Logic and Logical Fallacies

As we have discussed in class, education as a reinforcer/transmitter of culture depends upon systems of meaning such as language. Embedded in our concept of Democracy is an educated citizenry, each of whom is able to critically evaluate information. Therefore it is incumbent upon each of us to be clear as to what constitutes acceptable reasoning, as opposed to manipulation or erroneous thinking. If the conflict theorists are correct, and the social foundations of education are up for grabs by competing groups, then it stands to reason that sophists from each camp will stand and argue not necessarily to search for common truth but to advance their own agendas.With this in mind, I will be spending the first portion of next week's class (September 6) on logic, including the structure of basic syllogisms and argumentation. Please review the following list of logical fallacies (misleading or unsound arguments), adapted from California State University Northridge (http://www.csun.edu/~dgw61315/fallacies.html), and consider whether any of these were used in the argument you selected. Please note that this list covers many of the most commonly used fallacies, but it is not comprehensive; if you identify a flaw in the argument you selected, but don't see the structure here, bring your question. Come to class prepared to discuss.

After you have read this list, please consider a policy statement (either formal, or something that you heard/read) that you consider absurd. See if you can catch a logical fallacy that informs the policy, and write a statement in which you rebut the argument.

Argumentum ad antiquitatem (the argument to antiquity or tradition). This is the familiar argument that some policy, behavior, or practice is right or acceptable because "it's always been done that way." This is an extremely popular fallacy in debate rounds; for example, "Every great civilization in history has provided state subsidies for art and culture!" But that fact does not justify continuing the policy.
Because an argumentum ad antiquitatem is easily refuted by simply pointing it out, in general it should be avoided. But if you must make such an argument -- perhaps because you can't come up with anything better -- you can at least make it marginally more acceptable by providing some reason why tradition should usually be respected. For instance, you might make an evolutionary argument to the effect that the prevalence of a particular practice in existing societies is evidence that societies that failed to adopt it were weeded out by natural selection. This argument is weak, but better than the fallacy alone.

Argumentum ad hominem (argument directed at the person). This is the error of attacking the character or motives of a person who has stated an idea, rather than the idea itself. The most obvious example of this fallacy is when one debater maligns the character of another debater (e.g, "The members of the opposition are a couple of fascists!"), but this is actually not that common. A more typical manifestation of argumentum ad hominem is attacking a source of information -- for example, responding to a quotation from Richard Nixon on the subject of free trade with China by saying, "We all know Nixon was a liar and a cheat, so why should we believe anything he says?" Argumentum ad hominem also occurs when someone's arguments are discounted merely because they stand to benefit from the policy they advocate -- such as Bill Gates arguing against antitrust, rich people arguing for lower taxes, white people arguing against affirmative action, minorities arguing for affirmative action, etc. In all of these cases, the relevant question is not who makes the argument, but whether the argument is valid.
It is always bad form to use the fallacy of argumentum ad hominem. But there are some cases when it is not really a fallacy, such as when one needs to evaluate the truth of factual statements (as opposed to lines of argument or statements of value) made by interested parties. If someone has an incentive to lie about something, then it would be naive to accept his statements about that subject without question. It is also possible to restate many ad hominem arguments so as to redirect them toward ideas rather than people, such as by replacing "My opponents are fascists" with "My opponents' arguments are fascist."

Argumentum ad ignorantiam (argument to ignorance). This is the fallacy of assuming something is true simply because it hasn't been proven false. For example, someone might argue that global warming is certainly occurring because nobody has demonstrated conclusively that it is not. But failing to prove the global warming theory false is not the same as proving it true.
Whether or not an argumentum ad ignorantiam is really fallacious depends crucially upon the burden of proof. In an American courtroom, where the burden of proof rests with the prosecution, it would be fallacious for the prosecution to argue, "The defendant has no alibi, therefore he must have committed the crime." But it would be perfectly valid for the defense to argue, "The prosecution has not proven the defendant committed the crime, therefore you should declare him not guilty." Both statements have the form of an argumentum ad ignorantiam; the difference is the burden of proof.

Argumentum ad logicam (argument to logic). This is the fallacy of assuming that something is false simply because a proof or argument that someone has offered for it is invalid; this reasoning is fallacious because there may be another proof or argument that successfully supports the proposition. This fallacy often appears in the context of a "straw man" (see below) argument.

Argumentum ad misericordiam (argument or appeal to pity). The English translation pretty much says it all. Example: "Think of all the poor, starving Ethiopian children! How could we be so cruel as not to help them?" The problem with such an argument is that no amount of special pleading can make the impossible possible, the false true, the expensive costless, etc.
It is, of course, perfectly legitimate to point out the severity of a problem as part of the justification for adopting a proposed solution. The fallacy comes in when other aspects of the proposed solution (such as whether it is possible, how much it costs, who else might be harmed by adopting the policy) are ignored or responded to only with more impassioned pleas. You should not call your opposition down for committing this fallacy unless they rely on appeals to pity to the exclusion of the other necessary arguments. It is perfectly acceptable to use appeal to pity in order to argue that the benefits of the proposed policy are greater than they might at first appear (and hence capable of justifying larger costs).

Argumentum ad nauseam (argument to the point of disgust; i.e., by repitition). This is the fallacy of trying to prove something by saying it again and again. But no matter how many times you repeat something, it will not become any more or less true than it was in the first place. Of course, it is not a fallacy to state the truth again and again; what is fallacious is to expect the repitition alone to substitute for real arguments.
Nonetheless, this is a very popular fallacy, and with good reason: the more times you say something, the more likely it is that the audience will remember it. The first thing they'll teach you in any public speaking course is that you should "Tell 'em what you're gonna tell 'em, then tell 'em, and then tell 'em what you told 'em." Unfortunately, some debaters think that's all there is to it, with no substantiation necessary! The appropriate time to mention argumentum ad nauseam in a debate round is when the other team has made some assertion, failed to justify it, and then stated it again and again. The Latin wording is particularly nice here, since it is evocative of what the opposition's assertions make you want to do: retch. "Sir, our opponents tell us drugs are wrong, drugs are wrong, drugs are wrong, again and again and again. But this argumentum ad nauseam can't and won't win this debate for them, because they've given us no justification for their bald assertions!"

Argumentum ad numerum (argument or appeal to numbers). This fallacy is the attempt to prove something by showing how many people think that it's true. But no matter how many people believe something, that doesn't necessarily make it true or right. Example: "At least 70% of all Americans support restrictions on access to abortions." Well, maybe 70% of Americans are wrong!
This fallacy is very similar to argumentum ad populum, the appeal to the people or to popularity. When a distinction is made between the two, ad populum is construed narrowly to designate an appeal to the opinions of people in the immediate vicinity, perhaps in hope of getting others (such as judges) to jump on the bandwagon, whereas ad numerum is used to designate appeals based purely on the number of people who hold a particular belief. The distinction is a fine one.

Argumentum ad populum (argument or appeal to the public). This is the fallacy of trying to prove something by showing that the public agrees with you.

Argumentum ad verecundiam (argument or appeal to authority). This fallacy occurs when someone tries to demonstrate the truth of a proposition by citing some person who agrees, even though that person may have no expertise in the given area. For instance, some people like to quote Einstein's opinions about politics (he tended to have fairly left-wing views), as though Einstein were a political philosopher rather than a physicist. Of course, it is not a fallacy at all to rely on authorities whose expertise relates to the question at hand, especially with regard to questions of fact that could not easily be answered by a layman -- for instance, it makes perfect sense to quote Stephen Hawking on the subject of black holes.
At least in some forms of debate, quoting various sources to support one's position is not just acceptable but mandatory. In general, there is nothing wrong with doing so. Even if the person quoted has no particular expertise in the area, he may have had a particularly eloquent way of saying something that makes for a more persuasive speech. In general, debaters should be called down for committing argumentum ad verecundiam only when (a) they rely on an unqualified source for information about facts without other (qualified) sources of verification, or (b) they imply that some policy must be right simply because so-and-so thought so.

Circulus in demonstrando (circular argument). Circular argumentation occurs when someone uses what they are trying to prove as part of the proof of that thing. Here is one of my favorite examples (in pared down form): "Marijuana is illegal in every state in the nation. And we all know that you shouldn't violate the law. Since smoking pot is illegal, you shouldn't smoke pot. And since you shouldn't smoke pot, it is the duty of the government to stop people from smoking it, which is why marijuana is illegal!"
Circular arguments appear a lot in debate, but they are not always so easy to spot as the example above. They are always illegitimate, though, and pointing them out in a debate round looks really good if you can do it. The best strategy for pointing out a circular argument is to make sure you can state clearly the proposition being proven, and then pinpoint where that proposition appears in the proof. A good summing up statement is, "In other words, they are trying to tell us that X is true because X is true! But they have yet to tell us why it's true."

Complex question. A complex question is a question that implicitly assumes something to be true by its construction, such as "Have you stopped beating your wife?" A question like this is fallacious only if the thing presumed true (in this case, that you beat your wife) has not been established.
Complex questions are a well established and time-honored practice in debate, although they are rarely so bald-faced as the example just given. Complex questions usually appear in cross-examination or points of information when the questioner wants the questionee to inadvertently admit something that she might not admit if asked directly. For instance, one might say, "Inasmuch as the majority of black Americans live in poverty, do you really think that self-help within the black community is sufficient to address their problems?" Of course, the introductory clause about the majority of black Americans living in poverty may not be true (in fact, it is false), but an unwary debater might not think quickly enough to notice that the stowaway statement is questionable. This is a sneaky tactic, but debate is sometimes a sneaky business. You wouldn't want to put a question like that in your master's thesis, but it might work in a debate. But be careful -- if you try to pull a fast one on someone who is alert enough to catch you, you'll look stupid. "The assumption behind your question is simply false. The majority of blacks do not live in poverty. Get your facts straight before you interrupt me again!"

Cum hoc ergo propter hoc (with this, therefore because of this). This is the familiar fallacy of mistaking correlation for causation -- i.e., thinking that because two things occur simultaneously, one must be a cause of the other. A popular example of this fallacy is the argument that "President Clinton has great economic policies; just look at how well the economy is doing while he's in office!" The problem here is that two things may happen at the same time merely by coincidence (e.g., the President may have a negligible effect on the economy, and the real driving force is technological growth), or the causative link between one thing and another may be lagged in time (e.g., the current economy's health is determined by the actions of previous presidents), or the two things may be unconnected to each other but related to a common cause (e.g., downsizing upset a lot of voters, causing them to elect a new president just before the economy began to benefit from the downsizing).
It is always fallacious to suppose that there is a causative link between two things simply because they coexist. But a correlation is usually considered acceptable supporting evidence for theories that argue for a causative link between two things. For instance, some economic theories suggest that substantially reducing the federal budget deficit should cause the economy to do better (loosely speaking), so the coincidence of deficit reductions under Clinton and the economy's relative health might be taken as evidence in favor of those economic theories. In debate rounds, what this means is that it is acceptable to demonstrate a correlation between two phenomenon and to say one caused the other if you can also come up with convincing reasons why the correlation is no accident.

Cum hoc ergo propter hoc is very similar to post hoc ergo propter hoc, below. The two terms can be used almost interchangeably, post hoc (as it is affectionately called) being the preferred term.

Dicto simpliciter (spoken simply, i.e., sweeping generalization). This is the fallacy of making a sweeping statement and expecting it to be true of every specific case -- in other words, stereotyping. Example: "Women are on average not as strong as men and less able to carry a gun. Therefore women can't pull their weight in a military unit." The problem is that the sweeping statement may be true (on average, women are indeed weaker than men), but it is not necessarily true for every member of the group in question (there are some women who are much stronger than the average).
Most of the time, it is not necessary to call an opposing debater down for making this fallacy -- it is enough to point out why the sweeping generalization they have made fails to prove their point. Since everybody knows what a sweeping generalization is, using the Latin in this case will usually sound condescending. It is also important to note that some generalizations are perfectly valid and apply directly to all individual cases, and therefore do not commit the fallacy of dicto simpliciter (for example, "All human males have a Y chromosome" is, to my knowledge, absolutely correct).

Nature, appeal to. This is the fallacy of assuming that whatever is "natural" or consistent with "nature" (somehow defined) is good, or that whatever conflicts with nature is bad. For example, "Sodomy is unnatural; anal sex is not the evolutionary function of a penis or an anus. Therefore sodomy is wrong." But aside from the difficulty of defining what "natural" even means, there is no particular reason to suppose that unnatural and wrong are the same thing. After all, wearing clothes, tilling the soil, and using fire might be considered unnatural since no other animals do so, but humans do these things all the time and to great benefit.
The appeal to nature appears occasionally in debate, often in the form of naive environmentalist arguments for preserving pristine wilderness or resources. The argument is very weak and should always be shot down. It can, however, be made stronger by showing why at least in specific cases, there may be a (possibly unspecifiable) benefit to preserving nature as it is. A typical ecological argument along these lines is that human beings are part of a complex biological system that is highly sensitive to shocks, and therefore it is dangerous for humans to engage in activities that might damage the system in ways we cannot predict. Note, however, that this approach no longer appeals to nature itself, but to the value of human survival.

Naturalistic fallacy. This is the fallacy of trying to derive conclusions about what is right or good (that is, about values) from statements of fact alone. This is invalid because no matter how many statements of fact you assemble, any logical inference from them will be another statement of fact, not a statement of value. If you wish to reach conclusions about values, then you must include amongst your assumptions (or axioms, or premises) a statement of value. Once you have an axiomatic statement of value, then you may use it in conjunction with statements of fact to reach value-laden conclusions.
For example, someone might argue that the premise, "This medicine will prevent you from dying" immediately leads to the conclusion, "You should take this medicine." But this reasoning is invalid, because the former statement is a statement of fact, while the latter is a statement of value. To reach the conclusion that you ought to take the medicine, you would need at least one more premise: "You ought to try to preserve your life whenever possible."
The naturalistic fallacy appears in many forms. Two examples are argumentum ad antiquitatem (saying something's right because it's always been done that way) and the appeal to nature (saying something's right because it's natural). In both of these fallacies, the speaker is trying to reach a conclusion about what we ought to do or ought to value based solely on what is the case. David Hume called this trying to bridge the "is-ought gap," which is a nice phrase to use in debate rounds where your opponent is committing the naturalistic fallacy.
One unsettling implication of taking the naturalistic fallacy seriously is that, in order to reach any conclusions of value, one must be willing to posit some initial statement or statements of value that will be treated as axioms, and which cannot themselves be justified on purely logical grounds. Fortunately, debate does not restrict itself to purely logical grounds of argumentation. For example, suppose your opponent has stated axiomatically that "whatever is natural is good." Inasmuch as this statement is an axiom rather than the conclusion of a logical proof, there can be no purely logical argument against it. But some nonetheless appropriate responses to such an absolute statement of value include: (a) questioning whether anyone -- you, your judge, or even your opponent himself -- really believes that "whatever is natural is good"; (b) stating a competing axiomatic value statement, like "whatever enhances human life is good," and forcing the judge to choose between them; and (c) pointing out logical implications of the statement "whatever is natural is good" that conflict with our most basic intuitions about right and wrong.

Non Sequitur ("It does not follow"). This is the simple fallacy of stating, as a conclusion, something that does not strictly follow from the premises. For example, "Racism is wrong. Therefore, we need affirmative action." Obviously, there is at least one missing step in this argument, because the wrongness of racism does not imply a need for affirmative action without some additional support (such as, "Racism is common," "Affirmative action would reduce racism," "There are no superior alternatives to affirmative action," etc.).

Post hoc ergo propter hoc (after this, therefore because of this). This is the fallacy of assuming that A caused B simply because A happened prior to B. A favorite example: "Most rapists read pornography when they were teenagers; obviously, pornography causes violence toward women." The conclusion is invalid, because there can be a correlation between two phenomena without one causing the other. Often, this is because both phenomena may be linked to the same cause. In the example given, it is possible that some psychological factor -- say, a frustrated sex drive -- might cause both a tendency toward sexual violence and a desire for pornographic material, in which case the pornography would not be the true cause of the violence.

Red herring. This means exactly what you think it means: introducing irrelevant facts or arguments to distract from the question at hand. For example, "The opposition claims that welfare dependency leads to higher crime rates -- but how are poor people supposed to keep a roof over their heads without our help?" It is perfectly valid to ask this question as part of the broader debate, but to pose it as a response to the argument about welfare leading to crime is fallacious.
It is not fallacious, however, to argue that benefits of one kind may justify incurring costs of another kind. In the example given, concern about providing shelter for the poor would not refute concerns about crime, but one could plausibly argue that a somewhat higher level of crime is a justifiable price given the need to alleviate poverty. This is a debatable point of view, but it is no longer a fallacious one.

Slippery slope. A slippery slope argument is not always a fallacy. A slippery slope fallacy is an argument that says adopting one policy or taking one action will lead to a series of other policies or actions also being taken, without showing a causal connection between the advocated policy and the consequent policies. A popular example of the slippery slope fallacy is, "If we legalize marijuana, the next thing you know we'll legalize heroin, LSD, and crack cocaine." This slippery slope is a form of non sequitur, because no reason has been provided for why legalization of one thing leads to legalization of another. Tobacco and alcohol are currently legal, and yet other drugs have somehow remained illegal.
There are a variety of ways to turn a slippery slope fallacy into a valid (or at least plausible) argument. All you need to do is provide some reason why the adoption of one policy will lead to the adoption of another. For example, you could argue that legalizing marijuana would cause more people to consider the use of mind-altering drugs acceptable, and those people will support more permissive drug policies across the board. An alternative to the slippery slope argument is simply to point out that the principles espoused by your opposition imply the acceptability of certain other policies, so if we don't like those other policies, we should question whether we really buy those principles. For instance, if the proposing team argued for legalizing marijuana by saying, "individuals should be able to do whatever they want with their own bodies," the opposition could point out that that principle would also justify legalizing a variety of other drugs -- so if we don't support legalizing other drugs, then maybe we don't really believe in that principle.

Straw man. This is the fallacy of refuting a caricatured or extreme version of somebody's argument, rather than the actual argument they've made. Often this fallacy involves putting words into somebody's mouth by saying they've made arguments they haven't actually made, in which case the straw man argument is a veiled version of argumentum ad logicam. One example of a straw man argument would be to say, "Mr. Jones thinks that capitalism is good because everybody earns whatever wealth they have, but this is clearly false because many people just inherit their fortunes," when in fact Mr. Jones had not made the "earnings" argument and had instead argued, say, that capitalism gives most people an incentive to work and save. The fact that some arguments made for a policy are wrong does not imply that the policy itself is wrong.
In debate, strategic use of a straw man can be very effective. A carefully constructed straw man can sometimes entice an unsuspecting opponent into defending a silly argument that he would not have tried to defend otherwise. But this strategy only works if the straw man is not too different from the arguments your opponent has actually made, because a really outrageous straw man will be recognized as just that. The best straw man is not, in fact, a fallacy at all, but simply a logical extension or amplification of an argument your opponent has made.

Tu quoque ("you too"). This is the fallacy of defending an error in one's reasoning by pointing out that one's opponent has made the same error. An error is still an error, regardless of how many people make it. For example, "They accuse us of making unjustified assertions. But they asserted a lot of things, too!"