditions. A statement of the form All Fs are Gs asserts that being an F, is a sufficient condition for being a G. For example: All people on the bus have tickets asserts that if someone is on the bus they must have a ticket - so being on the bus is sufficient for being someone who has a ticket. Other words such as "every", or "any" may take the place of "all". For example: Every person on the bus has a ticket. Anyone who is on the bus has a ticket.

Only F

If G

3.6.2 "Only Fs are Gs"-

Are G

Only F

Corresponding to every "All" statement is an "only" statement. While the former emphasises the sufficient condition, (it tells you that if something has a certain property, that is enough to ensure that it has another property) the latter emphasises the necessary condition (it tells you what property something must have, in order to have another). So: Only those with tickets are on the bus. means that having a ticket is necessary for being on the bus. In each of the following conditional statements, the sufficient condition is in bold, and the necessary condition is italicised. All budgerigars are birds. Only birds are budgerigars. All students are conscientious people. Only conscientious people are students. All rocks are heavy. Only heavy things are rocks.

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Every cloud has a silver lining. Only things with silver linings are clouds. Anyone who would try that is a fool.

Then B

Only foolswould try that.

If A

3.6.3 "If A then B"

Necessary and sufficient conditions are also often related in sentences of a form such as: If we keep producing greenhouse gases, then global warming will continue. Although we are using the name more generally to refer to any statements which relate necessary and sufficient conditions, "If... then..." statements are what are traditionally referred to as conditional propositions. In a proposition of the form "If.... then ....", the part which comes after "if" is the antecedent, the part which comes after "then" is the consequent . The above statement asserts that our continued production of greenhouse gases is a sufficient condition for the continuation of global warming. So when a sentence is in "If... then ..." form, the antecedent is the sufficient condition, and the consequent is the necessary condition. Conditional propositions involving "If" are not, however, always in the same form. Consider the proposition: Global warming will continue if we keep producing greenhouse gases. As was the case with the equivalent "all" and "only " statements mentioned previously, it is clear that although the order in which the conditions appear in the sentence has changed, the sentence means the same thing. It is still saying that the production of greenhouse gases is sufficient for global warming continuing. If B

3.6.4 A Only if B (Only A if B)

Only A

What about sentences such as: I will take my umbrella only if it is raining. Which is the necessary and sufficient condition here? The sentence is stating that raining is necessary for my taking my umbrella. This one can be misleading, since it seems odd to say that my taking my umbrella is sufficient for it raining, but it is still accurate. If the sentence above is true, then your having your umbrella is sufficient to ensure that it must be raining, since you would only take your umbrella if it was raining. Sentences involving "only" tend to emphasise what is necessary, so a good way to determine the conditions in a sentence involving "only if" or "only" is just to ask yourself what it is saying is necessary - which condition is it saying must hold for the other condition to hold. If you are unsure, think of an example where the conditions are clearer: You will win the lottery only if you buy a ticket.

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Buying a ticket is necessary, but (sadly) not sufficient for winning the lottery. So again, in the form "p only if q", p is the sufficient condition, q the necessary condition. Some of the most common forms of conditional statement, then, are: 1. 2. 3. 4. 5.

If [ the sufficient condition holds] then [the necessary condition holds]. [The necessary condition holds], if [the sufficient condition holds]. [The sufficient condition holds] only if [the necessary condition holds]. All [things satisfying the sufficient condition] [satisfy the necessary condition] Only [things satisfying the necessary condition] [satisfy the sufficient condition].

However, not all conditional sentences will have one of these forms. Rather than just memorising a series of sentence types, then, it is important to be able to identify necessary and sufficient conditions however they are stated.

3.7 Checking Necessary And Sufficient Conditions If you are unsure about the necessary and sufficient conditions in a particular conditional statement, there are a number of methods you can use to try to determine which is which, each of which will be discussed below. IF YOU ARE UNSURE WHICH CONDITION IS NECESSARY AND WHICH IS SUFFICIENT: Try paraphrasing the statement into more familiar forms without changing the meaning. Ask yourself the following question: According to the statement, which condition can hold without the other? The condition which can hold without the other condition will be the necessary condition. Check your answer with a diagram.

3.7.1 Paraphrasing If a conditional statement is in an unfamiliar form, it can help to paraphrase the sentence, to preserve the meaning but make the form of the sentence clearer. For example: You can't get in unless you have ID This sentence relates two conditions - getting in and having ID - but exactly how they are related may be unclear. To work out what is going on in this sentence, try expressing the same fact in different ways, until you can express it in a way which makes the necessary and sufficient conditions more obvious, for example: You can't get in unless you have ID. You need ID to get in. ID is necessary for getting in. So, this makes it clear that "You have ID" is a necessary condition for "You get in".

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You will sometimes find that with these more complex expressions involving negation, there may be several ways you can understand the necessary and sufficient conditions. For example, another way to express the same fact is: If you don't have ID, you won't get in. That paraphrase makes it clear that "You don't have ID" is a sufficient condition for "You won't get in". That is also correct. What this shows is that: A is a necessary condition for B if and only if not-B is a necessary condition for not-A. It is possible to give many examples of such equivalences, which you could memorise, but a far better way to approach such questions is to be able to work out from the meaning of the statement, what is necessary and what is sufficient. To do this, get used to paraphrasing sentences into different forms which mean the same thing. If they all mean the same thing, then they will all have the same necessary and sufficient conditions. So, faced with an unfamiliar form, try to find an equivalent statement in a form such as "If p then q", or "All Fs are Gs", or "Only Fs are Gs". You will then be able to determine which condition is which. For example, all of the following sentences are, for our current purposes, synonymous. They all have the same necessary and sufficient conditions . All those who live in Sydney, live in Australia. If someone lives in Sydney, that person also lives in Australia. Living in Sydney is a sufficient condition for living in Australia. Living in Australia is a necessary condition for living in Sydney. You can't live in Sydney unless you live in Australia. You live in Sydney only if you live in Australia. Only if you live in Australia, do you live in Sydney. Which condition could hold without the other? A conditional statement will assert that one thing is sufficient for another - if the sufficient condition holds then so will the necessary - so according to the conditional statement, it's not possible for the sufficient condition to hold without the necessary condition. So, try asking yourself: According to the conditional statement, which condition could hold without the other? The one which could, according to that conditional statement, hold without the other condition is the necessary condition. For example: The only people who are on the bus are those with tickets. This sentence involves "only", but the order in which the conditions occur in the sentence is different from the example we saw above, "Only people with tickets are on the bus". So are the necessary and sufficient conditions the same, or reversed? To work this out, just think about what the sentence means. According to the statement "The only people who are on the bus are those with tickets" - is it possible to be on the bus with no ticket? Is it possible to have a ticket but not to be on the bus? The sentence tells us that it is not possible to be on the bus with no ticket, but there is no reason to think that you couldn't have a ticket without being on the bus. So having a ticket is the condition which could hold on its own. Having a ticket is necessary for being on the bus, and being on the bus is sufficient for having a ticket.

3.7.2 Diagrams The relationship between necessary and sufficient conditions can also be represented by way of a diagram.

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The class of things of which, or situations in which, the sufficient condition holds, is represented by the inner circle. The class of things of which, or situations in which, the necessary condition holds is represented by the outer circle. Since nothing can be in the inner circle without also being in the outer circle, being in the inner circle is a sufficient condition for being in the outer circle, and being in the outer circle is necessary for being in the inner circle. These diagrams can be a useful way to check your necessary and sufficient conditions. Say you were trying to determine the necessary and sufficient conditions in: Only students are eligible for the discount. (Perhaps you want to check whether you will get the discount). You may think that the being eligible for the discount is sufficient for being a student, but want to check whether this is right. Draw a diagram, labelling the inner circle with what you think is the sufficient condition, and the outer circle with the necessary condition, ie:

What we want is for this diagram to reflect the original statement, that "Only students are eligible for the discount." That is, there should be no-one who is eligible for a discount who is not a student. Our diagram does reflect this - because anyone who is inside the "eligible for a discount" circle must also be inside the "Students" circle. So because the inner circle is always the sufficient condition, and the outer circle is always the necessary condition, according to this statement being a student is necessary for getting the discount, and being eligible for the discount is sufficient for being a student. So, are you, as a student, eligible for the discount? Perhaps not. All we have been told is that no-one who is is not a student will get the discount, but as is clear in the diagram, there may also be students who are ineligible.

3.7.3 Ambiguity Sometimes conditional statements, particularly those involving "Only" can be ambiguous, and you will need to apply the principle of charity when deciding how best to interpret the statement, and how best to isolate its necessary and sufficient conditions. We have seen previously, that a statement such as Only University students pay HECs can be thought of having the form: Only [things satisfying the necessary condition] [satisfy the sufficient condition] and asserting that paying HECs is sufficient for being a uni student, and being a uni student is necessary for paying HECs.

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But what about the sentence: Only very hungry people would eat dog food. This might sound true, but it doesn't seem to follow the same pattern as the ones we have seen before. The sentence is not to be understood as asserting that being a hungry person is necessary for eating dog food, or that eating dog food is sufficient for being a hungry person -- surely dogs eat dog food too. What is meant here could more fully be expressed as : The only people who would eat dog food are very hungry. or All people who would eat dog food are very hungry. So the necessary condition is being very hungry, the sufficient is being a person who would eat dog food. It is important, therefore, to be sensitive to the context of the sentence, and interpret a sentence in the way it is most likely to have been intended.

3.8 Counterexamples Once you have a clear understanding of how the necessary and sufficient conditions of a sentence are related, it is possible to see the circumstances in which conditional statements could be shown to be false. Consider the sentence: All politicians are honest. According to this sentence, the fact that someone is a politician is sufficient to ensure that that person is honest. And being honest is necessary for being a politician. If you were to find a politician who was not honest, it would mean that the statement was false. A dishonest politician would be a counterexample to the statement. A counterexample to a conditional statement is something which has the sufficient condition, but lacks the necessary condition. If there is such a thing, the statement is false. If there is no such thing, the sentence is true. For example: CONDITIONAL STATEMENT

COUNTEREXAMPLE

All swans are white

A swan which is not white

Only English teachers like Shakespeare.

Someone who is not an English teacher, but who likes Shakespeare

If John goes to a party, Sue will go too.

An occasion when John goes to a party, but Sue doesn't

It will only rain if we do a rain dance.

A time when it rains, although we don't do a rain dance

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Every rebel has a cause.

A rebel without a cause

Being aware of what would provide a counterexample can help with our reasoning about conditional statements. Consider again the problem from the first lecture:

Recall that the red sides represent covers, concealing either a blank space or a circle. The problem was to determine whether it was true for all these cards that: If there is a circle on the left, then there is a circle on the right. Which cards would need to be "unveiled" for you to test this statement? You should now recognise this as a conditional statement, and you should now be able to tell easily what would be a counterexample. A counterexample to the statement "If there is a circle on the left, then there is a circle on the right" would have to be a card which had a circle on the left (the sufficient condition), but did not have one on the right (the necessary condition). Looking at the cards, we can see that the only cards which could provide that counterexample would be A or D. So these are the ones you would need to see. SKILLS FOR WEEK 3 You should be able to:    

Identify target arguments and counterarguments Standardise target arguments and counterargument Identify the necessary and sufficient conditions in a conditional proposition Work out what would provide a counterexample to a given conditional statement

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4 CONDITIONAL ARGUMENTS (Week 4) In the previous lecture we defined a valid argument as an argument with the feature that if the premises were true, the conclusion would also have to be true. An understanding of necessary and sufficient conditions, and the conditional propositions in which they occur, will now allow us to determine the validity or invalidity of an important kind of argument - conditional arguments.

4.1 Valid Conditional Argument Forms There are two main forms of valid conditional argument. These are called "affirming the sufficient condition", and "denying the necessary condition". (This classification of conditional argument forms is from Thinking Clearly , by Jill LeBlanc)

4.1.1 Affirming the sufficient condition Consider the following standardised argument: (6a) 1: If you have a blood alcohol level of more than 0.05, you are not legally allowed to drive. 2: You have a blood alcohol level of more than 0.05. C: You are not legally allowed to drive.

The first premise of this argument is a conditional proposition. Because it is in "if... then..." form, we know that the sufficient condition is "you have a blood alcohol level of more than 0.05", and the necessary condition is "you are not legally allowed to drive". The second premise affirms the sufficient condition: "You have a blood alcohol level of more than 0.05". The conclusion states the necessary condition of the conditional premise: " You are not legally allowed to drive". As we established in the last lecture, if a conditional statement is true, and its sufficient condition holds, then the necessary condition also holds. What that tells us in this case is that if the first premise (the conditional statement) is true, and the second premise (the sufficient condition) is true, then the conclusion (the necessary condition) must also be true. This argument, then, is valid, since if its premises are true, its conclusion must also be true. This will be the case for any argument which has this structure:

(6b) 1 [Conditional premise] 2 [sufficient condition of conditional premise] C [ necessary condition of conditional premise]

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Some examples are: (6c) 1 If we are only aware of our own mental states, we cannot know whether the external world exists. 2 We are only aware of our own mental states. C We cannot know whether the external world exists.

(6d) 1 All cats hate water 2 Fluffy is a cat C Fluffy hates water

(6e) 1 We couldn't live on Mars if there is no oxygen on Mars 2 There is no oxygen on Mars C We couldn't live on Mars

This argument form is referred to as affirming the sufficient condition. As with all the conditional argument forms we will be looking at, the name of the form describes the role of the non-conditional premise, relative to the conditional premise.

4.1.2 Denying the necessary condition The other basic valid conditional argument form is that of an argument such as: (6f) 1 If we are going to get there on time, we will have to leave here by 7 o'clock 2 We won't be leaving here by 7 o'clock C We won't get there on time.

The conditional premise of this argument states that leaving by 7 o'clock is a necessary condition for getting there on time. The second premise says that we won't be leaving by 7. So if leaving by 7 is necessary for getting there on time, but we won't be leaving by 7, it follows that we won't get there on time. So this argument is also valid. If both the premises were true, the conclusion would also have to be true. This form is called denying the necessary condition, since the non-conditional premise denies the necessary condition of the conditional premise. (6g) 1 [Conditional proposition] 2 [denial of the necessary condition of the conditional]

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C [denial of the sufficient condition of the conditional]

By "denying" here, we really mean "contradicts" or "says the opposite of". So the following would also be an example of denying the necessary condition:

(6h) 1 If the grass is artificial, it will not grow. 2 The grass does grow C The grass isn't artificial

Since here, also, the non-conditional premise says the opposite of the necessary condition, and the conclusion says the opposite of the sufficient. Other examples of this form are:

(6i) 1 Only those who have talent should be allowed to do karaoke 2 Bert has no talent C Bert should not be allowed to do karaoke

(6j) 1 They would have contacted us if we'd won the lottery. 2 They haven't contacted us C: We didn't win the lottery

(6k) 1 If you're nice to the dog, he doesn't bite. 2 The dog bit you C: You weren't nice to him Confirm for each of these arguments that the second premise denies the necessary condition of the first.

4.2 Invalid Conditional Argument Forms There are also two common invalid forms of conditional argument. Superficially they are similar in form to the valid arguments - again, we have a conditional premise, and a premise which affirms or denies one of its conditions. In the case of the two invalid forms, however, the truth of the premises does not guarantee the truth of the conclusion.

4.2.1 Affirming the necessary condition Suppose we know it is true that:

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If Bill is a flautist, then Bill is a musician. The sufficient condition here is "Bill is a flautist", and the necessary condition is "Bill is a musician". Suppose that we also know that the necessary condition holds - that Bill is a musician. Would this entitle us to conclude that he is therefore a flautist? It would not - the fact that the necessary condition holds tells us nothing about whether the sufficient does or not. He could play the trombone, or sing, for example. For that reason, the argument: (7a) 1 If Bill is a flautist, then Bill is a musician. 2 Bill is a musician C Bill is a flautist.

is invalid. The premises could be true without the conclusion also being true. Following the convention that the name given to the form refers to how the non-conditional premise relates to the conditional premise, this form will be called affirming the necessary condition. Other examples of this form are: (7b) 1 If someone is a known criminal, they won't be accepted into the police force 2 Al was not accepted into the police force C Al is a known criminal

(7c) 1 All supermodels are over 6 foot 2 Roger is over 6 foot C Roger is a supermodel

(7d) 1 Only adults can vote in Australian elections. 2 President Bush is an adult. C President Bush can vote in Australian elections. In each case, it would be possible for the premises to both be true, but the conclusion false. These arguments, then, are invalid.

4.2.2 Denying the sufficient condition The other most common invalid conditional argument form is denying the sufficient condition . (7e) 1 If Bill is a flautist, then Bill is not a musician

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2 Bill is not a flautist. C Bill is not a musician In this case, the second premise denies the sufficient condition of the first. Again, this is an invalid form, since the fact that Bill's being a flautist would be sufficient for his being a musician, does not make it necessary. He could be a musician even though he is not a flautist, so the failure of the sufficient condition tells us nothing about whether or not the necessary condition holds. Other examples of arguments of this form are: (7f) 1 The rich have a responsibility to help the poor. 2 I am not rich. C I do not have a responsibility to help the poor.

(7g) 1 If something contains a lot of salt, it is bad for you 2 This chocolate fudge cake does not contain a lot of salt C This chocolate fudge cake is not bad for you

(7h) 1 You are not allowed to drive if your blood alcohol level is over 0.05 2 Your blood alcohol level is not over 0.05 C You are allowed to drive

4.3 Examples We will now evaluate some conditional arguments. They may occur within larger arguments, either as the main argument or a subargument, but when this is the case remember that it is only the part of the argument which is a conditional argument we can show to be valid or invalid by these methods. (8a) UN intervention in Northern Ireland could succeed only if there was a solution to which both parties would agree. There is, however, no such solution, since both sides are convinced of the rightness of their respective causes. It follows that UN intervention in Northern Ireland cannot succeed. First, work out what the basic components of the argument are, and identify any premise or conclusion indicators: [UN intervention in Northern Ireland could succeed only if there was a solution to which both parties would agree]. [There is, however, no such solution] , since [both sides are convinced of the rightness of their respective causes]. It follows that [UN intervention in Northern Ireland cannot succeed]. The conclusion here is contained in the last sentence "UN intervention in Northern Ireland cannot succeed". The main premises in support of this conclusion are "UN intervention in Northern Ireland could succeed only if there was a solution to which both parties would agree" and "There is no such solution". The main argument could be standardised as: 1: UN intervention in Northern Ireland could succeed only if there was a solution to which both parties would agree

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2: There is no solution to which both parties would agree C: UN intervention invention in Northern Ireland cannot succeed.

The occurrence of the premise indicator "since" tells us that the remaining premise, "Both sides are convinced of the rightness of their respective causes" is a premise in support of 2. The whole argument, then, is standardised as follows:

1: UN intervention in Northern Ireland could succeed only if there was a solution to which both parties would agree 2.1: Both sides are convinced of the rightness of their respective causes. 2: There is no solution to which both parties would agree C: UN intervention invention in Northern Ireland cannot succeed.

The main argument here is a conditional argument. Premise 1 is the conditional premise, so the first thing to do is work out which condition is the necessary condition and which is sufficient. Sentences involving "only" tend to emphasise what is necessary, so a good way to determine the conditions in a sentence involving "only if" or "only" is just to ask yourself what it is saying is necessary - which condition is it saying must hold for the other condition to hold. This sentence asserts that there being a solution to which both parties would agree is necessary for UN intervention to succeed. So we have:

Sufficient condition: UN intervention could succeed Necessary condition: There is a solution to which both parties would agree.

The name of the form comes from how the non-conditional premise relates to the conditional premise. The non-conditional premise in this conditional argument is "There is no solution to which both parties would agree". The second premise therefore denies the necessary condition of the first. This is one of the valid forms of conditional argument. So, this conditional argument is valid, since it denies the necessary condition.

One more long example: (8b) [It would be reasonable for Australia to criticise Japan for its continued whaling if Australia did not also have industries which involve killing animals.] But [many animals are killed for the sake of Australian industry], since [meat production is an important Australian industry], and [killing animals is necessary for the production of meat]. So [Australia cannot reasonably criticise Japan for whaling]. Here, we have two conditional arguments, where one is a subargument of the other. The argument can be standardised as follows:

1: It would be reasonable for Australia to criticise Japan for its continued whaling if Australia did not also have industries which involve killing animals 2.1 Killing animals is necessary for the production of meat

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2.2 Meat production is an important Australian industry 2: Many animals are killed for the sake of Australian industry C: Australia cannot reasonably criticise Japan for whaling.

The main argument and the subargument can each be evaluated by our methods above. First, the main argument. The conditional premise of the main argument is premise 1, which is of the form A, if B. It says that if Australian industries did not involve the killing of animals, that would be sufficient for its being reasonable for Australia to criticise Japan for whaling. The second premise is "Many animals are killed for the sake of Australian industry". This premise denies the sufficient condition of premise 1. (Remember that "denying" here just means "contradicts" or "says the opposite of", so it doesn't matter which premise contains the "not").

The main argument, therefore, is invalid, since it denies the sufficient condition.

The subargument is also a conditional argument .The conditional premise of the subargument is premise 2.1 "Killing animals is necessary for the production of meat". Here, the statement of the necessary condition is quite explicit. The non-conditional premise of the subargument, "Meat production is an important Australian industry", can be understood to affirm the sufficient condition. (If you're unsure of this, think of the argument in the following form: " Killing animals is necessary for the production of meat, Australian industry involves the production of meat, therefore Australian industry involves killing animals.") It follows that the subargument affirms the sufficient condition, and is therefore valid. A conditional argument may occur as a main argument or a subargument. Conditional arguments contain one conditional premise, and one premise which affirms [denies] one of the conditions. The conclusion will affirm [deny] the other condition. The valid forms are affirming the sufficient condition, and denying the necessary condition. The invalid forms are affirming the necessary condition, and denying the sufficient condition It doesn't matter which order the premises appear in the argument. There should be one conditional premise, and one premise which either affirms or denies one of the conditions of the conditional, but their order is unimportant.

4.4 Using Diagrams To Check Your Answers If you found diagrams helpful in identifying necessary and sufficient conditions, you may also find them useful as a way to check the validity or invalidity of conditional arguments. In the last lecture, a diagram was used to represent the necessary and sufficient conditions in the sentence: Only students are eligible for the discount.

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Now consider the following conditional arguments, based on that conditional statement:

(9a) 1 Only students are eligible for the discount 2 Ed is not a student C Ed is not eligible for the discount and

(9b) 1 Only students are eligible for the discount 2 Ed is a student C Ed is eligible for the discount.

Recall that the diagram represents the information given in the conditional statement. Using this diagram as an aid, we can see that the first argument is valid. The second premise tells us that Ed is not a student, so if we were to place Ed on the diagram, he would have to be outside the circumference of the larger circle. But then if he were outside the larger circle, he would have to be outside the inner circle as well, so he could not be eligible for the discount. The second argument, however, is invalid. We know from premise 2 that Ed is a student, but all that tells us is that Ed is somewhere inside the larger circle. It does not guarantee that he is also inside the inner circle. So it would be possible for the premise to be true, and the conclusion false - there is space on our diagram for someone who is a student, but ineligible for the discount.

4.5 Validity (Deductive Validity) In the last lecture, we established a way to decide whether a given conditional argument was valid or invalid, by looking at its form. The important feature of a valid argument was that the truth of its premises would guarantee the truth of its conclusion - it would be impossible for the premises to all be true, but the conclusion false. An argument is valid if it would be impossible for all the premises to be true but the conclusion false. If an argument is invalid, however, it would be possible for the premises to be true and the conclusion false. If an argument is invalid, then even if all the premises are true, this does not establish the truth of the conclusion.

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The analysis of validity and invalidity need not, of course, be restricted to conditional arguments. Consider, for example, the following argument: (1a) 1: Either whales are fish, or whales are mammals. 2: Whales are not fish. C: Whales are mammals

This argument is clearly valid, since it would be impossible for the premises to be true and the conclusion false. If we know that whales are either fish or mammals, and they're not fish, it follows that they must be mammals. Similarly, these are valid arguments: if their premises are true, their conclusions must also be true: (1b) 1Nothing is both a fish and a mammal 2 A whale is a mammal C A whale is not a fish.

(1c) 1 Whales live underwater 2 Whales are mammals C Whales are mammals which live underwater.

There are many other forms of argument whose validity we could assess by similar methods, and formal logic is concerned with exploring in detail ways of proving arguments valid or invalid. Our concern in this course, however, is to examine ways in which arguments may be good or bad which go beyond an analysis of their validity or invalidity. Consider, for example, the following argument:

(1d) Every flame I have ever put my hand in has burnt me. Therefore, if I put my hand in this new flame, it will burn me. Is this argument valid? Does the truth of its premise guarantee the truth of its conclusion? It does not guarantee its conclusion even if its premise is true, because it is possible that putting my hand in this new flame might not burn me. Perhaps this flame is entirely different from every other flame I have experienced, and would have some entirely different effect. It would be possible for the argument to have its premise true and conclusion false, so the argument is not valid. But is this a reason to doubt the conclusion? Should you really think that despite all the experience of the past, you should be unsure about the effect of this future flame, and about whether or not to thrust your hand into it?

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Even if we do not always think of our inferences in terms of explicit arguments, the argument above clearly involves a kind of reasoning we engage in all the time. We do feel confident about the conclusions drawn through such reasoning, although the truth of those conclusions may not follow, with absolute certainty, from the premises. Because arguments can be good, convincing arguments without being valid in the sense we have defined, it will be necessary to distinguish arguments which can be evaluated as valid or invalid from those where such an evaluation is inappropriate. Whether an argument is valid or invalid was said to be a matter of whether the conclusion of the argument would be guaranteed by the truth of the premises. So it will only be appropriate to assess an argument as valid or invalid if the arguer intends the premises and conclusion to be related in this way.

4.6 Deductive And Inductive Arguments The purpose of any argument, we have seen, is to convince an audience to accept a conclusion, by providing reasons or evidence. But although this is the common purpose of all arguments, there are different kinds of reasoning associated with different kinds of evidence that might be given for a conclusion. Two broad classifications of reasoning are deductive and inductive reasoning. Deductive and inductive arguments are distinguished according to the kind of support their premises are supposed to offer for their conclusions. An argument whose conclusion is supposed to follow, with certainty, from its premises is a deductive argument. The conditional arguments we looked at last lecture, and arguments (1a) (1b) and (1c) above, are all examples of deductive arguments. (Note that we don't say an argument is deductive only if its conclusion does follow with certainty from its premises, since that would not be true of invalid deductive arguments.) Why do deductive arguments have this feature? You will notice that for each of these deductive arguments, the information contained in the conclusion is, in a sense, already contained in the premises. For example if we know that all dentists are wealthy, and we know that Sam is a dentist, then we do already have enough information to know that Sam is wealthy. The point of the argument is just to draw out this fact for some purpose, and to make that proposition explicit. In drawing a conclusion deductively from a set of premises we do not go beyond the information we already have, we just make explicit some point which was implicit, or extract some particular piece of information from the content of the premises. This is why the conclusions of successful (that is, valid) deductive arguments follow from their premises with certainty. An inductive argument, on the other hand, is one in which the truth of the premises would make the conclusion likely to be true, or probable. In any argument, the premises will be used to attempt to convince you of the truth of the conclusion. The difference between deductive and inductive arguments in this regard is that someone giving an inductive argument will not be trying to convince you that the conclusion is absolutely certain; only that, because of the evidence given in the premises, you have good reason to believe that the conclusion will be true. Deductive arguments were described as either valid or invalid, but these descriptions will not be applied to inductive arguments. Inductive arguments may be described as strong or weak, and unlike deductive validity, inductive strength is a matter of degree. How strong an inductive inference is will be a matter of how much support the premises give for the conclusion. Inductive inferences may be strengthened or weakened with the addition of new evidence. The fact that the conclusions of inductive arguments do not follow with certainty from their premises should not be taken to mean that the conclusions of inductive arguments are things that we are really unsure about -- for many such conclusions there will be no real doubt. In the case of the flame example above there is no genuine doubt about whether the new flame will burn your hand -- the fact that an argument is inductive is not a reason to be unduly sceptical about its conclusion. It is just a fact that for many of the propositions we might want to establish, no absolute certainty is possible. The proponent of an inductive argument may not

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make the uncertainty explicit by prefacing the conclusion with "It is likely that ..." and in many cases it would seem inappropriate to do so. But, if challenged, someone presenting an inductive argument would have to admit that the conclusion did not follow with absolute certainty from the premises. Many common kinds of arguments are inductive, for example (2a) Every day I have driven along here there has been a speed camera just around the corner. So it will probably be there today as well. (2b) In recent polling, only 10% of those surveyed said they intended to vote for a minor party, and 5% for an independent. So an overwhelming majority of Australians will be voting for one of the major parties in the next election. (2c) The car won't start and the lights won't go on. It must have a flat battery. (2d) The patients who took the new drug recovered, on average, six days before patients treated with the standard medicine. Some of them did, however, complain of headaches or a rash, which had not occurred with the conventional treatment. The new drug, it appears, leads to a faster recovery, but may also cause minor side effects. (2e) The original movie was dreadful. The sequel has the same writer, the same director and the same cast. So it will be dreadful too. In each case, the conclusion is likely, given the truth of the premises, but it is not certain. It won't be certain because in drawing an inductive inference, we go beyond the information we already have, to draw a conclusion which involves new claims which were not already contained in the premises. This is why inductive arguments are less certain -- even a strong inductive argument with true premises may turn out to have a false conclusion -- but it is also why they are so important in arriving at new information. The means by which we will evaluate inductive arguments will be different to our means of assessing deductive arguments, since their strength or weakness is not just a matter of their form. The five arguments above are examples of the main kinds of inductive arguments we will be studying. Argument (2a) is an inductive generalisation, which uses a premise about something which has been experienced or observed to draw a conclusion about something which has not. Argument (2b) is a statistical generalisation. These are a kind of inductive generalisation, which use a premise about the prevalence of a certain property within a sample of experienced cases, to draw the conclusion that the prevalence of that property is similar in the population. Argument (2c) is an inference to the best explanation. From premises which describe certain observed facts, a conclusion is drawn on the basis that it is the best explanation for those observed facts. Argument (2d) is a causal argument. From observing relationships between certain kinds of events in a sample of observed cases, a general conclusion is drawn about causes and effects. Argument (2e) is an argument from analogy. An argument from analogy uses the similarity between two or more things or events in certain respects as evidence for a conclusion that they will also be similar in other respects. This argument suggests that because the two movies are similar in some ways (same writer, director and cast), that they will probably be similar in another way (dreadfulness). Each of these kinds of inductive argument will be explored over the coming lectures.

4.6.1 Deductive and inductive arguments: summary A DEDUCTIVE ARGUMENT: 1. Is one whose premises, if true, are supposed to guarantee the truth of its conclusion 2. May be valid or invalid 3. Will be valid if it would be impossible for the premises to all be true but the conclusion false

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4. Will be invalid if it would be possible for the premises to be true but the conclusion false. 5. Will be sound if it is valid, and has true premises (and therefore a true conclusion) 6. Does not go beyond the information contained in the premises. A deductive conclusion may be used to make explicit something which was implicit, but will not allow us to arrive at genuinely novel facts. AN INDUCTIVE ARGUMENT: 1. Is supposed to provide good reasons for thinking the conclusion is likely, or probable, but does not establish its conclusion with certainty. 2. Will not be evaluated as valid or invalid, but according to its inductive strength, which is a matter of degree. 3. Allows us to go beyond the information contained in the premises, to establish new information in the conclusion 4. Even if it has true premises, and is inductively strong, is still open to possible disconfirmation: We could find some new piece of evidence which shows the conclusion is false.

4.7 A Note On Types Of Reasoning The distinction between deductive reasoning and inductive reasoning is not always clear, and is not exhaustive. Conditional arguments are a clear case of deductive argument: the conclusion is supposed to follow with certainty from the premises; and some of the kinds of reasoning we will look at over the next few lectures are clearly inductive: we go beyond the things we actually have knowledge of, to draw new conclusions. The premises of these arguments are supposed to establish that these conclusions are likely to be true, or probable. Some kinds of reasoning do not fit into either of these categories: ethical reasoning, for example, is often intended to be persuasive without either being certain or based on probability. It is useful to be aware of the distinction between different kinds of reasoning, because whether an argument is intended as deductive, inductive, or something else will affect the way we should approach it in an evaluation.

SKILLS FOR WEEK 4   

You should be able to recognise a conditional argument, and determine its form, and whether it is valid or invalid. You should know the difference between deductive and inductive arguments You should be able to decide whether a given argument is intended as deductive or inductive, by deciding whether the truth of the premises is supposed to guarantee the truth of the conclusion, or merely to show that it is likely to be true

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5 INDUCTIVE ARGUMENTS (Week 5,6,7)

5.1 Overview There are five main types of inductive arguments 1. Inductive generalisation, which uses a premise about something which has been experienced or observed to draw a conclusion about something which has not. 2. Statistical generalisation. These are a kind of inductive generalisation, which use a premise about the prevalence of a certain property within a sample of experienced cases, to draw the conclusion that the prevalence of that property is similar in the population. 3. Inference to the best explanation. From premises which describe certain observed facts, a conclusion is drawn on the basis that it is the best explanation for those observed facts. 4. Causal argument. From observing relationships between certain kinds of events in a sample of observed cases, a general conclusion is drawn about causes and effects. 5. Argument from analogy. An argument from analogy uses the similarity between two or more things or events in certain respects as evidence for a conclusion that they will also be similar in other respects. This argument suggests that because the two movies are similar in some ways (same writer, director and cast), that they will probably be similar in another way (dreadfulness).

5.2 Inductive Generalisations We have seen that an inductive argument, unlike a deductive argument, does not purport to guarantee its conclusion on the basis of its premises, but is intended to convince the audience of the conclusion by offering as premises good reasons for believing that the conclusion is likely to be true. One of the most common and characteristic types of inductive inference is often referred to simply as inductive generalisation. In making an inductive generalisation, we make an inference from the observed to the unobserved. We use what we know from experience to justify our claims about things we have not yet experienced.

An inductive generalisation makes an inference from the observed to the unobserved. It is based on the assumption that things we have not experienced, will be similar to things of the same type that we have experienced.

The simplest case of inductive generalisation is when we conclude that all members of a certain class of things have a particular property, because all of the members of that class which we have observed have that property. If all the canaries we have ever observed can sing, for example, we may infer that all canaries sing. We may also conclude, on the same grounds, that a particular member of the class which we have not yet observed -- a canary we have never observed, or a future canary -- has that property.

The two main uses of inductive generalisations are: 

Generalisations about populations based on the sample of cases we have observed.

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

Inferences about the future, based on experiences of the past.

In making such generalisations, we make an "inductive leap", by using the experience we have had to reach conclusions about things we have not experienced. Unlike deductive inferences, inductive inferences allow us to go beyond the information contained in the premises, to arrive at new information in the conclusion. For example:

(1a) In all tests which have been conducted, water has boiled at 100 degrees celsius. So water always boils at 100 degrees Celsius. (1b) All the cows we have observed produce more milk in warm weather than in cold weather. So all cows produce more milk in warm weather than in cold weather. (1c) I have had an allergic reaction to every kind of cheese I've tried. So I'm probably allergic to all cheeses. (1d) Every winter so far, the tree has lost its leaves. So the tree is likely to lose its leaves every winter. (1e) There is usually a thunderstorm after a day as hot as today, so there may well be one tonight. (1f) Edna has always written good essays before, so this one's likely to be good too. (1g) No-one has ever been attacked by a koala. So koalas don't attack people.

All these sound like reasonable inferences, but notice that in none of these cases would the truth of the premise guarantee the truth of the conclusion: it would be possible for the premise to be true but the conclusion false. The premises only make the truth of the conclusion likely. This is a characteristic of any inductive argument - it will be possible that the conclusion might turn out to be false, even though the premises are true. Good inductive arguments, however, will usually be reliable.

5.2.1 Components Of An Inductive Generalisation An inductive argument uses as a premise a claim about cases which have been observed or experienced. This is the sample.From the premise about the sample, we draw a conclusion about the population, which is the entire set of observed and unobserved cases. In a generalisation to a particular individual (such as (1e) and (1f) above), we draw a conclusion about a particular member of the population. This can be thought of as a generalisation with an extra step: if we can infer that the entire population has a certain property, that we can infer that any given member of the population has it. So in the arguments above, the samples and populations would be as follows:

SAMPLE

POPULATION

Water boiled in the past Cows we have observed

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All the cheeses I've tried Every winter so far Past days as hot as today Edna's previous essays Koalas we have observed

All cheese All winter All days as hot as today (member: today) All Edna's essays (member: this essay) All koalas

The general form of an inductive generalisation is to say that because the members of the sample have had a certain property, for example boiling at 100 degrees, or not attacking humans, the members of the whole population, or some unobserved part of it, will also have that property. Underlying such inferences is the assumption that the cases we have observed are similar in relevant respects to the population as a whole, and that the future will in general resemble the past. We assume, that is, that the sample is representative of the population.

Inductive generalisations rely on the assumption that the sample is representative of the population in relevant ways. A sample is representative if relevant differences in the population are also reflected in the sample.

5.2.2 Evaluation Of Inductive Generalisations Reliable: An inductive generalisation is likely to be reliable if its sample is representative of the population in relevant ways. We will look in more detail in the next lecture about ways to ensure that a sample is representative, but in general, there are two closely related issues which need to be considered. 1. Sound: A measurement instrument which measures what it claims to measure 2. Reliable: A measurement instrument which is likely to give consistent results is: 5.2.2.1 (i) Is the sample large enough? Because the arguments above are inductive, the truth of their premises never guarantees the truth of the conclusion. However many koalas we may have experienced, the fact that none of them have attacked humans does not mean that this will hold for every koala -- perhaps the next koala we come across will be particularly vicious. But the more koalas we have come across, the more convinced we will become that the features we have observed in koalas we have seen, will be features of all koalas. One of the main things which needs to be considered in evaluating an inductive generalisation, then, is how large the sample is. Other things being equal, the larger the sample, the better supported the conclusion. When someone fails to take this into account, they may be said to be committing the fallacy of 'hasty generalisation', by drawing a conclusion which is not supported by the evidence. One reason this tends to happen is that people often place undue emphasis on particular cases which might be significant to them. A conclusion about "all dogs" based on evidence about your pet dogs alone will not be a very strong inference, but if you have found that the few dogs you have owned have all enjoyed ice cream, you may well be inclined to infer that this is true of all dogs. This is the kind of inference we often make, but it is not well justified, because the sample is too small to be reliable.

5.2.2.2 (ii) Is it likely that the sample reflects relevant differences in the population? Ensuring that a sample is large enough, however, is really only a means to the end of trying to make sure it is representative: the reason it is better to have a large sample is that it makes it more likely that the sample

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you have observed will reflect any relevant differences in the population. If you have only ever observed two or three koalas, your conclusion about all koalas will not be well supported, because the feature about them you have observed may just be a feature of those particular koalas. As your sample gets larger, it is more likely that any differences which exist in the population will be represented in your sample. To ensure a representative sample, however, we need to do more than make the sample large. A large sample may still be unrepresentative if it is skewed in some way. To consider again the conclusion you may want to draw about "all dogs", even a large sample might not justify your conclusion if your sample consists only of poodles, for example. There could be relevant differences between poodles and other dogs, which make the conclusion less probable. To make the inference stronger, you should either include a greater variety of dogs in your sample, or restrict your conclusion to a claim about "all poodles" instead of "all dogs". Another reason that having a large sample will help to ensure that your sample will be as representative as possible is that it helps rule out coincidences. If you rolled a die twice and you rolled a 6 both times, it would be premature to conclude that the die would always come up as a 6. With a small sample, any phenomenon you observe could be the result of coincidence. If you rolled the die 100 times the run of sixes would be very unlikely to continue. Larger samples tend to rule out coincidences. (If you did roll 100 consecutive sixes, this might give you reason to suspect that the die was loaded.) There is much more to be said on this matter, but we will defer a detailed discussion of evaluation of samples until we have considered one very important kind of inductive generalisation -- statistical generalisation.

5.3 Statistical Generalisations Many inductive generalisations are statistical generalisations. We have seen how induction can be used to draw a conclusion about a population from the sample of cases we have actually experienced. Statistical arguments are an important and common species of inductive argument. Their distinguishing feature is that rather than merely drawing an inference about whether the population has a certain property we have found in a sample, statistical arguments draw a conclusion about the distribution of a range of properties, or the frequency of occurrences of a certain property within a population. This is the kind of inference which is employed, for example, in political polling. If a sample is studied, and it is found that a certain percentage of voters intend to vote for the Liberal Party, then a conclusion may be drawn about the proportion of the population as a whole who are likely to vote for the Liberal Party. In market research, such reasoning is used to draw conclusions about the opinions of a population, based on the opinions of an appropriately selected sample. As with other inductive generalisations, the strength of the argument will depend partly on the representativeness of the sample, that is, the similarity between the sample and population. If the sample and population are not similar in relevant ways, then the statistical generalisation drawn from the argument may be inaccurate. Part of the role of a statistician, in conducting statistical research, is to ensure that the sample is relevantly similar to the population. While we do not need to go into the details which you would investigate in a statistics course, we will look at some of the issues which have to be considered in setting up, or evaluating, arguments based on statistical research.

5.3.1 Evaluating Statistical Generalisations Because statistical generalisations are a kind of inductive generalisation, the sorts of things which need to be considered in the evaluation of any inductive generalisations about the size and representativeness of the

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sample will apply to statistical generalisations. Statistical generalisations, however, frequently occur in the context of formal research, where the details of the premises are expressly given. In that context the means of evaluating them can also be stated more precisely. The reliability of a statistical inference will be affected by the adequacy of the sample, and of the research methods adopted. We will begin by considering issues related to samples, and then look at the evaluation of statistical research methods.

5.3.2 Evaluating Samples These considerations are primarily aimed at ensuring the representativeness of the sample with respect to the property under investigation. A good sample, we have seen in the discussion of other inductive generalisations, is one which is large enough, and which is representative of the population. We will now consider in more detail the reasons for the importance of these criteria, and the ways we may try to ensure that they have been satisfied.

5.3.2.1 (i) SAMPLE SIZE Other things being equal, the larger the sample, the better supported the conclusion will be. If we want to conclude that all dogs bark, we should ensure that we have observed a significant number of dogs, not just one or two. If we want to justify a claim that two thirds of voters prefer John Howard to Peter Costello, we will need to have asked a substantial number of voters for their opinion. The size of the sample will determine the margin of error in a statistical inference. The margin of error, expressed as a percentage, is the allowance you would have to make for inaccuracy in your statistical generalisation. The smaller the sample, the greater the likelihood of inaccuracy and therefore the greater the margin of error. Suppose, for example, your surveyed a sample of 100 voters, and discovered that 55% of them were planning to vote for a particular candidate. Even with an ideal sample, a sample of 100 will give you a margin of error of around 10%, so you could not conclude from the research you had conducted that 55% of the population would vote for that candidate. At best, you would be justified in concluding that 50-60% of voters in the population would vote for that candidate. It is not necessary for our purposes to know the details of how margins of error are calculated. (Anyone interested could have a look at http://nilesonline.com/stats/ : an introduction to statistics designed for journalists, but useful for any non-statisticians ). The important thing to remember is that a larger sample will give you a smaller margin of error, meaning that the prevalence of the property in the sample which is being used as the basis of the generalisation is likely to be closer to the actual prevalence of that property in the population. The size of the sample is often emphasised as being of great importance, but ensuring that we have a sufficiently large sample is really just a way of trying to ensure that the sample is representative of the population. How large is large enough will depend on the confidence we have that the sample is likely to be representative. The two main influencing factors in determining how representative a sample is likely to be are how the sample is chosen, and the homogeneity of the population with respect to relevant properties.

5.3.2.2 (ii) REPRESENTATIVENESS To ensure representativeness of the sample to the population, a researcher must make sure that any differences which exist in the population which might be relevant to the property under investigation are represented in similar proportions in the sample. This is easier said than done, but we will look at a few of

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the points which need to be addressed. Specifically: Is the population likely to be homogeneous with respect to the property under investigation? and How should the sample be chosen?

5.3.2.3 Is the population homogenous with respect to relevant properties? A population is homogenous with respect to a certain property, if that property is one which can be expected to occur fairly evenly throughout the population. If the property is one which is subject to a lot of variation in the population, you will need a larger sample to take account of possible differences within the population. A population which has a lot of variation with respect to a property, is said to be heterogeneous with respect to that property.

A population is homogeneous with respect to a property if that property is distributed evenly throughout the population. A population is heterogeneous with respect to a property if the property is unevenly distributed throughout the population. A larger sample will be needed for heterogeneous populations, to make sure that the differences in the population are reflected in the sample.

For example, the population "humans" is heterogeneous with respect to a property such as opinions on a particular topic, or favourite colours, or religious beliefs. If you wanted to get an accurate impression of the occurrence of such properties within the community, you would need to have a large and well chosen sample to make sure that all relevant differences were reflected in that sample. The same population, however, would be homogenous with respect to other properties, like having two kidneys. If you wanted to know how many kidneys human beings had, you would not need to examine very many, since physiological characteristics like this are known to be fairly constant across all human beings. Note that to make these sorts of decisions requires some background knowledge. It is only because we know something about physiological characteristics of humans that we are able to conclude that a small sample would be sufficient. This can lead to difficulties, because in some cases it is hard to know what properties of a population are relevant in determining the size of sample required for a particular investigation. What are the 'relevant properties'? This question is impossible to answer in any precise and general way, but in many cases what will be relevant to a particular investigation will be fairly clear. For example, if we wanted to investigate the voting intentions of Australians, such characteristics as age and socio-economic background might be relevant, but characteristics such as eye colour and singing ability will presumably not be. Once we have an idea of how large the sample would have to be to reflect relevant differences in the population, we still need to think about how the sample should be chosen, to ensure a representative sample which is not biassed in any way which might compromise the reliability of the research.

5.3.2.4 How was the sample selected? The manner in which a sample is chosen will often affect its representativeness, because some methods of sample selection are more likely to lead to biassed samples than others. Examples of good sampling methods are random sampling, and stratified sampling: Random samples: A sample is random if every member of the population has the same chance of being part of the sample. Assuming the sample is sufficiently large, having a random sample is the best way to ensure that there are no biases built in.

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Random samples are particularly beneficial if it is not obvious what properties are relevant to the characteristic you are investigating. The problem with random sampling is that it is impractical for many purposes. Stratified samples: Where random sampling is not possible, a stratified sample is the next best thing. In a stratified sample, researchers determine what properties they think are relevant to the property they are investigating, and construct a sample which has a similar distribution of those properties to the population. Suppose, for example, a bank wanted to get an accurate impression of how it was viewed by its customers. It would be advisable to choose a sample which was stratified in such a way that it represented the different kinds of customers (hose with transaction accounts, credit cards, residential loans, investment loans, business accounts and so on) in similar proportions to their actual representation in the population of the bank's entire customer base. If the sample were skewed in favor of home loan customers, for example, or businesses, the results obtained from the research would not be generalisable. Examples of sampling methods which can be problematic are choosing samples in a way which is relevant to the property under investigation, and self selection.

Was the sample chosen in a way which was relevant to the property under investigation? (Is it likely that the sample are atypical with respect to that property?) Be cautious of samples which have been selected in such a way that the sample is likely to over or under represent properties relevant to the one under investigation. One famous example of this problem in political polling occurred in the 1936 US presidential election. A magazine sent out a questionnaire to determine voting intention, and received two and a half million responses. Based on this very large sample, they predicted a landslide win to Landon over Roosevelt. In fact, there was a landslide in favour of Roosevelt, who won with 62% of the vote. The accepted explanation for what went wrong in this sampling was that the questionnaires were mailed out to people selected from the telephone book, and club membership lists. But in 1936, only wealthy Americans had telephones, and only the wealthy were club members, so the less affluent voters were significantly underrepresented in the sample. Roosevelt, the Democrat candidate, received a greater proportion of the votes from less affluent Americans, with the result that he won the election, contrary to the poll's prediction. A local example of this sort of problem was a phone poll conducted by Triple J in 1992, on the subject of whether or not marijuana should be decriminalised. They had over 10,000 responses, of which 96% were in favour of decriminalisation. This is a large sample, but unlikely to be representative, because it might be expected that Triple J's audience is not representative of the population of Australians in their attitude towards marijuana. Another reason that this sample would not be representative, is that it was self-selected.

Was the sample self-selected? A sample is self-selected if the members of the sample chose to be part of the sample. Phone-in polls are a common kind of self-selected sample. The reason that they are generally unrepresentative is that only people who feel strongly about a particular issue would bother calling in. This means that the views of those who ring in are unlikely to represent the views of the population as whole. (5a) After Princess Diana's death in 1997, The People, a British Sunday newspaper, conducted a phone poll on the question: "Were Diana and Dodi killed as part of a secret operation?". They had nearly 6000 responses, of whom 98% answered "yes". In that case it may seem obvious that the people who rang up are unlikely to reflect the views of the population, but this sort of problem often occurs in more subtle ways. These are examples of poll results from polls conducted on Channel Nine's Sunday program:

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(5b) "Do you believe you have ever been sick or suffered illness because of bad air on planes?" (4/6/00) Result: Yes - 63.5%; No - 36.5% (5c) "Should the Reserve Bank intervene to ensure the banks deliver lower credit card transaction fees?"(25/3/01) Result: Yes - 92.5%; No - 7.5% (5d) "Would you donate a kidney for a friend or loved one?" (26/11/00) Result: Yes - 83%; No - 17% None of these results are likely to be representative of the views of the population. In all of these polls, people who would vote "yes" are likely to feel more strongly about these issues, and are therefore more likely to vote at all. (Even given the option, people don't tend to spend time and money ringing up to say "I don't know" or "I don't care".) In the first case above, it seems unlikely that many people would bother to ring up to say that aeroplane air had not made them sick. This poll could certainly not be validly used to infer that 63.5% of people had suffered illnesses because of bad air on planes. In the second case, again, those people who wouldn't agree with this proposal would probably mainly be those who didn' t think that credit card transaction fees were an important enough issue for the Reserve Bank to become involved. They would also be unlikely to think it was an important enough issue to cast their vote on. In the third example, the issue is not a trivial one, but it seems unlikely that people would ring up to say that they would not be prepared to donate a kidney. Again, the people who would be most likely to vote are the people who would be going to vote yes. There is also the possibility that this result would not reflect the proportion of people who would actually donate a kidney, because it is far easier to ring in and say that you would donate a kidney, than to actually commit to doing so. Self-selection will quite often be an issue to some extent, because in most cases people cannot be forced to take part in a study, so respondents will have selected themselves by agreeing to take part. This will be something to think about with market research conducted by telephone, for example, because such a large proportion of people who are invited to take part will not do so. When evaluating research, think about whether there are likely to be relevant differences between the people who respond, and those who don't. These are the sorts of issues which need to be considered in relation to the adequacy of the sample, when evaluating statistical arguments. It is also important to think about the adequacy of the research methods used.

5.3.3 Evaluating Statistical Research Methods 5.3.3.1 What was the measurement instrument? The measurement instrument is whatever is used to collect the data: for example questionnaires, anonymous questionnaires, tests, telephone surveys, phone in polls, face-to-face interviews or third party observation.

Reliable vs Valid

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A good measurement instrument is one which is both reliable and valid. Reliability is just a matter of consistency. A reliable measurement instrument is one which would give the same results under the same conditions. A valid measurement instrument is one which measures what it claims to measure. An example of a measurement instrument which is sometimes claimed to be reliable, but not valid, is IQ testing. IQ testing is reliable, because if you give someone a series of IQ tests, they will generally get similar results each time. Critics have claimed, however, that the tests do not accurately measure intelligence, because they only test a particular kind of intelligence. Those critics claim, therefore, that IQ tests are not valid as a measure of intelligence. When you are evaluating a piece of statistical research, consider whether the measurement instrument is likely to have been reliable and valid. Any kind of measurement instrument might have advantages and disadvantages. What kind of method will be appropriate will depend to some extent on what you are researching. For researching sensitive issues, for example, a measurement instrument which allows people to respond without identifying themselves might be more likely to get accurate results than a method of research which relied on people discussing their responses with a researcher. For more trivial questions, ( "What is your favourite breakfast cereal?"), researchers would be likely to get a much better response rate by conducting face to face interviews, than by sending out questionnaires which had to be filled out and returned. Political polling agencies differ in their opinions about what is the most reliable measurement instrument. The three main polling agencies in Australia are Newspoll, A C Neilson and Roy Morgan Research. Newspoll and Nielson conduct telephone polls to gauge voting intentions, because these have the advantage of giving a more immediate account of the opinions of the electorate, and the subjects can be randomly selected. Roy Morgan research, however, claim that the most accurate way to measure voting intention is to have subjects write their voting intention down, and putting it anonymously into a box, since that most closely replicates the action of voting. (See box below). Even when statistical research is conducted by professional agencies, it has been found that some measurement instruments provide much more accurate results than others. Telephone polls, for example, have been found to reflect much more dramatic swings than face-to-face interviews. This difference was clearly exhibited in political polls conducted by Roy Morgan research on the 15th-16th of September 2001, the weekend after the terrorist attacks in New York, around the time of the Tampa refugee crisis and the collapse of Ansett. Roy Morgan conducted two polls on the same weekend - one phone poll and one face-to-face poll. The phone poll reported Federal voting intention on a two-party preferred basis at 60% for the Coalition, against 40% for Labor. This was the first result to be made public and was widely reported as showing a significant swing -- the best Coalition result in twenty-five years. When the results of the face-to-face polls were released, however, the split was 49% to 51% ... in favour of Labor. This is despite the fact that the polls were conducted simultaneously by the same research agency. References: More detail about the results of these polls is available at Roy Morgan's website: results of telephone poll "Electors Strongly Back Howard Government Following Week Of Turmoil" (http://www.roymorgan.com/polls/2001/3445/) results of the face-to-face poll "Howard's New Popularity Not Reflected in Voting Intention" (http://www.roymorgan.com/polls/2001/3448/)

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Also have a look at a paper by Gary Morgan about possible reasons for such differences "Telephone polls have a history of inaccuracy" (http://www.roymorgan.com/speeches/19951606.html) [Postscript: in the 2001 Federal election, it turned out that the final telephone polls were more accurate. The last Morgan poll was still predicting a Labor victory, while the Newspoll and Nielson polls predicated a win to the Coalition. For Morgan Research's discussion of this result, see: Did the debate over refugee boat people in the last two days change the electorate or was the Morgan poll wrong? ] (http://www.roymorgan.com/polls/2001/3472/)

5.3.4 What was tested? What questions were asked? It is also important to consider exactly what was tested, or what questions were asked. How has the phenomena under investigation been operationalised by researchers? Have they asked appropriate questions, to learn what they want to learn? Some common problems are: 1) Questions may be phrased in an imprecise way, so that different respondents may interpret the question differently: (7a) Do you watch a lot of television? To ensure that all respondents are responding to the same question, it may in such cases be necessary to give a more specific operational definition of any concepts which might be open to multiple interpretations. So the concepts of "a lot of television" should be operationalised, as, for example, " more than x hours a week", where the number of hours per week is specified. By asking the question as it is phrased above, you would not be able to infer anything about the amount of television people watched, as the question is too subjective.

2) Questions may be asked in a persuasive or loaded way, to suggest a particular answer. (7b) "Is the Federal government's funding of schools appalling?" " Yes or no." (Ninemsn.com 10/9/01) (7c) " Will John Howard's proposed baby bonus buy your vote?" (Ninemsn.com 29/10/01) Loaded questions will include presuppositions which may make it difficult to answer an apparently straightforward question with a "yes" or "no". For example someone who thought the 'baby bonus' was a good idea and did think that it provided a good reason to vote for Howard would still be unlikely to want to answer "Yes" to the question in example (7c).

3) Questions may be asked in a way which places unrealistic limitations on the possible responses, so that people may be unable to respond accurately: (7d) Two days after the terrorist attacks on New York, Netscape had a poll on the question: "How do you feel about Tuesday's terrorist attacks?" Respondents could choose one of "angry", "sad" or "shocked" (Netscape.com 14/9/01) This is not likely to elicit very meaningful responses, since most people probably felt a combination of all of these things. (If a similar number of people chose each of these responses, would it be reasonable to report that, for example, "Only one third of respondents to the survey felt sad about the attacks?")

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Netscape have a disclaimer on their site where the poll results are given, stating that: "Netscape polls reflect the views of those who choose to respond and are not scientifically valid surveys." But do they even accurately reflect the views of those who choose to respond, if questions are asked in a way which places artificial restrictions on the possible responses?

5.3.5 Do The Statistical Results Justify The Conclusion? One final thing to think about when evaluating a piece of statistical research, is whether the evidence given actually proves what it claims to prove. This is partly an issue of whether a valid measurement instrument is used: if you dispute the validity of IQ tests, for example, then you might question whether research based on IQ tests really justifies any conclusion about intelligence. A more common problem, however, particularly in media such as newspaper reports of statistical research, a conclusion will be drawn which is not really justified by the evidence. Even if the researchers claims were quite modest, a more sensational claim might be reported.

(8a) A study conducted in 1996 asked Australians to rank what they took to be the major problems facing Australia for the coming year. The number one issue concerning Australians was the environment. A similar study conducted in 2001 found that environmental issues had slipped to number 3. This is reported under the headline "Australians becoming less concerned about environment." Assuming that the studies themselves were well conducted, is this conclusion justified? 5.3.5.1 Examples: A few years ago, Herron paracetomol had an advertising campaign focussing on the fact that Herron is Australian owned, while the leading brand of paracetomol, Panadol, is foreign owned. As part of one television advertisement, they had a telephone poll, in which viewers were invited to call in and vote for one of the following:

"YES. It does matter that Herron keeps all profits in Australia" or "NO. It does not matter that Panadol sends millions of dollars back to a multi-national parent."

The results yielded by the poll in this advertisement would be unlikely to accurately represent the Australian public's attitude towards the issue of Australian vs foreign ownership. Why? Think of two reasons. One Nation's website hosts a "People's poll", where visitors to the site can vote on various issues. In the information about the people's poll, the question is raised "Do you think the results will be a good representation of people's opinions? The answer which is given is: "We believe the People's Poll is an excellent way for people to voice their opinions. This is a new initiative and we will be monitoring the results carefully. One Nation has always been well informed about the views of the people. We believe the People's Poll will enhance our traditional feedback strategies. People

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should be allowed to express their views online if they wish." Is this an adequate response? What issues about the sample might be relevant to deciding whether the results of the polls were representative of the views of the Australian public?

Exercise: Find an example of a flawed survey question or poll in a newspaper or website, and post it to the Discussions board. 5.3.5.2 Evaluating statistical research: Summary The Sample: 1. Is the sample representative? o A sample is representative if relevant differences in the population are also

reflected in the sample. o o o o

Large enough How was it selected? Was it random? Stratified? self-selected ?

The research: 2. What was counted / collected o What data was collected? o 3. How was it counted/collected o What was the measurement instrument?  Reliable and Valid? o Some measurement instruments are more reliable than others. o What was tested? What questions asked o What questions were actually asked?  loaded,  Imprecise - interpreted differently by different people  Unrelaistic limitations on the possible results – people can not respond accuratly

The Conclusion: 4. Is the conclusion which has been drawn justified by the results of the research? Does the research really show what it claims to show?

5.3.6 Example: This is an extract from a report about a survey on children's drinking habits, which appeared in the Sydney Morning Herald on 25 October 2001: "Underage binge drinking rampant

More than eight in 10 children between 12 and 17 have tried alcohol, and 6 precent of boys admit to being heavy drinkers, a new survey reveals. The survey, of more than 7,000 students in 122 schools in NSW, also shows about one-third of students had drunk "hazardous" amounts of alcohol in the two weeks before the survey was conducted."

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This is all the information which was given about the survey in the newspaper report. This does not mean that the survey itself provided no further details, but there are questions we would need answered before we were able to interpret and evaluate the results of the survey as presented. Consider some of the points which would have to be queried, in relation to the questions suggested above. The sample: 7000 students is a large sample, and we are told that they were drawn from 122 NSW schools in NSW. We are not told, however, whether the schools were selected in a representative way. There may be differences between, for example, urban and rural schools, affluent and poorer schools, or private and public schools. Within those schools, were girls and boys appropriately represented? Were the children selected or did they volunteer? Did they find their 7,000 students at Schoolies' week on the Gold Coast? The population: The conclusion in this report concerns "children" generally, but it is unwise to generalise too far beyond what you have studied in your sample. The sample consisted only of NSW school children, so the population should really only extend as far as NSW school children as well. The measurement instrument: The report did not specify how the results were obtained, and this seems to be a case where the way the research was conducted may have an influence on the honesty with which the subjects answer the questions. It seems likely that many young teenagers would give different responses to questions about their drinking habits in the presence of a parent or teacher, to those they would give in the presence of peers they were trying to impress. To make face-to-face research reliable, you need to ensure that there was nothing about the circumstances in which the interview is conducted which would influence the answers the subjects would give. (This is something to think about when evaluating research into anything which is illegal, immoral, or even just embarrassing. Was the research conducted in a way likely to elicit honest responses?) The operationalisation: It is unclear what is meant by, for example, "heavy drinkers" and "hazardous amounts". These would have to be more precisely defined. Also, what is meant by having "tried" alcohol? If this includes any alcohol at all (a champagne toast? a liqueur chocolate? communion wine?), it is perhaps rather surprising that only 80% of children had tried alcohol. Is the conclusion justified? The headline "Underage binge drinking rampant" seems, as headlines often do, to overstate the case a bit. It is true that a high proportion of children were found to have "tried" alcohol, but, as was suggested above, this seems to be a less sensational claim. And while it may be of concern that any of the school children were classed as heavy drinkers, 6% of boys does not really justify the claim that it is rampant. The best support for this claim comes from the final sentence, which asserts that one third of the students had consumed "hazardous amounts" in the two weeks before the survey. Other problems: One final concern about this report is that if it was really supposed to give us information about whether we as a society should be concerned about children's drinking habits, then the classification of subjects should probably be done a bit differently. While the legal drinking age is 18, attitudes towards 17 year olds trying alcohol are likely to be different from attitudes towards 12 year olds drinking. So it would be

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more informative to have the group broken up into smaller age divisions, rather than just "12-17 year olds".

5.3.7 Statistical Syllogisms Before we leave statistical arguments altogether, there is one other common kind of argument which involves statistics: the statistical syllogism. While a statistical generalisation draws a statistical conclusion on the basis of particular observed cases, a statistical syllogism uses a statistical premise to draw a conclusion about an individual.

For example: 95% of trade union officials vote for the Labor party. Bill is a trade union official Therefore Bill votes for the Labor party. In such an argument, the statistical generalisation itself may well have been arrived at by an inductive argument, but the conclusion itself is also derived by an inductive inference. The fact that Bill is a trade union official and 95% of trade union officials vote Labor does not establish with certainty that Bill votes Labor, but makes it likely.

5.3.7.1 Evaluating statistical syllogisms 5.3.7.1.1 (i) How strong is the statistical premise? One thing which needs to be considered in evaluating a statistical syllogism is the strength of the statistical premise. The argument above seems quite persuasive, because 95% is a very high proportion. If only 60% of trade union officials voted Labor, the conclusion that Bill votes Labor would be much less well supported.

5.3.7.1.2 (ii) Is the individual likely to be representative of the population? As was the case with statistical generalisations which went from particular cases to a general conclusion, another important factor in evaluating the strength of a statistical syllogism is how representative the particular case is of the general. This argument would be weakened if we had reason to believe that Bill was in some relevant way atypical, and unrepresentative of the population of all trade union officials. If Bill, for example, is wearing an "I love John Howard" t-shirt, this would count as negatively relevant evidence, or counterevidence. Knowing this fact about Bill would outweigh the strength of the statistical premise, since a fact about Bill gives us more direct knowledge of Bill than a fact about a class to which he belongs. Even if 95% of trade union officials do vote Labor, Bill's t-shirt might provide strong evidence to believe that he was part of the other 5%. Remember that for any kind of inductive argument, there is always the possibility of finding some piece of contrary evidence which would show that although the premises may be true, we have good reason not to accept the conclusion. When evaluating such an inference, think about what would count as contrary evidence. Do we have reason to believe that there might be such counterevidence?

SKILLS FOR WEEK 6

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You should be able to: Identify inductive generalisations, and be able to identify their samples and populations evaluate inductive generalisations Identify statistical generalisations Evaluate statistical research, considering such issues as the representativeness of the sample, and the adequacy of the research methods used.

5.4 Inference To The Best Explanation When drawing a conclusion inductively from a set of premises, we are making an inference from what we already know to a conclusion about what is likely to be the case in some situation about which we do not yet have knowledge. In arguments which make inductive generalisations, underlying these inferences has been the belief that things we have not experienced are likely to be similar to other things which we have experienced, where those things are alike in various other ways we have deemed relevant. Our use of inductive reasoning, however, goes beyond its uses in making simple generalisations from samples to populations. A general kind of inductive reasoning of this sort is employed in many - perhaps most - of the inferences we make about the way things are. Given any set of observations, we may draw conclusions which are not guaranteed, but provide the most reasonable understanding of the situation. This kind of inference is sometimes referred to as inference to the best explanation.

Consider one of the first arguments you saw in this course: (1a) There are some grey shapes under the water. There must be some dolphins there. On what grounds would we accept this inference? This is an inductive argument, but is it simply an inductive generalisation? It could be, if the argument is based on the principle that whenever we have seen grey shapes under the water in the past there have been dolphins. But there seems to be more going on here, and more background information we are using in drawing our conclusion. Even if we have never seen such grey shapes before, and we therefore lack relevant past experience, if we know that this is an area where there are a lot of dolphins and the grey shapes are more or less dolphin shaped, and moving at a speed we know dolphins tend to swim, then we may conclude that there are dolphins. We would draw this conclusion because given the knowledge we have, the best explanation for the shapes we observe is that there are dolphins. Here are some other examples of arguments where the conclusion is justified because it is the best explanation of a phenomenon described in the premises, given the situation as reported: (1b) There is a thunderstorm outside, and we're having a blackout. Some powerlines must have been damaged. (1c) As the number of feral cats in the area was brought down, the population of mice increased. The feral cats must have been eating the mice. (1d) Ever since he was hit by the bus, the patient has been unable to move his legs. He has probably suffered spinal damage. There are no simple rules which will tell you what the best explanation is for a set of observations. When you come across an argument which seems to be making an inference to the best explanation, you need to think about whether there are any other explanations which seem equally good, or better. Try to think of better explanations than the ones which have been inferred here:

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(1e) This liquid looks like water, but even when its temperature was brought down to minus five degrees Celsius, it did not freeze. Water must not freeze at zero degrees Celsius after all. (1f) My eyes are red, I have a massive headache, and I can't remember anything that happened after the end of the pub crawl last night. I must have been abducted by aliens. (1g) John's essay is exactly the same -- word for word-- as the one his older brother handed in for this subject last year. Genetics must play a more significant role than we thought in determining essay writing skills. (1h) There were three burglaries committed in the area last week. In each case, there was a single burglar, and the descriptions of the burglars given by the victims have been very similar. They must have been identical triplets. The sorts of criteria which are relevant in deciding whether one explanation is better than another include plausibility, consistency with other beliefs, and simplicity. As with any inductive argument, however, even what we take to be the best explanation may turn out to be wrong. Examples: Sherlock Holmes Although Holmes himself often refers to his inferences as deductions, many of Sherlock Holmes' inferences are really inferences to the best explanation. In these examples from two of the Holmes books by Arthur Conan Doyle, Holmes draws a conclusion from the evidence he has observed. There would be other explanations for the phenomena he has observed, but he draws as a conclusion what he takes to be the best explanation. In the first example, Holmes concludes that Watson has come from Afghanistan. "I knew you came from Afghanistan. From long habit the train of thoughts ran so swiftly through my mind that I arrived at the conclusion without being conscious of intermediate steps. There were such steps, however. The train of reasoning ran, ‘Here is a gentleman of medical type, but with the air of a military man. Clearly an army doctor, then. He has just come from the tropics, for his face is dark, and that is not the natural tint of his skin, for his wrists are fair. He has undergone hardship and sickness, for his haggard face says clearly . His left arm has been injured. He holds it in a stiff and unnatural manner. Where in the tropics could an English army doctor have seen such hardship and got his arm wounded? Clearly, in Afghanistan.’ The whole train of thought did not occupy a second. I then remarked that you came from Afghanistan, and you were astonished." From A Study in Scarlet, Chapter 1 In the second example, Holmes astonishes Watson again by establishing that Watson has returned to his medical practice, has recently been wet, and has a clumsy servant. "[M]y eyes tell me that on the inside of your left shoe, just where the firelight strikes it, the leather is scored by six almost parallel cuts. Obviously they have been caused by someone who has very carelessly scraped round the edges of the sole in order to remove crusted mud from it. Hence, you see, my double deduction that you had been out in vile weather, and that you had a particularly malignant bootslitting specimen of the London slavery. As to your practice, if a gentleman walks into my rooms smelling of iodoform, with a black mark of nitrate of silver upon his right forefinger, and a bulge on the right side of his top-hat to show where he has secreted his stethoscope, I must be dull, indeed, if I do not pronounce him to be an active member of the medical profession." From The Scandal in Bohemia, Chapter 1

5.4.1 Inference To The Best Explanation In Scientific Reasoning One of the most important contexts for inference to the best explanation is in scientific reasoning, where a hypothesis or theory is proposed to explain a set of observed phenomena. Once an explanation has been proposed, scientists can then test the hypothesis with further experimentation. This process of testing is a

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way of ruling out rival explanations, to ensure that the one which has been proposed is the best explanation, and the theory which is most likely to be correct. Perhaps the most important use of inference to the best explanation in scientific reasoning is in establishing whether two phenomena are causally related.

5.5 Causal Arguments In our study of inductive reasoning, we have examined arguments including statistical arguments, and inferences to the best explanation. We will now turn to causal reasoning, which involves elements of both. This is the kind of reasoning which leads us to conclude that one thing or type of thing causes another: eg smoking causes heart disease; pornography causes consumers to commit crimes of sexual violence against women; watching too much television causes a reduced attention span; heat causes metals to expand. What sort of evidence do we require to justify such conclusions? These arguments involve an element of statistical generalisation, because we draw a general conclusion about causes and effects from our observations of a sample. So all the criteria we looked at before about evaluating samples and populations are still important. But there are also other things we need to think about in relation to causal arguments because it is not simply a matter of generalisation. We do not get direct evidence of a "cause" and an "effect" through the observations we make. What we need to establish, then, is that the causal explanation is the best explanation for what we observe.

5.5.1 Correlations If two phenomena are generally found to occur together, they are said to be positively correlated. The identification of a correlation is often the first step towards the identification of a causal relationship. For example, we believe that smoking causes lung cancer because there has been found to be a significantly higher incidence of lung cancer among smokers than among non-smokers. Smoking is positively correlated with lung cancer. Finding a correlation between two things, however, is not enough to establish a causal connection. We also need to be convinced that the causal explanation is the best explanation available. Giving a causal argument involves:  

using statistical methods to find correlations considering whether the causal explanation is the best explanation for that correlation.

The first step towards establishing that there is a causal connection between two phenomena is to find that there is a correlation between them. It is not enough to show that one thing was followed by another, we need evidence of some regular correspondence between the two events to justify a claim that they are causally related.

To assume prematurely that X causes Y, merely because X happened then Y happened is to commit the post hoc fallacy (from the Latin post hoc, ergo propter hoc, "after this, therefore because of this"). This is a fallacy because mere temporal order is not enough to guarantee a genuine correlation between two types of events, and even if there is a correlation, there may be explanations which are not causal. Research should be conducted in such a way that it establishes where genuine correlations occur, and, where possible, gives enough information about the correlation to justify the claim that the connection is a causal one. We will look first at the statistical methods used to establish correlations, and then at how we

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can see whether any correlations which are found are evidence of the causal relationship we want to establish. 5.5.1.1 Samples and populations Causal research generally proceeds like other statistical research. If we want to make a general claim about causes and effects in a population, we begin by finding the relationship between the supposed cause and effect in a sample. As with other statistical research, the reliability of that generalisation will depend on the representativeness of the sample. Look for any relevant differences between the sample and population. These will weaken the inference. Example: Research conducted in Canada in 1977 found that 50% of laboratory rats fed large doses of saccharin developed bladder cancer. From this evidence about a sample, a conclusion was drawn that saccharin would also cause cancer in humans, and as a result the use of saccharin was banned or restricted in a number of countries. In the 1990s, these restrictions were lifted, when it was found that there was no correlation between saccharin consumption and cancer in humans, and that it was particular features of rat physiology which made them susceptible to saccharineinduced tumours. The conclusion drawn about a population including humans from a sample of rats was unreliable in this case, because there turned out to be relevant differences between the sample and population. 5.5.1.2 Test groups and control groups Suppose we want to show that X causes Y. It would not be enough to examine a sample of things with the property X, and show within that group there was a high incidence of property Y. To establish the correlation we would need to show that there are more Ys among Xs than among non Xs. For example to show that smoking causes lung cancer, you would need to show not just that there was a significant incidence of lung cancer among the smokers, but that there was a higher incidence of lung cancer among smokers than among non-smokers. The observation of the smokers alone will tell you nothing unless you have something to compare them to. For that reason, in causal research, the sample is divided into two parts - the test group and the control group. The test group is the group which has the feature whose causal properties you want to investigate. The control group is the group which does not have that feature. To make the comparison fair, and give the most accurate results, the test group and control group should be as similar as possible apart from the presence or absence of the suspected causal factor. The test group and control group should be similar in all relevant ways, except that the test group has the suspected causal factor and the control group does not.

The selection of test groups and control groups can be either active or passive. For some purposes, we can actively construct the test and control groups by giving the alleged cause to one part of the sample and not the other. For other purposes, we must passively make observations of correlations already occurring. 5.5.1.2.1 Active test group selection Test and control groups are actively selected when researchers randomly divide the sample in two, and give the supposed cause to one group, making that the test group. When it is possible to actively construct the

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test and control groups, this allows researchers to have the most control, and helps to ensure that there will be no other relevant differences between the test group and control group. Examples of research where the test and control groups can be actively constructed are experiments conducted in laboratories, where all the other factors can be controlled, and research using people where the causal factor is not considered harmful. A blind study is one where even the subjects in the test and control groups do not know which group they are in. In medical research, for example, the test group may be given a drug which researchers want to test, and the control group is given a fake drug, or placebo. None of the subjects would know whether they had received the real drug or the placebo. This is to ensure that any differences measured between the test and control groups are the effect of the drug, and not psychological effects of people thinking they are being cured. 5.5.1.2.2 Passive test group selection In some cases, however, it is not possible to construct test and control groups by providing the supposed cause to one group and not the other. In such cases, it is necessary to passively select a test group and control group by finding subjects with and without the supposed causal factor, to discover whether there is a higher incidence of what you take to be the effect in the former group than the latter. This may be necessary for practical or ethical reasons, for example: (4a) If, for example, you wanted to work out whether unusually heavy rain had an effect on wheat yields, you cannot do this by 'giving' one area particularly heavy rain. You would have to find wheat-growing areas which had had heavy rain, and use them as your test group, comparing their yields with otherwise relevantly similar areas which had average amounts of rain. (4b) If you want to find out whether people who had pets as children suffer from more respiratory problems in old age, it would be impractical to investigate this by giving people pets and waiting sixty or seventy years. Even apart from the practicality, it would be unlikely that the test and control groups which were relevantly similar as children would still be relevantly similar as adults, since other aspects of their lives may ultimately have a greater effect on their respiratory health than whether they had pets as children. A better way to carry out this research would be to find elderly people, some of whom had had pets as children and some not, but who were similar in other relevant respects. This selection would be passive, in the sense that the researchers did not provide the alleged cause, but chose their test and control groups to have the properties they required. In those two cases, it would be impossible to actively divide the sample into test and control groups for practical reasons. The active construction of a test group by providing the suspected cause may also be impossible in some cases for ethical reasons: (4c) Research has been conducted recently into the question of whether painkillers taken during pregnancy increase the incidence of miscarriage. If this is suspected, it would be unethical to give pregnant women painkillers to see if they had miscarriages. But given that some women are taking painkillers, they can be used as a test group to see if they have a higher incidence of miscarriage than other women. 5.5.1.2.3 Are there any relevant differences between the test group and control group? Just as it is important to try to make the sample representative of the population, it is important to try to make the control group and test group as similar as possible (apart from the presence in the test group of whatever you are investigating). Many flawed causal claims are made because there were differences between the test and control group other than the one which was being investigated, so that the differences which were subsequently observed may have been a result of something other than the suspected cause. When you are evaluating a causal argument, think about whether there are likely to have been relevant differences between the test group and the control group, other than the one under investigation.

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eg Researchers have found a correlation between body piercing and HIV infection, and this has led some to conclude that HIV may be transmitted through body piercings. Another explanation which has been suggested, however, is people who are inclined to have body piercings may also be more inclined than the rest of the population to engage in other behaviour such as IV drug use which would be relevant to the risk of HIV infection. The suspicion, then, might be that the higher incidence of HIV among people with piercings is in fact a result of relevant differences between the test group of pierced people and the unpierced control group, and this is something which would have to be kept in mind in selecting those groups. This is an situation where it would be unethical, and impractical, to actively construct a test group by selecting a sample of people and then randomly piercing half of them. It would be unethical because if there is a suspicion that the action might lead to your test group becoming infected with HIV, it would be unreasonable to expose them to that risk. It would also be impractical, because they would be unlikely to go along with it. In passively choosing your test and control groups, therefore, you would need to control for any other factors which might be relevant to HIV infection, which means that you would have to make sure that the test group and control groups were evenly matched with respect to these factors. Taking these things into consideration, the methods of statistical research may be used to draw a conclusion about a correlation in a population from an observed correlation in a sample. The next step is to establish whether this correlation is evidence of a causal relationship.

5.5.2 When Can A Cause Be Inferred From A Correlation? Suppose we have found, using appropriate statistical research methods, a positive correlation between two phenomena, X and Y. This is not yet sufficient to establish that X causes Y, because now we need to ensure that there is not some other explanation for the correlation. The reason we cannot draw the causal inference on the basis of the correlation alone is that there are other possible explanations for the correlation which would need to be ruled out before we can justify the causal claim. To claim that X causes Y is a much stronger claim than to claim that they are correlated, so the burden of proof is with the person making the causal claim to establish that the causal explanation is the best one. There are four possible explanations for a positive correlation between X and Y:    

X causes Y Y causes X Something else causes both X and Y The correlation between X and Y is coincidental

Before we can confidently accept the first explanation, that X causes Y, we must consider whether any of the other three potential explanations rivals it.

5.5.3 Is The Causal Explanation The Best Explanation? 5.5.3.1 Could Y have caused X? In most cases, the order in which X and Y occur will help to rule out Y as a cause of X, since the cause must precede the effect. (6a) If every time you flick a certain switch, a light goes on, you would not be tempted to suspect that the light going on caused you to flick the switch immediately beforehand. (6b) If whenever you pull your dog's tail, he bites you, you cannot claim that his biting you causes you to pull his tail.

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In other situations, however, things are not so simple, because it is not obvious which one came first. (6c) A recent study shows that poverty and an inability to manage money wisely are positively correlated. The study concludes from this that an inability to manage money wisely is a significant cause of poverty. It is difficult to say in this case which comes first, since often neither poverty nor the inability to manage money wisely have a clear starting point; both may have been present for generations. Rather than it being the case that inability to manage money causes poverty, it could be that poverty is a cause of people's inability to manage money wisely: people who haven't had much money, and who do not anticipate getting much money, may not have the inclination or the opportunity to learn good money management skills. (6d) There has been found to be a positive correlation between high stress levels and insomnia. Therefore stress causes insomnia. A person who suffers from high stress levels and insomnia may not be able to identify which began first, since both are afflictions which may arise gradually. In this case, then, even if there is a causal link between stress levels and insomnia, it could be that stress causes insomnia, or that insomnia causes stress. Note that this will really only be an issue in cases where the test group and control group are passively selected. In any case where researchers can actively construct a test group by supplying the alleged cause, a significant correlation will be good evidence of the causal relationship we are supposing to exist. As a general rule, however, we will not be justified in accepting the claim that X causes Y unless there is some reason to think that that is a better explanation for the correlation than taking Y to be a cause of X.

5.5.3.2 Could something else have caused both X and Y? Frequently, two events may be correlated not because one causes the other, but because they have some common cause, of which they are both effects. (6e) There is a strong positive correlation between higher divorce rates and women entering the workforce. Can we conclude from this that women entering the workforce is the cause of higher divorce rates? No: there is a third (and perhaps even fourth or fifth... ) causal factor that could explain both: perhaps women were unhappy in their marriages and that explains both the higher divorce rates and the increase in women's employment outside the home; or perhaps the institution of the Family Act which allowed 'no fault' divorces played a causal role. (6f) A recent study (embraced by tobacco companies!) claims that smoking does not cause heart disease. Rather, there is a gene (dubbed the 'smoking gene') which predisposes people both to heart disease and to want to smoke. When there are relevant differences between a test group and control group, this can lead us to infer than X causes Y when in fact there is another causal factor. (6g) A high school teacher offers a special extension program of voluntary after school classes, allowing students to do extra high-level work in areas not directly related to the curriculum. It is found that students who attend the extra classes do better in their HSCs than those who do not, even though the extra work they are doing does not relate to their HSC subjects. Does this show that the extra work causes them to do better? The difficulty with drawing this conclusion is that because the extra work was voluntary, it is likely that there was a relevant difference between the students who took part in the program (the test group) and those who did not (the control group). It is likely that the test group was more motivated and hard-working, and these qualities may have been the cause of their enrolment in the extension program, and their success in the HSC.

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Again, this problem is really only an issue when the test group is passively constructed. If researchers have randomly assigned the alleged cause to actively construct a test group, it would be unlikely for a significant correlation to be the result of a third cause. 5.5.3.3 Could the correlation be a coincidence? Some correlations are purely coincidental. Suppose after conducting a survey of a small sample you found that there was a correlation between, say, people whose star sign is Capricorn and Holden drivers. We would be unlikely to accept that there was a causal connection here. It is far more likely that the correlation was a coincidence. The likelihood of coincidence is reduced if we have a sufficiently large sample. If there were only two Capricorns in your sample and both of them drove Holdens, this would be very likely to be the result of coincidence. Because there seems to be no connection between star sign and car choice, it is unlikely that this correlation would be found in a larger sample. Not all coincidental correlations are trivial, and in more serious cases people are sometimes too quick to attribute a causal relationship between two things which may only be coincidentally correlated. Suppose that two children in a primary school are diagnosed with leukaemia in the same year. Because the rate of leukaemia is so low in the general population, this would be statistically well above average. In such a situation, the community might be concerned about the cause of the apparent correlation, and this is the kind of thing which leads people to change schools and move houses, but it is also the kind of correlation which could just be coincidental. If only two cases have been observed, coincidence cannot easily be ruled out. This discovery could certainly justify further research into the school's environment, proximity to power cables and so on, but the causal claim that something about the school resulted in the cancer could not really be supported by the evidence of those two cases. The causal conclusion could be justified if the sample size were increased by examining the school over a period of time, and the prevalence of the cancer continued to be above average. With a small sample, however, it can be difficult to rule out coincidence

5.5.4 What Makes One Explanation Better Than Another? As with any inferences to the best explanation, our ability to identify a cause and effect relationship as the best explanation will be affected by our level of background knowledge. If we can imagine a causal mechanism that would make sense of a causal claim we want to make, that will make the inference more plausible. Part of the reason for looking for another explanation -- coincidence -- in the case of Capricorns and Holden drivers is that it is hard to imagine what the causal mechanism might be which would predispose people with a particular star sign to drive a certain car. We would be inclined to look for a better explanation here, since a causal explanation of this correlation would not fit in well with our other beliefs about what sorts of things are likely to be causally related. Of course, sometimes our research will allow us to make certain causal claims without understanding the mechanism by which the causal link operates, but when faced with otherwise equally plausible explanations, we need to have some way of deciding between them. Finding an implausible causal explanation will give us reason to seek out differences between the test and control groups, or possible third causes. (7a) Research shown that people whose names end in vowels, at least in English speaking countries, tend to be shorter than people whose names end in consonants. Is this a causal relationship? Does having a name ending with a vowel stunt your growth? A better explanation for the correlation is that more names ending in vowels are female names than male names, and females tend on average to be shorter.

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Often, if we are uncertain about which is the best explanation, thinking about the different possible explanations can provide a guide to future research. (7b) If people in the West adopted the Japanese diet, the incidence of heart attacks would decrease. In Japan, where the diet is much lower in fat content and much higher in fibre, the incidence of heart attack is much lower than it is in the west. So if people in the West were to adopt a Japanese low fat/high fibre diet, they would be much less likely to die of heart attacks. Before we accept this conclusion, we might wonder whether the difference between the incidence of heart attacks in Japan and in the west was a result of diet alone, or whether there were other causal factors: such as lifestyle or genetic factors, which might explain the correlation observed. Rather than just looking at heart attack figures from Japan as a whole, and from 'the West' as a whole, we could examine test and control groups of people who ate a Japanese diet, as opposed to a Western diet. We could include among the test group not only Japanese people, but western people living in Japan, and include Japanese people living in the west on a western diet in the control group. To identify diet as the cause, we would need to have test and control groups which are similar in other ways which are relevant to the likelihood of having a heart attack. If it is not clear which explanation is the best, then, additional research can be conducted to rule out other explanations.

5.5.5 Is The Causal Conclusion Accurate? The other thing to look out for is that as in the case of statistical research, it often happens that the conclusion drawn from the argument is not really justified by the evidence. Even if there is some sort of causal connection, there is still a tendency to sometimes oversimplify the nature of the causal relationship. (8a) Researchers have claimed that some people are genetically predisposed to alcoholism, because boys whose fathers are alcoholics are three to four times more likely than average to become alcoholics. Suppose there is a causal link between the alcoholism of a father, and of a son; does the evidence given provide any reason to think that the causes are genetic? It would seem at least as likely that the causes are social -- the higher incidence of alcoholism among sons of alcoholic fathers could be a matter of "nurture" rather than "nature", so that it was the effect of the father as role model which led to the tendency towards alcoholism. There could also be a common third cause -- if the father and son live in the same sort of environment, that environment could have contributed to the alcoholism of both. We should not accept the conclusion that the causes are "genetic" without some evidence that that is a better explanation than the alternatives. (8b) Researchers have found that in Australia, the average number of children born to a woman with no post-school education is 2.15, while women with a university education have an average of only 1.55 children. This shows that too much thinking lowers fertility levels. The causal claim is not justified as stated, because although more education may cause women to have fewer children, this cause is not as direct as suggested by the conclusion of this argument. More probable explanations for this trend would that women who choose to have more children may make that choice over choosing further study, or that women inclined towards more study may be more career oriented and not choose to have as many children, or women who study for longer are older by the time they establish careers, and just don't end up having as many children. We would need more evidence than has been given to justify a claim that there is a direct link between thinking and fertility.

5.5.6 Discussion exercise When we say that X causes Y, we sometimes mean that X is a sufficient condition for Y (Y will occur

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whenever X occurs), sometimes that X is a necessary condition for Y (Y won't occur without X), sometimes that X is both necessary and sufficient (Y will occur when and only when X occurs), and sometimes we don't mean that it is either necessary or sufficient (X occurring makes it more likely that Y will occur, but either could occur without the other). Distinguish these four uses in the examples below:

(a) Dropping a fragile glass onto concrete from a great height will cause it to break. (b) Smoking causes cancer. (c) Someone going through that red light caused the red light camera to go off. (d) Exceeding the speed limit caused you to get booked for speeding.

Which of these senses would be most common? How would this difference affect the methods used to test each of these kinds of causal claims?

Skills For Week 7 You should be able to: Identify an inference to the best explanation Identify a causal argument Understand the roles of the test group and control group within a sample in causal research, and how they may be selected Understand the nature of a correlation, and how one can be discovered using the methods of statistical research Understand the use of inference to the best explanation in inferring a cause from a correlation Evaluate causal arguments

5.6 Analogical Reasoning So far, we have looked at several kinds of inductive arguments: generalisations, including statistical generalisations, inferences to the best explanation, and causal arguments. In this lecture, we will begin to look at another common kind of inductive argument — arguments from analogy. We will then go on to look at other examples of analogical reasoning which do not bear such a close relation to the types of inductive reasoning we have examined.

5.6.1 Simple Inductive Analogical Arguments Consider the following arguments:

(1a) The apartment next door is the same size and has a similar outlook to ours, and it sold recently at auction for $400,000. So we can expect our apartment to go for about the same. (1b) The election of the Freedom Party in Austria is a significant danger. Their extremist right-wing racist views should remind us of that other Austrian, Adolf Hitler, whose reign of terror in Germany in the 1930s and 1940s had such disastrous consequences for the world.

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(1c) When a stream of air proportionally equivalent to a strong wind was blown over a scale model of the Olympic stadium, a 'wind tunnel' effect was noted. Therefore in a strong wind, the Olympic stadium could also be expected to suffer from this effect. In each case, an analogy is drawn between two things which are said to be similar, because of certain features they share. It is then argued that because one of the things being compared has some further property, it is likely that the other one does too. In the first case, we are given evidence of several ways in which the two apartments are similar - they are the same size, and have similar outlooks. Because one of them sold for $400,000, therefore, we can expect the other to sell for a similar amount. In the second argument, we are given several similarities between the current Austrian government and Hitler. Both are Austrian, right wing and racist. The argument suggests on the basis of these similarities that the disaster that was Hitler's rule in Germany, is likely to be repeated now in Austria. In the third argument, while the stadium and the model are different in a lot of ways, they are similar in design, and it is argued that they will therefore also be similar in the effects wind has on them.

Identifying an argument from analogy:

 

Does the argument involve the claim or assumption that two things are similar in some ways? Is it concluding on this basis that they are also similar in some other way?

5.6.2 Components Of An Argument From Analogy An argument from analogy compares two things, and argues that because they are similar in some ways, they are likely to be similar in another. The two things being likened will be referred to as the subject and the analogue. The subject or primary subject is the subject of the conclusion -- it is whatever the conclusion gives us new information about. The analogue is whatever the subject is said to be similar to. It is whatever we have information about already.

While an argument from analogy may not be given in this explicit form, the basic structure behind many such arguments is this:

The subject and analogue are have certain known similarities. The analogue has some additional property (the target property). Therefore, the subject also has (or is likely to have) that additional property. Examples: (2a) The software runs on my PC, so it should work on yours too, since they are the same make and age.

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(2b) Broome probably has a long wet season over summer, because Townsville does, and they are at about the same latitude. (2c) The black shoes won't fit you, because they're the same size as the brown ones you just tried on, and those were too small.

(2d) Rover was an Alsatian, and he was an excellent guard dog. So if we get another alsatian, it should be a good guard dog as well. (2e) You had an allergic reaction to an antibiotic containing penicillin. So you would probably be allergic to this antibiotic as well, because it also contains penicillin.

5.6.3 Evaluating Arguments From Analogy A good argument from analogy is one where the similarities exhibited by the subject and analogue are strong enough to make it likely that they will also share other properties apart from those we already know about. The known similarities do not only need to be strong, however, they also need to be relevant to the conclusion being drawn. Two things may be very similar in some ways, and very different in others. The two main things to ask yourself are: Are the similarities positively relevant to the target property? And are there any negatively relevant differences which outweigh the similarities?

5.6.3.1 Are the similarities positively relevant to the conclusion? A similarity will be positively relevant to the conclusion if the properties noted as similarities are relevant to the target property, in such a way that the similarity noted between the subject and analogue makes it more likely that they will also be similar with respect to the target property. For example, consider these two arguments from analogy.

(3a) The software runs on my PC, so it should work on yours too, since they are the same make and age, and are equally powerful. (3b) The software runs on my PC, so it should work on yours too, since our PCs weigh the same amount.

What makes the first argument persuasive and the second not is that while the make, age and power of a computer are relevant to whether it can run a particular piece of software, its weight is irrelevant. Similarly, the first of these next arguments is much stronger than the second:

(3c) You had an allergic reaction to an antibiotic containing penicillin. So you would probably be allergic to this antibiotic as well, because it also contains penicillin. (3d) You had an allergic reaction to an antibiotic which came in a blue box. So you would probably be allergic to this antibiotic as well, because it also comes in a blue box.

Whether an antibiotic contains penicillin is relevant to whether it will cause an allergic reaction. The colour of the box it comes in, however, is irrelevant.

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5.6.3.2 Are there any negatively relevant differences? As well as similarities, there will always be differences between the subject and analogue. These will weaken the analogy if they are negatively relevant to the conclusion. A difference you may identify between the subject and analogue will be negatively relevant to the conclusion if the existence of that difference makes the conclusion less likely to be true. Despite the similarities noted between the primary subject and analogue, you may be able to identify some additional property which the subject has and the analogue has lacks, or the subject lacks and the analogue has, which makes it unlikely that the subject will have the target property. This will often take some background knowledge, since the differences may not be noted in the argument. (3e) John caught a flu-like viral infection, and was hospitalised for several weeks. Now his teenaged grandson has caught the infection, so he will probably also have to be hospitalised. The subject of this analogical argument is John's grandson, since he is the one we are concluding something about. John is the analogue. The known similarity which is mentioned is that they have the same viral infection. John was hospitalised, and it is concluded that his grandson will also be hospitalised. The known similarity which is mentioned is clearly relevant to the target property - the fact that someone has viral infection is relevant to whether they will be hospitalised. But in this argument, there is also a negatively relevant difference between the subject and analogue -- specifically, their respective ages. This is negatively relevant because age is relevant to how serious a flu-like infection might be, and the fact that they are different ages makes it likely that the effect of the infection on each of them would be different.

ANALYSING ARGUMENTS FROM ANALOGY:     

What is the analogy between? Of the things being compared, the subject is what the conclusion is about. The analogue is what it is said to be similar to. What is the conclusion - what point is being made? What are the similarities which are stated or assumed in the premises to hold between the subject and analogue? Are those similarities positively relevant to the conclusion? Are there any differences between the subject and analogue which are negatively relevant to the conclusion? A good argument from analogy will be one where the subject and analogue have strong positively relevant similarities, and where there are no significant negatively relevant differences.

5.6.4 Uses Of Analogical Reasoning The arguments from analogy we have seen so far are a typical simple kind of inductive argument. Like an inductive generalisation, they conclude that a thing will have a certain property, because we know that something which is similar in other respects has that property. The argument is based on the belief that because two things are similar in some ways, that they will be similar in others :

Simple inductive form of analogical argument: The subject and analogue are similar, because they share certain stated similarities. The analogue has some additional property.

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So the subject is also likely to have that property.

If we think of analogical arguments as a kind of inductive generalisation, however, we are faced with a problem. Sample size is an important consideration in the evaluation of inductive generalisations, but in analogical reasoning we very often base our conclusions on a sample of one (the analogue). Is this kind of reasoning, then, just a weak form of generalisation? In some cases, the answer is probably yes. An argument such as:

(4a) Bill and Phil are both doctors. Bill had a calming bedside manner, so Phil probably does as well.

is not going to be well supported. To make a generalisation about doctors, you would need to have a sample of more than one, since doctors are a fairly heterogeneous group. The similarity noted may be positively relevant -- doctors are trained to have a good beside manner, but there may be many other relevant differences between Bill and Phil, or just between Bill and other doctors generally, so it would be unwise to base our conclusion on just one sample case. What we need to consider now, then, is in what situations analogical arguments are good arguments, despite their apparent weakness by the standards of inductive generalisation. With respect to analogues as samples, when doesn't size matter?

5.6.5 When Is A Single Analogue A Sufficient Sample? 5.6.5.1 (i) When the analogue and subject are similar with respect to all relevant properties Let's think again about why sample size in inductive generalisations is important. The larger the sample, the more likely it is that any relevant differences in the population will be reflected in the sample. Thus in the argument above, the problem with using our analogue, Dr Bill, as a sample, was that we had no reason to expect that he was likely to be representative of other doctors in all the relevant respects. If, however, we have a situation where we are aware of what properties are going to be relevant, and we know that the subject and analogue share those properties, then the conclusion will be justified. The reason we generally need a large sample is to ensure that all relevant properties have been taken into account, so if we can establish by some other means that all relevant properties have been taken into account then we can do without a large sample. Consider, for example, the argument about the architectural model of the olympic stadium. While the subject (the stadium itself) and the analogue (the model) are very different in some respects, they are known to be similar with respect to the properties relevant to wind displacement. The conclusion about the stadium could therefore be accepted based on the information we have about the model. Provided the model was accurately constructed, and the experiment correctly carried out, it would not make sense to ask for a larger sample -- more models -- before accepting the conclusion. (It has already been decided what properties are relevant, and these properties have been replicated in the model, so if we did build more models, they would just be the same as the existing one.) The point here is that generally we need a large sample to ensure that the sample and population are similar in relevant ways. If we already know that the analogue and sample are similar in all the relevant ways, then the fact that we are basing our judgment on a single case is not to be considered a flaw. In such cases analogical reasoning may be strong and accurate.

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5.6.5.2 (ii) Normative analogical arguments (in which the assumption is not that things similar in some respects are likely to be similar in others, but that things which are similar should be treated similarly) There is an important distinction between descriptive and normative claims. Descriptive claims are claims about what is the case; normative claims are about what should be. Analogical reasoning is often used in situations which are not straightforward inductive arguments in support of a descriptive conclusion -- in cases where we are not trying to establish a particular fact, but are trying to justify some normative or ethical claim, by showing that a situation under consideration is similar to some other situation, and that we should therefore treat them similarly. Suppose, for example, that I were trying to convince you that you were wrong to support the death penalty. If I knew that you were not in favour of lynchings by vigilantes, I might argue as follows:

(5a) An offender being killed by the state is just like that offender being killed by a vigilante lynch mob. Both actions result in the offender's death, both are based on some concept of retribution, and the state and the lynch mob both feel that their actions serve the interests of justice. So how can you consistently support the death penalty, when you are opposed to vigilante lynchings? This is an argument from analogy, since I point out various similarities between the death penalty and lynchings, and suggest on the basis of these similarities that you cannot consistently support the death penalty, since you are opposed to the vigilantes. Now you may dispute my argument by pointing out relevant differences between the two situations (the death penalty is the end result of a long legal process, for example), but you would not criticise my argument on the grounds that I am basing my argument on a single analogue - vigilante lynch mobs. You would not object to my conclusion by saying that I have only shown that the death penalty is similar to one thing you disapprove of, and that you would require a larger sample before you change your attitude towards the death penalty. The difference is that the effectiveness of an inductive generalisation from a sample to a population is based on the fact that if we examine a large enough sample of a certain type of thing, we can expect that the features common to that sample are common to all things of that type. If something is true of the sample, it is likely to be true of the population. In analogical arguments making ethical or normative claims, we are not trying to establish the probability of a certain proposition being true, we are basing our argument on the idea that similar things should be treated similarly. The underlying rationale of these argument types is different. For inductive generalisations, and simple inductive analogical arguments with descriptive conclusions, the basis of the argument is that things which are similar in some ways are likely to be similar in other ways. The strength and relevance of the similarities makes the descriptive conclusion more likely to be true, or more probable. It does not, however, make sense to think of an ethical claim as being made more probable by a larger sample. We are trying to show that the conclusion should be accepted, but that is not a matter of establishing that it is likely to be true. The strength and relevance of the similarities between the subject and analogue, and the absence of negatively relevant differences will affect the persuasiveness of analogical arguments with normative conclusions, the size of the sample will not.

When is an argument from analogy just an inductive generalisation from an inadequate sample? Ask yourself whether the conclusion would be better supported if there was a larger sample, rather than just a single analogue. If so, then this will be a flaw in the

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argument. But for many analogical arguments, especially those which are normative rather than descriptive, a larger sample would not make a significant difference to the strength of the argument.

Inductive generalisations, which we examined previously, are used to establish factual or descriptive claims. It would be a mistake to think of all analogical reasoning as serving this purpose, because some of the most powerful and frequent uses of inductive argument are not to establish facts, but to try to persuade an opponent in areas where the disputes are not factual disputes, but disputes about the interpretation of those facts. Good analogical reasoning takes creativity -- the most effective analogical arguments are often those which draw the audience's attention to some analogy they may not otherwise have considered, to influence their thinking about a subject, and encourage them to think about things in a new way. Even where the conclusion does not convince an opponent, it may inspire them to think more deeply about an issue, challenging them to come up with an explanation of why the supposedly analogous situations differ. Analogical arguments : Summary

The simplest form of analogical argument is:

1. The subject and analogue are similar, because they share certain stated similarities. The analogue has some additional property. So the subject is also likely to have that property. In this form, the argument is similar to an inductive generalisation, with the analogue taking the place of a sample, and the subject taking the place of the population. Despite the fact that it is not based on a large sample, these arguments may be effective if we have reason to believe that the analogue and subject are likely to be similar with respect to whatever properties are relevant to the conclusion.Arguments from analogy can also take other forms, and are commonly used to make normative claims about what should be done, as opposed to a simple descriptive claim about what properties a thing is likely to have. Common forms of analogical argument for normative conclusions include: 2. The subject and analogue have certain stated similarities.We do not allow the analogue, so we should not allow the subject either. 3. The subject and analogue are similar, because they have certain similarities. We treat the analogue in a certain way, so we should also treat the subject that way. 4. The subject and analogue are similar, because they have certain similarities. You cannot consistently accept one but not the other. 5. The subject and analogue are similar, because they have certain similarities. You treat the subject one way and the analogue another. You are behaving inconsistently.

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The distinguishing feature of analogical reasoning, then, is not its exact form. The distinguishing feature is that whatever conclusion is drawn is drawn on the basis of the similarities between the subject and analogue. A strong analogical argument is one where the subject and analogue are similar with respect to the properties relevant to the conclusion, and where there are no negatively relevant differences.

CASE STUDY - THE TAMPA REFUGEE CRISIS

Arguments from analogy are commonly used in areas of controversy. If disagreements are deep, it will often be impossible to convince an opponent about the rightness of your position by debating facts, since the disagreement is often not about facts, but about their interpretation. In such cases, people will often try to convince their opponents by arguing about how the situation or action should be interpreted, and how that situation or action should be understood to relate to others.

Example In August 2001 a boatload of mainly Afghan nationals were on their way to Australia to seek asylum. They had paid Indonesian people-smugglers for their passage, and when the boat in which they were travelling began to sink, they were rescued by the MV Tampa, a Norwegian freighter. The captain of the Tampa planned, in accordance with maritime law, to take the asylum seekers to the nearest safe harbour which would have been in Indonesia, but agreed under duress to take them to Australian territory. The Australian government refused to let them land, and sent the SAS to take control of the ship and drive it out of Australian waters.

These events generated strongly mixed feelings in the Australian public. Some felt that the government had been heavy-handed and was not honouring its international obligations - legal or moral. Others felt that the government's action was justified, because illegal people-smugglers need to be discouraged, and because by threatening the crew of the Tampa, the asylum seekers had shown themselves to be unworthy of our assistance.

Over a period of days, many letters employing arguments from analogy were published in Australian newspapers. These arguments were used because disagreements were not in general about the facts of the matter, but about how the actions of the asylum seekers or the government should be viewed. Different positive or negative impressions of each of the parties could be given by invoking different comparisons in those analogies.

The disagreements were not about what happened, but about how we should think about what happened.

Exercise 1 All of the analogies below were drawn in letters to the editor about the Tampa crisis published in the Sydney Morning Herald between the 29th of August and the 3rd of September 2001. In each case, what do you think the similarities between the subject and analogue were supposed to be? What conclusion do you think was to be drawn from that analogy? What point of view is the

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author endorsing about the situation? How strong do you think the analogy is?

i. An analogy between Howard's refusal to let the Tampa land in Australia and the refusal of the US Government in 1938 to allow the SS St Louis, a ship containing mostly German refugees fleeing the Nazis, to land. ii. An analogy between the asylum seekers and aeroplane hijackers. iii. An analogy between the people smugglers and those they transport, and Schindler and the Jews he smuggled out of Germany during World War II iv. An analogy between the Australian government's treatment of Afghan refugees and the treatment of those same people by the Taliban when they were in Afghanistan. v. An analogy between Australia's treatment of middle-eastern refugees, and the way we would treat white farmers from Zimbabwe if the situation there continued to deteriorate and they wanted to leave Zimbabwe and settle in Australia.

Exercise 2 Read the letters to the editor in current newspapers, and see how many arguments from analogy you can identify. (You will be surprised how common they are!) Evaluate them according to the criteria we have identified, and post examples to the discussions board.

5.6.6 Other Examples Of Analogical Reasoning Before we move on, we will look at three further uses of analogical reasoning. While these are quite different kinds of argument, they are all arguments from analogy: they all draw their conclusion based on an observed similarity between two things or situations, and they can all be evaluated by thinking about how strong and relevant the similarities are, and whether there are any negatively relevant differences.

5.6.6.1 (i) Legal Precedent In making a judgment, or deciding on a sentence, judges make use of legal precedents: previously decided cases which are determined to be relevantly similar. The doctrine of stare decisis requires that judges should 'stand by that which is decided' , and make use of such analogical reasoning, by basing new decisions on those made in other cases which were analogous in relevant ways. Because the current case is analogous to certain previously decided cases with respect to the nature of the offence, the offender's situation and so on, the sentence imposed in the previous cases provides a guide to what would be reasonable in the current case. Disputes about sentences often concern which precedent should be taken to provide the strongest analogue for the case under consideration. Any particular offence will bear similarities to a variety of previous offences which have been committed, and in deciding which precedents to take as the analogues, the judge must decide what features of the case are most relevant, and choose precedents which are similar in those respects. Example One example of a judgment where issues of legal precedent are discussed extensively is the case of R v Lewfatt , a judgment of the Northern Territory Supreme Court, in which a woman was sentenced to a relatively lenient suspended sentence for armed robbery.

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The defendant had been found to have robbed a nursery by threatening the shop attendant with a knife. There were various considerations which were mentioned by the judge in deciding which precedent cases should be taken to be analogous to this one. The offender had carried out the robbery without much forethought, without a serious attempt at concealing her identity, and only a small amount of money was stolen. The cases which were considered most closely analogous were those classed by the Director of Public Prosecutions as "unprofessional, silly robberies" carried out by inexperienced criminals without much planning, as opposed to more serious planned armed robberies against major targets like banks. A number of relevant cases were cited, and the sentences imposed in those cases considered. Even compared to the sentences in those cases, however, the judge felt that there were extenuating circumstances -- that is, relevant differences between the subject case and the analogues -- which would justify a lighter sentence. The uses of analogical reasoning in this case could be represented as follows:

(6a) This defendant's case is similar to the other cited cases, because of similarities such as the unplanned and unprofessional nature of the robberies. In the previous cases, the sentence imposed were within a certain range, so this defendant's sentence should be within that range. However, there are negatively relevant differences between this defendant and the defendants in the other cases. So a lighter sentence would be justified. Precedents, while not binding, must be taken into account, and sentences which seem inconsistent with precedents are often the subject of appeals. In this case, the judge warned that he thought the sentences which had been passed in previous cases were in general too light, and he planned in the future to impose harsher sentences. The justification for his intention to impose harsher sentences than he would by following the precedents was that the incidence of armed robbery in Darwin (where this trial took place) had become much higher, and the general threat of armed robbery therefore was more serious than before. This, the judge was suggesting, was a relevant difference between the situations in which the earlier sentences had been imposed, and the situations in which future sentences would be imposed, which would justify harsher sentences in the future.

5.6.6.2 (ii) Analogical Thought Experiments One common use of analogical argument in philosophy is in thought experiments, or "intuition pumps". Thought experiments are imaginative exercises designed to clarify thinking about a certain issue, or to explore the consequences of a view. Thought experiments often involve analogical reasoning. In arguing about a difficult or contentious issue, the proponent of some position might suggest a story which provides an analogue, but where it is supposed to be clearer why their view is the correct one. The example below is a famous analogical thought experiment, from Judith Jarvis Thomson's "A Defense of Abortion", intended to convince an audience that abortion is justified, at least in cases of rape. This issue is one about which people may have strong feelings, so the purpose of the analogy is to remove the question from its emotive context, and think about the issues in a less controversial setting: (6b) [L]et me ask you to imagine this. You wake up in the morning and find yourself back to back in bed with an unconscious violinist. A famous unconscious violinist. He has been found to have a fatal kidney ailment, and the Society of Music Lovers has canvassed all the available medical records and found that you alone have the right blood type to help. They have therefore kidnapped you, and last night the violinist's

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circulatory system was plugged into yours, so that your kidneys can be used to extract poisons from his blood as well as your own. The director of the hospital now tells you, "Look, we're sorry the Society of Music Lovers did this to you - we would never have permitted it if we had known. But still, they did it, and the violinist now is plugged into you. To unplug you would be to kill him. But never mind, it's only for nine months. By then he will have recovered from his ailment, and can safely be unplugged from you.1

The point of the story is that in the situation described you may feel justified in unplugging the violinist. Unplugging him means that he will die, but the Society of Music Lovers had no right to kidnap you in the first place, and you have no moral obligation to sustain the violinist. If you think that unplugging the violinist would be justified, however, then you should accept that abortion in the case of rape is justified, since these two situations, Thomson argues, are analogous. The analogical argument is something like: (6b-i) Unplugging the violinist in the situation described is similar to aborting a foetus whose conception resulted from rape, since in both cases your attachment to the other party was involuntary and the result of someone else's wrong action; in both cases the severing of the attachment will result in the other party's death; in both cases you would otherwise have to remain attached for nine months. You think it would be acceptable to unplug the violinist. So you should also consider it acceptable to abort the foetus. For current purposes, we do not need to sort out this ethical issue. The important thing for our purposes is to see how the analogical reasoning works. If you wanted to criticise the inference, you would need think about relevant differences between the analogue (the violinist) and the subject (the foetus), which would justify their being treated differently.

5.6.6.3 (iii) Refutation by analogy One final important context for analogical argument is refutation by logical analogy, when an analogy is drawn between the forms of arguments themselves. I might try to show you that your argument is fallacious, by showing that it has the same form as some plainly unacceptable argument. We saw some examples of this sort of reasoning in our discussion of conditional arguments. If someone were to present the argument:

(6c) All people with anorexia are thin. Calista is thin, so Calista must be anorexic.

You could demonstrate that this was a bad argument by showing that it was analogous to the obviously invalid argument:

(6d) All people who are more than ten feet tall are more than three feet tall. Calista is more than three feet tall, so she must be more than ten feet tall. This refutation is a piece of analogical argument: Arguments (6c) and (6d) have the same logical form, (which is the feature relevant to their validity). Argument (6c) is invalid, so argument (6d) must be invalid too.

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In fact, we know that these are invalid arguments because they affirm the necessary condition, but an argument can be refuted by providing a logical analogy even when you do not have a convenient way of describing its flaw. For example we could object to the argument: (6e) People should be allowed to decide what is best for themselves. So if they want to take drugs, then we have no right to prevent them. by arguing that it is analogous to the obviously bad argument: (6f) People should be allowed to decide what is best for themselves. So if they want to commit mass murder, then we have no right to prevent them. As with any argument from analogy, we can criticise this analogy by pointing out relevant differences between (6e) and (6f) -- mass murder has much more effect on other people than drug taking, for example, but this does at least suggest that some modification should be made to the premise in argument (6e) -people shouldn't be able to do whatever they want to do.

Analogical reasoning is a very common and important kind of reasoning. You can identify a piece of reasoning as an analogical argument if it draws an analogy between two or more things, usually by pointing out some specific similarities, and then basis its conclusion on that analogy. A good analogical argument is one in which the similarities between the subject and analogue are strong and positively relevant to the conclusion; and there are no negatively relevant differences. 1

"A Defence of Abortion" by Judith Jarvis Thomson is reprinted in Fogelin and Sinnott-Armstrong "Understanding Arguments", 445-458

SKILLS FOR WEEK 8 You should be able to:   

Identify analogical arguments, and recognise simple inductive analogical arguments and other kinds of analogical reasoning Identify the subject and analogue in an analogical argument, what their similarities are, and what point is being made on the basis of the analogy Evaluate analogical arguments, by considering such issues as the strength and relevance of the similarities between the subject and analogue, and whether there are any negatively relevant differences

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6 CLARIFYING ARGUMENTS (WEEK 9)

6.1 Introduction Over the last few weeks, you have begun to analyse and evaluate a number of types of argument. We have seen arguments which are deductive, such as conditional arguments, and learnt to establish whether some such deductive arguments are valid or invalid. We then considered a number of important kinds of inductive arguments: statistical and other inductive generalisations, inferences to the best explanation, causal arguments and analogical arguments, and established methods for evaluating the strength of those arguments. In the final section of the course, we will be considering things which should be considered in the evaluation of any kind of argument, by close analysis of a variety of longer passages. While the exact criteria according to which an argument will be evaluated may vary depending on what kind of argument it is, the success of any argument will ultimately depend on the strength of its inferences, and the acceptability of its premises, the assessment of each of which will be the focus of upcoming lectures. The lectures will be structured in a way that will parallel the actual process you might go through in evaluating a text. The argument texts that have been made available will provide the basis for our discussion for the rest of the course. We will apply the evaluation skills you are learning as you learn them, to build up a full analysis of these texts. The piece of written assessment for the course will require you to go through a similar process with another text: either one of the 'assignment texts' which have been handed out, or another text of your choosing. More information about this assignment will be given in class. -------------------------------------------------------------------------------The question we need to be thinking about in developing a general approach to the evaluation of arguments is this: Under what circumstances should we allow ourselves to be convinced by an argument? A good argument needs to have acceptable premises, and strong inferences, so two of the things we will be focussing on over the next few weeks will be the evaluation of premises and inferences. But when an argument is embedded within a long or complex text, it is necessary to begin by clarifying what the argument is: what is the author trying to convince the audience of, and what kinds of reasons or evidence have been given?

In this lecture we will focus on clarifying arguments in longer passages. We will begin by looking at how to give argument summaries, to extract from a longer text the main conclusion of an argument, and the main evidence which has been provided for that conclusion. The premises and inferences form the rational core of the argument, which is what should, if it is successful, influence us to accept its conclusion. This rational core may be distinguished from the other features of the argument text which may be used to make an argument seem more persuasive, such as emotional language, or other rhetorical devices. The use of such persuasive techniques will not necessarily be considered a flaw in an argument, and their use is part of the skill of arguing in some contexts. It is important, however, to be aware of what techniques an author is employing to convince you of a conclusion, apart from providing you with good evidence. These persuasive devices will be the focus of the second part of this lecture.

The aim of today's lecture is to help you to develop the ability to separate the rational force of an argument from its persuasive force, so that you will only be convinced by arguments which are rationally strong.

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6.2 Summarising An Argument One very important skill to develop which will help you in whatever you are going to read, for whatever purpose, is the skill of summarising an argument analytically. This is a very different activity to note-taking, and far more useful for the analysis of an argument text. People often take notes in an uncritical way -- by starting at the beginning, and taking down each point as it is made. While this is appropriate if what you want is just a list of facts, it is an unhelpful way to approach an argument. The result of approaching a text in this way is that you will end up with notes which are comprehensive, but in which the structure will be no more clear than the passage with which you began. You may even find that some of the inferential links in the argument are lost, since in noting discrete points, you may well do away with the words and phrases which indicated the structure of the argument.

A far more useful approach for texts whose arguments you want to evaluate, is to read the text through, thinking about questions such as:   

What is the arguer trying to convince me of? What kind of evidence is given? What is the tone, and what is the context?

Even if you don't write anything down on your first reading of the argument, these are the sorts of questions you should have answers to by the time you finish reading it. It can however be helpful to write down a brief summary of the main argument in your own words. This will give you something to refer back to, and having to put it in your own words will ensure that you do understand the main point of the argument. Approaching the whole argument text at once in this way may sound difficult, but it is really quite a natural way to approach a piece of reasoning. Think about the way you would listen to someone presenting an argument. Usually by the time an arguer finished speaking you would know what that person was trying to make you believe, and what sort of evidence had been offered. You would also often have an idea of what attitude was conveyed by the tone and language. Often this is not the way people approach a written text, but in the first instance it is probably the way we should approach it.

How much of a long text you should deal with in one go will depend on how it is structured. A book or long journal article will usually be broken up into discrete sections giving arguments for separate points, so these sections can be treated individually. For a shorter text such as a newspaper article or short essay, the text can be treated as a whole.

Remember, though, that there is no point in approaching a text a page at a time, or five pages at a time. The basic units of an extended piece of reasoning are its inferences, not its pages, and to understand the structure of a piece of reasoning you will need to approach it in natural divisions.

Summarising arguments is a first step towards a comprehensive analysis of long arguments. When we first developed the method of standardisation, many of the arguments we looked at were simple arguments, appearing in isolation, so that it was easy to find what the premises and conclusion must be, and the difficulty was merely in discerning the relationships between those individual propositions. As we go on to look at more complex arguments, and more complex passages which contain arguments, you will find that not everything in a passage is part of the argument. It becomes more important to be able to draw out an argument from its context.

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We will go on to look more at giving an appropriate standardisation of a long argument, but the first thing you need to practice is extracting a simple version of the argument from a text. We will begin by looking at some relatively short passages, and with the aim of summarising the main arguments as briefly as possible.

6.2.1 Examples Consider the following passage:

(2a) From education to banking, more and more aspects of Australian life are falling under some kind of user-pays system. But inevitably, whatever the benefits of the service, whenever some new fee or charge is introduced there are always complaints from people who will end up paying it. Some objections are reasonable, some are not. When the Lane Cove Tunnel linking the Gore Hill freeway to the M2 motorway, was built, for example, it ended the twice-daily gridlock on Epping Road through Lane Cove. While Epping Road commuters had been complaining about the traffic for years, many of them complained about the toll on the tunnel, too. But the fact is that this is misplaced whinging about a toll which is entirely reasonable. For one thing, the cost of the toll is outweighed by the savings drivers make by using the tunnel. Anyone who has ever been stuck in peak hour traffic on a daily basis knows the effect it has on a car. Manual gearboxes, in particular, take a battering. Being able to cruise through the tunnel instead of creeping slowly and inefficiently along Epping Road saves drivers money on petrol and, by reducing wear and tear, car maintenance costs. Another reason it is unreasonable to whinge about the toll is that people are not compelled to use the tunnel. As is the case with the M2, there is still the old route as an alternative, so if you don't want to pay the toll, don't use the tunnel. That is how the user pays system works. For those who object to having to pay toll on principle, or who are just too stingy to pay $2 for a more efficient and pleasant trip to work each day, the old road is still there. To begin an analysis of the argument contained in the passage above, rather than just starting at the beginning and making notes, read through the entire passage and think about the argument. What is the author trying to convince you of? The main conclusion is that complaint about the toll on the Lane Cove tunnel are unreasonable.

What reasons are given to convince you of that?

There are two main reasons: Firstly, the cost of the toll is outweighed by the savings drivers make by using the tunnel. Second, there is an alternate route, so drivers are not forced to use the toll road.

Note that this simple summary of the argument will be more useful as a basis for analysis than a longer and more comprehensive set of notes with references to everything from education and banking to manual gearboxes. --------------------------------------------------------------------------------

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(2b) A number of local councils in Sydney are considering adopting new legislation covering cat ownership, which parallels that introduced state-wide for dog owners two years ago. Under the Dog Control act, dogs must be microchipped and registered, and dog owners can be fined for allowing their dogs to roam in public. Some parks have been designated as dog exercise areas, but these are the only public spaces in which dogs are legally allowed off the leash. These dog exercise areas are found in most local council areas. These measures have been largely successful in reducing the number of problems such as dog attacks on children and several councils are for that reason now considering similar legislation to overcome some of the problems caused by cats. These councils have argued that the cat legislation is even more justified that the dog laws, because of the harm done to the environment by wandering and feral cats.

Cat owners in these areas, however, have come out in force against the proposed changes, which would require them to keep cats within their own properties. They have argued that this legislation cannot practically be applied to cats, as fences do not keep cats in, and the laws would in effect require that cats be kept indoors. This would create difficulties for tenants whose landlords would not allow them to have pets inside. It is also difficult to housetrain a cat which has been brought up living outside. They also claim that the laws would be ineffective. They maintain that the environmental damage is done by feral cats, rather than wandering domestic cats, so placing restrictions on domestic cats would not solve the problem.

First, note that two arguments are being presented: an argument (the argument of the local councils) and a counterargument,( the argument of the cat owners). In giving a summary of the passage, then, you should summarise each of these arguments: state the conclusion, and describe the evidence given in support of it. For example:

Some Sydney councils are considering adopting new cat control legislation, because cats harm the environment, and similar legislation applied to dogs has been successful in overcoming dog-related problems. Cat owners object to the proposed legislation, on the grounds that it would be impractical to implement, and would not be effective anyway.

Note that part of this dispute is conducted in analogical reasoning. The councils argue that the laws have been successful for dogs, and so should also be implemented for cats. The cat owners argue that there is a relevant difference between cats and dogs, with respect to the difficulties of keeping them within a property. -------------------------------------------------------------------------------The skills of summarising are best developed with practice. Try this week's self-test and exercises , but also get into the habit of trying to summarise in your own words the main arguments of texts you are reading. Even if it is just a letter to the newspaper, ask yourself : what is the main point the author is trying to convince me of? What kinds of evidence do they provide?

Once you have a clear idea of what the argument's conclusion is and what kinds of evidence have been given for it, you are able to move on to the next stage of analysis. That will involve thinking about what else the author is doing to attempt to convince you of his or her conclusion, apart from giving evidence or reasons for it. --------------------------------------------------------------------------------

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6.3 Persuasive Language And Other Rhetorical Devices In an activity like debating, the point is simply to win an argument, and to employ whatever techniques are necessary to beat your opponent. This is not, however, the way we should understand the purpose of argument in general. We do not argue solely to make someone agree with us, but to find the truth about some matter, and to provide good reasons for others to believe our conclusions. If our aim were just to elicit agreement, we could achieve this by lying, or perhaps by intimidation -- persuasive success is not the only measure of a good argument.

A good argument should, of course, be convincing, but it should be convincing because it provides strong evidence for its conclusion. We should be aiming to enlighten, not just to win.

We may consider the rational core of an argument to be its premises and inferences. A good argument is one which begins with true, or at least acceptable, premises, and from those premises draws a conclusion which does follow from them. Rhetorical devices, generally speaking, may defined as elements of an argument or argumentative text which are intended to be persuasive, but which are distinct from this rational core.

Rational force vs persuasive force The persuasiveness of an argument may depend on:

•the acceptability of its premises •the strength of its inferences •the persuasive or rhetorical devices employed in its presentation

It is only the first two factors, however, which make an argument rationally strong. It is important to be able to separate the rational force of an argument from its persuasive force, to avoid being swayed by rhetoric into accepting a conclusion for which no good reasons have been given.

One important species of rhetoric is the use of persuasive language. We will begin with a discussion of persuasive language, and then go on to look at other persuasive techniques used in arguments.

Persuasive language, which is used to put a positive or negative spin on something without actually providing any good reasons, is sometimes referred to as "slanting". Slanting may occur when someone tries either to evoke an emotive response, or to prevent one that might be appropriate, or in any case where language is used in an attempt to arouse a response or perspective which is not justified by the evidence.

It is a weakness in an argument if it is superficially convincing because of the language in which it is stated, but lacks real inferential substance. We will look at a number of common uses of persuasive language which can be fallacious. These are all examples of ways that people may choose language in a way which makes their argument seem stronger than it really is, or in a way which is intended to hide its flaws. Remember that ultimately when you are evaluating the strength of an argument, you will be evaluating the content of its premises and the strength of its inferences, irrespective of the particular language in which it is presented.

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These are a few examples of ways language might be used persuasively:

6.3.1 Emotional charge Emotionally charged language is language intended to evoke a particular emotional response. This may not be a fallacy --indeed in some cases emotionally language is appropriate, and our language would be much poorer without it. It is a problem when the emotional force is what is supposed to sway the audience: when it is used as a substitute for good reasoning. For example, emotional force may be used to obscure poor reasoning: to obscure the fact that the argument presented lacks substance:

(3a) Every year, millions of beautiful, sacred trees -- their very existence a testament to mother nature's beneficence -- are heartlessly, violently sacrificed. We should stop this wanton destruction. Here, the arguer uses emotional language to appeal to the sentiment of the audience. If we were to strip the argument back to its non-emotive content, it is clear that there is not much to it: (3a-i) Every year, millions of trees are cut down. So we should stop cutting down so many trees. We shouldn't allow the force of the language to persuade us in this case, because no real reasons have been given for accepting the conclusion. The converse danger with emotionally charged language is that even if the argument is a reasonable one, couching it in strong emotional language can obscure its good features. In particular, it is likely to make an opponent less sympathetic to the argument. For example, this argument looks not much better than the one above, but does in fact present genuine reasons to accept its conclusion:

(3b) For tens of thousands of years, the great trees of the Tasmanian wilderness have grown, strong and proud, the wisdom of the years held in their mighty branches. Why should these trees be slaughtered, hacked down for woodchips? Elsewhere, we have armies of fast-growing young plantation timbers, better for chipping, and renewable, so that when one is cut down, another quickly arises to stand its place. We should not continue to sacrifice the old giants of the forest. Have we no respect? The argument here is that we should not cut down ten thousand year old trees from old growth forests for woodchips, because we can get better woodchips from fast-growing renewable plantation timbers. This is a reasonable argument, but the way it was presented above would be likely to make opponents hostile, and less likely to take the argument seriously. While there is nothing intrinsically wrong with using emotional language in some contexts, ensure that you do not allow emotive language to persuade you of something you would not otherwise accept. When giving an argument, do not let emotive language obscure the argument you are trying to present.

6.3.2 Euphemism

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While emotionally charged language is used to stir up emotions, language may also be used to play down the emotional impact of a subject matter. When the language is used to suppress what might be an appropriate emotional response, this is an example of euphemism.

Euphemism is commonly used for propaganda purposes, or in other discourse where an arguer may want to make something sound more innocuous than it really is. For example, if a company wants to make use of a merger so that it can fire people without getting sued for unfair dismissal, this policy could be represented euphemistically as:

(3c) The proposed merger should go ahead. It will allow us to streamline the workforce, without getting caught up in bureaucratic red tape. Many examples of euphemism are to be found in the language of war - such as "friendly fire" and "collateral damage".

6.3.3 Loaded terms Sometimes unjustified persuasive force will be carried just by the words which are chosen to describe an action, event, person or issue. A loaded term or description is one which is presented as a simple description, but which actually involves significant assumptions. If we choose to describe euthanasia as murder, then we will be trying to convey a certain opinion through the choice of words. Similarly a decision about whether to refer to someone as a "conservationist" or a "tree-hugger" will carry different connotations.

Sometimes, a particular choice of description will do more than just convey emotive connotation -- it may result in a subtle distortion of the facts. An example of this throughout the recent refugee debate is the difference between describing people as "refugees", "asylum seekers" or "illegals". This is not simply a matter of free linguistic choice, since these are factually distinct descriptions, but they are used more or less synonymously by people expressing different opinions in the debate.

When you are evaluating the use of language in an argument, think about how the author has described the subjects of the argument (whether these are people, issues, events... ). Is the description one that an opponent would accept? What you should be looking for in this context is not what is actually claimed, with evidence, about the subject of the argument but what implications are carried by the way those subjects are referred to or described.

6.3.4 Suggestions of certainty or doubt Language can be used, sometimes quite subtly, to suggest that some matter is either more or less certain than it is. Certainty is often suggested with the inappropriate use of such 'assuring terms' as "Clearly" or "it is obvious that"

Examples of illegitimate suggestions of certainty include:

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Noone could seriously suggest that training for people on the dole could do any good, since it is well known that most of them simply have no interest in working. Australia is obviously not in a position to increase its refugee quotas.

In each of these cases, the use of language suggests that the claims being made are undeniable, but they would not be accepted by opponents. Language is used in this way to stifle debate, by presenting a controversial claim as though it were not a point at issue. Language can also be used to suggest doubt, where doubt is unreasonable, particularly in counterconsiderations where the point may be to downplay the significance of a potential objection.

Admittedly, there is evidence to suggest that smoking may not be good for you, but... If the sales figures are to be believed it would seem that a lot of children like the Harry Potter books.

Like other kinds of persuasive language, this is a way of misleading an audience without making claims which are factually incorrect.

6.3.5 The appropriateness of rhetoric in a context

When you are thinking about uses of persuasive language or other rhetorical devices in a text, bear the context of the argument in mind. A certain amount of persuasive force is to be expected in some contexts. There is a difference, for example, in the kind of language and argumentation which would be appropriate in a newspaper editorial, and a news report in the same paper. Editorials are expected to be opinionated and will often use persuasive language which would be inappropriate in a news feature, where information should be presented impartially.

Thus the use of persuasive language or other persuasive devices is not something which should be treated as a flaw in all contexts. But even where its use is not inappropriate, it must be treated with caution. Caution should be exercised by the arguer, so that these devices are not allowed to obscure the inferential structure of the argument, and by the audience, so that you are persuaded only by arguments which are rationally persuasive. --------------------------------------------------------------------------------

The classification of kinds of potentially problematic persuasive devices discussed above is not intended to be exhaustive. Persuasive devices like those above will often be used non-fallaciously, and not every fallacious use of rhetoric will fit into one of the categories we have discussed. The best way to approach the evaluation of the language and rhetorical devices of a text is first to read the text, and think about what it is trying to convince you of, and write a brief summary of the main arguments. Once you know what the basic point of the argument is, you are in a position to read through it again, and make a note of the extent to which the language and other persuasive devices are what carries the force of the argument. How does the author use those devices to convince you of the conclusion? Ultimately what we will be doing at the end of an evaluation is coming back to look at how much of the persuasiveness of the

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argument is a result of the strength of the inferences, and how much is the result of the use of persuasive language and rhetorical devices. --------------------------------------------------------------------------------

6.3.6 EXERCISE - emotionally charged language In September 2001, asylum seekers from Iraq and Afghanistan were picked up by the HMAS Manoora, an Australian Navy troopship, and were taken to Nauru to have their applications for refugee status determined. Some of the asylum seekers, who had intended to land in Australia, refused to leave the ship in Nauru. After several weeks of negotiations, they were forcibly removed from the ship by the Australian military. Read the following articles, available in e-reserve (go to http://www.lib.mq.edu.au/resources/reserve/ and search under "PHL137" ):

"Electoral games a nation's shame" by Mark Day and "When force is the right response" by Campbell Reid

Both of these articles were published in the Daily Telegraph in response to the Tampa crisis and the government's response. The two articles - one an opinion piece and one an editorial, present opposing viewpoints, and both use strongly emotionally charged language. Evaluate the use of language in each case. Note the examples of emotional language, and consider whether the use of such persuasive language is appropriate. What is the factual content of each of these extracts, once the persuasive language is stripped away? -------------------------------------------------------------------------------

6.4 Text For Analysis "The case for cloning humans" by Colin Honey available in e-reserve ( http://www.lib.mq.edu.au/resources/reserve/ ) under "PHL137".

This is a text we will return to in these notes as we gradually build up a comprehensive strategy for evaluating arguments. As a new skill is introduced, it will be applied to this argument.

To begin with, we will give an argument summary, and consider the effect of author's use of language.

6.4.1 Summary of Text The first thing you should think about when analysing an argument is the conclusion: what does the author want you to accept? From the headline, you may initially suppose that the author's purpose is to convince readers that human cloning should be allowed, but this may be a little too strong. Remember that while headlines are often a good guide to the purpose of an argument, they can be misleading: they sometimes express a more exaggerated position than the article they precede, since their purpose is to attract

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attention. In many cases the headlines of articles appearing in newspapers are not even chosen by the author of the text, but by a sub-editor, so they should not be relied on as evidence of the author's intentions.

While the author of this argument does seem to be in favour of cloning, the point of this article is not to convince readers that human cloning should be accepted. The position he adopts is a more modest one: that human cloning should not be ruled out without due consideration being given to the arguments for and against it. It would be contrary to the principle of charity to present this as an argument for cloning if the author's point is not actually that strong, since the reasoning he provides is better evidence for the weaker claim, that cloning should not be ruled out too quickly, than for the strong claim that it should be supported or allowed to go ahead.

To argue for this conclusion, the author adopts a largely negative method, in the sense that the argument consists mainly of responses to objections that have been raised against cloning. He also attempts to undermine the objections of medical scientists, by suggesting that they have ulterior motives for their rejection of cloning.

The catalyst for this article, it appears from the introduction , is the claim of Brigitte Boisselier and the Raelians (a sect who believe that humans were created by aliens via cloning) to have cloned a child in late 2002. As someone who thinks cloning should be given serious consideration, it is likely that the author does not think the public should be put off cloning by its association with such groups.

6.4.2 Summary It is not necessary to write out a summary, but it can be useful at least to think about how the argument could be summarised briefly. Without going into detail about the actual objections considered, we could summarise the main structure of the argument as follows

The author argues that human cloning should not be ruled out without serious consideration. He argues that several common objections to cloning are unjustified, and that medical scientists' objections to reproductive cloning are probably an attempt to make stem cell research more acceptable.

6.4.3 Uses of language The tone of the article is colloquial and informal, but generally judicious and reasonable, and largely free from emotional charge. There are, however, a few uses of language that could be noted in an evaluation of the text. Not all of these points would need to be included, but these are the sorts of things you might think about.

For example, consider the effect of the opening phrase "Human cloning will happen". This is stated as though it were a significant point in the argument, but in fact it is being used for rhetorical effect. Not only is Honey not trying to argue that human cloning will actually happen, the position is not even consistent with the argument as a whole. He later acknowledges that cloning may turn out to be impossible, so it appears that this opening is just being used to grab the attention of the audience.

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Another piece of language that could be considered in an evaluation is the use of the word "cloning" throughout the argument. The author argues that medical scientists are overemphasising the distinction between cloning human beings and stem cell research. In this text, the author goes the other way and obscures that distinction, by the use of the terms "reproductive cloning" and "therapeutic cloning" to refer to these two processes. This could be interpreted as a subtle kind of loading, as part of the author's argument in several parts of the text is that if you are willing to accept stem cell research, you should also be willing at least to consider reproductive cloning. By linking the two linguistically, he is emphasising their similarity in a way that people who believed in one and opposed the other would not do.

A similar effect is achieved by describing twins as "naturally occurring clones", and clones as "twins". By using these words interchangeably, the author underplays the distinction between them. None of this is factually incorrect: his use of words is perfectly legitimate. To describe it as a kind of loading is just to say that it is a choice of words that presupposes a particular attitude, and would not be likely to be used by an opponent.

The article is relatively free from emotionally charged language, but what is there is again used in the comparison of stem cell research and reproductive cloning. To the extent that the author does want to distinguish between these, he is arguing that stem cell research should be considered more objectionable. Thus he describes the process involved in stem cell research quite provocatively as "killing off embryos" and "harvesting" cells.

The other examples of language being used for persuasive effect, which can be considered later in the evaluation of specific subarguments, are several unjustified assertions of certainty, where something is presented as being common knowledge but really is not. For example his claim regarding IVF and surrogacy that "we have come to accept both". Surrogacy, at least, is still quite controversial. More problematically, when drawing the analogy between reproductive and therapeutic cloning, the author asserts that "there is widespread agreement as to the rightness of therapeutic cloning". While it is true that stem cell research is much more widely accepted than reproductive cloning, it remains very controversial.

Not all of these points may need to be raised in an evaluation of the text, but try to be aware of anything which is being used to convince you to accept the conclusion of an argument. An argument may employ all sorts of rhetorical devices and still be a good argument when they are stripped away, but a healthy scepticism about the use of such techniques in arguments you read and hear will help to immunise you against the influence of bad arguments.

We will return to this text for more discussion, after establishing some further principles of argument evaluation.

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7 BROAD STANDARDISATION (Week 10)

7.1 Close Standardisation And Broad Standardisation When we initially began with standardisation, the process involved identifying the conclusion of the argument and each of the premises, and specifying the inferential relationships between them. This is a useful exercise for short arguments, when you need to examine precisely how the inference works, (for example the standardisation of the "Monty Hall" solution in Week 2 ) but is going to be impractical, and not especially helpful, if the argument you want to assess is the argument of an entire journal article, or even a book. For these purposes, it is useful to have some kind of intermediate level of analysis, between simply reading the argument as it actually occurs embedded within a text and summing up the main argument on the one hand, and providing a full standardisation on the other. For these purposes, we will construct what will be referred to as a broad standardisation of an argument, which contains the essential features of an argument for analysis. Broad standardisation will be distinguished from close standardisation, which is the comprehensive kind of representation we were constructing previously for shorter arguments. In a close standardisation, the aim was to include each individual premise in the standardisation, so that the standardisation would provide a comprehensive representation of the original argument. A broad standardisation of a longer text does not need to be comprehensive: it is not intended as a replacement for the argument itself but as a basis for its analysis. The standardisation is meant to guide you in your evaluation, and allow you to see clearly what the argument is. It gives you a foundation from which to start your evaluation, and clarifies the structure of the inferences. You can always refer back to the text for more details. One of the difficulties in giving a brief, functional standardisation of a long or complex argument is knowing what to include and what to omit. The short, and perhaps initially not very helpful answer to this is that you should include as much as is important to give an appropriate representation of the argument for the context of your analysis. In these lectures, we will think about ways to decide what has to be included to give a short but fair representation of an argument for analysis.

To construct a broad standardisation, we will need to:

1) Identify the overall conclusion, paraphrasing if necessary

2) Identify the main lines of reasoning in support of that conclusion and represent these as the main premises of the argument (1, 2, 3 etc). Again, it will probably be necessary to paraphrase.

3) For each of the main premises, identify the main pieces of evidence used to support it. These will be the subpremises (1.1, 1.2 etc).

As rule of thumb, going back as far as one level of subpremises will be sufficient to give an overall representation of the argument.

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7.2 Text For Analysis Link to text in e-reserve: ( http://www.lib.mq.edu.au/resources/reserve/ )

7.2.1 Standardisation We now return to the text of Colin Honey's article we began looking at previously. (It would probably be convenient to print it out, but otherwise you can open it in a new window through e-Reserve.) As a basis for a full analysis of this argument, our earlier summary would be insufficient, and so we need to build up a more comprehensive representation of the argument by giving a broad standardisation of it, to capture the main lines of reasoning in a text, without giving all the detail.

When you present your analysis for the assignment, you will be required to begin with a broad standardisation of the argument. Recall that you should include in a broad standardisation as much as is necessary to give a fair representation of the main lines of reasoning in the text, and as a rule of thumb that will normally mean that you will need to go back as far as one level of subpremises. Often the simplest way to begin is by identifying the main premises of the argument, and then going back to find the subpremises in support of each.

The conclusion of the argument should be stated in a way that is fair to the author's intentions, but it does not need to be taken straight from the text. In this case, the conclusion could be phrased, for example, as " Reproductive cloning should not be ruled out without further serious consideration".

To begin, it can help to go through and identify the different "themes" of the argument. The first series of issues in this text, for example, concern questions about the identity and individuality of a clone. We noted above that the premises in this argument are mostly negative, in the sense that they are offered as responses to objections to cloning, rather than providing positive reasons that cloning should be accepted. The first line of reasoning responds to the concern that clones may not be individuals.

Because a series of objections to cloning are responded to in this argument, it might be tempting to treat those objections as a target argument, to which Honey's argument responds as a counterargument. This would not, however, be appropriate in this case because the objections suggested are not attributed to any particular person or group. If it were presented as a target argument, the implication would be that someone (or some people), put all these points forward as an argument against cloning, but it may be that no-one makes all of these points. While in this case it would not seem very wrong to present it this way, as a matter of general practice it would be unwise to present a series of distinct objections as a target argument, since in some cases the objections made by different people or groups might be inconsistent with each other. To treat such a series of distinct points as a single, internally inconsistent target argument would not be a fair representation of those objections.

If you did want to include the objections in the standardisation, you could present them as counterconsiderations. If you do, make sure you state them in an appropriate way. Remember that a counterconsideration is not just an objection, it is something that is admitted by the author of the argument, so rather than saying " Clones would not be individuals", you would need to put it in a form like. "Some people argue that clones would not be individuals". This difference is significant because the author would accept the latter, but not the former, and by presenting it as a counterconsideration in his argument, you are attributing the claim to the author.

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In my standardisation, I will not explicitly include the objections to cloning as counterconsiderations, because the fact that the premises are offered as responses to these sorts of concerns can be made clear in the phrasing of the premises themselves. Because in a broad standardisation you will generally paraphrase premises, rather than drawing them directly from the text, you are free to choose a formulation that makes clear the place of the premise in the argument. For example, we could state premise 1 as " Concerns about individuality should not lead us to rule out reproductive cloning."

How far does this first subargument extend in the text? In one way or another, the issue of individuality continues throughout the first half of the article, until the end of the tenth paragraph ("... their life experiences cannot be identical without recourse to a time machine").

The structure here could be a bit confusing on a first reading. For example it might be thought that the references to God in paragraph 8 and in paragraphs 11 and 12 should be treated as part of the same subargument. If you consider the point made in each of those discussions, though, it should be clear why they are distinct. God is introduced in the eighth paragraph in an argument about souls. The point being argued about with reference to souls, however, is a point about individuality: can clones have their own souls? This part of the argument is therefore relevant to premise 1. The references to God in paragraphs 11 and 12, however, are not about individuality. They are about the question of whether cloning should be resisted because it is "playing God". Because that is a separate issue, we can treat paragraphs 11 and 12 as a new subargument. Premise 2 would be something like "Concerns about 'playing God' should not lead us to rule out cloning."

The next paragraph is a response to the objections raised about people's motivations for cloning, and about whether the clone would be valued for itself. This subargument only continues for that single paragraph, so premise 3 could be stated simply as " Concerns about clones not being valued for themselves should not lead us to rule out cloning".

The author then goes on to suggest a possible reasons or motivations for people's opposition to cloning. The fourth premise, based on an analogy drawn between cloning and other reproductive technologies which were initially opposed is something like : "Much of the opposition to cloning is a result of its being new, and this opposition will be overcome".

In the second last paragraph of the article, the author tries to undermine the objections of medical scientists, by attributing to them an ulterior motive for opposing reproductive cloning. He suggests that they oppose reproductive cloning, because by drawing a distinction between reproductive and therapeutic cloning (stem cell research), they hope to make stem cell research seem more acceptable. We could state this final premise as "Objections from medical scientists may just be attempts to gain support for stem cell research ".

The last thing we should probably include before going back to look for subpremises is the counterconsideration contained in the third last paragraph. The author acknowledges that cloning "may yet turn out to be impossible -- and certainly the practical difficulties are enormous -- or too costly. Perhaps the confusion in relationships will be unacceptable. " These seems to be quite a significant admission in the context of the argument, and would therefore be worth including as a counterconsideration.

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The main argument, then, would look something like this:

[cc: practical difficulties, cost or confusion in relationships may yet make reproductive cloning impossible.]

1: Concerns about individuality should not lead us to rule out cloning 2: Concerns about 'playing God' should not lead us to rule out cloning 3: Concerns about clones not being valued for themselves should not lead us to rule out cloning 4: Much of the opposition to cloning is a result of its being new, and this opposition will be overcome 5: Objections from medical scientists may just be attempts to gain support for stem cell research C: Reproductive cloning should not be ruled out without further consideration

7.2.2 Subpremises Now that we have a clear idea of what the main premises are, we are in a position to go back and see what support was given for each of them. As with the main premises, some paraphrasing will be necessary to come up with a simple statement of each premises to be included.

7.2.2.1 Subpremises supporting premise 1 The subpremises supporting premise 1 will be any reasons given for thinking that concerns about individuality should not lead us to rule out cloning. There is an extended discussion on this issue, so to identify subpremises pick out the main reasons given for this subconclusion. We don't need to include every detail, so rather than including the details about Prince Harry's paternity, for example, you would just want to capture the point made in that section. For example: 1.1: Family resemblances are generally considered a good thing

The analogy with identical twins is then introduced. The point of the analogy is that identical twins are, in a sense "naturally occurring clones" since they are genetically identical, and since they are individuals, so would clones be. This could be captured in two linked premises:

1.2: Identical twins are genetically identical 1.3: Identical twins are individuals

The next subpremise in support of premise 1 is similar, but is now based on the question of whether or not clones would have individual souls. We could link the following premise to 1.2 as well:

1.4: Identical twins have souls, if souls exist.

The final reason given for thinking that clones would be individuals is that an individual's personality is greatly influenced by his or her experiences and environment, and clones would differ in these respects:

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1.5: Individuality is a matter of environment as well as genetics, and clones would grow up in different environments

7.2.2.2 Subpremises supporting premise 2 Premise 2 states that we should not reject cloning because of a fear that it would be "playing God". The reason given for thinking that this fear is unjustified is that stem cell research seems to be more problematic from that point of view, and yet stem cell is widely considered acceptable: 2.1: There is widespread agreement about the rightness of therapeutic cloning 2.2: From the point of view of 'playing God', therapeutic cloning (which results in the death of the foetuses) is more objectionable than reproductive cloning. These premises are linked in support of premise 2.

7.2.2.3 Subpremises supporting premise 3 The third premise concerns the issue of whether a clone would be valued for itself, or whether it would be created just to satisfy someone else's "selfish desires".

Two distinct lines of reasoning are presented for this premise. First, it is suggested that this may be the only way some couples could have a child, in which case it might be unreasonable to deny them that opportunity:

3.1: For some people cloning is the only way of having a child.

Secondly, an analogy is drawn with the motives of couples who have children the normal way: we do not test their motives, so why should we test the motives of those who want to have a child by cloning.

3.2: We do not question the motivations of parents who have children the conventional way

7.2.2.4 Subpremises supporting premise 4 Premise 4, which states that many of the objections to cloning are just because it is a new possibility and these will be overcome is supported by an analogical argument, this time drawing an analogy between reproductive cloning and other more established reproductive technologies.

4.1: IVF and surrogacy were opposed when they were new technology 4.2: We have now come to accept IVF and surrogacy

7.2.2.5 Subpremises supporting premise 5 Premise 5 is the author's suggestion that the "real reason" for the scientific community's opposition to reproductive cloning is that they are trying to gain support for stem cell research. The only evidence given as support for this suggestion is that

5.1: By emphasising the distinction between reproductive and therapeutic cloning, medical scientists can make therapeutic cloning seem more acceptable

Full standardisation

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Putting all those premises together, the broad standardisation we end up with is this:

[cc: practical difficulties, cost or confusion in relationships may yet make reproductive cloning impossible.]

1.1: Family resemblances are considered a good thing 1.2: Identical twins are genetically identical 1.3: Identical twins are individuals with the same rights 1.4: Identical twins have separate souls, if souls exist 1.5: Individuality is a matter of environment as well as genetics, and clones would grow up in different environments 1: Concerns about individuality should not lead us to rule out cloning

2.1: There is widespread agreement about the rightness of therapeutic cloning 2.2: From the point of view of 'playing God', therapeutic cloning (which results in the death of the foetuses) is more objectionable than reproductive cloning. 2: Concerns about 'playing God' should not lead us to rule out cloning

3.1: For some people cloning is the only way of having a child. 3.2: We do not question the motivations of parents who have children the conventional way 3: Concerns about clones not being valued for themselves should not lead us to rule out cloning

4.1: IVF and surrogacy were opposed when they were new technology 4.2: We have now come to accept IVF and surrogacy 4: Much of the opposition to cloning is a result of its being new, and this opposition will be overcome

5.1: By emphasising the distinction between reproductive and therapeutic cloning, medical scientists can make therapeutic cloning seem more acceptable 5: Objections from medical scientists may just be attempts to gain support for stem cell research

C: Reproductive cloning should not be ruled out without further serious consideration

As with any broad standardisations, there will be alternative ways to do this, but the standardisation above seems to give a fair representation of the author's main lines of reasoning.

We will come back to some further analysis of this text over the final two weeks of the course.

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7.3 The Acceptability Of Premises In our discussion of deductive arguments, we saw that to guarantee its conclusion, a deductive argument had to be valid and have true premises. This applied only to deductive arguments, but a more general criterion may be given for the success of any argument: For an argument to be successful -- to rationally convince its audience of its conclusion -- it needs to have strong inferences and acceptable premises. We will not always be in a position to know whether every premise of an argument is true, but in this lecture we will consider ways of determining whether they are likely to be acceptable. In any complex argument, some of the premises will be supported by subarguments, and some will not. Clearly, not every premise can be supported by a further premise, or the arguments would have to go on forever. There are some things which will just have to be asserted. What we need to think about in evaluating the premises of an argument is when the premises can just be accepted, and when further evidence would be required. The main questions to consider in this regard when analysing an argument are: 1) Which premises can be accepted without further justification? 2) Of those which cannot, what sort of evidence would we need? Is such evidence provided? Remember that which premises are considered acceptable is important, because no matter how strong the inferences in an argument are, if you don't accept the premises, you have no reason to accept the conclusion.

7.3.1 Common knowledge Whatever the context in which an argument is presented, there will be some common background knowledge which the audience of the argument will be expected to share. A proposition which can be assumed to be common knowledge in a particular context, can reasonably be offered as a premise without further support. What counts as common knowledge will vary depending on the audience. The following propositions are all such as might be assumed to be common knowledge among Macquarie University students: Macquarie University is in Sydney. Trees are plants. John Howard is the Prime Minister of Australia. Some people are tall. Unleaded petrol is better for the environment than leaded petrol. If you don't breathe, you will die. J comes before K in the alphabet.

Some of these are trivial, some aren't, but their common feature is that all of them are the kinds of propositions which could be used as premises in an argument (for the audience currently under consideration) without further justification. If a premise is not common knowledge, we may require more evidence before we accept it. Suppose someone wants to convince you that some animals were telepathic, and offers the following argument:

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(3a) 1 Dogs are animals 2 Some dogs have telepathy therefore C Some animals have telepathy

How strong is this argument? It is valid, so if you accept the premises, you will also have to accept the conclusion, but would you accept the premises? The situation with respect to each of these two premises is rather different. The first premise is the sort of claim which someone presenting an argument could reasonably expect an audience to accept. That dogs are animals could be assumed to be common background knowledge, and in ordinary circumstances it would be unreasonable to criticise the argument for failing to give any evidence for the first premise. The second premise, however, is certainly not commonly known, and this is a premise which would need to be given some support in an argument.

7.3.2 The importance of common knowledge in constructing a broad standardisation If a premise is not common knowledge, we need to have some reason to believe it. This is not a reason for undue scepticism, but it is a reason to think about why we believe the things we do. There is no point is simply disputing every premise of every argument which is not independently supported, but bear in mind when you go on to evaluate arguments that even for good arguments, the conclusion is only as certain as its premises.

(3b) 1 The intended purpose of airbags is to reduce the likelihood and severity of injuries in road accidents 2 they have been found to be ineffective in achieving this. C: it is not worth paying extra to have airbags fitted when you buy a car.

This argument has two premises. The first might be acceptable as common knowledge, as anyone who knows enough about the matter to know what an airbag is would also be likely to know that this is their purpose. The second premise, however, which claims that airbags are not effective in reducing the likelihood and severity of injuries in road accidents, is something for which we would probably want extra evidence. The fact that such evidence is not given is not a reason to reject the argument, but an appropriate attitude to take might be to admit that if it is true that they have been found to be ineffective, then it would not be worth paying extra to have airbags fitted. If you are not certain of the premise, then that uncertainty will carry across to the conclusion. We will in the next lecture at when it is reasonable to accept some premise because of its source, but for the moment our concern is to think about how much of the argument needs to be included in a brief standardisation, or considered in your evaluation. If there is a premise which is common knowledge, you may not need to include all premises which are given in support of it in your discussion, since even if the evidence given is not strong, the premise will still be accepted. But if premises are given in support of some proposition for which evidence is required, then it would be contrary to the principle of charity to omit such evidence. If you are planning to evaluate the argument, you need to evaluate a strong form of it, so it is unreasonable to leave out evidence which has been provided for premises which require such evidence. Consider the longer passage, in which the argument above occurs.

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(3b-i) As car buyers, it is often difficult to know what options are worth paying for and which are not. Sometimes, we know that we are making decisions which are purely a matter of personal preference -- Do I want airconditioning? Do I prefer metallic paint? Can I live without a cup holder, or a CD player, or electric mirrors? When it comes to airbags, though, people think that they are making an important choice about safety, but is this really the case? If a car is involved in a collision, a small explosion is set off in the airbag, causing it to inflate rapidly. The intended purpose of airbags is to reduce the likelihood and severity of injuries in road accidents -- if you look at any manufacturers' information about airbags, this is always what it says, and we know that the original inventors of the airbags invented them to reduce the number of road deaths each year. But, despite these intentions, they have been found to be ineffective for this purpose. A study of 10,000 motor vehicle accidents in the US in 1990 showed that there was no significant difference between the number of deaths and hospitalisations incurred in cars without airbags, and cars with airbags. It follows that it is not worth paying extra to have airbags fitted. You might just as well spend the money on those cup holders.

The main argument is the one given above. How much else would we include if we were giving a standardisation for the purposes of evaluation? It was noted previously that "The intended purpose of airbags is to reduce the likelihood and severity of injuries in road accidents" is something which could be accepted as common knowledge, and would not be a subject of dispute in the evaluation of this argument. The author of the argument does provide some evidence in support of this "if you look at any manufacturers' information about airbags, this is always what it says, and we know that the original inventors of the airbags invented them to reduce the number of road deaths each year." But because noone is likely to object to this premise, it would be reasonable not to incorporate these extra premises in your broad standardisation, or to consider them explicitly in your evaluation. What is more important is the evidence which is given for the more controversial claim, that airbags are ineffective. The evidence for this is the report of statistical research which had been conducted into the effectiveness of airbags. In evaluating the argument, it would be important to include this evidence. If you leave out the support an arguer has given for a controversial claim, you are not being fair to the author. You cannot object to a controversial premise without having considered the evidence which was given in support of it. The principle of charity requires that you present the argument according to its best reasonable interpretation. If you misrepresent the argument you are evaluating, and make it appear weaker than it is by leaving out evidence for important and controversial claims, you are committing the straw person fallacy. Your criticisms will be unsuccessful, since they may not be relevant to the argument you are supposed to be evaluating .(More on this fallacy later).

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8 EVALUATING INFERENCES (Week 10)

8.1 Introduction Once you have a working standardisation -- whether it is a close or broad standardisation -- and you have considered the acceptability of any unsupported premises, the next thing you need to consider is the strength of the inferences represented in that standardisation. We have seen a number of kinds of arguments where particular patterns can be considered to decide whether or not an inference should be accepted : ways of assessing deductive validity in the case of conditional arguments, for example, and the measures of inductive strength appropriate to various kinds of inductive arguments. In many cases, however, there is no particular set of rules to be applied. Instead, what we need to do is consider each of the inferences which has been represented and decide whether the premises really provide good reason to accept the conclusion. Inferences will have to be assessed on a case by case basis, but in these notes we will look at a few common ways that things might go wrong. We will look first at assumptions, or suppressed premises, which may be identified as occurring when the premises which are given in support of a particular conclusion require some additional claim to be assumed. This will be a flaw in the argument if what is assumed is something for which we would require evidence. We will then go on to look at some examples of common fallacies, with a particular focus on fallacies of relevance, which are committed when a premise is presented as though it offered support for a conclusion to which it is actually irrelevant.

8.2 Suppressed Assumptions When standardisation was first introduced, we saw that it is sometimes necessary to make explicit a premise which was not fully stated in the argument. (2a) Only outstanding musicians are accepted into the orchestra. So given what we know about Wally's musical talents, he is not going to get in.

Would be standardised as: 1 Only outstanding musicians are accepted into the orchestra 2 Wally is not an outstanding musician C Wally is not going to get into the orchestra. The second premise has been put into a clear propositional form, and we can see from this standardisation that the argument is a valid conditional argument. In many longer arguments, the conclusion will not be stated at all, and in those cases it is necessary to decide what point the author of the argument is trying to convince the audience to believe, and use that as the main conclusion in your standardisation. This is something you have had practice of in giving argument summaries, and broad standardisations. Whenever it has been necessary to make a premise or conclusion explicit, we apply the principle of charity, by choosing a statement of the proposition which is no stronger than it needs to be (hence we state premise 2 in the argument above as "Wally is not an outstanding musician", which is all that is needed for the argument, rather than "Wally is an abysmal musician", which might be more than was intended.)

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The point of finding missing premises or conclusions like this was just to make the argument clearer, by putting all the parts of the argument into clear propositional form. In this sense, clarifying missing premises or conclusions is just a matter of explicitly and clearly formulating all parts of the argument . There is, however, another sense in which an argument may contain a missing premise, which may not be so innocuous. In many cases an argument will involve suppressed premises: it will be making assumptions which are necessary for the inference to be acceptable, but which are not stated, and are therefore not given any justification. Sometimes the assumptions which are made will just involve commonly accepted background information, but in other cases, assumptions may be made which are far more controversial. If controversial premises have just been assumed without justification, this will be a weakness in the argument.

The fact that an argument involves suppressed assumptions may or may not be a problem. It is not a problem if it is only generally accepted beliefs which are assumed. It is a problem if the assumptions are controversial.

To clarify this distinction, consider the following arguments, each of which seem to rely on the assumption of information which is not explicitly stated: (2b) That car is hardly big enough to fit twelve clowns in it, so there is no way they could fit twenty. (2c) Fido is a dog, so he couldn't live underwater. (3d) Abortion is wrong, because killing a human being is always wrong.

In each of these arguments, we need to bring some extra information to the argument to understand why the conclusion is supposed to follow from the premise. In the first argument, the assumptions which might be being made are all uncontroversial: "twenty is more than twelve" perhaps, or "If you can hardly fit twelve of something somewhere, you can't fit twenty". These are propositions which anyone would accept, so you would not need to make a point of this if you were evaluating the argument. The second case involves an assumption that dogs can't live underwater. Again, this relies on some background knowledge, but it is something that anyone would accept as common knowledge, so the fact that the argument does not make this explicit would not be a reason to object to the argument. Provided that the intended audience was composed of people we could expect to share our basic background beliefs, these inferences would be acceptable. The third case, however, is different. The argument as it stands is: (2d-i) 1 Killing a human being is always wrong C Abortion is wrong Does the conclusion follow from the premise? It follows only if we accept the controversial assumption that abortion involves killing a human being, ie that a foetus is a human being. The intended argument seems to be something like this: (2d-ii) 1 Killing a human being is always wrong [2 Abortion involves killing a human being] Suppressed premise C Abortion is wrong

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This new premise, 2, is not something which can just be assumed as background knowledge, because this is really one of the important points of dispute in the abortion debate. When an argument relies on a controversial assumption, this is something which should be noted in your evaluation, because it constitutes a flaw in the argument. If a premise is controversial, as we have seen, it should be supported by some evidence. It is not permissible to furtively sneak premises into your argument if they are premises with which an opponent might disagree. To work out if there are any suppressed premises/assumptions which need to be noted in your evaluation of an argument, look at any inferences which seem incomplete, and ask yourself "What would the author have to have been assuming, to think that the conclusion followed from these premises? If there are assumptions which are just common knowledge, then this is not a problem, but if you find something which is being assumed, but which would require further justification, this is something to which an objection should be raised.

Examples

Each of these arguments involve some kind of suppressed premise. In which case is a questionable assumption made, and in which cases is it acceptable, relying only on what could reasonably be considered background knowledge? (1) We should not allow boat people to into this country, because we do not want terrorists based here. This argument is based on the suppressed premise that boat people are likely to be terrorists. This is not a premise which could be accepted without being supported by evidence.

(2) On average, women get paid less than men. This shows that despite sex discrimination laws, men still get paid more for the same work. This argument relies on the assumption that women and men do the same work. This is probably not true, because more women than men stay home with children or work part-time, thereby bring down the average income, and the sexes are not evenly represented in different professions. Therefore the fact that on average women do not get paid as much as men does not establish that they get paid less for the same work.

(3) You can't keep a cat in your unit, because it's a condition of your lease that you don't keep any pets. This involves a suppressed premise that a cat which you keep in your unit would be a pet. This seems acceptable as common background knowledge.

(4) Brad votes Labor. So Brad is probably a communist. This rests on the assumption that people who vote Labor are likely to be communists. This is not an acceptable assumption.

(5) Debbie has two children. So Debbie is a mother. This conclusion follows from the premise if we assume that "Debbie" is likely to be a woman's name, rather than a man's. While we cannot be certain of this, it would be acceptable to assume this as a commonly shared belief, at least in our society.

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(6) Britney was miming at her concert. She must not actually be able to sing. The assumption here is that if Britney could sing, she would have done so. This may not be justified, because there may have been other reasons that Britney mimed at her concert.

(7) Abortion is perfectly legal, so obviously there's nothing wrong with it This argument rests on the assumption that if something is legal, then there is nothing wrong with it. This would not be acceptable in the context of an argument over the acceptability of abortion, because the point of dispute would not be about whether abortion was legally permissible, but about whether it was morally permissible. The question you should be asking yourself in evaluating any inference is: Do these premises really provide good evidence for the conclusion? Do they give me good reason to accept the conclusion? Arguments (1), (2), (4), (6) and (7) above are examples of arguments which are flawed, because they require us to assume things that we shouldn't simply assume. By thinking about what the assumption is (rather than just saying the inference is no good), we get a better idea of what is going wrong in the argument, and what kind of evidence would be required to fix it.

8.3 Fallacies Overview We will now consider other ways that inferences might go wrong. Traditionally, one common approach in critical thinking texts has been to approach the evaluation of inferences by looking at a great number of distinct named fallacies which may occur in arguments. (One text you may find in the library identifies ninety-three different named fallacies). Others avoid this approach by eschewing the individual discussion and naming of fallacies altogether, since for practical purposes, it is much more useful to be able to identify things which seem wrong and explain what is wrong with them, than be able to assign names to specific fallacies you have learnt about. Apart from anything else, the point of a critical thinking course is to allow you to develop skills which are transferable to other contexts, so you need to be able to argue with people who have not done critical thinking courses, and don't know the technical jargon. Our discussion of fallacious inferences will strike a balance between these two approaches. There are some fallacies which are so common and so frequently discussed, that it is worth examining them individually. But it is important to remember that any individual fallacies we might discuss -- even if we were to discuss ninety-three of them -- should be thought of as examples only, and species of more general problems. To help understand those general problems, it is useful to have particular clear examples to refer to. But the most important skill to develop is not to be able to name fallacies which occur in an argument, but to be able to find and explain what might have gone wrong in any inference you are evaluating. All that said, we will adopt a useful three-way classification of fallacies introduced by Fogelin and SinnottArmstrong in their text Understanding Arguments. They distinguish three kinds of fallacies: fallacies of clarity, fallacies of vacuity and fallacies of relevance. Fallacies of clarity occur when language is used in an intentionally or unintentionally misleading way. Unclear language will be fallacious either if it makes the argument itself unclear, so that it is difficult to tell how much support has been given for the conclusion, or if an argument exploits the unclear language, to obscure the argument's weakness. Fallacies of vacuity occur when an argument is presented as making some genuine inference, but actually just assumes what it is supposed to prove.

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Fallacies of relevance occur when premises are presented as though they offer support for the conclusion, but where they are actually not relevant. The most important reason, I think, for not focussing too heavily on individual fallacies is that most bad inferences are not bad because they commit some particular named fallacy, but just because they fail to provide strong enough evidence for the conclusions which are supposed to follow from them. And an inference is not to be judged good just because it doesn't commit any fallacy you can identify. Inferences need to be evaluated on a case by case basis. Knowledge of the sorts of fallacies which may appear will help you to recognise the kinds of things which might be going wrong in an inference, but there is more to an analysis of arguments than that.

8.4 Fallacies Of Clarity Fallacies of clarity are committed when language is used in an unclear way, where that lack of clarity either makes the argument itself unclear, or where the argument exploits that lack of clarity in such a way that it cannot be resolved. Two of the most common sources of these fallacies are ambiguous or vague language.

8.4.1 Ambiguity A word or expression is ambiguous if it has a number of distinct possible meanings. The word "bank", for example, is often given as an example of an ambiguous word, because it could mean either a financial institution, or the edge of a river. Many words are, in isolation, ambiguous, but in a great many cases the ambiguity will be resolved by the context in which a word is used. There are very few situations where is it likely that a genuine confusion would arise about which kind of 'bank' was referred to in a particular context. Ambiguity can also be a property of longer phrases or sentences. A recent newspaper headline reported that : (4a) "Poll finds 80% back PM over terrorism" (Sunday Telegraph, 16/9/01) Does this mean that 20% would prefer terrorism? The headline is ambiguous, because it has two possible meanings. These examples may sound trivial, but ambiguity can lead to more serious problems in arguments. It is important to be able to identify when the occurrence of ambiguous expressions is a flaw in an argument. 8.4.1.1 When Is Ambiguity A Problem? The fact that an argument contains ambiguous terms is not necessarily a problem, since in many cases a word could be considered ambiguous without it creating any confusion. If a job applicant presented the argument: (4b) "I worked at a bank for ten years, and therefore have experience handling large amounts of cash" we would be unlikely to object to the inference on the grounds that the premise would not provide good evidence for the conclusion if the bank at which the applicant had worked was a river bank. Applying the principle of charity, we interpret the argument so that it makes the most sense, and assume the applicant worked in a financial institution. We can assume that this is what the person meant, because he or she would not have presented that as an argument if the work cited did not involve cash handling. There are two situations when ambiguity should be considered a problem: (i) When the ambiguity makes the argument unclear or (ii) When the argument relies on the ambiguity, committing the fallacy of equivocation. An example of an argument which is made unclear by ambiguity is:

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(4c) Sally introduced Geoff as her partner, so she and her husband Steve must have broken up. The word "partner" is ambiguous, because it can indicate either a personal relationship or a business one. Before you accept the conclusion (before you decide to ask Steve out, for example) it would be a good idea to seek clarification of that ambiguous term, and work out what kind of partners Sally and Geoff are. If they are merely business partners, the premise would not support the conclusion. Note that the principle of charity would not help us here as it did in the case above, because the person putting forward the argument may themselves have been misled by the ambiguity in Sally's introduction. Ambiguity is to be avoided when you are presenting an argument -- any ambiguous expressions which might make your meaning unclear should be replaced by something which is not ambiguous. If you are evaluating someone else's argument, seek clarification if possible, but otherwise apply the principle of charity, and at least make it clear how you are interpreting the expression in your analysis.

8.4.2 The Fallacy Of Equivocation More serious problems arise when an argument relies on an ambiguity - when an ambiguous word or expression is used to mean two different things within one argument. This is called the fallacy of equivocation. For example: (4d) Australia is obliged to bring the Manoora refugees here to have their status assessed, and cannot leave them in Nauru. Under the international agreement on refugees to which Australia is a signatory, if someone arrives in a country and makes a claim for asylum, their refugee status is to be determined in that country. It therefore follows that if someone is seeking asylum in Australia, they must be processed in Australia. But as we have known all along that is precisely what those on the Manoora are seeking -- asylum in Australia. This argument could be standardised as: 1.1 Under the international agreement on refugees, to which Australia is a signatory, if someone arrives in a country and makes a claim for asylum, their refugee status is to be determined in that country. 1 Someone seeking asylum in Australia must be processed in Australia. 2 What those on the Manoora seek is asylum in Australia. C Australia is obliged to bring them here, not leave them in Nauru, to have their status assessed.

This argument is fallacious, because it relies on an ambiguity in premise 1 about what is meant by 'seeking asylum in Australia'. Australia's obligation, as reported in 1.1, is to assess the refugee status of those who seek asylum in Australia, in the sense that they are in Australia, seeking asylum. The sense in which the Manoora refugees are seeking asylum in Australia, however, is that what they seek is asylum in Australia. They are in Nauru. An argument such as this one depends on the ambiguity of a word or phrase, and the ambiguity cannot be fixed by restating the argument, and offering a paraphrase. The reason it cannot be so easily resolved is that there is no way of rewriting premise 1 unambiguously in such a way that it follows from 1.1 and can be linked to 2 to support the conclusion. Here is another example of an argument committing the fallacy of equivocation:

(4e) If something is certain, then it is true. I am absolutely certain that Elvis is alive. Therefore, it must be true that Elvis is alive. The ambiguity in this case rests on two different senses of certainty. In the first premise, certainty is used in an objective sense -- to say that something is certain, means that it is true, or definite. But the sense in which

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"certain" is used in the second premise is a subjective sense, the sense that we say that we are certain to mean that we feel convinced about something. The fact that you might feel certain about something, however, does not make it true. One final example is from an argument in Plato's Euthydemus, 298e, in which Dionysodorus forces Ctesippus to accept that his father is a dog, and he has puppies for brothers: (4f) You say that you have a dog. Yes, and a villain of one, said Ctesippus. And he has puppies. Yes, and they are very like himself. ... Then he is a father, and he is yours; ergo, he is your father, and the puppies are your brothers. The central argument could be standardised as: 1.1 Your dog is yours. 1.2 Your dog is a father. 1 Your dog is your father. C Your dog's puppies are your brothers There is an ambiguity here about what is meant by something being "your father". When we say that someone is "your father", we do not normally mean just that he is a father that you own, but this is how it must be understood in premise 1, for it to follow from 1.1 and 1.2. In order for premise 1 to support the conclusion, however, we must understand "your father" in the more conventional way. The effectiveness of this argument, therefore, also depends on an ambiguity. There is no clear way that "your father" can be understood so that 1 follows from 1.1 and 1.2, and supports C. If an argument commits the fallacy of equivocation, it is a serious flaw in the argument, since there is no way of repairing the argument by resolving the ambiguous term, and replacing it with a clear paraphrase. Once the ambiguous term is paraphrased in a way that makes that term clear, the inference collapses.

8.4.3 Vagueness A word or expression is vague if it is unclear, and has no definite meaning. Many words in English are vague tall and short, red and orange, warm and cool -- for each of these, there will be some cases where it is not obvious whether or not something has that property. As was the case with ambiguity, the mere existence of a vague term in an argument is not necessarily a problem. Because so many concepts are vague to some extent, most arguments will contain some vague concepts, and yet function perfectly well. Like ambiguity, vagueness will only be a problem when the argument depends on it, or when it is simply not clear what the argument is saying. Political parties often make use of vague expressions to convince you to vote for them, by supporting such laudable but unspecific goals as providing a better future, caring for the aged, strengthening families, protecting Australia's security, providing employment opportunities and so on. So much of the rhetoric associated with political policy is stated in vague terms, that it is not always clear what you're being asked to accept.

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In the 2001 election campaign, for example, both parties have used as a premise something like the proposition that every family should have access to a good school education for their children. But what does this mean? Because it is stated in vague terms, this can be used either to support the conclusion that private school fees should be subsidised so that everyone can afford the good education provided by a private school, or that that money should be directed towards public schools, so that the public education system, to which everyone does have access, will provide a "good education". Despite differences in policy, it can be difficult to match a party to a stated policy goal, since they are often stated in such a vague way that while no-one would object to them, there is no way of determining from the stated principle what the policy is. Would you be able to work out which party claims to support each of these principles?       

Quality education for all Australian children A fair tax system Spending wisely Better care for older Australians Investment in the future A safer more secure Australia Opportunities for all

If a party's support for such a policy was intended to provide a reason to accept the conclusion that you should vote for them, you would be well advised to investigate their actual policies, to seek some clarification of the meaning of the statement, before deciding whether it did provide such a reason. The fact that you might support the aim of providing "opportunities for all" cannot provide a good reason to vote for one party, if it would be an equally good reason to vote for the other. So it is with any argument containing vague terms. If the vagueness of a word or phrase obscures the meaning of the premise or conclusion, we may need to have those terms clarified, before we can decide whether the inference is acceptable. In the discussion of statistical generalisations, we saw an example of an argument where the vagueness of a term in the premises made it unclear whether the conclusion followed. The argument used as a premise the claim that more than 8 in 10 children between 12 and 17 had "tried alcohol" as one of the pieces of evidence for the conclusion, as stated in a headline, "Underage binge drinking rampant". To decide whether the premise offered any support for that conclusion, we would need to know what was meant by having "tried" alcohol. If this just means that those people have had at least one taste of an alcoholic substance once, then this premise does not seem to offer much support for the conclusion. It is a good idea to clarify any terms which are vague, and which are liable to cause confusion. This can be done, for example, by providing a stipulative definition, so called because it stipulates precisely what the term means for the purposes of the argument. So in the argument above, researchers could give an exact definition of "tried alcohol", which would make it clear precisely what had been measured. We would then be in a position to decide whether the conclusion was well supported.  

A word or expression which has more than one possible meaning is ambiguous. A word or expression which has no clear meaning is vague.

Ambiguity or vagueness in arguments should be considered fallacious if it makes the meaning of the premises or conclusion unclear, or if the apparent strength of an argument depends on the ambiguity or vagueness of an expression occurring in it.

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8.5 Fallacies Of Vacuity An argument which implicitly or explicitly assumes what it is trying to prove, may be said to be circular, or to beg the question. In ordinary discourse, to "beg the question" is often used to mean "to invite the question", or "to prompt the question", but this is not actually what the expression means. A question-begging argument is one which uses or assumes as a premise what it is supposed to be trying to prove.

8.5.1 Question-Begging Arguments An argument may beg the question by using as a premise something which no-one would accept unless they already accepted the conclusion. (4a) The teachings of the Catholic church must be correct, because the Pope is infallible. The point of an argument, remember, is to convince your audience of your conclusion by showing that it follows from premise that they would accept. So a question-begging argument cannot be successful in persuading someone of the conclusion, because they won't accept your premises unless they accept your conclusion already. This argument could not convince anyone of the correctness of the church's teachings if they were not already convinced, since Papal infallibility would not provide strong evidence for someone who did not accept the church's teachings. Suppressed question-begging assumptions Often the question-begging assumption will be a suppressed premise. When you are identifying suppressed premises, look out for cases where what has to be assumed is something which would only be accepted by someone who already accepted the conclusion. (4b) Of course there is life on other planets! Mars is another planet. The argument "Mars is another planet, therefore there is life on other planets" relies on the hidden assumption that there is life on Mars. This assumption begs the question, because no-one would accept that there is life on Mars without already accepting the conclusion, that there is life on other planets. This argument has a hidden premise which assumes what the argument is supposed to prove.

8.5.2 Circular Arguments The most explicit form of question-begging argument is when the conclusion and one of the premises given are more or less synonymous: (4c) You're not likely to amount to anything, because you've got no potential. (4d) Daryl is the best candidate, because he is better than all the others. (4e) The GST is an unfair tax, because it is not fair to put a tax on goods and services. These are often described as circular arguments.

8.6 Fallacies Of Relevance As we have seen before, in discussions of arguments from analogy, an argument can succeed only if the premises are positively relevant to the conclusion. When you are evaluating an inference, think about whether the premises genuinely offer support for the conclusion, or whether they are actually irrelevant. A fallacy of relevance is committed when an arguer presents an irrelevant premise as though it provided support for the conclusion.

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There are many common patterns of inference which can suffer from a fallacy of relevance. The important thing to remember though which will help you to decide whether or not an argument commits a fallacy of relevance is that the reason these kinds of arguments can seem persuasive, despite their fallaciousness, is that they are very similar to good patterns of argument. A pattern of argument will be acceptable if the premises do provide relevant support for the conclusion, while an apparently similar argument will be fallacious if its premises are not relevant. We will look in some detail at a few varieties of fallacies of relevance, and the difference between those fallacious arguments and superficially similar arguments which are not fallacious. At the end, we will have some brief examples of other potential fallacies of relevance, and their relevant counterparts.

8.6.1 Straw Person Fallacy The straw person fallacy is committed when a counterargument, or an argument against someone else's position on some issue, misrepresents the argument or position in order to make it easier to refute. For example consider the following argument and counterargument. (5a) Target argument: The use of cluster bombs in Afghanistan should not be continued. While the US is justified in trying to destroy Al-Qaeda, cluster bombs, like land mines, pose a serious threat to innocent people. Cluster bombs contain a package of bomblets, not all of which may detonate on impact. Many children have been injured by picking up unexploded bomblets, mistaking them for aid packages. Counterargument: It is naive and foolish to suggest that the USA should not retaliate for the attacks on New York. America was targeted, and has been threatened with ongoing attacks. The war on terror in Afghanistan is the only way to stop Bin Laden and the Al-Qaeda network from carrying out further terrorist attacks on America, and other Western nations. It would be irresponsible for the US to sit back and let that happen. The counterargument here is not relevant to the target argument, because it misrepresents the position of the original argument. The first arguer was not claiming that the US should not be allowed to launch its 'war on terror', but that it should not use cluster bombs, because of the danger they pose for civilians, and children in particular. The straw person fallacy will not only occur in counterarguments responding to an specific target argument. It may be committed in any argument which misrepresents someone's view, or argues against a position which noone actually holds. (5b) How can anyone support euthanasia? There are a lot of people who are old, and who are sick, but who still have a will to live. How can you deny those people their right to life? This is also a straw person fallacy, since people who are in favour of euthanasia are not (in general) in favour of involuntary euthanasia. It is a misrepresentation of the position of those who are in favour of giving people in certain circumstances 'the right to die' to suggest that they would advocate forced euthanasia. This argument is irrelevant to whether or not people who support euthanasia are wrong to do so, since it attributes to them a view they are unlikely to hold, and criticises only that weaker view.

8.6.2 Appeals To Authority A lot of the things we accept, we accept because we believe what someone has told us. We often make an appeal to experts in a particular field, or someone else who could be expected to have knowledge of the subject, for their opinion. That is, we often infer a conclusion "p" from a premise of the form "A says that p". These arguments are appeals to authority. In making an appeal to authority, we accept someone's word because they are an expert, speaking within their area of expertise. The following examples contain good, relevant appeals to authority:

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(5c) It is far from certain that mobile phones are a cancer risk. The cancer council reports that despite extensive research it has no found no firm evidence to support the link. (5d) Dr Barbara Jones, from the Centre for Reptile Research at Taronga Zoo, says that brown snakes are the most dangerous snakes found in Sydney. Red-bellied black snakes are also found in Sydney, so they must be less dangerous than brown snakes. The question to consider when evaluating the strength of the evidence provided as an appeal to authority is whether that person is a genuine expert, speaking within their area of expertise. An appeal to authority is fallacious if the alleged authority is not really an expert, or if they are not speaking within their area of expertise, or if the subject is simply one on which there could be no "authority": (5e) I'm going to stop taking my medication. My clairvoyant said it would not cure me. (5f) My teacher is a very intelligent man, and knows a lot about the way the world works. He says that God does not exist. So God does not exist. We may also be suspicious about alleged authorities who are unlikely to be impartial. (5g) Research carried out by a manufacturer, reported in an advertisement. (Should we really accept the findings of the Ponds Institute?) (5h) Reports by medical experts employed by the Nazis about the inequality of different racial groups. When you come across an appeal to authority , ask yourself whether the authority is a genuine expert, speaking within his or her area of expertise. If not, then the appeal is irrelevant and the inference fallacious, since their opinion alone will carry no more weight than anyone else's.

8.6.3 Appeals To Tradition An argument appeals to tradition when it is argued that something should be done or believed because that is what has always been done or believed. An appeal to tradition is fallacious when the fact that something has been done traditionally has no bearing on whether we should continue to do it, and particularly where the appeal to tradition is invoked to outweigh significant reasons for change. For example, junior doctors in hospitals often work unreasonably and dangerously long shifts. The justification which is sometimes given for this is that it is a 'rite of passage' which doctors have always had to go through when they are starting out in the profession. Recently there have been moves to try to eliminate this tradition, which puts doctors and their patients at serious risk. The fact that other doctors have had to endure these working conditions is not relevant to whether the practice should be sustained, so to try to justify these conditions through an appeal to tradition is fallacious. In other cases, tradition is relevant, and when there are no significant reasons to break a tradition, an appeal to tradition may provide support for a conclusion. There are a lot of traditional aspects of many ceremonies, such as a graduation ceremony. The reason that we still have academic dress for graduations, for example, is grounded in a long standing tradition. It does not seem to be fallacious to say that graduands should wear academic dress because that is what has always been worn, since the ceremonial aspect of the occasion is significant, and there are no compelling reasons to abandon the tradition. There are some situations when it is not clear whether tradition should be thought of as a relevant reason for allowing something to continue or not. The recent republic debate is an example of this. Many of the arguments for remaining under the monarchy were based on our traditional links with Britain, and our heritage as part of the Commonwealth. Republicans argued that this tradition was no longer relevant to

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modern Australia, but Monarchists argued that a nation's history is central to its national identity and sense of cohesion, so tradition was a relevant reason to leave constitutional arrangements as they were. An appeal to tradition will be appropriate when the fact that something has occurred traditionally is relevant to whether it should continue, and there are no overriding reasons that the tradition should be abandoned.

8.6.4 Ad Hominem Arguments An ad hominem argument is a criticism of someone's position or argument which attacks the person who gave the argument, rather than the argument itself. This will be a fallacy when whatever claim is made about the character or situation of the person is not relevant to the strength of their argument. Two forms of ad hominem arguments are conventionally distinguished: abusive and circumstantial ad hominems. Abusive ad hominems involve a personal attack on the person whose argument is being criticised, while a circumstantial ad hominem involves the unwarranted suggestion that their argument should be rejected because of some irrelevant fact about the arguer's circumstances. Abusive ad hominems will normally be easily identified, since abuse of an arguer is generally irrelevant and fallacious. There are unlikely to be many situations in which personal abuse of someone is an appropriate and relevant way to respond to an argument that person has put forward. Circumstantial ad hominems, however, are more difficult to identify, since sometimes the source of an argument is relevant to our assessment of it. So when is it acceptable to judge an argument by its source? An ad hominem fallacy is committed when an argument is rejected because of some fact about the arguer. It is a fallacy if the merits of the argument are not assessed objectively but the argument is just dismissed without proper consideration. Criticisms concerned with the circumstances of the arguer are irrelevant when those circumstances are not relevant to the quality of the argument. Sometimes the author's situation is relevant. It will be appropriate to object to an argument, or at least to be more than usually sceptical, because of the author's circumstances if: [1] the author is likely to be displaying bias because they have some kind of vested interest. eg if a Labor politician argued that you should vote Labor because the GST was bad for small business, and the rate of the GST is likely to go up, it would be reasonable to expect some more evidence for these claims. The fact that the argument comes from someone with a vested interest in getting you to vote a particular way may make you more suspicious about the reliability of their claims.

[2] Even where this bias is unintentional, an author's circumstances may be relevant if their position makes it unlikely that they will have all the facts. Suppose a teacher at a selective school reports that the new HSC syllabus should be made harder, since most of the students she had spoken to had found it quite easy. The fact that the argument comes from a teacher at a selective school is relevant to our evaluation of that argument, since the teacher's position suggests that she is likely to have based her conclusions on an unrepresentative sample of students. The students at her school would be likely to be more capable than average. If you were evaluating these arguments, then, it would be relevant to point out the potential problem of bias which may arise because of the arguer's circumstances. To ensure that you do not commit an ad hominem fallacy, don't use the person's circumstances as a reason to dismiss their argument outright -- even someone who might be expected to display a bias might be presenting a perfectly good argument. Explain why their circumstances might have led to a distortion of the facts, or a less reliable inference, and consider the points they have made, to ensure that your response is relevant. Example:

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An exchange of letters appeared recently in a local newspaper, about a proposal for a pub to be opened in a shopping centre. The first letter which appeared was opposed to the development, on the grounds that the development application included a proposal for poker machines, which the letter-writer argued should not be permitted. His argument was based on the claim that poker machines were a serious problem in our society, since they encouraged gambling addiction, were bad for families, and so on. Shortly afterwards, another letter was printed in reply. The second correspondent was one of the people responsible for the development application, and he pointed out that the first writer was the proprietor of another pub in the vicinity. The second writer suggested that if the first correspondent was really so concerned about the evils of poker machines, he might consider giving up some of those in his own establishment. Did the writer of the second letter commit an ad hominem fallacy? Or was this response justified? The reason it might seem justified is that the circumstances of the first letter writer are relevant to our impression of the sincerity of his argument, and may perhaps cast some doubt on the strength of the inference: If the evils of poker machines have not convinced the first letter writer to give up his own, should we be convinced by his argument? Note, however, that whatever the source of an argument, it should be addressed fairly in a counterargument. The circumstances of the arguer should not lead us to reject an argument without assessing its merits in a way that we would assess the argument had it been given by another source. The counterargument could be strengthened, perhaps, by pointing out that because there are already poker machines in the vicinity (in the first letter-writer's pub) the community already has access to them, and this would therefore not be a reason to prevent the new development. This argument might be said to commit a "tu quoque" fallacy. This is a fallacy of relevance which can be thought of as a subcategory of ad hominem. "Tu quoque" means "you too" and it is committed when the proponent of a counterargument attacks the target argument by accusing the arguer of hypocrisy, where that alleged hypocrisy is irrelevant to the strength of their argument.

8.7 Evaluation Link to text in e-reserve: ( http://www.lib.mq.edu.au/resources/reserve/ )

Text Evaluation Often the simplest way to evaluate an argument's inferences once you have broad standardisation is just to go through each of the arguments: the main argument, and each of the subarguments, and consider whether adequate support has been given in each of the inferences. For the purposes of writing an evaluation, however, it is not necessary to comment on every premise or every inference. Part of the skill involved in writing a short evaluation is to work out what is most important, and most relevant to the success of the argument.

Main argument One of the strengths of the main argument is that the conclusion, "Reproductive cloning should not be ruled out without further consideration" is relatively weak. To say that a conclusion is "weak" in this sense is not to criticise it (as you would by saying that an inference is weak, for example.) To say that a conclusion is weak means that it is not making too ambitious a claim, and thus it is more likely to be supported by the evidence. So this weak conclusion is a better one to draw from the premises than a strong conclusion like "Cloning should be permitted", which would require a lot more evidence.

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Although the author is not trying to justify cloning in this argument, nor is he trying to present an entirely objective view of the arguments for and against cloning. His point is to offer negative support for cloning by arguing that many of the objections made against it are not compelling, so it is at least too early to reject cloning now.

With any argument that proceeds by arguing against objections, the strength of the argument will depend in part on whether there are other significant objections that have not been addressed. Even if the author succeeds in arguing against the objections he mentions, cloning may still be unacceptable for other reasons. This is something the author of this text acknowledges, and we will return to this point later in the discussion.

Subargument supporting premise 1 The first subargument is the longest in the text, and involves a series of convergent lines of reasoning for the subconclusion that "Concerns about individuality should not lead us to rule out cloning".

The first of the subpremises, which says that family resemblances are generally considered to be a good thing, is not strongly relevant to the conclusion drawn from it. There seems to be some equivocation here about "individuality". While it is true that families may appreciate resemblances between their members, resemblances are really not evidence of a lack of individuality in the sense in which it may be feared that a deliberately created clone would lack individuality. The fact that some degree of similarity is considered a good thing does not provide good evidence that complete genetic similarity would or should also be considered a good thing. Therefore premise 1.1, which is convergent with the other subpremises in this subargument, is not strong.

Premises 1.2 and 1.3 are the first of the arguments from analogy in this text. It is argued that since identical twins are genetically identical, and yet twins are considered to be individuals with the same rights (and not 'abominations'), there is no reason for deliberately created clones to be lacking that same individuality.

As this is an argument from analogy, it can be evaluated using the techniques developed in the second section of the course: In particular, you should decide how strong and positively relevant the similarities between the subject and analogue are, and whether there are any negatively relevant differences that might outweigh those similarities. Clones are the subject in this argument, identical twins are the analogue. The similarities stated to exist between them is that a pair of identical twins, like a pair of clones, will be genetically identical. The property being extended from the analogue to the subject is the property of having individuality, and having the rights of an individual.

The similarity, genetic identity, does seem to be relevant, since if genetic identity does not prevent twins from becoming individuals, then the same could be expected to hold for clones. Genetic difference cannot be what determines individuality.

There are, however, significant negatively relevant differences as well, particularly if we consider the broader target property of being thought of by society as individuals, or not being considered 'abominations'. Twins do differ from clones in their origins: twins occur naturally, while clones have been

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created deliberately, and society might well treat them differently on that basis. Honey claims that no-one thinks that "the second twin is not an individual with the same rights", but even the use of the word "second" here points to a difference between clones and twins. Which of a pair of twins is the second is basically arbitrary: an accident of position at the time of birth. But the distinction between first and second in the case of clones is a genuine distinction, since one is a copy of the other.

The argument, however, is presumably intended as normative rather than descriptive (that is, as a claim that society should not treat clones as lacking individuality, rather than as a claim that it would not so treat them), in which case the author's claim could still be accepted.

The next inference concerns the question of whether clones would have distinct souls. Again, Honey uses the analogy with twins to argue that this would not be a problem: "the fact that there are identical twins counts against there being a problem. Twins seem to manage, and that seems to suggest that each person is able to be ensouled regardless of their genetic make-up." There are a few things worth noting about this argument. First, it would be wrong to criticise this argument by saying that it is based on the assumption that souls exist, and would therefore not be persuasive for an atheist, or anyone who does not believe in souls. The reason this would be inappropriate is that because this is offered as a response to an objection, it only needs to be persuasive to people who would find that objection compelling. While it is true that an atheist will not find Honey's claims about twins (and therefore clones) being "separately ensouled" convincing, neither would he or she have been persuaded by an objection to cloning on the basis that clones would not have souls.

I think that there is, however, a problem with Honey's response to the "souls" objection, and that is that it seems to mischaracterise the most likely form of that objection. Because no exact source for the objection is given it is hard to know exactly what was intended, but the objection to which Honey's argument would be a response does not seem to be the strongest version of this concern.

Honey argues that it is wrong to think that souls pose a problem for the individuality of clones, because twins seem to be separately 'ensouled', and because "It's hard to imagine that God would have any difficulty telling the difference between one clone and another". In arguing this way, he is assuming that the problem is firstly one about whether genetic individuation is necessary for the individuation of souls, and secondly about whether God could tell clones apart. The latter point is unlikely to be the one to have troubled any theist who thinks of God as omnipotent and omniscient, and the former objection, easily refuted by the twins analogy, also does not sound like an objection anyone would actually make. Those who do believe in souls generally believe that souls can exist independently of bodies, in which case there would be no good reason to think that a soul would have to be tied to a body of a particular genetic constitution.

A more likely objection based on the problem of souls would be one based again on the origin of the clone. Even if scientists could successfully clone a human, would they thereby create a soul for that person? It might be thought that our capacity for cloning only extends as far a cloning the physical body, so if there is something non-physical which is essential to a person's life or identity, clones would be missing it: Perhaps we can build a human like we can build a table or a chair, but it could be that only God can create souls. If the objection to cloning based on the question of whether clones would be adequately 'ensouled' is characterised along these lines, Honey's response would not be successful. If indeed Honey's argument does respond only to a weaker position than one actually held by his opponents, it commits the "straw person" fallacy.

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The final premise in the first subargument, premise 1.5, provides quite a strong reason to believe premise 1. The fact that a person's environment and experiences are relevant to determining their personality and what makes them an individual does give us a good reason to think that clones would necessarily differ in these respects. This is perhaps the strongest piece of evidence given in this subargument.

Subargument supporting premise 2 The second premise maintains that we should not be deterred from cloning just because we are reluctant to "play God". It is supported by a normative argument from analogy, comparing reproductive cloning to 'therapeutic cloning', or stem cell research. It is argued that since stem cell research is at least as problematic from a "playing God" point of view, and we accept stem cell research, we should also be prepared to consider reproductive cloning. In fact, the argument is a little stronger than this, since it is not claiming just that the two kinds of cloning are similarly objectionable, but that stem cell research (which relies on killing embryos unlike reproductive cloning which uses them for procreation), is more objectionable. So if we are prepared to accept that therapeutic cloning is acceptable, Honey argues, it is deeply inconsistent to oppose reproductive cloning. (It is interesting to note that this argument could not be used to support the claim that reproductive cloning would not involve playing God -- only that unlike therapeutic cloning, reproductive cloning involves playing God in a way that God might approve of).

One potential problem with a normative analogical argument like this, that is based on our inconsistent attitudes towards two similar things, is that the same analogy could be used to draw a different conclusion: in this case the conclusion that because of the similarity between therapeutic and reproductive cloning, we should not be prepared to countenance therapeutic cloning either. Normative analogical arguments rely on the audience being more committed to their attitudes towards the analogue than their attitudes towards the subject. Because a lot of people are strongly opposed to reproductive cloning, some readers of this argument may conclude from it not that reproductive cloning is as acceptable as stem cell research and should be allowed, but that stem cell research is at least as objectionable as reproductive cloning, and should be resisted.

Another possible objection to this subargument is that one of the two linked premises states that "there is widespread agreement about the rightness of therapeutic cloning." This seems to be overstating the case, since therapeutic cloning (stem cell research) is still a deeply controversial subject. If all that is required for the sake of the analogy is that stem cell research is more widely accepted than reproductive cloning, then that is undoubtedly true, but to claim "widespread agreement" appears to be a misrepresentation of the reality of the debate.

Subargument supporting premise 3 The third subargument argues that we should not reject cloning because of the danger of the clones not being valued for themselves. Honey does not deny that some of the motivations that have been suggested for cloning are selfish, but he thinks that the benefits to those who want to use cloning for good reasons, would outweigh any potential for harm arising from more 'unsavoury' motives. There are at least two problems with this argument. First, the premise that "there are people who can have a baby in no other way and who would be childless otherwise" might be questioned. It is true that there are some people who are unable to have a child using existing technology, but it is not true that those couples could conceive through cloning. As things are now, cloning technology is not sufficiently advanced to successfully clone humans, and there is no reason to think that cloning will succeed where other methods fail. It might in the future come about that there will be some people who can conceive only through cloning, but to state this as an unsupported premise suggesting that this is the case now is misleading.

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If it were true, would it provide good support for premise 3.1? Should we allow cloning so that otherwise childless people can procreate? Honey's explicit claim here is just that "If the technology becomes available there will need to be good reasons to deny people this opportunity." What is at issue in this debate, though, is whether we do in fact have good reasons to deny them the opportunity. If there are good reasons to oppose cloning, the desire of some childless people to have a child would be unlikely to outweigh those reasons. So this provides only weak support for premise 3.

Another problem with this subargument is in the implicitly analogical premise, 3.2. Honey responds to the objection that some people may clone themselves or others for selfish reasons, saying :" imagine what would happen if we tested the motives of couples wanting to have children the normal way!" The suggestion here seems to be that those who can conceive naturally are not prevented from doing so for having selfish motives, so those who want to reproduce by cloning should not be judged on their motives either. This is what is sometimes referred to as a "two wrongs fallacy". A "two wrongs" fallacy is a fallacy of analogical reasoning that occurs when an arguer attempts to justify one bad action by showing that it is analogous to another bad action that has been permitted. It is a fallacy because, as the saying goes "two wrongs don't make a right". A bad action is not made permissible just because some other bad action has been permitted.

Subargument supporting premise 4 The subargument supporting premise 4 is another analogical argument. It is argued that other reproductive technologies, such as surrogacy and IVF, were originally opposed and have become accepted, so the opposition to cloning can also be explained by its novelty, and, like the opposition to the other techniques, will wane over time.

The similarity between the subject and analogue is that they are each techniques allowing people who otherwise would not have had children to have them, and each was initially opposed. The property being extended from the analogue to the subject is that the initial opposition will not last. While the experiences of past attitudes to technologies like IVF may give advocates of cloning some hope that opposition to cloning will not last, there are other new possibilities that continue to be opposed, so the argument is not conclusive. (Buying children via the internet is also a new possibility allowing otherwise childless people to obtain children, but does the analogical argument give us any reason to think that the existing opposition to it will eventually evaporate?) Honey tries to support the argument with the generalisation that "Whenever a new possibility comes along, we tend to oppose it", but this is not really true of all new possibilities. It is true of some advances that seem to be potentially harmful, (as was the case with IVF), but the opposition fades only when those fears are shown to be unfounded. IVF was found to be safe, and became widely accepted, but it remains to be seen whether the same will be true of cloning.

This subargument also contains another example of an unjustified suggestion of certainty, in the claim with respect to surrogacy and IVF that "We have come to accept both". Surrogacy, at least, is still quite controversial.

This is not, I think, a very strong subargument. We have no good reason to think that cloning is being opposed just because it is new, and consequently no reason to think that the opposition is only temporary.

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Subargument supporting premise 5 Premise 5 suggests that the real reason for medical scientists' opposition to cloning is that they are trying to gain support for stem cell research. There is no direct evidence given for this claim: only the suggestion that scientists might be able to make stem cell research seem more attractive by contrasting it with the more controversial technology of reproductive cloning. Because there is no evidence for the 'conspiracy theory' proposed here, however, the subargument is not strong. We have no real reason to suspect that the objections of scientists are not genuine. To be fair to the author, he does not claim that this is certain, prefacing his claim with "I think it likely that the real reasons ..."but we still have not been given enough evidence to understand why he would consider that the most likely explanation. To reject an argument because of some unsupported speculation about how some person or group's views could explained by their circumstances is to be guilty of a circumstantial ad hominem fallacy. Even if their opposition can be explained in some other way, the objections of the scientists should be considered fairly.

Note: An alternate reading of the argument Applying the principle of charity, we might try a different reading of the argument, which would make premise 5 appear more motivated. On that alternative reading, which would require a revised standardisation, we could interpret the argument as saying that the real reason for the scientists' rejection of cloning must be that they are attempting to gain support for stem cell research by emphasising the distinction between therapeutic and reproductive cloning, since the other reasons for rejecting cloning (those discussed in premises 1, 2 and 3) are not genuine problems. If this is the correct reading of the argument, then the fifth subargument would not be a circumstantial ad hominem, because Honey would only be rejecting the scientists' objections after considering and responding to them. While it is true that this would appear to give some support for what is now premise 5, that premise would still not be strongly supported. The problem with this argument is that the reasons considered in the early part of the argument for rejecting cloning, based on issues including the problem of whether clones would have souls and of whether cloning would mean "playing God" are not those most readily associated with the scientific community. The objections most commonly heard from scientists concern more practical difficulties such as the serious health problems observed in cloned animals, and practical concerns about the application of the technology. Some such objections are noted in the counterconsideration, but no responses to them are offered. Thus, it seems most reasonable to standardise the argument as I have done above, as saying that a number of common concerns held by members of the public are not compelling, and the objections of scientists cannot be taken at face value.

Final evaluation of the argument You should finish your evaluation with some overall judgement about the success of the argument. Your conclusion in a short analysis need not be long or detailed because you will have addressed a lot of specific points in the analysis itself, but you should draw some conclusion from the points you have made, about whether or not you think the argument has achieved its purpose. Remember to consider the argument's good points as well as its bad points.

For example, although we have noted that by structuring the argument as a series of responses to objections to cloning the author leaves open the possibility that there may be other objections that have not been addressed, it would be unreasonable to condemn the argument on that basis. Whenever an argument offers responses to a series of objections, rather than a specific target argument, this will always be a possibility. In

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this case, the author has explicitly stated that his aim is to reopen and encourage debate in the area, and for that purpose his methodology, of entering into a discourse with opponents, is entirely appropriate. You may still want to suggest how the argument could have been strengthened, however. For example, if Honey had provided some information about the sources of the objections he cites, we would have a better idea of whether they are likely to be the most significant arguments to be responding to.

Note that the presentation and evaluation of the argument here has been a somewhat disjointed process, since it has been conducted in sections as different skills have been introduced. This has led to some repetition, since there are issues which come up in relation to the premises, and the language, and the inferences. The pattern in which we have conducted this evaluation is, however, a good general strategy for approaching an argument. It can be helpful to consider each of these issues separately, but in a written evaluation they do not have to be kept distinct.

When faced with an argument text for evaluation: 

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read though it, and summarise the main argument. Even if you don't write a summary down, make sure that you know what the point of the passage is: what the main conclusion is (or what the main conclusions are if a number of arguments are presented) what kind of evidence is given, and what the tone and context of the text are. If you're unsure, read through it again: what is it trying to convince you of? Now that you know what it is intended to convince you of, read through the argument again, thinking about the way persuasive language or other rhetorical devices are employed to convince you. Try to clarify any problematic vague or ambiguous terms, and make a note of any uses of persuasive language or other language which might need to be discussed. Standardise the argument. Look at what evidence is given to convince you of the conclusion, and then what evidence is given for each of the main premises. For long texts you will generally just be giving a broad standardisation for the purposes of evaluating the argument, so your concern should not be with how everything which occurs in the text should be fitted into your standardisation, but on what kinds of evidence are given for each important point. Think about the premises which are not given any further support. Are they likely to be commonly accepted, or should extra evidence have been provided? Keep track of any premises which should be accepted tentatively for the sake of the argument, but which have not been given strong support. The acceptability of the conclusion will be contingent on the acceptability of the premises. Evaluate the inferences: look for unjustified assumptions, and occurrences of any of the fallacies, but also consider more generally whether sufficient support has been given for the conclusions which have been drawn. You don't need a name for each fallacy which occurs, but you need to be able to explain why any unacceptable inferences are unacceptable. When thinking about unjustified premises, or insufficiently strong inferences, think about what would be needed to repair them. Can the argument be saved? To conclude, think about your overall judgment about the success of the argument. What is its intended purpose? Has that purpose been fulfilled?

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9 SAMPLE TEXT EVALUATION (Week 11) Over the last few weeks, we have built up an evaluation of an argument text. This final set of notes contains a sample evaluation, of the kind you will be submitting for your assignment, which is based on the evaluation we've developed. A similar example will be done in class.

Notes on writing your text evaluation The evaluation below is of a similar length and style to the evaluation you will do for your written assignment. It is here to give you an idea of what sort of thing you could include, but you are in no way bound by this format. For example, some people prefer to construct their analyses under subheadings, as I did in the longer discussion in the previous weeks' notes, and you are free to do that if you choose. What topics you focus on will depend on the argument text you select. Persuasive language, for example, does not play a strong role in this argument, so I have discussed uses of language mainly in connection with the particular subarguments in which they occur. If you were evaluating a text that made use of a lot of emotional language, however, you might want to treat this as a distinct section of your analysis. As was noted previously, you do not have to mention every premise in your evaluation. Try to keep your analysis succinct and to the point, and discuss the features of the argument that you consider most important and relevant. Broad Standardisation: 1.1: Family resemblances are considered a good thing 1.2: Identical twins are genetically identical 1.3: Identical twins are individuals with the same rights 1.4: Identical twins have separate souls, if souls exist 1.5: Individuality is a matter of environment as well as genetics, and clones would grow up in different environments 1: Concerns about individuality should not lead us to rule out cloning 2.1: There is widespread agreement about the rightness of therapeutic cloning 2.2: From the point of view of 'playing God', therapeutic cloning (which results in the death of the foetuses) is more objectionable than reproductive cloning. 2: Concerns about 'playing God' should not lead us to rule out cloning 3.1: For some people cloning is the only way of having a child. 3.2: We do not question the motivations of parents who have children the conventional way 3: Concerns about clones not being valued for themselves should not lead us to rule out cloning 4.1: IVF and surrogacy were opposed when they were new technology 4.2: We have now come to accept IVF and surrogacy 4: Much of the opposition to cloning is a result of its being new, and this opposition will be overcome 5.1: By emphasising the distinction between reproductive and therapeutic cloning, medical scientists can make therapeutic cloning seem more acceptable 5: Objections from medical scientists may just be attempts to gain support for stem cell research

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C: Reproductive cloning should not be ruled out without further serious consideration

Evaluation: Honey's purpose is to convince the audience that without more debate it would be premature to rule out reproductive cloning of humans. He attempts to show that objections commonly made to cloning are not compelling, and that there are other ways to explain the motivations of scientists and others for condemning cloning. The argument appeared as an opinion piece in a newspaper, and is written in a colloquial style appropriate to that context. Although the style is informal, the author rarely adopts emotionally charged or persuasive language, writing in a mostly composed and judicious style. That is a strength of the argument, since many readers will have strong views on cloning, and this text is written in a way that is unlikely to antagonise. What uses there are of persuasive language are quite subtle. The author's use of the word "cloning", for example, to refer not only to reproductive cloning, but to stem cell research, ("therapeutic cloning") and identical twins ("naturally occurring clones") is a way of making reproductive cloning sound innocuous. The main argument has five premises. The first three premises counter specific objections to cloning that have been cited by the author, who claims that none of these objections constitute a reason to reject reproductive cloning. The fourth and fifth premises are more general, suggesting not that particular objections are wrong, but that the reasons people have for their condemnation of cloning may not be based on genuine objections at all. These premises are negative, in that they do not provide evidence that cloning should be accepted, but only reasons to question objections to it. Although this methodology would not provide support for a strong conclusion like "cloning should be permitted", Honey's conclusion is the weaker claim that we do not yet have reason to rule out cloning, and that a careful debate on the issue is needed. It should be noted, however, that any argument that proceeds only by responding to objections leaves open the possibility that there are other significant objections that have not been addressed. This can be especially problematic in a case like this where no source information is provided for the objections that are considered. We will return later to the implications of the author's method, but will now turn to an evaluation of each of the subarguments, since even if the main premises provide sufficient support for the conclusion, our acceptance of the conclusion would still be contingent on our acceptance of those premises. In the first subargument, Honey provides a series of responses to the objection that clones may lack individuality. The different arguments Honey provides relate to different aspects of this concern, since "individuality" is understood by his opponents in a number of ways: as a matter of personality, or of rights, or in a more spiritual way. Honey argues that however this objection is understood, it does not provide sufficient reason to reject cloning. Two parts of this first argument are based on an analogy drawn between identical twins and clones. The similarity between the subject and analogue is that sets of identical twins, like sets of clones, are genetically identical. Honey argues first (in premise 1.3) that twins are individuals with the same rights, and second (1.4) that if souls exist, twins must each have a soul. Based on the analogy, Honey argues that the same would be true of deliberately created clones. The analogy here is quite strong, at least if we are thinking about individuality in terms of something like personality: genetic individuality cannot be necessary for individuality. There is a normative aspect to this argument, since the author says that twins are treated as individuals with the same rights, so clones should be as well. This might not work as a descriptive argument, since people do not have the same attitudes to clones as they have to twins, but if we accept the rest of the analogy we

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should probably also accept the normative conclusion that clones should be treated as individuals with the same rights. The other part of the analogical argument is supposed to show that if souls exist, clones would have them. This is less successful than the earlier part of the analogical argument. All the argument would establish if successful would be that a person's soul is not just a matter of their genetics, and it seems unlikely that this is the real issue. This is a point in the argument where it would be useful to have a reference to some particular objection that had been made on the basis of the problem of souls, since the objection the author attacks does not seem to be the most likely one. If someone believes in souls and considers them a reason to reject cloning, it is unlikely they would do so because they were concerned that a person's soul is determined by their genetic make-up, so sameness of DNA would entail sameness of soul. Souls, traditionally understood, are non-physical, and it seems much more likely that the fear would be that cloning would only reproduce the physical properties of a person, so the clone would not get a soul. Twins would be relevantly different to clones, on this argument, because both twins would have been created by God, who could have given them independent souls. Scientists may not have that power. If Honey is responding to a weaker version of the argument than one that is actually given by opponents, he is committing the straw person fallacy. The strongest evidence for premise 1 may be premise 1.5, which argues that since a lot of what individuates a person is a consequence of their environment and experiences, the separation in time between people and their clones would guarantee individuality in that sense. The second main premise states that it would be unreasonable to rule out cloning because of a desire to respect human limitations and a reluctance to play God. Honey supports this claim by comparing reproductive cloning with stem cell research and argues that stem cell research is more problematic in this regard, since while reproductive cloning uses embryos for reproduction, stem cell research ('therapeutic cloning') results in the death of the embryos used. Honey argues that since "there is widespread agreement as to the rightness of therapeutic cloning" we should also be prepared to consider reproductive cloning. The most serious problem with this argument is the assertion that there is such widespread agreement. Stem cell research is still very controversial in many circles, particularly among religious people who are likely to be those most opposed to 'playing God', and to whom this part of the argument needs to be directed. Those people may take the analogy Honey suggests as a further reason to reject stem cell research, rather than as a reason to allow cloning. In the third subargument, Honey responds to the objection that clones would be created for selfish reasons and not valued for themselves. Honey argues that this is not a good reason for rejecting cloning, firstly because although he admits some people may have selfish motivations, "there are people who can have children in no other way". Given current technology, this is not true, but even if it becomes true it may not be a reason to permit cloning. Honey says that if the technology is available "there will need to be good reasons to deny people that opportunity", so even he does not think that this would necessarily outweigh other considerations if there are yet good reasons not to allow cloning.Consequently, this can provide only weak support for premise 3. In the final two subarguments, Honey suggests that there may be explanations for the opposition to cloning among the public and scientists that are not based on real issues to do with cloning. His suggestion in the fourth subargument that the public just tend to oppose new technologies and will become used to the idea as they have with IVF and surrogacy has some merit as an inductive argument: we have seen in the past that some controversies fade over time. But to the extent that those techniques have become accepted, their acceptance was a result of their success, and it remains to be seen whether the same will be true of cloning. New techniques that are found to be unsafe, for example, do not become accepted.

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The final subargument suggests that the real reason for medical scientists' opposition to cloning is that they are trying to gain support for stem cell research. There is no direct evidence given for this claim: only the suggestion that scientists might be able to make stem cell research seem more attractive by contrasting it with the more controversial reproductive cloning. There is no evidence given for the explanation proposed here, however, and we have no real reason to suspect that the objections of scientists are not genuine. Honey does not claim that this is definitely the true explanation, prefacing his claim with "I think it likely that the real reasons ..." but we still have not been given enough evidence to understand why he would consider that the most likely explanation. It is a circumstantial ad hominem fallacy to dismiss someone's argument because of an unjustified claim about their circumstances. Although some of these subarguments are not well supported, the main premises are convergent and we do not have to accept all of them to have reason to accept the conclusion. Honey has, I think, succeeded in achieving his stated purpose. Because he is not trying to defend a strong positive conclusion, but only trying to show that we do not yet have conclusive reasons to abandon cloning and should debate the arguments, his article is effective. He has shown that at least some of the objections to cloning may be questioned, and although not all such objections have been refuted, Honey's article may constitute one part of the ongoing debate he sought.

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10 CONCLUSION (WEEK 12) In the final lecture, we will look at how the evaluative skills you've been picking up in this unit can be used to improve your own arguments, in academic and other contexts.

The strategies you have been learning have one of their most useful applications in the evaluation of your own work. The process of evaluation encourages you to think closely about each inference: would an opponent accept your premises? How could you make them more acceptable? What criticisms could be made of your inferences and how could you strengthen them?

If you can approach your own essays and other writing with the kind of evaluative skills you would apply to the arguments of another, you will learn to write stronger arguments, and fortify them against possible criticisms. More importantly, by thinking seriously about whether your premises support your conclusions, and even whether the reasons you have for believing the things you believe are good reasons, you will improve your chances of making good decisions and of believing only those things you can justify.

The strategies you now have at your disposal are also extremely useful for the construction of arguments in academic contexts such as essay writing.

Standardisation for essay writing In the final lecture, we will go through the process of developing an essay using the strategies developed in this unit.

Here are some useful tips:

1: Standardise your essay as an outline •Work out what your conclusion is •Outline the main reasons you have for accepting that conclusion as main premises •Include the main kinds of evidence you will be using in support of that conclusion as your subpremises

2: Looking at your standardisation, evaluate the inferences you have represented : do your premises support the conclusions they're supposed to support? 3: Ask: Is your audience likely to accept your unsupported premises, or should you provide more evidence for them? 4: Include counter considerations to show how you can respond to likely objections. 5. Remember that all the things that made other people's arguments easy or difficult to understand will also make your argument easy or difficult to understand. So:

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State your overall conclusion clearly. For each new line of reasoning, make the conclusion clear. (It will often be helpful to state the main premise before the reasons for it). Use indicator words, to make the structure clearer Keep your points in a coherent order. Don't jump back and forth between points. Keep your language as clear as possible.

As you progress through your academic careers, you are likely to develop your own essay-writing techniques. This method provides a very useful basis, however, because it encourages you to think of your essay as an argument rather than simply a series of points, and gives you the best chance of making that argument persuasive.

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