“Chapter 17. Fallacies of Distorting the Facts” in “Critical Thinking, Logic, and Argument”
Chapter17Fallacies of Distorting the Facts
Another kind of error of presumption we might make is to distort the facts. One of the ways to distort facts is by making them seem more or less significant or relevant than they really are. This section on distorting the facts discusses false analogy, fallacies of false cause, slippery slope, and irrelevant thesis (sometimes known as “red herring”).1 Fallacies of false cause occur in general when there has been faulty reasoning about causality. In other words, we could say that the fallacy of false cause distorts what actually occurs in a causal chain. In order to correct for these, we have to know a lot about causality to be able to make good causal claims. The fallacy of irrelevant thesis essentially changes the topic of an argument midstream or brings in claims that are beside the point. It is a kind of derailing, but it has some appeal, since the outside information it brings in can also be of importance or factual.
17.1 Analogy
A powerful method of illuminating or distorting facts is the use of an analogy. We use analogies all the time in explaining how the world works. If an analogy isn’t fitting, it doesn’t help. But if an analogy is fitting, it is very useful. Analogy is a powerful tool because it allows us to understand an unfamiliar or difficult thing or set of facts by comparing it to something that is better known or understood. In fact, we can hardly help doing this when we are in an unfamiliar situation; our first step toward orienting ourselves is to try to discover something that seems to be similar, in important or relevant ways, to something with which we are already familiar.
In an analogical explanation, one attempts to explain how something works or what something is like by comparing it to something else and claiming that it is like that other thing in an explanatorily relevant sense.
The aim of an analogical explanation is to transfer the understanding we have of the thing we are making an analogy to (the explanans) to the understanding we have of the thing we want to further explain (the explanandum) (fig. 17.1). We transfer understanding from one thing to another if the two are similar in the right ways.
Figure 17.1 Analogical reasoning. Artwork by Jessica Tang.
A productive way to think about analogies is to see them as relying implicitly on explanatory models. Both parties to the comparison have features that can be explained using a similar story. In other words, if one thing or process is analogous to another in a way that is genuinely explanatorily relevant, then the two share a set of features that constitute an explanatory model of a set of phenomena of which they are both examples. By contrast, a false analogy offers such an analogical explanation when the purported similarity is not relevant and there is no explanatory model that fits both cases.
Unlike a valid deductive argument that pays its way by proving what is at issue, analogies can only offer the promissory note that there is an underlying account that explains what the analogy points to; it offers the mind a model or interpretation that makes something initially strange seem more familiar. As we will see through an in-depth discussion of analogies, they operate on all kinds of levels and do different kinds of intellectual work. Behind the analogy is always (in theory), some kind of hidden sameness or relevant likeness that gives it explanatory power. This just tells us that analogies are analogies, not explanations proper. They are incomplete by themselves even when they are good. As we will see in the coming discussion of how analogy fuels scientific discovery, analogies point to explanations that they do not themselves give.
The Water Closet Model of Instinct
Konrad Lorenz, the famous ethologist who received the Nobel Prize in 1973 (together with Karl von Frisch and Nikolaas Tinbergen for discoveries concerning organization and elicitation of individual and social behaviour patterns) posited a psychohydraulic model to explain instinctive behaviour in birds. He called this the “water closet (a.k.a. toilet) model” of instinctual behaviour. The model pointed to two similarities: once you flush a toilet by pulling the handle, all the rest follows in a rush, and then it takes the tank a while to fill again, so if you flush it again before the tank is full, the flushing response is much weaker. It is a hydraulic model because it compares instinctual motivation to the liquid in a water closet, whose accumulation and discharge influences behaviour. The time it takes for the tank to refill corresponds to the time between occasions of instinctually driven behaviours.
Lorenz et al. were trying to understand the relationship of the length of time between instinctual motivation and the strength of the response. Thinking of instinctual motivation as hydraulic, as toilet-like, helps us understand, for example, how pressure builds after a release, and so on. The water closet model allowed us to organize a wide range of different behaviours together and was very fruitful in efforts to explain animal motivation. Of course, it is just a model. What we really need is an account of the physical structures that exist within an animal’s brain, how they work, how the animal interacts with environments, and so on. But what was valuable about it was that it offered an intuitive way of visualizing how various unknown systems need to work together to organize an animal’s response to its internal and external environment. What made the analogy fruitful in organizing research was that the phenomena under study really do stand in a set of relations that in a very simplified way actually do operate similarly to how a toilet works. So it was a good analogy because it was fruitful and helped animal behaviourists come to understand instinctual behaviour better. But the world might have turned out differently; instinct might have worked differently, in which case the analogy would have been a bad one. So in this case, the analogy was a hunch about a structural hypothesis or model that paid off because the world turned out to fit the hunch.
Archimedes and Heiro’s Golden Crown
Here is a quite different example. In the first century BCE, Heiro II, the king of Syracuse, commissioned some goldsmiths to make a crown in the form of a wreath of laurel leaves as a religious offering and gave them a specific weight of gold. Upon receiving the finished crown, Heiro suspected that they might have replaced some of the gold with an equal weight of silver, a lighter (and importantly, less dense) and much less valuable metal. Heiro reputedly asked his friend, the famed mathematician Archimedes, to determine whether the wreath was pure gold or had been adulterated with silver. But because the wreath was dedicated to the gods and was thus a holy object, Archimedes could not melt it down or harm it. So how would he find out what it is made of?
As the story goes, Archimedes went to the baths, and upon entering the water, he noticed that the water level rose as his body displaced some of it; in a flash of analogical insight, he imagined that the wreath crown would, like his own body, displace liquid relative to its volume. Archimedes had a solution: take a weight of gold equal to the crown and determine how much water was displaced by the weight and the crown and compare them. Thinking analogously with his body, Archimedes thought that he would find out what the crown consisted of by how much water it displaced. He figured that, if the crown had been adulterated with silver, it would have a greater volume for the same weight and would displace a greater quantity of water. Since the relative densities of gold and silver were known, the precise amount of silver (if any) could be accurately calculated. Famously, Archimedes was excited by this insight and ran naked through the streets to his home crying, “Eureka!” (“I have found it!”), and the goldsmith who had indeed adulterated the gold got his head cut off. Now, the analogy in this case is quite different: the crown was like Archimedes’s body not in its shape or size or weight but in its capacity to displace a volume of water when compared to weight. That reveals density, and in this respect, the two are exactly alike and so behave in exactly the same way. While this didn’t by itself give Archimedes his solution to the problem—he needed also to know some mathematics and how to calculate the relative density of gold and silver—once he had entertained the solution, the rest was just measurement, and the analogy did not function merely as a potentially fruitful guide to research or a hypothesis that needed to be tested, but as an intuition into geometrical relationships.
Torricelli and the Sea of Air
Let us give one more example from the history of science that falls between the two prior examples, both historically and conceptually. Evangelista Torricelli lived in the first half of the seventeenth century and was a student of Galileo; his work on the motion of fluids and his invention of the mercury barometer initiated a flurry of scientific research into the nature of gases and atmospheric phenomena. Unlike Galileo, who believed that air was weightless, Torricelli conjectured that air, like water, has weight and that we live “immersed at the bottom of a sea of elemental air.”
The discovery came about as a result of a practical problem in mining. The miners in the late Middle Ages developed suction pumps to pump water out of mineshafts, but a suction pump will only lift water about nine metres.
Galileo attributed this limit to the cohesive strength of water. But Torricelli was able to show that the limit of nine metres of water in the suction pump was due to atmospheric pressure—the weight of the “sea of air” above us—which pushed the water up the pipe when air was sucked out of it. By experimenting with heavier liquids, first honey and then mercury, Torricelli showed that the height of a column of liquid in an evacuated tube placed in a bowl of the liquid was proportional to the density of the liquid (fig. 17.2). By using mercury, which has a density of 13.6 g/mL, Torricelli could observe the effect of a vacuum in reasonably short tubes sealed at one end. Torricelli could fill a tube about a metre long with mercury, put his finger on the open end, and then invert the tube in an open bowl of mercury. The column of mercury would drop partway down the tube, leaving an empty space (vacuum) at the top of the tube. By measuring the height of the mercury column (about seventy-six centimetres), Torricelli showed it to be proportional by weight to the nine-metre column of water at its limit in a suction pump. This in effect settled an important scientific debate of the time about the nature of the vacuum: the vacuum does not pull mercury up the tube; instead, the weight of air pushing down on the dish of water prevents the mercury column in the tube from falling out of the tube.
Later Pascal, with the help of his brother-in-law Périer, designed an experiment taking a tube of mercury to the top of a local mountain to determine whether the height of the column would drop (as one would suspect if Torricelli’s explanation were correct, since the “sea of air” would be “shallower” at the top of a mountain), which confirmed Torricelli’s account (and showed at the same time that a barometer and an altimeter are really the same instrument calibrated and used for different purposes). The analogy of the sea of air proposed that gases are like fluids in relevant respects and thus opened up a number of important questions for empirical study. In addition to suggesting an explanation of air pressure and why the miners were having issues pumping water, this analogy opened up the empirical study of weather.
Figure 17.2 Toricelli’s experiment proving the weight of air. Artwork by Jessica Tang.
This analogy is unlike the water closet model because it proposes an actual identity of explanatorily relevant properties in gases and fluids, whereas Lorenz’s analogy proposes nothing about the causal structure of the mechanisms of instinct but merely a certain formal structure. It also differs from the Archimedes example in two important ways. First, it both proposed and required very precise empirical confirmation. For all Torricelli and Galileo (and everyone else of the time) knew, the world might have been as Galileo believed; air might have had no weight, and the problem of the limits on suction might have been explained as being due to limits of the cohesive force of water. Had that explanation been correct, then the height of columns of different fluids in suction pipes could not have been expected to vary with the density of the fluid but instead with some other property having to do with cohesive force. As it turned out, Torricelli was right and Galileo was wrong, so the sea of air hypothesis was a genuine bet with empirical consequences that further research could confirm or refute. The second way it differed from the Archimedes example was that the analogy is explicitly partial. Gases are not literally fluids and Torricelli knew this. In particular, gases are highly compressible and liquids are not, and although Boyle’s law was not discovered until twenty years after Torricelli’s death (and probably could not have been without Torricelli’s work as a backdrop), Torricelli was well acquainted with the fact that gases expanded when heated and made use of that fact in his study of weather.
Scientific theories can be seen as precise theoretical models, where certain phenomena—the ones captured by the model—stand in exact mathematical relationships to each other. We saw that Torricelli’s sea of air hypothesis had precisely confirmable predictions. Two columns of fluids of different densities will have heights exactly proportional to their densities; by showing that the height of the column of mercury stood in relation to the height of a column of water—the water was 13.6 times as high—Torricelli effectively settled the issue of what mathematical model (or more properly, what class of models) governed the behaviour of gases. The design of an experiment offering empirical confirmation of a model will depend on facts about the model and may be very complicated, but usually the epistemic character is rather simple.
Torricelli and Galileo suggested that there were explanations to be found in a certain direction of study that, when found, could stand on their own. Analogical reasoning, therefore, is like writing a cheque from the bank of empirical explanations: if the explanation is in the bank, the cheque can be cashed, but otherwise it bounces. Analogies are members of a large family of suggestive concepts: metaphor, analogy, hypothesis, model, proposal, and so on. Their utility is partly a function of whether they can be cashed. Of course, now we have used the metaphor of a cheque to explain analogies! We are not suggesting that we can or should always attempt to cash the analogical and metaphorical structures in our thinking by turning ourselves into unrelenting scientists. Life is too complicated and fleeting to make quantifying everything a remotely attractive epistemic policy. But at the same time, we want the feelings of explanatory success we experience when we use a good analogy or metaphor to be grounded in some promise of genuineness.
Let us summarize some of the properties that good analogies have:
17.2 False Analogy
Given that we have discussed how analogies can be useful, our discussion has pointed the way toward limits of analogical reasoning. Sometimes analogies are not contextualized in terms of their provisional nature or their relevant dis-analogies. Sometimes they are presented in quite the opposite way—full of certainty and as if they are comparing two things that are completely alike.
The fallacy of false analogy is the comparison of two things that are only superficially similar or that, even if they are very similar, are not similar in the relevant respect.
One way analogies go bad is that they drastically oversimplify a complex process by comparing it to something simple. Look for cases of false analogy in the speeches of politicians and cranky letters to the editor. American President Reagan, for example, was especially fond of comparing complex international events to homely events that the ordinary person could “figure out” using common sense. The first key to identifying cases of false analogy is to notice when an explanation makes use of a comparison with something else.4
All that is needed is to examine the comparison to see whether the explanation is based on a relevant likeness. Here are a few examples:
In example 1, another’s disbelief in the religious views of the speaker is inappropriately compared to insanity. The comparison is between delirious people and people who are non-delirious who do not accept the speaker’s version of religion. Even on the assumption that it is justifiable to use force against the will of a delirious person to save their life, this gives no reason to think that one is justified in using force against a person’s will. There are not enough relevant similarities between preventing self-harm and holding different religious beliefs.
Example 2 uses an offensively simplistic analogy. There is no way it could be relevant, since there are no relevant comparison classes at all. We may notice, however, that this argument also contains a double standard between “our great civilization” (the delicious omelette) and “the other culture” (the eggs that need to be broken to make the omelette). False analogy is the friend of bigotry and special privilege.
Example 3 compares students to consumers. There are two levels of difficulty with this analogy. First, is the question of whether the situations of students and consumers are relevantly similar, and second is the question of whether consumers are accurately portrayed. In response to the first question, one might point out that while a consumer knows what goods he or she is purchasing beforehand, the student does not know the subject before learning it. This suggests at least one relevant difference. In response to the second question, one must ask whether what the consumer buys depends entirely on what the consumer is interested in. When you think about it, it begins to look as though the consumer has to buy more or less what is available, or at least there are important constraints operating in the background that limit what that consumer can buy. In addition, there are enormous pressures acting on consumers telling them what they want—pressures that are largely absent in university. In fact, the comment that the consumer knows what goods they are purchasing beforehand is not completely true. You can buy a television set or a computer for the first time and only after you take it home can you really begin to understand the effects that your purchase has on your life. In fact, it begins to look as though consumers are rather more like students in the sense of not knowing the effects of learning in advance.
Example 4 attempts to make a claim about fairness. The two crucial considerations are the difference in the danger and physical difficulty of the two kinds of work and the difference in the rates of pay. It is not appropriate to compare physically exhausting and dangerous work for low pay to well-paid, prestigious, physically easy work, at least not without an argument. As one looks at claims like this, one begins to see that there are many different considerations that are relevant to the judgment of what is fair and what is not; the claim in 4 looks more like a way of shutting down thinking about fairness rather than furthering it. We saw that good analogies should be fruitful—they should open up our understanding to better and more complete explanations. The bad analogies we have just looked at seem to function most successfully in negative gossip and pseudo-explanation situations that entrench the speaker in their views by isolating them from scrutiny. Prejudice and bigotry thrive on a rich diet of fallacies that work together to buttress and fortify bad opinions from being challenged, and one of the best ways to combat prejudice is to have a number of ways of point out and dissolving fallacies at the ready.
17.3 False Cause
Many arguments rely on causal reasoning to establish conclusions. Usually in causal reasoning, the conclusion takes some form of “X caused Y.” But it is very difficult to know what causes events in the world. Causality is complex, and usually these causal arguments are wrong just by virtue of identifying single factors, especially when the claims have to do with populations or events. Many arguments that try to establish causal chains do not have adequate evidence to isolate the particular cause being argued for.
It is difficult to know what causes events in the world, especially if you are trying to make a definitive statement. For example, What caused the Titanic to sink? Take the distinction between a proximal (immediate) and distal (further) cause. Most people would identify the iceberg as having been responsible for the Titanic sinking. But what about the captain’s inattention? The design of the watertight compartments? Often causal stories oversimplify and identify the most proximal cause. This cuts the causal chain somewhat arbitrarily and brings the focus to one cause just because it is proximal.
In addition to issues isolating causes, there are also issues of identifying causal factors from correlated factors. Fallacies of false cause generally derive from the fact that not every correlation between events (and of course there are all sorts of correlations between events) has explanatory power in accounting for those facts. Many superstitions depend on the fallacy of false cause (“I was thinking of you, then you called me on the phone”). So do many advertisements (beautiful women draped on a Camaro in an advertisement asks you to believe that buying a Camaro will attract beautiful women to you). Also, a newspaper might make claims that reading their paper makes you wealthier. In one sense, if you are more informed about certain things, you might be able to make better decisions. But this is a very different claim than “reading our newspaper makes you wealthy.” We might equally consider that a certain demographic of people with wealth are already more likely to subscribe to a particular newspaper, since they are looking for advice and information on investing. So actually, it is the fact that they are already wealthy that causes them to read a particular newspaper, not the other way around.
The fallacy of false cause is actually a family of related fallacies that occur when an arguer gives insufficient evidence for a claim that one thing is the cause of another.
All these examples demonstrate how causal reasoning makes the case that one event or event-kind is an explanation for the occurrence of another event or event-kind. Causes do not occur in isolation: every event that occurs depends on a set of conditions being satisfied, and a person requesting a causal explanation typically knows some of these conditions and not others. As a result, an appropriate answer will depend on the set of interests and background information that sets the question. Here are four common kinds of false cause fallacies.
Post Hoc, Ergo Propter Hoc (Latin for “After This, Therefore Because of This”)
Post hoc, ergo propter hoc is a mouthful. It means that a relationship of time is confused with a relationship of causation.
Post hoc, ergo propter hoc: This fallacy occurs when we assume, without adequate reason, that one event B was caused by another event A because B happened after A.
Compare the three different causal claims below:
- 1. “I took Echinacea for my cold, and a few days, later my cold was gone. Therefore the Echinacea cured my cold.”
- 2. “I got a cold after using Bill’s hankerchief.”
- 3. “I have a cold because I used Bill’s handkerchief to wipe my nose; cold viruses can be transmitted through nasal membranes, and Bill had a cold.”
Since colds typically clear up in a couple of days anyway, identifying taking Echinacea as the sole reason it cleared up in a few days is fallacious. Maybe it would have cleared up faster without it. A single instance is a usually risky basis for making a causal generalization. Compare statement 3 above with the following:
- 4. “It is reasonable to think that I may have caught my cold by using Bill’s handkerchief because cold viruses can be transmitted through nasal membranes.”
In the case of 4, the event is not cited as the reason to believe that colds are transmitted through contact with the virus through the nasal membrane, but rather given the implicit assumption that the causal generalization is true, the event of my cold is explained as an instance of it. Good causal explanations always refer at least implicitly to causal laws or structures, and this can be made explicit by expanding the explanation to contain the law or structure supporting it.
Mere Correlation
Mere correlation. Here we assume that B was caused by A merely because of a positive correlation between A and B.
Mere correlation is essentially the idea that things that are associated together must have a causal relationship. Unlike in post hoc, ergo propter hoc, here we have two things that may be occurring simultaneously with some kind of trend or fact that is considered important enough to posit a causal relationship. There are a lot of memes made based on mere correlations. For example, there was a graph circulated online that compared the age of the women that Leonardo DiCaprio dates (stagnate at about twenty-four to twenty-five years old for the last twenty-five years with the age of Leo himself trending upward each year). See “Leonardo DiCaprio Only Dates Below 25—Correlation Between Leonardo DiCaprio’s Dating Pattern and Productivity and Average Real Earnings,”5 Know Your Meme, August 31, 2022.
This graph shows one line going straight up from twenty to his current age, which is over forty, and a line that stagnates at about twenty-three/twenty-four years. Next to this graph was an almost identical graph with one line that’s identified as “major sector productivity” going up just like Leo’s age and the stagnated line is identified as “real wages of goods-producing workers.” Here the x and y axes are basically irrelevant because no one would think that there’s a causal relation behind this positive correlation. How could the facts about Leo’s life and wages/productivity be related? This demonstrates that when we do hear about positive correlations, we are assessing causality against what we know about how the world works. Since we are often uninformed and/or acting out of confirmation bias,6 we often mistake correlation for causality. Or, to make this point more subtly, we often mistake mere correlation (meaning there is no relation at all) with there being some kind of causal connection (when there isn’t).
Example 1 is a case of mere correlation: it would be a mistake to infer from the correlation that either was the cause of the other. There are at least two reasons for this. First, no reasonable causal mechanism can be assumed, since the events are spatially unconnected and no causal laws have been proposed. This is why it is so important, as a critical thinker, to have an accurate model of how the world works. Second, an enormously large number of population-related variations occurred between 1911 and 1916 (the number of left-handed people born in Mongolia, the number of widows of cowboys killed in Argentina, the number of children born in Montreal to bilingual parents, and so on endlessly). If one looked hard enough, one could find many near-perfect correlations that are completely accidental, so it is reasonable given the first point to think that this is one of them.
Example 2 tries to reverse a trend by reversing a presumed causal connection. This just won’t work, since the positive correlation identified in this example is not indicative of a causal mechanism; there are no doubt many factors that have changed involving teenagers in some way or another, and absolutely no reason has been suggested to think that the factor mentioned is a causally relevant one. We should ask ourselves whether anything else explains these two rises (which are themselves vague).
Reversing Cause and Effect
This brings us to reversing cause and effect. This false cause fallacy is where someone notices a positive correlation and posits a causal relationship but gets the direction wrong.
Reversing cause and effect: Here we conclude that A causes B when B causes A, so there is a causal connection, but not the connection we believe.
It might seem unlikely to reverse cause and effect, but it does happen. Causal mechanisms are complicated, and we have to have very sophisticated models of how the world works in order to get causal directions right. Here we are pointing out that there is a causal connection (and we are right) but that it has been misidentified. Kristin’s grandmother is famous (in her family) for saying, “If you want to get sick, go to the doctor,” or “The hospital kills people.” This, of course, is a kind of superstition that gets the causal direction wrong: people go to the doctor because they are sick, and people are admitted to the hospital and put in palliative care because they are dying.
Example 1 is the fallacy of reversing cause and effect: apparently lice do not like the body they live on to be too warm, so in the example, when a person had a fever, their lice would depart to search for cooler bodies to live on. Since lice were common in the New Hebrides, there was a positive correlation, and the correlation was indicative of a causal connection, but the conclusion reverses the cause and effect.
Example 2 and 3 are related (fig. 17.3). In example 2, the causal connection depends on the fact that (financially) successful executives can afford to buy their spouses expensive clothes and that doing so is part of a more opulent lifestyle that, given they can afford it, they prefer. In example 3 (also a fallacy of division, discussed in Chapter 14), a disproportionate number of people who enroll in Yale are from wealthy families, so Yale graduates may tend to be wealthy, but wealth is the relevant causal factor in graduating from Yale in the first place rather than the other way around. It might depend on what/who we are talking about (trends or individuals), but generally speaking, this claim seems to get the causal direction wrong.
Spurious Correlation
Spurious correlation: Here we conclude that A is the cause of C when in fact both A and C are the effects of some event cause B.
Figure 17.3 Examples of reversing cause and effect. Artwork by Jessica Tang.
For example 1, after investigation, it turned out that the rate of absenteeism depended entirely on the fact that married women had more housework in the home due to gender inequality. So, the causal connection was correct, but it is importantly mediated by a fact about who does more housework. Thus, being married did cause more absenteeism, but this tells an incomplete story. The incomplete story matters because now we have more tools for understanding what can be done (more help at home).
For example 2, upon examination, it was found that the rate of candy consumption was actually strictly a function of age and that married and single people of the same age had the same rates of candy consumption. So getting married was not the cause of a decrease in the consumption of candy—the correlation is spurious. The causally relevant factor was age; aging both increased the likelihood of marriage and decreased the consumption of candy. This case makes a causal claim that initially looks like A caused B, but really C causes both A and B. This is visualized in figure 17.4.
Figure 17.4 Example of spurious correlation. Artwork by Jessica Tang.
In example 3, the fact of women entering the work force is not the cause of the other changes in family life, but like them, it is the effect of broader underlying changes in the structure of society; in example 4, migraine headaches cause both the nausea and the feeling of faintness.
17.4 Slippery Slope (Wedge) Argument
In the slippery slope argument, a person will reason improperly from a claim that it has a terrible result or consequence and use that terrible consequence as evidence against the initial claim (fig. 17.5). In season 5, episode 4 of Parks and Recreation, in response to a character’s advocacy for sex education for seniors, a disgruntled citizen claims, “If you teach grandpa how to use a condom, next thing you know, you will have babies in thong underwear. Is that what you want?” This comedy is (hopefully) making fun of slippery slope arguments, but you must recognize the form of the argument. Something relatively reasonable is proposed (sex education for seniors), and it is presented as the beginning of a chain of dominos leading to a terrible conclusion (babies in thongs). In the sense of fearing negative consequences, the slippery slope shares features with the appeal to force or fear (discussed in Chapter 15). The slippery slope argument has appeal because the terrible conclusion is usually terrible, and if it is in fact the logical consequence of what is being proposed, then there is a good reason to reject the initial claim. So the question then becomes, Is the terrible conclusion necessary? That requires more argumentation.
Figure 17.5 Fallacy of slippery slope. Artwork by Jessica Tang.
In the fallacy of slippery slope, a person asserts that some event must inevitably follow from another without any argument for the inevitability of the event in question.
In the Parks and Recreation case, it should be clear that there are no necessary dominos connecting the two happenings. But the fallacy of slippery slope presupposes without sufficiently demonstrating the necessity of a series of steps between events or ideas and rushes to an end. Let’s look at a commonly occurring example:
Here, the negative consequence is government overreach, which is presented as an inevitable consequence of the daycare subsidy. Here we can ask a few things. First, is a daycare subsidy the same thing as telling parents to use daycare? Is this a good characterization? And even if it was, does this mean all aspects of parenting will inevitably be under state control? Usually in a slippery slope argument, there are a series of questioning points where something presented as inevitable is not inevitable. Each step needs to be justified and explained. Usually there are a series of steps (such as the steps between a daycare subsidy and state control of parenting) and each step presents an opportunity for rational debate and questioning. For example, the government might demonstrate that a subsidy does not at all make parents use daycare, but rather it makes it a more affordable option for some, and overall, daycare use might go up by parental choice.
Example 1 might seem like it needs contextualizing. Let’s imagine that tuition at the time of writing this for undergraduate studies is about eight thousand dollars a year. It definitely depends on where you are and what school you are attending. But at least in Canada, the amount of money a post-secondary institution can increase fees is set at a determined rate. Governments are also able to set a “tuition freeze,” so that tuition must remain at the same dollar amount per year. So in this case, imagine the government is proposing that tuition goes from eight thousand dollars a year to nine thousand dollars a year (when this fallacy is called a “wedge argument” this is considered the thin edge of the wedge). This is no small change. But it is very unlikely that the very next thing that happens is that tuition is forty thousand dollars a year (this would be the wide end of the wedge). If there are good reasons to stop the increase to nine thousand, then those reasons need to be laid out. The conjecture that it will immediately and necessarily be forty thousand dollars a year is not established. The arguer should talk about cost of living, access to education, fairness, social justice, and so on. Arguments against tuition increases can be made much more successfully than using a slippery slope!
Example 2 uses “send in thousands to die” as a necessary conclusion of getting involved with other country’s militaries. No one here is advocating for military intervention, but we need more information. We do not know the military intervention that is being discussed. It could be providing training and equipment but no soldiers. How, then, could thousands be sent to die? Again, we have to consider step by step how there are moments of pause and discussion within the military governance and ideally also with the public they are accountable to. Example 2, while best described as a slippery slope, also has an element of an appeal to force or fear because it relies on a scare tactic of the disastrous conclusion.
Example 3 starts with the government being involved in health care decisions and slides down the slope to death panels. “Death panels” is a kind of question-begging epithet, since it is unlikely that anyone would advocate for a death panel (and it is a prejudicial term or, minimally, we can only hope they wouldn’t actually call it that).
Example 4 was a very common argument in the political discourse in Canada, especially before 2005. It is possible that people still make this argument in Canada and other places, but hopefully we can see that not only has the disastrous consequence (people legally marrying animals) has not occurred, but the argument itself was, in addition to being homophobic and discriminatory, an appeal to force or fear.
With a slippery slope, the arguer suggests that one move (of any size) toward a particular direction starts something down a path that slips all the way down to an inevitable terrible conclusion. This metaphorical slope is irrational because an arguer can just add consequence after consequence without sufficiently arguing that each consequence is absolutely necessary. Slippery slopes are bad arguments par excellence.
17.5 Irrelevant Thesis (Ignoratio Elenchi)
The fallacy of irrelevant thesis is, along with straw person and inappropriate appeal to authority, perhaps one of the most common fallacies you will spot out in the world of argumentation. This fallacy is often called ignoratio elenchi (ignoring a refutation) or red herring. A way to characterize irrelevant thesis is that it violates a core relevance feature that both arguers have to be talking about the same thing. Recall Walton’s five features of fallacies: irrelevant thesis has all five! Without listing them all, the important part is that in a dialogue aimed at truth, we must stay on topic. In addition, irrelevant thesis does carry some semblance of correctness because the place that it derails you to might also be of importance—it just needs to be of importance in another dialogue. The persuasive power of this fallacy derives from the fact that it often does prove something, and people simply fail to notice that the thing proved is not the thing at issue. The fallacy of irrelevant thesis is often used intentionally to sway people, sometimes by good arguments, to positions that have nothing directly to do with those arguments. Politicians and advertising designers are usually experts at this sort of thing.
In the fallacy of irrelevant thesis, an arguer attempts to sidetrack their audience by raising an irrelevant issue and then claims that the original issue has been effectively settled by the diversion.
Irrelevant thesis is a very common feature of call-in shows. Many years ago, the CBC radio program Cross Country Checkup (a call-in show) featured a discussion about health care policy, specifically about what to do about wait times for surgery. Most of the discussion centred on whether it would be fair to implement a two-tier system, which was suggested as one of the leading options to fix the issue. One caller called in and essentially said that wait times are not an issue because there are people dying of starvation in other parts of the world. The host said it was “a good point” before heading to the next caller. This is irrelevant thesis in action. Should we have a discussion about global food supply and the harms of global poverty? Absolutely. This is why the caller’s point had rational force. They are correct that this discussion should take place. Where they were arguing incorrectly is that the initial discussion of wait times is effectively ended by bringing in another topic.
Example 1 offers us a shift of topic from being better off in the long run to producing an Eden on earth. Even if it were easy to show that an ecological lifestyle will not produce an Eden on earth, that isn’t the topic. This is inflationary irrelevancy. Being better off has been inflated to mean having an Eden on earth—which would be much harder to prove than the original conclusion.
Example 2 is a very common form of irrelevancy. The original claim being argued is that hunting is cruel (let us assume that this is discussing sport or trophy hunting, versus subsistence hunting). The respondent shifts the topic to pleasure and economic goods, which are different subjects. There is a subtle connection; people who profit from hunting and those who enjoy it will not wish to feel that they are engaging in a cruel sport and so they will have an emotional reason to want to reject the conclusion that hunting is cruel. But the question of whether hunting is cruel or not has to do with how the animals suffer (or not) and not with how hunters feel, so it is irrelevant thesis. The only way to repair this issue is to make a further argument that the pleasure and economic benefit outweigh the harm to animals, which requires justification.
Example 3 violates relevancy also, since the issue is not whether fourteen-year-olds are as smart as adults but whether they meet sensible conditions of eligibility for having a driver’s license (being responsible, having a need for transportation, etc.). Infants are also intelligent (in fact, they are excellent learners), but they do not meet sensible eligibility requirements for having a driver’s license. The claim is therefore irrelevant to the issue in question.
We saw example 4 when we discussed the appeal to pity. This example is also an irrelevant thesis. Here the question is whether Mr. Cratchit merits a raise for his work, not whether he has need of more money.
Key Takeaways
- • Analogy is a powerful tool because it allows us to understand an unfamiliar or difficult thing or set of facts by comparing it to something that is better known or understood. A false analogy offers such an analogical explanation when the purported similarity is not relevant.
- • Good analogies are relevant, insightful, partial, provisional, and fruitful.
- • The fallacy of false analogy is the comparison of two things that are only superficially similar or that, even if they are very similar, are not similar in the relevant respect.
- • The fallacy of false cause is actually a family of related fallacies that occur when an arguer gives insufficient evidence for a claim that one thing is the cause of another.
- • Post hoc, ergo propter hoc: This fallacy occurs when we assume, without adequate reason, that one event B was caused by another event A because B happened after A.
- • Mere correlation: Here we assume that B was caused by A merely because of a positive correlation between A and B.
- • Spurious correlation: Here we conclude that A is the cause of C when in fact both A and C are the effects of some event cause B.
- • In the fallacy of slippery slope, a person asserts that some event must inevitably follow from another without any argument for the inevitability of the event in question.
- • In the fallacy of irrelevant thesis, an arguer attempts to sidetrack his or her audience by raising an irrelevant issue and then claims that the original issue has been effectively settled by the diversion.
Exercises
Identifying Fallacies of Distorting the Facts
Identify the fallacies of distorting the facts, and explain why they are the particular fallacies you identify and what is wrong with them.
- 1. God must exist, since if everyone believed that there was no God, then we would have no reason not to obey the law, and the world would be in chaos.
- 2. It was forty-three degrees Celsius when Albert finished the eighteenth hole on the golf course. He drank seventeen glasses of water in quick succession. Then he drank a beer and immediately passed out. Albert should not have had that beer.
- 3. Climate change is not warming the globe. It was warm yesterday, and now today it is cooler. It is cooling down!
- 4. Tuition prices keep going up. But you have to also consider how housing and food prices are going up too.
- 5. Students are using ChatGPT to write essays, therefore university has no point anymore at all.
- 6. Anger is like steam under pressure. Keep it bottled up and let it build, and the next thing you know, someone might get killed.
- 7. When people get severe migraine headaches, they get nauseous and feel faint, so nausea makes you feel faint.
- 8. Journalist: “How will you address the education crisis when you are elected?” Politician: “I am glad you asked that. My new unemployment legislation will bring jobs to Alberta.”
- 9. If we allow medical assistance in dying (MAID) to those with terminal illnesses, then not only will doctors just be deciding to off people whenever; citizens will be taking MAID over any minor inconvenience.
- 10. When Joe drinks, he is no fun to be around. He is unhappy, he hates his job, and Marcia picked up with another guy. Really, Joe should stop drinking. Drinking makes him a real bummer, man.
- 11. Recent studies show that the death rate in Canadian hospitals is considerably higher than the overall Canadian death rate. Obviously Canadian hospitals are failing to care for patients, if not making their situations worse.
- 12. I wore knee-high socks to the last Oilers game, and after that they won. They will surely lose unless I do the same this evening.
- 13. Children have more screen time than ever. Inflation is also on the rise. If children were being raised without screen time, we would curb inflation.
- 14. I got COVID-19 two days after I got the COVID-19 vaccine. Obviously, it has the live virus in it, since the vaccine must have given me COVID-19.
- 15. I sell so much more ice cream when the weather is hot. These warm temperatures are great for my ice cream business.
4 Here’s an absurd example comparing gay marriage to a plane: Pat Cross, “‘Same-Sex Marriage’ Just Won’t Fly,” National Catholic Register, July 21, 2022. https://www.ncregister.com/cartoons/pat-cross-20220720-42m8ef5b
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