Think Again: How to Reason and Argue

by Walter Sinnott-Armstrong

  Tardy friends are annoying, but other slippery slope arguments raise much more serious issues, such as torture. Torture is immoral in almost all cases, but the guarding term “almost” is crucial. There is no justification for useless torture, as at Abu Ghraib, but some ethicists defend torture when it is likely to avoid extreme harm, as in ticking time bomb cases. Imagine that the police capture an admitted terrorist who has planted a time bomb that will kill many people soon if not defused. The police can stop the slaughter if and only if the terrorist tells them where the bomb is, but he refuses to talk. There is some chance that he will reveal the bomb’s location if they inflict enough pain on him, such as by waterboarding.

  Such cases are controversial, but the point here is just that common arguments on both sides depend on vagueness and slippery slopes. One continuum is the number of people who would be harmed if the bomb went off. There is no precise number needed to justify torture. Another continuum is probability. Torture usually produces false information but still has some chance of success. It is impossible to say precisely how high the probability of gaining accurate information needs to be in order to justify torture to save a certain number of lives. A third continuum is the amount of suffering caused by torture. Waterboarding for a minute is one thing, but it can go on for hours. And what about beating, burning, and electrocuting? Are they also allowed? How much? How long? Again, it is impossible to say precisely how much pain is permitted for a specific increase in the chances of saving a specific number of lives.

  These continuums enable conceptual slippery slope arguments. Here’s one: Police would not be justified in inflicting extreme pain only to reduce the chances of a terrorist stink bomb by 0.00001%. A tiny increase in the amount of harm prevented or in the probability of success or a tiny decrease in the amount of pain inflicted cannot change unjustified torture into justified torture. The same goes for the next tiny increment and so on. Therefore, no torture—indeed, no infliction of any pain during interrogation—is ever justified.

  This argument is reversible. Police would be justified in making a suspect sit in an uncomfortable chair for a minute in order to reduce the chances by 10% of a terrorist nuclear explosion that will kill millions. A tiny decrease in the number of people saved or in the probability of success or a tiny increase in the amount of pain cannot change justified interrogation into unjustified torture. The same goes for the next tiny increment and so on down the slippery slope. Therefore, no torture is ever unjustified.

  When an argument runs equally smoothly in either direction, it fails in both directions because it cannot give any reason why one conclusion is better than its opposite. The general lesson is that we all need to test our own arguments by asking whether opponents can give similar arguments on the other side. If so, that symmetry is a strong indication that our own argument is inadequate as it stands.

  That lesson still does not tell us how to stop sliding down the slippery slope. One potential solution is definition. The United States government at one point declared that interrogation is not torture unless it causes pain equivalent to organ failure.4 That definition was supposed to allow interrogators to waterboard suspects for a long time without engaging in torture. However, opponents could simply define torture more broadly. They might say, for example, that police torture whenever they intentionally cause any physical pain. Then even a few seconds of waterboarding counts as torture, but so does requiring suspects to stand (or sit in an uncomfortable chair) for an hour if that is intended to make them more compliant. Thus, as before, opponents can make the same move in opposite directions.

  Nonetheless, definitions do provide some glimmer of hope. It is not enough for such definitions to capture common usage, as in a dictionary. Common usage is too vague to resolve this issue. Instead, definitions of torture aim at a practical or moral goal. They try to (and should) group together all cases that are similar in moral respects. As a result, opponents can discuss which definition achieves this goal. That debate will be complex and controversial, but at least we know what needs to be done to make progress on this issue: We need to determine which definition leads to the most defensible laws and policies.

  What about the causal slippery slope? Here the two sides are not as symmetrical. If we start waterboarding a little bit, this first step onto the slippery slope seems likely to break down psychological and legal barriers to torture, which will lead to waterboarding for longer periods of time in more situations with less harm to avoid and less chance of success. That causal slippery slope could eventually lead to widespread unjustified torture. In the other direction, if we reduce extreme torture a little bit, it seems much less likely that this minor mercy will make police give up interrogation entirely. The strong motives for interrogation will probably stop that causal slippery slope from leading to disaster. Thus, the causal slippery slope argument against torture cannot be dismissed as symmetrical in the same way as the conceptual slippery slope argument for the same conclusion.

  As always, I am not endorsing this argument or its conclusion. Indeed, classifying it as a causal slippery slope instead of a conceptual slippery slope reveals places where opponents can object. This argument depends on a controversial prediction: A little bit of waterboarding will eventually cause a lot of waterboarding. That premise might be accurate, but it is not obvious, especially because institutions can adopt rules that limit the degree and amount of torture that is allowed. If we want to avoid extreme torture, two options might work. One is to forbid all torture. Another is to enforce rules that limit torture. Of course, opponents of all torture will deny that such limits can be enforced effectively, but they need to argue for that claim. In reply, defenders of limited torture need to show how institutions really could restrict torture effectively. It is not clear how to establish either of these conflicting premises, but our analysis of these arguments as causal slippery slopes has made progress by locating and clarifying the crucial issue.

  Whether or not you accept the argument against torture, it reveals what we need to do to assess any slippery slope argument. First determine whether the slippery slope is conceptual or causal. If it is conceptual, ask whether the slope is equally slippery in the opposite direction and whether the problem can be solved by a definition that is justified by its practical or theoretical benefits. If the slippery slope is causal, ask whether setting foot on the slope really will lead to disaster. Asking and answering these questions can help us determine which slippery slopes we really do need to avoid.

  CAN I TRUST YOU?

  Our second group of fallacies raises questions about when premises are relevant to the conclusion. It is surprising how often arguments jump from premises about one topic to a conclusion about a different topic.

  Blatant examples occur when people fail to answer the question that was asked. This scam saturates political debates and undermines understanding. We all need to learn to spot it and stop it. We need to notice when people fail to answer questions and then call them out publicly.

  Here we will focus on more subtle instances of irrelevance. Specifically, many arguments present premises about a person as reasons for a conclusion about some proposition or belief. These arguments can be positive or negative. One might argue, “He’s a bad person, so what he says is false.” Alternatively, one might argue, “He’s a good person, so what he says is true.” The former is described as an ad hominem argument, whereas the latter is an appeal to authority. The difference lies in whether the argument invites me to distrust or to trust the person.

  Attacking People

  Here is a classic example of the negative pattern:

  It’s an interesting question: Why do so many political protesters tend to be, to put it mildly, physically ugly? . . . [I]t is simply a visual fact that the students and non-students marching in these picket lines with hand-lettered placards are mostly quite unattractive human beings . . . . They are either too fat or too thin, they tend to be strangely proportioned . . . . But if nature failed to
give most of these people much to work with, they themselves have not improved matters much. Ill-fitting blue jeans seem to be the uniform. Sloppy shirts. Hair looks unkempt, unwashed. They wear a variety of stupid-looking shoes. Yuck.5

  This writer is clearly trying to get readers to distrust and dismiss the protesters because of their appearance.

  It is hard to imagine that anyone would be misled by such a blatant fallacy, but sometimes it does work by associating the target with negative feelings, such as disgust, contempt, or fear. These negative emotions can produce distrust, even when the features that trigger the negative emotions are irrelevant to the topic at hand. This trick has been used to exclude the views of dissident groups throughout history. It might also lie behind laws (throughout much of the United States) that deprive ex-felons of a right to vote, even on issues which they know and care a lot about, such as criminal policy. And it infects criminal trials when juries distrust a rape victim’s allegations because she had previously had voluntary sex more than they think proper.

  Ad hominem arguments vary in flavor. The most flagrant fallacy occurs when someone argues, “She has a bad feature, so what she says must be false.” A less blatant form occurs when reliability is doubted, as in “She has a bad feature, so you cannot trust what she says.” The crucial difference between these two varieties is that the former concludes that a claim is false, whereas the latter leaves us not knowing what to believe. A third version denies someone’s right to speak at all, “She has a bad feature, so she has no right to speak on this topic.” This conclusion again does not tell us what to believe, because it leaves open the question of whether her views would be true and reliable if she did speak. Often, as in the quotation above, it is not clear which of these points is being made, even though the point lies somewhere in this general area.

  Each kind of ad hominem fallacy is able to mislead partly because other arguments of the same kind do provide reasons for their conclusions. Spectators do not have the right to speak during parliamentary debates, no matter how reliable they would be if they did speak. You really should not trust someone who failed physics but takes a strong stand on a controversy in physics. And sometimes features of people may even give reasons to believe that what they say is false, such as when the owner of a cheap clothing shop tells you that his products are made of the finest silk.

  Despite this possibility, ad hominem arguments are fallacious often enough that they should be inspected with great suspicion. You should always take great care before reaching a conclusion about a belief from negative premises about the believer.

  Unfortunately, people are rarely this careful. As we saw in Part I, conservatives often reject their opponents’ views by calling their opponents liberal, just as liberals often dismiss their opponents’ views by calling their opponents conservative. Such classifications commit ad hominem fallacies insofar as they use premises about the person’s being liberal or conservative to reach conclusions about particular claims by those people. Liberals are right sometimes, and so are conservatives, so it is very dubious to argue that any belief is true or false just because the believer is liberal or conservative.

  The mistake is different when someone calls opponents stupid or crazy. These are attributes of the person, so this argument is still an ad hominem. Nonetheless, it is legitimate to distrust the views of people who really are stupid or crazy, at least when their views are idiosyncratic. The main problem here is instead that the premises are usually false, because the person being attacked is not really stupid or crazy.

  A general tendency to be fooled by these fallacies feeds the political polarization that impedes cooperation and social progress. When we dismiss opponents on the basis of what they are, we cut ourselves off from any hope of understanding them or learning from them. That is one reason why we need to be careful to avoid this kind of fallacy.

  In general, whenever you encounter any ad hominem argument that moves from premises about a person’s negative features to a conclusion about that person’s claim, you should critically evaluate whether the premises are true and also whether the negative feature really is relevant to the truth of the claim, to the reliability of the person, or to the right of this person to speak on this issue. Asking these questions will help you reduce both personal errors and social polarization.

  Questioning Authority

  The positive pattern of arguing from people to positions is at least as common as the negative pattern. The tendency to trust people whom we like or admire has been described as the halo effect (after angels with halos), and the tendency to distrust people whom we dislike has been called a horn effect (after devils with horns). We are subject to both effects: halos and horns. We trust our allies as much as we distrust our opponents. Indeed, we often trust our allies too much.

  When people trust an authority, they argue from premises about that authority to a conclusion about what that authority said. I might argue, “My friend told me that our neighbor is having an affair, so our neighbor is having an affair.” This argument is only as strong as my friend is reliable on issues like this. Similarly, I might argue, “This website or news channel told me that our president is having an affair, so our president is having an affair.” This argument is only as strong as this website or news channel is reliable on issues like this. If a friend or news channel is not reliable on issues like this, then sources like these do not deserve our trust on these issues. But if they are reliable, then they do deserve at least some trust.

  How can we tell whether a source of information is reliable on a particular issue? There is no foolproof test, but a good start is to ask a simple series of questions.

  The first question that we always need to ask is simple: “Did the arguer cite the authority correctly?” The news article that we reconstructed in Chapter 8 quoted Robert Jauncey and paraphrased an Asian Development Bank (ADB) report. We should have asked, “Did Jauncey really say these precise words? Did the ADB really report what the article claims?” It is surprising how often people misquote authorities either intentionally or by mistake. Even when authorities are quoted accurately, their words are sometimes pulled out of context in ways that distort the meaning. Jauncey was quoted as saying, “There has been a rapid rise of urban villages in recent years due to increased poverty and the negative impacts of climate change.” Now imagine that his next sentence was, “Fortunately, these trends are slowing and even reversing, so we do not need to worry about urban villages in coming years.” If he had said this—he didn’t, but if he had—then the quotation in the article would have been extremely misleading, even though he did say exactly what it reported that he said. Thus, whenever you encounter an appeal to authority, you should ask not only whether the appeal accurately reported the authority’s words but also whether the appeal correctly represented the authority’s meaning.

  The second question to ask about appeals to authority is more complex: “Can the cited authority be trusted to tell the truth?” Whereas the first question was about words and meanings, this second question is about motives. If the authority had some incentive to lie, or if the authority has a tendency to report its findings loosely or in misleading ways, then it cannot be trusted even when it is quoted correctly. For example, if Jauncey were trying to raise money for a charity that employs him, so that he would benefit personally if he could convince you to donate money to help solve problems of urban villages, then you would have reason to wonder whether he was exaggerating the problem for his own purposes. His self-interest then grounds mistrust, since it could lead him to report a falsehood even when he knows the truth.

  What should we do if an authority cannot be trusted because of self-interest or whatever? One approach is to check independent authorities. If different authorities do not depend on each other and have no motivation to promote the same view, but they still agree, then the best explanation of why they agree is usually that their belief is accurate, so we have reason to trust them. To justify trust, seek confirmation. />
  The third question is even trickier: “Is the cited authority in fact an authority in the appropriate area?” It takes a lot of work to become an authority in even one area, so few people are able to achieve authority in a wide range of areas. People who know a lot about history usually do not know as much about mathematics, and vice versa. Real masters of all trades are extremely rare. Nonetheless, even when their expertise is limited to a specific topic, authorities often think they know more about other topics than they actually do. Success in one area breeds overconfidence in others.

  The most obvious cases occur when athletes endorse cars or other commercial products that have nothing do with the sports in and on which they are experts. Sports heroes as well as actors, business leaders, and military heroes also often endorse political candidates, even when there is little or no basis for assuming that these experts in their own fields know more than anyone else about political candidates or policies.

  A similar problem arises in law. Psychiatrists and clinical psychologists are trained in diagnosis and treatment of mental illnesses, but lawyers sometimes ask them to predict future crimes by defendants. Are they authorities in this area? No, according to their own professional organization: “It does appear from reading the research that the validity of psychological predictions of dangerous behavior, at least in the sentencing and release situation we are considering, is extremely poor, so poor that one could oppose their use on the strictly empirical grounds that psychologists are not professionally competent to make such judgments.”6 In short, authorities on psychiatric diagnosis and treatment are not authorities on prediction of criminal behavior. As a result, to appeal to their authority as a basis for legal decisions is fallacious. This fallacy can be uncovered and avoided by asking whether the cited authorities are authorities in the right area.