Relevance in Argumentation

Douglas Walton

• Publisher: Routledge
• Year: 2003
• ISBN:
  9781135618957
• Edition: 1
• Topic: Lingue e linguistica
• Subtopic: Studi sulla comunicazione

In Relevance in Argumentation, author Douglas Walton presents a new method for critically evaluating arguments for relevance. This method enables a critic to judge whether a move can be said to be relevant or irrelevant, and is based on case studies of argumentation in which an argument, or part of an argument, has been criticized as irrelevant. Walton's method is based on a new theory of relevance that incorporates techniques of argumentation theory, logic, and artificial intelligence.
The work uses a case-study approach with numerous examples of controversial arguments, strategies of attack in argumentation, and fallacies. Walton reviews ordinary cases of irrelevance in argumentation, and uses them as a basis to advance and develop his new theory of irrelevance and relevance. The volume also presents a clear account of the technical problems in the previous attempts to define relevance, including an analysis of formal systems of relevance logic and an explanation of the Grecian notion of conversational relevance.
This volume is intended for graduate and advanced undergraduate courses in those fields using argumentation theory--especially philosophy, linguistics, cognitive science and communication studies, in addition to argumentation. The work also has practical use, as it applies theory directly to familiar examples of argumentation in daily and professional life. With a clear and comprehensive method for determining relevance and irrelevance, it can be convincingly applied to highly significant practical problems about relevance, including those in legal and political argumentation.

1

Examples of Irrelevant Arguments

To begin to investigate the concept of relevance, one should examine how it is used, or how it is useful, in everyday argumentation. What function does relevance have as a tool to help promote goals of rational argumentation? This question initially appears to be vague and abstract and, therefore, hard to answer. One can make it more specific by concentrating on the negative side of it, posing it in a different way as follows. What function does the objection “That’s irrelevant” have in argumentation? This question is easier to answer because one can focus on specific kinds of criticisms that are found in common examples and are fairly concrete. This negative way of putting the question in terms of irrelevance immediately links it to common examples of argumentation where irrelevance has been perceived to be a problem and where steps have been taken to solve the problem. Examination of these practices can give insight into why irrelevance is a problem in argumentation and what means have been devised to attempt to deal with it. Chapter 1 introduces the reader to some classic examples of this sort.

An important source of examples is the traditional part of logic concerned with informal fallacies. Irrelevance itself has often been categorized as a fallacy. But other fallacies have also been traditionally recognized that focus on certain specific kinds of problematic and fallacious irrelevance. The logic textbooks are full of examples of such arguments that offer clues on why irrelevance should be taken to be problematic in rational argumentation. Whereas a detailed survey of the textbook accounts is given in chapter 2, a few classic examples of irrelevant arguments from those accounts are presented in chapter 1 to help the reader grasp how the tradition of fallacies is important for understanding irrelevance as an objection.

One type of example often cited in the textbooks illustrates irrelevance in legal argumentation. In court, a lawyer arguing for one side in a trial can often be observed to object to an argument, question, or other move made by the lawyer for the other side by saying, “That’s irrelevant.” Irrelevance is taken to be a serious matter in court, and rules of evidence are very carefully devised to exclude or remove any argument or question deemed to be irrelevant.

Another type of example often cited occurs in political argumentation. The rules governing irrelevance in political debates tend to be looser, less precise, and less strictly enforced than those in legal argumentation. But such rules do exist in parliamentary and legislative debates, and the objection “That’s irrelevant” has some force in them.

Still another source is the history of rhetoric. Ancient Greek rhetorical writers were particularly concerned with irrelevant emotional appeals, for example those used in legal or political arguments that could sway an audience or a jury. Examination of these historical sources can cast light on relevance and irrelevance in argumentation, but aside from brief mention in chapter 1, historical matters will be treated in the integrated survey of chapter 2.

1. THE EXCLUSIONARY FUNCTION

The main function of the concept of relevance, as used in debates, discussions, and meetings, is to keep the discussion within productive boundaries. Used for this purpose, relevance fulfills what can be called a gatekeeping or exclusionary function in argumentation. Using the criticism “That’s irrelevant!” is a way of keeping the argumentation from straying off into less productive lines of reasoning that would not contribute to the resolution of the problem or conflict of opinions posed in the discussion. The problem in many such cases is that time for the meeting may be limited, and yet the problem to be solved may be urgent. In other cases, having a lengthy debate may be very costly. Hence, in order to solve the problem within the given constraints of time and money, it may be useful, or even necessary, to draw boundaries of relevance.

A good case in point is the example in Walton (Inf. Log., 1989, p. 71) where a meeting of a university library committee has the issue on its agenda of whether library hours should be extended on Sundays. The Student Association has made a proposal to extend them on Sundays from eight hours to ten hours. Part of the dialogue in the meeting runs as follows:

Case 1.1:	Harry:	Not only should the library remain open longer so that students can have a place to study, but student tuition fees should be lowered as well.
	Pam:	Hold on, Harry. The topic of this meeting is the proposal for the extension of library hours. What does the topic of tuition fees have to do with it? I don’t see the relevance of that issue.
	Harry:	Well, if students didn’t have to pay so much tuition, they could afford better lodging, and therefore better facilities to study at home. I mean it’s all connected because many factors are responsible for not providing students with adequate facilities for studying. Therefore my point is relevant.

The problem in this case is to decide whether Harry’s argument is relevant or whether Pam’s objection to it on grounds of its irrelevance is reasonable.

The first thing to be noted in this case is that Harry’s line of argument is at least potentially relevant. As his reply shows, there is a legitimate connection between the question of student tuition fees and the issue of library hours. But is it the kind of connection that justifies the claim that Harry’s argument on tuition fees is relevant to, and ought to be included in the discussion in the library committee meeting? In an actual case, this is the question that would have to be determined by the chairman of the library committee or whoever is chairing the meeting of the committee that day.

The practical problem confronted by whoever is chairing the meeting is that the issue of how long the library should be open on Sundays needs to get a proper hearing so that all concerned parties can express their views. But the time that can be given for this purpose may be fixed. It is important, before a vote is taken, that the participants in the meeting should take all the relevant considerations into account if the discussion is to provide a good basis for deliberation on the issue. If the discussion gets sidetracked and spends too much time on one narrow side issue, then other, perhaps even more important considerations, may not be taken into account. If so, too much discussion on one limited side issue may block off the possibility of taking time to discuss main issues. This blocking-off effect may mean that the purpose of the discussion fails to be fulfilled.

The ultimate instance of this blocking-off effect is the use of the tactic called the filibuster in debate. For example, in a congressional or parliamentary debate, one participant may read from the Bible, or any book available, simply to fill enough time to prevent the other side from taking their turn. This tactic can be used to block debate on a bill, for all intents and purposes, by preventing the opposition from saying anything at all. In such a case, we can clearly see how the real purpose of the dialogue is blocked by this tactic of irrelevance. The reading of the Bible, or whatever document is used, contributes nothing to the argumentation in the discussion of the bill at issue. Its only function is to block out any arguments that might be used by the other side. The tactic is similar to the case of a football team that is not trying to score a goal, but simply to hang on to the ball long enough to maintain their lead until the few minutes left in the game have elapsed.

But it is a problem, at the initial stages of a dialogue, that it is difficult to tell which directions the argumentation may take in the subsequent discussion that will be productive. When the objection “That’s irrelevant!” is made, a participant may reply, “If you will take my word for it, you will see later how this point will become relevant in the line of argument I will develop.” So one who uses this criticism of irrelevance may also have to show some latitude and judgment in exercising the exclusionary function. The chairman will have to evaluate how well the discussion has succeeded at the particular point reached when Harry’s argument was introduced, and judge how further discussion of this issue will contribute to or block the argumentation needed to resolve the problem of extending library hours on Sundays.

2. IRRELEVANCE IN A POLITICAL DEBATE

Copi’s textbook, Introduction to Logic, has now gone through eleven editions, and was the most popular introductory logic textbook in the western world (and perhaps in the whole world) for the first forty years or so it was in print. Copi treated irrelevance in argument under the heading of fallacies, as many logic textbooks have done. Copi (1968) divided fallacies into two broad categories: fallacies of relevance (a total of ten) and fallacies of ambiguity. Among the various fallacies of relevance (Copi, p. 72), the fallacy of ignoratio elenchi (irrelevant conclusion) is said to be “committed when an argument purporting to establish a particular conclusion is directed to proving a different conclusion.” The case cited here is from the third edition (1968), but it is very close to that of the first edition (1953) and similar in outline to that of the ninth edition (coauthored with Carl Cohen, 1994):

Case 1.2:

For example, when a particular proposal for housing legislation is under consideration, a legislator may rise to speak in favor of the bill and argue only that decent housing for all the people is desirable. His remarks are then logically irrelevant to the point at issue, for the question concerns the particular measure at hand. Presumably everyone agrees that decent housing for all the people is desirable (even those will pretend to agree who do not really think so). The question is: will this particular measure provide it, and if so, will it provide it better than any practical alternative? The speaker’s argument is fallacious, for it commits the fallacy of ignoratio elenchi, or irrelevant conclusion (p. 72).

Copi’s commentary provided a readily understandable version of the ignoratio elenchi fallacy for modern readers by explaining it as a failure to present evidence of the kind needed in a debate. As Copi explained it (p. 72), the fallacy is committed by the legislator’s argument because it has failed to meet the requirement of providing evidence “capable of establishing the truth of the conclusion” to be proved (p. 72). The reason the argument in this case is said to be a fallacy of ignoratio elenchi is that the legislator should be confining his arguments to matters that are relevant to the specific housing bill under consideration in the debate. Instead, he argues in a rhetorically rousing manner for the proposition, ‘All people should have decent housing.’ But this general proposition is something that everyone accepts. Nobody in the debate, on either side, disputes it. Proving or disproving it is not relevant to settling the issue of the debate—namely the particular housing bill being considered. Hence, the senator’s rousing rhetoric is dismissed (Copi, 1968, p. 72) as a fallacious ignoratio elenchi.

One problem with this analysis is that the legislator’s proposition, ‘All people deserve decent housing’ is relevant to the housing bill under consideration in a clearly definable sense. Both propositions are about housing. There is some subject-matter overlap between the two propositions. One is topically related to the other. Hence, the senator’s argument for the proposition ‘All people deserve decent housing’ is relevant, in one sense, to the issue of the particular housing bill being debated. But if it is relevant, how can we say that a fallacy of ignoratio elenchi, or failure of relevance, has occurred? This apparent contradiction is a problem for the traditional textbook treatment of the ignoratio elenchi as a fallacy. One step toward a solution to this problem is to invoke a distinction between topical and material relevance. The first step in approaching the problem is to concede that the senator’s proposition, ‘All people deserve decent housing’ is topically relevant to the issue of the debate on the housing bill. However, as indicated above, it does not seem to be materially relevant. But even taking this step presents another problem. The senator’s argument could be more than just topically relevant. It could also be relevant to the issue of the housing bill, in the sense that, potentially, it could be part of some sort of argument, yet unidentified, that could be used as part of a sequence of argumentation to give evidence to support the bill being debated. We could say that it is potentially relevant evidentially, as well as topically, to the issue under consideration. In this sense, it could be relevant, depending on the details of the case the senator might be trying to make. At least it might be premature to declare that his argument is irrelevant.

But is potential relevance enough, in this case, for us to conclude that the senator has not committed a fallacious ignoratio elenchi? Perhaps not, if the distinction between potential and material relevance can be clarified. The senator’s rhetorical flourish may be potentially relevant. But is it materially relevant? In other words, is it relevant in a sense that makes it a really useful contribution to the debate the participants are supposed to be engaged in? It can be argued that it is not, because it is not materially relevant to the resolution of the dispute on the housing bill. Let’s say that the debate on the housing bill is limited to a certain time in the Senate. The purpose of the debate is to bring reasonable arguments to bear that might swing a significant number of the senators one way or the other. By looking at the arguments on both sides, a senator can come to a reasoned decision to vote for or against the particular bill being debated. This bill could be any specific bill—let us say it is about government subsidies proposed to help first-time house buyers to finance their mortgages. The two sides in the Senate might be locked in disagreement on whether to vote for this bill or not. Let’s say, for example, that they disagree about the costs of the proposed legislation, whether its benefits outweigh its costs, what its consequences are likely to be, whom it will really benefit, and so forth. An argument is materially relevant in the context of this debate on this particular bill if and only if it will bear strongly enough on one or more of these arguments so that it may shift the balance of considerations in the vote one way or the other. Otherwise it is not materially relevant in this particular context. It is on this basis, then, that the senator’s argument for the proposition, ‘All people deserve decent housing’ could be rejected as not materially relevant. The failure of material relevance is a failure to be a strong enough argument to significantly influence the argumentation in the dialogue one way or the other.

This case shows a number of interesting things about irrelevance. One is that it is considered a fallacy by logic textbooks. Another is that irrelevance occurs in political arguments like legislative debates and can be an important problem in them. Another is that the problem apparently relates to the exclusionary function described in the previous section. If an arguer goes on and on with irrelevant arguments, the danger is that it could prevent relevant arguments from being heard, thus defeating the purpose of the debate.

Another thing shown by this case is the difficulty of dealing with irrelevance. The Speaker of the Senate is supposed to prevent this kind of problematic rhetorical digression from ruining a debate. But it may not be easy to do that in some cases. For, as we have seen, several different kinds of relevance are involved. The senator can argue that even though his argument is not relevant in one sense, it may still be relevant in another. There are rules of relevance for specific kinds of political debates, as will be shown in the next chapter. But if it is even difficult to define relevance, or to distinguish between different kinds of relevance, it may be difficult to identify irrelevance clearly and definitively in a given case.

Finally, there is one more lesson to be drawn from this case. It suggests a danger of irrelevance in argumentation, over and above the problem posed by the exclusionary function. This danger is that the senator might give such a crowd-pleasing speech on how all the people deserve decent housing that a majority of the senators are persuaded to vote for the bill. The danger is that the crowd-pleasing argument, even though it is materially irrelevant, might be psychologically successful in persuading the senators to go along with it. According to Copi’s analysis of the fallacy in case 1.2, the speaker tries to evoke an attitude of approval for himself so this attitude can be transferred to his conclusion by “psychological association.” But it is not logically relevant because he has not proved that the bill is in the public interest (p. 72). It is not logically relevant, in Copi’s sense, because (as things stand, in the case) it is incapable of establishing the truth of the conclusion. The danger is associated with what some might call the prejudicial power of the argument. The argument could appear to be relevant to an uncritical audience, even though it is not, in some sense, logically or materially relevant.

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