2. Argument Structure & Standardization

Transcription

1 2. Argument Structure & Standardization 1 Some Review So, we have been looking at arguments: What is and is not an argument. The main parts of an argument. How to identify one when you see it. In the exercises for Chapter One, most of the examples are relatively short and straightforward; the structure of the reasoning in each example relatively easy to see 2 1

2 This is not always the case in real world argumentation, however. Our goal in the coming weeks is to evaluate arguments, sorting out good ones from bad ones. But before evaluating an argument, we have to understand it. That s were standardization comes in 3 The Standard Model Recall from last time, what Govier calls the Standard Model of Arguments Premise 1 Premise 2 Premise 3 Premise n Conclusion 4 2

3 Standardization To standardize an argument is set it out in in the standard form; to set out its premises and conclusion in clear, simple statements with premises preceding the conclusion (25). In standardizing an argument we will assign an identifier (a number, though it could just as well be a letter or other symbol) to each statement so that we can refer to specific statements efficiently. 5 Govier s Example It is a mistake to think that medical problems can be treated solely by medication. That s because medication does not address psychological and lifestyle issues. Medical problems are not purely biochemical. They involve issues of attitude and way of life. Standardized: 1. Medication does not address psychological and lifestyle issues 2. Medical problems are not purely biochemical 3. Medical issues involve issues of attitude and way of life 4. Medical problems cannot be treated solely by medication 6 3

4 Note that, in this example, the conclusion appeared before the premises. In order to show reasoning from the premises to the conclusion, the conclusion is moved to the end in standard form. In this case, the order of the premises does not really matter (but, as we ll see it does matter in the case subarguments and dependent argument forms). Note also that the statements are simplified and that the subject of each statement has been specified explicitly, by replacing pronouns with the noun phrase medical problems 7 Another Example Every right places a corresponding obligation upon someone. If I have a right to life, then you have an obligation not to kill me. If you have a right to free passage, then I have an obligation not to hinder your progress. If we both have a right to be treated equally before the law, then society has an obligation to see that this is so. 8 4

5 In Standardized Form: 1. If I have a right to life, then you have an obligation not to kill me. 2. If you have a right to free passage, then I have an obligation not to hinder you 3. If we both have a right to be treated equally before the law, then society has an obligation to make this so 4. Every right places a corresponding obligation on upon someone. 9 Alternative (More Simplified) Version: 1. My right to life implies that you have an obligation not to kill me. 2. Your right to free passage implies that I have an obligation not to hinder you 3. Our right to equality before the law, implies that society has an obligation to make this so 4. Every right implies a corresponding obligation for someone else. 10 5

6 A More Difficult Example Haven t we had enough letters to the editorial page of the Spectator every day and from cry-baby steel workers talking about how the Stelco strike is killing them? I am sure there are hundreds of pro-union letters going into the Spectator office, but only the anti-union ones get printed. I would not be a bit surprised if Stelco and the Spectator were working together to lower the morale of the steel workers who chose to strike for higher wages. (Letter to the Editor, Hamilton Spectator, 2002) 11 Standardized Form It is not completely obvious that this passage actually contains an argument (e.g., there is no clear conclusion indicator). If we interpret I wouldn t be surprised if as a indicator, we might standardize the argument as follows: 1. We have had enough letters to the editor from cry-baby steel workers saying that the Stelco strike is killing them. 2. I am sure that hundreds of pro-union letters are received by the Spectator, but only the anti-union ones are printed. 3. There is reason to believe that Stelco and the Spectator are working together to lower the morale steel workers who chose to strike. 12 6

7 Structure Diagrams Each of the arguments that we have standardized so far has the following structure: Subarguments But not all arguments relate premises to conclusions in this straightforward (independent) way. Some arguments proceed in stages: A statement that functions as a premise in one argument becomes the conclusion to another. A subargument is a subordinate argument that is a component of a larger argument (the whole argument ) 14 7

8 Govier s Example A computer cannot cheat in a game, because cheating requires deliberately breaking the rules in order to win. A computer cannot deliberately break the rules because it has no freedom of action. 1. A computer has no freedom of action, Thus, 2. A computer cannot deliberately break rules 3. Cheating requires deliberately breaking rules 4. A computer cannot cheat. 15 In this argument (as standardized) premises 2 and 3 directly support the conclusion, while premise 1 supports premise 2 in a subargument. This can be diagrammed as follows:

9 About Subarguments Recall that, in offering an argument, you are trying to rationally persuade someone to accept the claim that you offer as your conclusion. In effect, you are asking your audience a) to accept your premises as true and b) to accept that your premises do in fact support your conclusion. A subargument is useful, e.g., in establishing premises that your audience might not already accept. 17 Other Subargument Forms Not every argument that contains a subargument is structured in the same way. For instance: Labor is the basis of all property. From this it follows that a man owns what he makes with his own hands and the man who does not labor has no rightful property. (Adapted by Govier from John Locke) 18 9

10 1. Labor is the basis of all property. 2. A man owns what he makes with his own hands. 1. Labor is the basis of all property 3. A man who does not labor has no rightful property. 19 This argument can be diagrammed in two different ways:

11 As Govier notes (29), there is no fixed theoretical limit to the number of subarguments an argument may contain n 21 Strategies for Standardization You would do well to review the General Strategies for Standardizing Arguments (34). These will be useful not only for the exercises in this chapter, but for translating arguments into categorical or propositional form in later chapters as well

12 Location of Conclusions To standardize an argument, you must be able to identify its conclusion. As we have seen, however, this can sometimes be rather difficult. Indicator words can help. (Though they may not always be present.) Also, the same conclusion may be stated more than once in a given argument. 23 Scope Consider the following statements: a) All sports are boring. b) Most sports are boring. c) Many sports are boring. d) Some sports are boring. e) A few sports are boring. Clearly these are importantly different claims. The main respect in which they are different can be called scope 24 12

13 A claim like a) All Xs are Y is a universal claim, it is a claim about all Xs without exception. Claims b), c), and d), by contrast, may be true even is there are exceptions; claim e), in particular, allows for many (possibly a majority) of exceptions. The idea of the scope of a claim will crucial later on. But it is also important when standardizing arguments: We don not want to attribute to someone a claim that is different in scope from the claim she actually is making. 25 Commitment Claims also vary in the degree of commitment they express. Smoking does cause cancer Smoking may cause cancer Smoking may be one factor in the development of cancer 26 13

14 Clearly the degree of commitment expressed in an argument is relevant in understanding and evaluating that argument. Unfortunately (as with scope) people are not always clear or consistent about the degree of commitment they intend their argument to have. 27 Patterns in Argument As we will see when we get to topics in categorical and propositional logic, the structure of argument is very important to assessing argument validity. At this early stage, Govier indicates a few basic forms of argument structure that are especially significant for standardization 28 14

15 Linear Sequential Support One premise supports the next, which supports the next and so on until the conclusion is reached/ 29 Linked Support Consider: 1. Vulnerability to heart disease is either inherited or environmental 2. Vulnerability to heart disease is not environmental 3. Vulnerability to heart disease is inherited 1) and 2) do not support the conclusion independantly, but only in combination; the premises are linked

16 Linked support can be diagramed as follows: Convergent Support In other cases, each premise supports the conclusion independently (i.e., separately) Consider: 1. Affirmative action hiring policies discriminate against qualified non-minorities. 2. Moreover, affirmative action policies create a disincentive for members of minority groups to seek qualifications for employment. 3. Affirmative actions hiring policies ought to be outlawed

17 This pattern of argument, which Govier terms convergent support, can be diagrammed as follows: Unstated Premises & Conclusions As Govier notes, real world arguments may often leave one or more premises, or the conclusion, unstated. In standardizing arguments, unstated premises and conclusions may need to be supplied 34 17

18 Charity When we supply missing premises and conclusions and when we interpret the intended scope and degree of commitment of unclear or ambiguous claims we should, however, seek to be as fair to the arguer as possible. Philosophers and logicians sometimes speak of the principle of charity : We should view other people s claims in the most reasonable light possible, interpreting them in their strongest, most coherent form. 35 Grice s Cooperative Principle Recall our earlier talk about entering into the game of giving and accepting reasons. This is directly related to what the British philosopher H.P. Grice has called the Cooperative Principle: People generally communicate for some purpose. In order to further their purposes, people generally cooperate in structuring their communication so as to, e.g., provide as much information as needed, avoid deliberate falsehoods, and be as clear as possible. Grice s point is not that people never lie or deceive, but that without cooperation communication itself would be impossible

19 Accuracy But, cautions Govier, it is possible to be too charitable in interpreting other people s arguments we may standardize them in a form that make them out to be more reasonable than they actually are. So, we strive to be both charitable and accurate in our interpretations. Accordingly, Govier recommends a principle of Modest Charity (57) 37 19