In earlier articles we have explored some basic elements of formal logic and the application of those elements to LD case development. Now we can consider the application of logic to cross-examination and rebuttals. These are the parts of a debate round where a working knowledge of logic can do most to transform a student’s performance from the ordinary to the outstanding. Students who have followed me this far may have the feeling that my advice here about rebuttals is less detailed than my earlier advice about (say) mapping case arguments. As the discussion moves deeper into the debate round, it becomes more difficult to offer helpful examples, because each example would require a description of an entire round, something space precludes. But I am confident that students who take the trouble to learn and implement the more detailed advice on formal logic and casing in the earlier articles will find it fairly easy to apply the general advice I give here about cross-examination and rebuttals.
In my first Rostrum article (April 1994), I lamented the rise of what I called “refutory debate”—debate guided be nothing more than a reflexive attempt to refute (usually several times over) anything and everything one’s opponent says. I believe reflexive refutation is still the norm in LD. The problem with such an approach, then and now, is that there is no real need to refute most of what one’s opponent says, and the attempt to do so ruins the force and clarity of each individual response.
It is all well and good to counsel students in the abstract to use a more selective strategy, hitting only the most important points. But the average student, confronted with such vague advice, may be unwilling to gamble on her own interpretations of what the most important points and most effective responses are. Instead, she will likely retreat to the mediocre comfort of peppering each of her opponent’s statements with as many objections as she can think up. Logic gives us the resources to be more helpfully articulate about strategies for selective, high-impact rebuttals.
I. Basic Principles
The key to making logic work for you in cross-examination and rebuttals is to interpret your opponents’ arguments (and, of course, your own) as formally valid premise-conclusion chains. This may sound obvious enough, but it can be surprisingly hard to do when you confront opponents who do not themselves have much understanding of the logical structure of their ideas and who therefore present them either in an undifferentiated stream of consciousness or in a logically confused series of “subpoints.”
The jargon of “points” and “subpoints” is among the most deceptive at work in LD today. Many students and judges imagine they are clearing things up by labeling sentences as distinct points or subpoints, but these terms usually obscure the logical structure of a case. What is needed, of course, is an analysis of a case into distinct arguments, and of each distinct argument into its conclusion and supporting premises. Only in light of such analysis can a debater make confident, informed decisions about what to attack and what to ignore.
Debaters and judges who do not understand the logical structure of arguments tend to treat each distinct assertion (or subpoint) of a case or contention as a separate bit of reason to accept or reject a resolution. This is why debaters feel compelled to attack everything their opponents say and why certain “progressive” judges make decisions on the basis of “dropped subpoints,” whatever the points may be. Logically astute debaters know that individual claims by themselves may not lend any support to a conclusion. Just as a healthy kidney will not by itself keep you alive, so a single “dropped subpoint” will not typically lend any free-standing support to a resolution. A kidney contributes to the life of an animal only in concert with other organs, and a distinct premise supports a conclusion only in combination with an appropriate set of other premises. Arguments function as organic wholes; take away any necessary part (i.e., premise) and the whole argument dies. Your goal in cross-examination and rebuttals is to make your judges and opponents see that this is so.
Analyzing an opponent’s argument into premise-conclusion form may reveal three types of problem. First, an opponent may present a valid argument with true premises for an irrelevant (i.e., non-resolutional) conclusion. Second, an opponent may present true premises in support of a relevant conclusion, but in a logically invalid form. Third, an opponent may present a valid argument for a relevant conclusion (the resolution or its negation), but with one or more objectionable premises. I will give an example of each sort of error and the corresponding response strategy below. Of course, it is possible that an opponent’s argument will display more than one of these three errors. The basic strategy of the logical debater is: (1) find the weakness, and (2) attack the weakness.
The logically savvy debater’s task is further complicated by the fact that not only his opponents, but also most of his judges, will be unaccustomed to interpreting arguments and responses according to their logical structure. The truth is that many experienced LD judges think that “argument” means simply “claim-warrant”; they are not acquainted with the formal inferential patterns that distinguish logically adequate warrants from imitations. So debaters who intend to use logic to their advantage must be prepared not only to make the correct strategic decisions but also to explain those decisions and their strategic force to judges who otherwise may not understand what’s happening.
We might, then, say that there are three stages to the use of logic in cross-examination and rebuttals. In the first stage, the debater must understand for himself the logical structure of an opponent’s position and decide how best to attack it. In the second stage, the debater must actually make the attack. And in the third stage, the debater must explain the impact of the attack to ensure that its power is not lost on judge or opponent.
II. Cross-Examination
There is a traditional story about cross-examination that goes something like this: Cross-examination has two main purposes. The first is to clarify an opponent’s case where it is unclear; this is the priority, but it is useful mostly for novices who haven’t learned to flow well. The second purpose, which is the main purpose for skilled debaters, is to discredit an opponent’s case by asking embarrassing questions about it.
This story is misleading. It is true that clarification should be the priority in cross-examination; there is no point in trying to discredit an argument before it is clear just what the argument is. But it is not true that clarification is primarily a task for novices. Most cross-examination time for most debaters (including skilled and experienced debaters) is best spent in clarification of one form or another. Debaters would do better to leave the discrediting for rebuttals and use cross-examination exclusively to clarify for themselves and for their judges the logical structure and commitments of an opponent’s position. This is crucial since, as noted above, most opponents and judges will not have a ready grasp of logical structure and implication. And mapping the logical structure of an unfamiliar case can be a challenge even for logically competent debaters. Cross-examination is the time in the debate when logical structure can be laid bare.
As you flow your opponent’s case, you should be trying to follow whatever logical structure there is and to impose whatever structure is missing. You are trying to identify each separate constructive argument, the conclusion of which is the resolution or its negation. Ideally, each contention will correspond to a separate constructive argument. But sometimes one contention will contain more than one argument, or one argument may be spread out over two or more contentions. Likewise, value premises and criteria will usually function as essential premises in constructive arguments, and definitions, observations, and other extra-contention elements may also contain premises on which constructive arguments depend. Even when you have identified a distinct constructive argument, its premises may be in an unnatural order which is hard to follow. Your primary goal in cross-examination is to review the logical structure of each constructive argument to prepare for your rebuttals.
There need be nothing sneaky about this cross-examination strategy. You can be entirely upfront with your opponent: “I’d like to make sure I understand each of your arguments.” You do not want to offer your opponent an open-ended invitation to restate each of her arguments. If you do, she is likely to (a) turn your cross-examination time into an extended constructive speech, and (b) restate her arguments in just as logically confusing a way as she presented them in the case. Instead, you should attempt to reconstruct each argument in a clear order, frequently asking your opponent if you have stated each step correctly. The goal is to translate each of your opponent’s lengthy, prosy constructive arguments into a short, clear set of premises which logically yield their conclusion.
If an argument relies on unstated assumptions for its validity, you should probably make those assumptions explicit. If an argument validly draws an irrelevant (i.e., non-resolutional) conclusion, you can call attention to this fact by asking, “So your second contention proves that [contention conclusion], right?” It is best to wait until your rebuttal to point out that this conclusion is different from the resolution and therefore that your opponent’s argument is irrelevant.
When you have laid out the logic of an argument, you can narrow your rebuttal burden considerably by getting your opponent to agree with you about what you must do to kill the argument. You should call attention to the premise or inferential step you plan to challenge in rebuttals and get your opponent to agree that that premise or step is crucial for the success of the argument as a whole. You should not come right out and say, “I plan to attack your value premise that if capital punishment deters crime, then capital punishment is moral.” Instead, say something like, “So it looks like this entire argument relies on the claim that if capital punishment deters crime, then it is moral. Is that right?” Suppose your opponent has provided statistical evidence that capital punishment does, in fact, deter crime, and suppose that you do not want to get into a statistical battle. You can neutralize any future accusation of “dropping” your opponent’s statistical “subpoint” by now asking, “So if I could prove that deterring crime does not automatically make capital punishment moral, then your evidence showing that it does deter crime would not matter, right?”
If there are sections of the case or contention which do not seem to be related logically to the main arguments, you can ask your opponent to explain briefly how each of those sections supports the main argument(s) at issue. If her answer makes clear that a particular section really doesn’t play an essential role in supporting (or defeating) the resolution, you can bracket this section as irrelevant for your rebuttals by asking, “So by itself, this overview does not prove the resolution, right?”
ying the logical structure of each constructive argument and reaching agreement about what would be sufficient to kill it will take most or all of your cross-examination time. As you become more proficient, you may finish this task early enough to leave time for other lines of questioning. That is, you may have time to begin to discredit arguments during cross-examination. If you understand the logical structure of each argument and have made that structure clear to the judge, you can begin to chip away at just the weak spots you plan to emphasize in your rebuttals.
The relevant weaknesses are the three mentioned in the last section: an irrelevant (i.e., non-resolutional) conclusion, an invalid form, or a false premise. Because this is not an article on cross-examination technique, I will not detail how to proceed on each of these three fronts. However, I will say that the best way to expose either the invalidity of an argument or the falsehood of a normative premise is to construct a counter-example.
A validity counter-example is an argument with the same logical form as the argument under consideration but which has obviously true premises and an obviously false conclusion. For example, suppose a debater argues that:
- (1) If pornography is proven to cause rapes, then censorship of pornography is justified.
(2) But pornography is not proven to cause rapes.
(3) So censorship of pornography is not justified.
Readers familiar with the first article in this series should immediately recognize this as the fallacy of denying the antecedent. To avoid the appearance of begging the question, a good counter-example should be on a completely different subject. Here is one:
- (1’) If speeding is proven to cause mass starvation, then speed limits are justified.(2’) But speeding is not proven to cause mass starvation.(3’) So speed limits are not justified.
Everyone recognizes that the premises of this counter-example are true but its conclusion is false. This is because there are many harms that, if caused by speeding, would justify speed limits (many true statements of the form “If speeding is proven to cause X, then speed limits are justified”). The fact that one such harm (mass starvation) is not in fact caused by speeding does not mean that there are not other significant harms that are caused by speeding and that justify speed limits. A validity counter-example makes clear for an audience just what is wrong with invalid reasoning.
To present a validity counter-example in cross-examination, you should simply ask your opponent if each of the counter-example’s premises is true (“Is it true that . . .?”). Then ask if the counter-example’s conclusion follows (“Does it then follow that . . . ?”). If your opponent agrees that the premises are true but the conclusion is false, move to the next point on your agenda; wait until your rebuttal to explain the logical parallel between your counter-example and your opponent’s original argument.
A counter-example to a normative premise is really an application of modus tollens. It begins with a normative principle which you intend to attack. You show that if the principle is true, then certain consequences follow logically from it, but that these consequences are false or morally unacceptable. Therefore, the normative principle which implies them must also be false. For example, if your opponent’s normative principle is that whatever promotes America’s national interest is moral, your counter-example might consider slaughtering Yemen’s population and seizing their oil fields. This action might be in America’s national interest but would clearly not be moral. As an argument, the counter-example looks like this:
- (4) If whatever promotes America’s national interest is moral, then it could be moral for America to slaughter Yemen’s population and seize their oil fields.(5) But it could never be moral for America to slaughter Yemen’s population and seize their oil fields.(6) So it’s false that whatever promotes America’s national interest is moral.
To present a normative counter-example in cross-examination, begin by asking your opponent to endorse the normative premise of his argument that you intent to challenge (“Your argument depends on the premise that if an action is good for America’s national interest, the action is moral, right?”). It is best to state the premise as a conditional, as in my example. Next, present the counter-example in such a way that it clearly satisfies the antecedent of the conditional (“Would it be in America’s national interest to gain massive new petroleum reserves?” [“Yes”] “Suppose America could gain these reserves by slaughtering the people of Yemen and taking over their land.”). Now ask whether the counter-example satisfies the consequent of the conditional (“Would slaughtering the people of Yemen to seize their oil fields be moral?”). If you get the admission you want, move to your next point; wait until your rebuttal to explain how the admission undermines the normative premise on which your opponent’s argument depends.
Finally, if you ask discrediting questions, it is unwise to draw out the full logical implication of your strategy in cross-examination. If your opponent agrees that the conclusion of a contention is somewhat different from the resolution, do not go on to ask, “So this contention is really irrelevant to the debate, right?” If you ask your opponent to admit outright that her argument is irrelevant, illogical, or unsound, she is going to deny the charge, and you may inspire her to do some quick thinking which will get her out of the bind you’ve helped to put her in. Lead your opponent right up to the edge of the precipice in cross-examination, but wait until your rebuttals to push her over the edge.
III. Rebuttals
Based on your cross-examin try to find the weakest two places in each constructive argument to focus your rebuttal attacks. If you attack more than two places in the argument, it is unlikely that any one of the attacks will be very persuasive or carry much weight, and you will likely fall back into a pattern of reflexive refutation. The whole point of thinking explicitly about logic in rebuttals is to help you overcome the need to attack everything your opponent says, or even everything with which you disagree. Because arguments function as organisms, with each premise or inferential step playing an essential role, you can afford to ignore most of your opponent’s claims and focus your attention on only one or two vital organs. At the same time, it is true that different responses appeal to different judges. Therefore, it is wise to find two ways to attack each argument, so that if you and your judge happen to disagree about which response is your strongest, you have not put all your eggs in one basket.
Of course, stipulating two attacks per argument is somewhat arbitrary, and wise debaters (a vanishingly small minority) may recognize occasional exceptions. For example, if an affirmative case presents only one long contention which makes a single constructive argument, it might be worthwhile to kill the argument three times over instead of just twice.
And there is one standing exception to my two-response rule: when your point about an argument is that it’s irrelevant, i.e., that it doesn’t prove or disprove the resolution, you should make that your single response to the argument. If you claim that an argument is irrelevant and then go on to attack its premises in detail, you show that you really do consider it an important argument to refute after all. At the very least, you show that you are not confident in your claim that the argument is irrelevant.
Here is a classic example of the irrelevance response: In an elimination round of Emory’s prestigious Barkley Forum several years ago, a talented affirmative debater who was favored to win presented two well-supported contentions which concluded that a journalist’s right to shield confidential sources was a very good thing. The negative debater granted the truth of the affirmative’s conclusion and the soundness of both her arguments. He did not attack a single statement made in the affirmative case. He simply pointed out that the resolution was that “A journalist’s right to shield confidential sources ought to be protected by the First Amendment,” and that being a good thing was not equivalent to being properly protected by the First Amendment. His negative constructive had argued for a strict original-meaning interpretation of the First Amendment which excluded the right to shield sources. The negative advanced on a 3-0 decision. However, had the negative spent (say) 20 seconds arguing that the affirmative’s contentions were irrelevant and then gone on to refute individual affirmative claims in detail, he might well have lost the round. The power of his single response depended on his willingness to stake the round on it. And since the affirmative was prepared to defend the soundness of her arguments (but not, unfortunately, their relevance), she would have come out looking much stronger had the negative engaged her on her own turf.
There are three basic ways to attack an argument: its relevance, its validity, or the truth of its premsises. We have just discussed a relevance attack; now let’s consider the other two options.
Suppose you want to attack an argument’s logical validity. If you have already set up a validity counter-example in cross-examination, you can refer back to it; if not, you will need to present a counter-example from scratch. When challenging validity, you must make it very clear from the beginning that your challenge, if successful, undercuts the entire argument. Before you present your counter-example, you should clearly identify the argument you’re attacking and state explicitly that you are attacking the entire argument. You do not need to encumber your rebuttals with logical jargon, but you should preview your strategy in a more colloquial way. You can say simply that the argument you’ve identified purports to prove the resolution (or its negation), but that in fact, even if all your opponent’s claims (i.e., premises) are true, the conclusion does not follow. Then say you can use identical reasoning to prove a false conclusion, and present your counter-example. After presenting the counter-example, state again that your opponent’s argument has exactly the same flawed logical form. If possible, point out in detail just where the inference goes wrong and explain further how your opponent’s premises are, in fact, compatible with your conclusion.
The third basic refutation option, challenging the truth of a premise (i.e., challenging the soundness of the argument), will be more familiar to most debaters. Attacking individual claims is the bread and butter of the logically oblivious refutory debate which dominates many circuits. An understanding of logic—i.e., of arguments as complex inferential wholes—enables one to refute premises much more selectively. If you have correctly mapped the logical structure of your opponent’s argument, you need only kill one of its premises to kill the entire argument. You do not have to refute each premise separately, and you do not have to provide multiple responses to a single premise. Indeed, if you plan to attack a premise, you are almost always better off explaining your best single response in detail rather than tossing off six different half-sentence hints. Compare the martial arts master who downs her opponent with a single well-placed punch to the clumsy school girl who flails out of control slapping, scratching, and pulling whatever she can get her hands on.
Choosing the weakest premise to attack and choosing the best single response to that premise are important skills, but they do not fall directly within the purview of this article. This is because logic, as you may recall from the first article, cannot tell you what premises are true. It can only tell you whether conclusions follow validly from whatever premises you accept.
When challenging a normative premise, you should use the counter-example strategy outlined above in the discussion of cross-examination. Point out your opponent’s normative premise and state that you can prove it’s false because it yields the wrong results in other situations. Then explain your counter-example using the modus tollens pattern illustrated in the last section.
If your opponent’s original premise sounded promising before you attacked it, try to provide an alternative true normative premise which accounts for the truthful ring of your opponent’s premise but avoids the counter-example and also does not support your opponent’s conclusion. For example, if the original premise was that if a punishment deters crime, then it is justified, you might provide an example of an effective deterrent which is unjustly applied to an innocent person. Now it looks like deterrence alone is not a sufficient justification for punishment; but surely there is something right about the notion that punishments should make society safer. Perhaps you could propose an alternative normative principle that if several punishments fit the crime equally well, then the criminal ought to suffer the one which is most likely to deter others from committing the same crime. This principle allows you to acknowledge that public safety matters while insisting on the priority of retributive justice.
Although logically minded debaters will be especially skilled at spotting common fallacies of statistical reasoning, there is no general recipe for refuting empirical premises. The key, again, is to choose the premise and the response carefully and explain the response in detail for maximum impact.
The primary contribution of logic to the refutation of individual claims is the understanding of how much damage an argument suffers from the death of a single premise. If the premise is necessary to the validity of the argument, the damage is fatal: death to the premise means death to the argument. As noted earlier, logical debaters must point this out to their judges at every opportunity. For judges accustomed to counting up “dropped sub-points,” the notion that refuting a single claim can kill a contention will be very surprising. You have already primed the judge to think of each argument as an interdependent whole in cross-examination. In rebuttals, you must preface and conclude each premise attack by pointing to the complete argument of which the premise is a part and explaining how the premise is crucial to the argument as a whole. You should say explicitly that even if every other claim in the argument is true, the argument fails to sustain its conclusion if this single crucial premise is undermined. If the premise you are attacking is a value premise (or some other premise shared by all your opponent’s constructive arguments), you may be able to wipe out a whole case with a single response. But you cannot trust your judge to notice that the case or contention is dead. You must point this out and explain why it is so.
Debaters are often admonished to “impact” their responses. I believe that pointing out the logical ramifications of a single response for an argument or case as a whole is one sensible interpretation of what it might mean to impact that response. As much as possible, such impacting should be saturated with the language of the resolution so as to remind your judge that it is ultimately the resolution which is to be proved or disproved, and it is the resolution which your opponent has, in light of your strategic attack, failed to prove or disprove.
IV. Final Issue Selection
Many debaters and judges believe it is especially important to spend the final minute or two of the negative rebuttal and the whole of the second affirmative rebuttal summarizing a few main issues in each round. Such a period of “crystallization” (as it is sometimes awkwardly called) may not be a bad idea, but it is probably less necessary for debaters who implement the model of selective, logical debate endorsed in the present series of articles. This is because the entire rebuttal speeches of such debaters will do exactly what the final summary of less logical debaters is intended to accomplish: make clear why the resolution is true or false given the success of one’s own constructive arguments and the given the failure of one’s opponent’s constructive arguments. Logical debaters select their issues before they begin to speak, and they speak only about those issues. There is no shapeless mountain of reflexively generated points and subpoints which must be knocked into some kind of order at the very end; the order has been obvious all along.
Nevertheless, learning to “seal the deal” is a valuable rhetorical skill, and some judges may expect a distinct treatment of final issues regardless of the clarity of your speeches as a whole. Conceiving of arguments as logical units will greatly simplify the construction of a final summation.
The advice given about final issue selection has often been quite vague: pick the most important issues (but how do you know what’s most important?), pick the issues you’re winning (but what counts as an issue?), tell a persuasive story about the round (what does that mean?). If you have developed your own case arguments as logical wholes, you know what you must do to sustain them: sustain a set of premises which together entail the truth (or falsehood) of the resolution. Likewise, you know what you must do to defeat your opponent: show that for every distinct constructive argument she makes, her argument is either irrelevant, invalid, or dependent on a false premise. Each distinct constructive argument still in play at the end of the round deserves attention in your closing statement—either to show why it succeeds (your argument) or to show why it fails (your opponent’s argument).
In order to prove the resolution true (or false), you need sustain only one constructive argument. Therefore, if one of your original constructive arguments is badly mangled by the end of the round, you may wish simply to ignore it in favor of a more defensible argument. If you adopt this strategy, you should not call attention to the argument you are ignoring. Specifically, you should not recite some awkward bit of debate jargon about “kicking out” of your original argument. Instead, call attenion to the argument you will defend by telling the judge that you believe it is your strongest and that it, by itself, is sufficient to prove the resolution true (or false). Of course, ideally you will not feel forced to choose between constructive arguments, since all your arguments will be ones you are well prepared to defend in the first place.
However many of your own arguments you are defending, your final summation should remind the judge in a few sentences of the main premises of each argument in such a way that the resolution (or its negation) obviously follows. Then pick out the most damaging or prominent objections your opponent has made to the argument and state briefly why the objections fail—i.e., why the argument survives.
You will not normally have the option to choose which of your opponent’s constructive arguments to review at the end. Since any one constructive argument is enough to carry the day, you must show why all of your opponent’s constructive arguments fail. The only exceptions to this rule are if either (a) your opponent has narrowed her position for you by abandoning one or another of her constructive arguments or (b) you are attacking a premise (such as a value premise) which is shared by several arguments, such that separate treatment of each argument is unnecessary. If one of these exceptions occurs, you should remind your audience at the end that it has occurred. You do not want an abandoned argument to be rescued after it is too late for you to object, and you do not want a judge to mistake your very efficient attack on several arguments at once for a failure to attack any of the arguments.
Whereas you may feel some pressure to respond to each major attack against your constructive arguments, your final review of your opponent’s arguments can be briefer. This is because, again, you do not have to refute everything your opponent says in order to kill her argument. If you have attacked an argument on several fronts, you should choose the one or two deadliest objections to reiterate at the end. Rhetorically, it is usually unwise to spend a lot of time talking about your opponent’s arguments. You have already killed the arguments during the main body of your rebuttals, and you are now simply reminding your listeners of the results you have achieved. It is especially important to emphasize that your one or two objections, whatever they are, kill the entire constructive argument.
A quick final accounting of the fate of each constructive argument can be very helpful to a judge, suggesting in advance the process of deliberation you want him to use to reach a decision. As with every argument during the round, the focus at the end should remain squarely on the resolution—on why the resolution is true or false. Your devastating objection to a crucial premise may be fruitless if your audience does not understand what bearing that premise has (via the argument of which it is a part) on the truth or falsehood of the resolution. Once again, the best way to ensure that you are explaining the full relevance of each distinct point is to force yourself to use the language of the resolution in making the point.
There are other closing strategies besides the review of constructive arguments that may be effective and appropriate in particular rounds. Knowing which to use when requires a more sensitive judgment than can be prescribed in an article like this one. But the review of constructive arguments is a safe and useful default strategy. And any good closing strategy must talk explicitly about the truth or falsehood of the resolution, which is usually going to involve discussing constructive arguments in one form or another.
These articles have obviously not provided complete instruction on how to debate. Indeed, it has been a recurring theme that logic alone will not suffice to establish the truth of any proposition (one must begin with true premises), and it should also be clear that logic in the strict sense of formal validity is not the decisive issue in most debate rounds. But logic is an indispensable tool of competent debaters. Similarly, no amount of anatomical and physiological knowledge would suffice to make a person a great surgeon; successful surgery also requires excellent judgment and physical technique. But an aspiring surgeon had better learn the anatomy and physiology of the human body. Random cutting and patching are at best pointless and at worst dangerous, even if they are technically graceful. Logic reveals the anatomy and physiology of arguments. Excellent debate requires trained judgment and rhetorical excellences beyond the scope of logic. But debate without a solid grasp of logic is just so much random cutting and patching.
(Jason Baldwin (jbaldwin@nd.edu) is a Ph.D. candidate in philosophy at the University of Notre Dame. A nationally successful debater and coach, he has taught LD at the Kentucky National Debate Institute since 1996. Many of his past Rostrum contributions can be found on NFL's online archive.)
