Lost Art of Logic: Irrelevant Reasons to Believe

Earlier this month, former Illinois governor Rod Blagojevich was sentenced for crimes committed while in office. Prior to sentencing, his attorneys were permitted to present arguments in favor of a lenient sentence.

Among their pleas was a letter from one of Blagojevich’s daughters, which read, in part, “I need [my father] there for my high school graduation…. I’ll need him when my heart gets broken.” The judge, apparently unmoved, sentenced Blago to fourteen years in prison.

Perhaps it wasn’t the first time that the judge had heard an argumentum ad misericordiam – an argument from pity. Blagojevich’s daughter’s plight is sad, to be sure – but it’s irrelevant to the question of how much time her father ought to serve for his crimes.

Argumentum ad misericordiam is one of several logical fallacies that fall into the category of fallacies of relevance. Such fallacies present evidence that is irrelevant to the argument being made. I’ve previously considered two other fallacies of relevance here: the ad hominem fallacy and the genetic fallacy.

In Aristotle’s logical treatises, he referred to this class of argument as ignoratio elenchi (“ignorance of refutation”). Another term sometimes used to refer generally to such fallacies is the “red herring.” Distracting one’s audience from the issue at hand is thus likened to dragging a smoked fish across the path of a bloodhound in order to throw it off the scent of its prey.

Fallacies of relevance can be difficult to untangle because conclusions drawn from them are not necessarily false. [ 1 ] While certain kinds of fallacious arguments are always invalid, conclusions derived using a fallacy of relevance may or may not be valid. The form of the argument makes it impossible to affirm that the conclusion is true – which is, after all, the goal of making an argument in the first place.

There are a number of other fallacies of relevance, including:

Argumentum ad populum
Argumentum ad ignorantiam
Appeal to consequences
Straw man argument

Argumentum ad populum
An argumentum ad populum seeks to justify a claim by appealing to popular opinion or to the actions of many. If your daughter says that you should buy her a car because all her classmates have one, she’s using argumentum ad populum. Her stated reason is irrelevant to the question of whether she needs or should have a car. A variant of the ad populum is sometimes called “flag waving.” If your daughter had instead argued that you should buy her a car because it’s the American thing to do, that’s a flag-waving argument, based on an irrelevant appeal to patriotism.

When I was a kid, if I tried to use argumentum ad populum on my mother, she would reply, “if everyone else jumped off a cliff, would you jump, too?”

Argumentum ad ignorantiam
Assertions that employ argumentum ad ignorantiam (argument from ignorance) can be beguiling.

Consider, for example, that among 17th-century Europeans, it was widely known that no one had ever seen a black swan. Over the course of centuries, in Europe, the Orient, Africa, the Americas, there were no black swans to be found. Hence, it was taken as a matter beyond dispute that no such thing as a black swan existed anywhere – until 1697, when Dutch explorers spotted large flocks of them in Australia.

The argument from ignorance says:

no one has ever proven that “X” is true; therefore, “X” must be false.

Europeans could have avoided their fallacious conclusion if only they had been content to affirm a more modest one: that no black swans existed anywhere in the known world.

Appeal to consequences
Suppose that someone were to argue as follows: Since teaching children to believe in Santa Claus motivates them to be well-behaved, Santa Claus must be real. While most people would recognize the falsity of this conclusion, many would not spot what makes the argument itself fallacious. This sort of argument confuses the truthfulness of a proposition with the consequences of believing that the proposition is true. Such is the fallacy of appeal to consequences.

Yet not all arguments involving consequences take part in this fallacy. Consider this one: Our oven does not work, and it’s so old that replacement parts for it cannot be found. Therefore, we should buy a new one, so we’ll be able to continue preparing our daily meals.

This argument appeals to consequences, but is it fallacious? In this case, the consequences of an action have a direct relationship to the desirability of the action. Here we are not trying to evaluate a propositional truth; instead, we are assessing the suitability of a plan of action on the basis of its consequences, and such reasoning is not fallacious.

There is yet another situation in which one may properly reason using consequences. Suppose that in arguing about the truth of a proposition, you determine the truth or falsity of the logical consequences of that proposition (rather than the desirability of the consequences of the proposition). For example: Ice is less dense than water. If so, ice should float when placed in water. Since ice does float in water, the proposition that ice is less dense than water must be true. This is a valid argument.

The fallacious appeal to consequences can show up whenever one argues that doing a certain thing is necessarily right (or wrong) because the consequences are attractive (or not). One might (fallaciously) argue thus: Saddam Hussein was a cruel, evil dictator. The 2003 invasion of Iraq led to his downfall. Therefore, the invasion was just and proper. Logically, the conclusion is not warranted. In order to make a logically consistent argument, one needs an argument that actually addresses the circumstances under which one nation may justly attack another.

The Straw-man Argument
Straw-man arguments always arise in response to some existing viewpoint or argument, yet they involve attacking a position that an opponent has not actually taken. Often the straw man fallacy is committed by someone who does not accurately understand the position that he seeks to refute.

Straw Man

Image by xomiele via Flickr

Sometimes the user of a straw-man argument deliberately distorts, exaggerates, or over-simplifies his opponent’s position in order to make the position easier to attack. For example, during the 1964 presidential campaign, Republican candidate Barry Goldwater gave a speech in which he said, “Extremism in the defense of liberty is no vice.” Liberals countered with the claim that if Goldwater were elected, he would use nuclear weapons in Vietnam. Lyndon Johnson aired the famous “Daisy Girl” ad to imply that a vote for Goldwater was a vote for nuclear holocaust. While Goldwater had expressed a willingness to use nuclear arms, the ad was a misrepresentation of a more complex set of facts – a “straw man” plea intended to capitalize on people’s fears. Straw-man arguments often seek such a visceral response, thus short-circuiting rationality.

If you accuse someone of making a straw-man argument, he may become angry with you, because this could imply that he either does not correctly understand your argument or that he has distorted it deliberately. But what can also happen is that your opponent makes a leap of logic that you have not made – he takes your argument and concludes that if you believe A, you must also believe B. Having done this, he then attacks B. But believing that B is true may not be an inevitable consequence of believing A. If it is not, attacking B is a straw man argument. In order to make a sound argument, your opponent must first prove that A necessarily implies B before he starts attacking you through a response to B. But a straw-man attack requires less effort.

Suppose, for example, you state that you are in favor of capitol punishment under certain circumstances. Your opponent replies, “well, everyone knows that some people executed for capitol crimes have later been shown to be innocent – how can you be in favor of a practice that involves executing innocent people?”

In fact, one could be in favor of capitol punishment in principle, while also believing that the standard for evidence in such cases needs to be high enough to avoid executing the innocent. Your opponent has leapt to a conclusion that you have not adopted and attacked that instead of responding to the position to which you actually adhere. In politics especially, this sort of attack may be used even when the attacker knows that it is a deliberate misrepresentation. The person thus attacked must now turn his attention from defending his position to explaining why the “straw-man” is a misrepresentation of his views.

Our culture’s tendency to embrace clever “sound bite” responses works against the successful detection of fallacies of relevance. We are generally more ready to latch onto a snappy reply than to take the time needed to discern whether an argument treats the issue at hand accurately, superficially, or not at all. An attempt to explain why a particular argument is irrelevant will often be met with blank stares, because the explanation is usually more complicated than the fallacious argument, and we admire simplicity. Even the very intelligent may be taken in by such arguments.

Fallacies of relevance are often used in political debates, but they are widely employed, even in the discussion of theological controversies.

In order to avoid fallacies of relevance, we must understand what they are. But we must also make diligent efforts to understand other people’s viewpoints before we try to engage them.

In an earlier post, I quoted the late Roger Nicole on dealing with those who differ with us, but the quote bears repeating in this context:

… what we owe that person who differs from us, whoever that may be, is what we owe every human being–we owe them love. And we owe it to them to deal with them as we ourselves would like to be dealt with or treated. (Matthew 7:12)

How then do we desire to be treated? First, we want people to know what we are saying or meaning. If we are going to voice differences, therefore, we have an obligation to make a serious effort to understand the person with whom we differ….In the case of an oral exchange where we don’t have any written words, we owe the person who differs from us the courtesy to listen carefully to what he or she says. Rather than preparing to pounce on that person the moment he or she stops talking, we should concentrate on apprehending precisely what his or her position is.

Alas, this sort of care in listening to others is not as common as it should be in Reformed circles. Often, as I encounter a position that initially sounds wrong to me, even as I listen my mind is focused on formulating a rebuttal. But to avoid attacking a “straw man,” I need to put my energy into understanding the other person’s position and thinking through it carefully. I may even need to ask some clarifying questions before I can be sure that I understand the position accurately. In doing so, I may even discover that there is no disagreement, and hence, no need for a rebuttal!

(1) This is a characteristic of the genus of fallacies known as informal fallacies.

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