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 Post subject: Logical Fallacy Guide
PostPosted: 22 Aug 2010, 20:51 
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We all know people who, when making an argument, seem to rub us the wrong way. We also know that sometimes people tell us we're using a fallacious argument, and maybe we don't know what that means. So, in order to help out anyone who hasn't done much debating, I'm going to describe some fallacies that commonly pop up in debates. This is meant as a guide to help you argue better, and to also help you pinpoint problems you might have with someone else's argument. (As a side note, the examples in here are purely fictional and don't reflect my views on any subject, nor are they meant to be examples of anyone on the forum.)

The fundamental rule in debate is to examine the logic and truthfulness of the argument. Where the argument comes from, how you feel about the argument, none of that stuff really matters in the long run. What matters is the facts, and if B logically follows from A. Any conclusion from an argument might be true. However, if the logic leading to that conclusion is faulty, we have no reason to accept the conclusion.

Ad hominem - There are several kinds of ad hominem attacks, but generally speaking it's when you attack the person and not the argument. Literally translated from Latin, it means "against the person." Basically, the outline for that looks like this:

1. Person A makes claim X.
2. Person A is (a) [whatever] or thinks [whatever].
3. Therefore, Person A's claim is false or lacks credibility.

It's kind of like saying, "Of course you're for welfare. You're a Democrat." It may be true. That person may be a Democrat. But that doesn't say anything about the pros and cons of welfare. It doesn't add anything to the argument.

Sometimes making a claim about a person can actually affect his/her credibility. This is true. But be careful when using something about a person in an argument, because chances are, it's ad hominem.

Other kinds of ad hominem attacks:

  • ad hominem tu quoque - When an argument is claimed to be false because a person's actions don't match up with his/her statements, or if his/her statements change over time. If someone was against the use of fur one month, and changes his/her mind the next month and says it's not that bad, this doesn't mean that either argument is invalidated. Using fur is not any more wrong because (s)he was originally against it, nor is it any more right because (s)he is no longer against it. Also, just because someone doesn't practice what (s)he preaches, doesn't mean that an argument is invalid.
  • Circumstantial ad hominem - When an argument is claimed to be false because a person may or may not have a motive of self-interest. This is very similar to the first example. Another example might be someone who is homosexual who feels strongly about allowing gay marriage, or a priest who is against abortion. Just because someone fits into a certain category doesn't mean (s)he doesn't have logical arguments for his/her beliefs. It's definitely important to try to find out where someone is coming from when (s)he is making an argument (and being skeptical of someone's motives is perfectly natural and acceptable), but it is far more important to figure out if the claims are true.

Note that ad hominems have an inverse: accepting someone simply because of who they are. For example, if a tobacco company says that tobacco doesn't cause cancer, and someone accepts the argument because it's a tobacco company--and who would know more about tobacco than a tobacco company?--they are falling for the same type of error, just not in an attacking manner.


Appeals
There are several fallacies that are appeals to something; note that none of them are appeals to fact.


  • Appeal to Authority - Just because someone is smart, or a teacher, or a parent, or an expert, doesn't mean that (s)he is completely infallible and his/her arguments shouldn't be held up to scrutiny. A doctor saying abortion is wrong doesn't make abortion wrong because that person is a doctor. His/her arguments may be more informed because of his/her experience, but again, knowing that would depend on actually listening to the evidence the doctor provides, as opposed to simply accepting the statement.
  • Appeal to belief/Appeal to popularity - Just because a lot of people, or a majority of people, belief X doesn't make X true. Even if a majority of people were to be against interracial marriage doesn't mean that it's not unconstitutional to deny an interracial couple from getting married.
  • Appeal to common practice - Just because something happens a lot doesn't mean it's okay. Murder happens a lot, but that doesn't mean it's okay. What are the actual arguments for and against murder being illegal? That is what matters.
  • Appeal to consequences of a belief - This is, in my experience, most commonly found in religious arguments. "God has to exist because if he didn't we wouldn't have a basis for morality!" and, "God has to exist because I believe in Him," are two of the most common arguments that fall under this fallacy. There is no proof in the first statement that morality requires a higher being, and as for the second statement, just because you want there to be a higher power doesn't make it any more likely for a higher power to exist. Wishful thinking doesn't an argument make.
  • Appeal to emotion (especially appeal to fear) - We see this one in politics a lot. Playing on the fears of Americans in regards to terrorism in order to prevent a mosque being built anywhere in the United States is an appeal to emotion (and in this case, an appeal to fear). Pro-Lifers often appeal to emotion when they talk about the babies' feelings; in particular I am reminded of a poem where a child who was aborted is talking to its mother, saying it was with God. Obama is another good example for this one; he used words like "hope" and "change," which bring up positive feelings for the future, in order to sway people to vote for him in the 2008 presidential election. Sadly, this is an effective fallacy. Everyone falls to it at some point. But remember, that doesn't make it okay to use.
  • Appeal to flattery - You know when someone is brown-nosing you. Just because you like someone (or are pretending to like that person) doesn't make his/her actions okay or arguments any truer.
  • Appeal to ignorance - When someone says, "There's no conclusive evidence so you should just say I'm right for argument's sake," it's an appeal to ignorance. This is often used in religious arguments. "There's no proof for or against God, so why don't you just say that there is a God?"
  • Appeal to novelty - Just because something is new doesn't mean it's good. We see this a lot in advertising and in elections. In advertising we see it when the company boasts its product has a new look, a new formula, etc. "Out with the incumbent!" is a good example for politics. Newer is not always better.
  • Appeal to pity - This is arguably an extension of the appeal to emotion. I've seen this the most in regards to interpersonal relationships. The argument goes as follows: "Because [insert sad thing] is happening in my life right now, you should [insert action]." For example, how many times have you heard this? "My grandmother died the other week... I think you should give me an extension on this paper." While most teachers would allow for the paper to be turned in on a later date, no student is entitled to an extension simply because his/her grandmother died.
  • Appeal to ridicule - This was used a lot during the struggle for women's suffrage, and is often used in the arguments against gay marriage. When women were fighting for the right to vote, many people made the argument, "What's next? Dogs voting?" Not only is this a slippery slope argument, but it's an appeal to ridicule. Most people would say, of course we wouldn't let dogs vote. But if you stop to think about it, what does that have to do with letting women vote? Likewise, what does letting a man marry his car (again, a laughable idea to many) have to do with letting a man marry another man? If an argument is silly, it should be deemed silly based on the merits of the argument, not on an offshoot attempt to insult the argument or its maker.
  • Appeal to spite - This one is particularly annoying, and is usually used in interpersonal relations. It's when someone brings up a claim to make someone spite another person making a claim. For instance, say Person X has an idea for a policy change. Persons Y and Z are talking about the idea. Person Y says it's a good idea. Person Z reminds Person Y of a time that Person X did something to annoy Person Y. Person Y decides not to support Person X's policy change as a result. Again, the focus is on the merits of the argument, not past histories between people.
  • Appeal to tradition - This is the opposite of an appeal to novelty. It's when you say, "Well that's how it's always been, so we should keep it that way." It would be like saying slavery is okay in a country that has had the convention of slavery for 300 years because slavery has been around that long.
Bandwagon - Most people have probably heard the phrase "jumping on the bandwagon." This has to do a lot with peer pressure. Just because a lot of people around you don't agree with your views doesn't mean that your views are wrong. Don't assume that people who disagree with you are trying to make you jump on their bandwagon, however; there may be valid reasons many around you don't agree.

Begging the question/circular reasoning - This one is found most often in religious arguments, but it certainly isn't limited to them. "God has to be real because the Bible says He does. We should believe everything the Bible says because the Bible was written by men who were talking to God." See the problem? There may or may not be a God, but that argument doesn't help anyone arguing for the existence of a higher power. Another example of this is when discussing whether something should be illegal or not. A common argument for not legalizing marijuana is, "Marijuana should be illegal because it's against the law."

Biased sample - This happens more often than people would like to admit. One common example, however, would go something like this, "I think most people are actually for gay marriage. After all, I don't know anyone who isn't." You have to be very careful in both talking about and reading about polls. An important question to ask of anyone talking about samples is whether it's a representative sample.

Burden of proof - This is when you place the burden of proof on the wrong side. What is the burden of proof? It's the responsibility of proving your statements. Say that Person X says there are aliens out there somewhere. Person Y says there's no reason to believe aliens exist. Person X says, "Prove it." Person X is the one actually making the claim; his/her claim is that aliens do in fact exist. Additionally, it's impossible to prove a negative. We can't PROVE that flying green-eyed blue-haired monkeys don't actually hold us down instead of gravitational forces, but that doesn't mean there's actually any reason to believe flying green-eyed blue-haired monkeys exist. So the burden of proof actually belongs to Person X. If you are making an affirmative statement (that is, if you're stating that Thing X exists, will happen, leads to something, etc.), the burden of proof is almost always going to be on you.

Composition - Let's say I see a brown cat while walking down the street in Indiana. Can I say that all cats in Indiana are brown? Not necessarily. If I like peaches, strawberries, and coconuts, does it mean I'll like a peach-strawberry-coconut smoothie? Not necessarily. If every player on the US national soccer team is amazing, does that mean the US national soccer team is amazing? Not necessarily. These are all examples of the fallacy of composition. Just because parts of a whole are one way doesn't mean the whole is that way. (This is not always a fallacy; if all of a cat's parts are made up of atoms, it's safe to say all of a cat is made up of atoms.)

Confusing cause and effect/ignoring a common cause - Good science students have probably had the phrase, "Correlation does not equal causation," drilled into their head. This fallacy is the result of not understanding that statement, of not understanding the difference between correlation and causation. Just because many cancer patients are depressed doesn't mean that depression itself causes cancer, or that cancer itself causes depression. Sometimes it's the stress that comes from having cancer that causes the depression. Additionally, sometimes a third variable comes into play that causes both things. For example, on a graph of ice cream sales versus violent crime, you may see a strong correlation. This doesn't mean that ice cream causes violent crime or that violent crime causes ice cream sales to go up. What it could mean is that during the hot summer months, many people enjoy a nice cold cone of ice cream, and the heat aggravates people, so they're more likely to commit violent crimes.

Denying the antecedent/post hoc - Assuming that Not P implies Not Q on the basis that P implies Q is denying the antecedent. For example, if it being cold outside needs to happen in order for it to snow, just because it's not snowing doesn't mean it's not cold. Post hoc fallacies are fallacies that assume that because Thing A came before Thing B, Thing A must have caused Thing B. Someone who buys a new racket and wins his/her next four tennis matches may attribute it to buying the new racket. However, the opponents could be easier than prior opponents, the player could have improved his/her technique, or any number of things. This isn't to say that the racket didn't help, only to say that it's not necessarily the only cause, if it is one at all. Superstitions fall under the post hoc fallacy. If a black cat crosses your path and then get hit by a car, it's not very likely that you got hit by a car because the black cat crossed your path. Yet many people don't like it when black cats cross their paths for fear of something bad happening to them.

Division - This is the opposite of composition. It's deciding that a part has all the attributes of the whole. If a country's deficit is large, it doesn't mean that each individual debt is large. Just because women on average get paid less than men doesn't mean that a randomly picked woman gets paid less than a randomly picked man with a similar job.

Equivocation - When someone argues using two different meanings to the word, they're equivocating. A popular example of this goes as follows: "A feather is light. What is light cannot be dark. Therefore, a feather cannot be dark." Make sure all important terms are defined when debating, or else you might find you've been arguing with someone who isn't even talking about the same thing.

False dilemma - This is extremely popular in politics. It's often used to garner support for wars. The fallacy goes as such, "If you're for the war, you're a patriot. If you're against the war, you're anti-[whatever country]." Those are not the only two options. Someone may be the biggest patriot in the country and not support the war. Likewise, someone may be a traitor to the country and support the war. Likewise, someone who is against school-sponsored prayers isn't necessarily a Christianity-hating atheist (nor is someone who is for school-sponsored prayer an Evangelical dingbat). Beware of any arguments saying, "Well either X is going to happen/is true or Y is going to happen/is true." (This isn't always a logical fallacy, by the way. If someone says, "Well either the guy is dead or he's alive," (s)he is right, unless (s)he is talking about Schrödinger's cat.)

Gambler's fallacy - This is when someone talks about luck. Thinking someone is bound to win at a game eventually because (s)he has been losing this whole time. This is different than understanding probability. If you understand that it's unlikely you'll get a streak of 25 tails in a row when flipping a fair coin, and that you're bound to get a heads eventually, you are not committing a gambler's fallacy. But thinking that something different will happen than what has been going on simply for the sake of something different happening, you are committing the fallacy.

Genetic fallacy - This fallacy is most notable in younger debaters, simply due to lack of experience. Basically it's believing that a claim must be true or false because of who made the claim. (This is closely tied in with appeal to authority, in some cases.) "My parents are Democrats, so Democrat must be the way to go," is an example of a genetic fallacy. Other popular ones are, "My family is Jehovah's Witness, so that religion must be the right one," "I learned in school that creationism is what really happened, so that's got to be what really happened," and "This guy used to be a socialist, so his health care plan must be socialist in nature." Again, if you're using this fallacy, you're looking at the origin of the argument and not looking at the argument itself.

Guilt by association - If you've ever been a kid, you've probably heard advice against being caught by this argument from your parents. "Don't hang out with those kids or people will think you're bad too." Just because the National Director of the KKK supports a position doesn't mean someone is a white supremacist because (s)he supports a position (unless of course, that position is white supremacy). Just because a guy from class that you hate likes a certain band doesn't mean that the band sucks. It just means you have something in common.

Hasty generalization - This is when you jump to a conclusion about a whole based on a small or misleading sample. It's very closely related to the composition fallacy. This fallacy comes in two forms: the first one is when a sample is too small to base anything useful on. For example, if I meet one homeless person and (s)he is articulate, and I assume that all homeless people are articulate, or I assume that women are unfit to be in combat duty because one woman screwed up an order, I am making a hasty generalization. The second form of a hasty generalization is when you assume a statistic from a small sample applies to a general population. For example, if I'm walking through a forest and I notice that 15% of the birds I see are blue, and I say, 15% of all birds in the southern Indiana region are blue, I am making a hasty generalization. (Note that if the sample size is large enough, it's not a hasty generalization.)

Loaded question - "Do you still beat your wife?" is a popular example of a loaded question. If you say yes, then you're admitting to beating your wife. If you say no, you're still admitting that you beat your wife. If you've never beaten your wife, you can't answer this question.

Middle ground - Moderation is not always the right position to take, especially if you're only taking that position to compromise. If Person X says all Jews should be exterminated, and Person Y says only enough Jews should be exterminated to make a point (around 25% by his/her reasoning), it does not follow that 62.5% of Jews should be exterminated. This one is a hard one to acknowledge sometimes, because the truth of the matter moderation is, a lot of the time, the best option. Moderate exercise is better than no exercise and extreme amounts of exercise. The difference is that with the exercise argument, you can explain why that is. No exercise is not good because we need to be active in some capacity in order to remain healthy. Too much exercise is harmful to the body. So a moderate amount of exercise sounds like a good idea, and it's backed by scientific evidence. Exterminating Jews however, doesn't have an intrinsic value to it. Exterminating no Jews would hurt no one. Exterminating all Jews would hurt a lot of people, even outside of the Jews being exterminated. Exterminating 25% of all Jews would also do damage. So how would exterminating 62.5% of them help anyone?

Missing the point - This happens when an argument is made and then the conclusion doesn't actually come from the argument. The best way to avoid this is to look at your conclusion and see if your argument actually supports your conclusion. An example of missing the point is, "The punishment should match the crime. As it is, selling illegal drugs gets you prison time. But drugs ruin lives. I think everyone who sells illegal drugs should be given the death penalty." There is nothing in there that actually supports giving the death penalty to drug dealers.

Misleading vividness - One extreme example that goes against statistical evidence does not mean the statistical evidence is wrong. One of the best examples I can think of involves plane crashes. Plane crashes are ugly: there's smoke everywhere, fires, twisted metal, and usually a lot of dead bodies. They're sensationalized on the news. Because of this, whenever a plane crashes, people head to the roads for their travel means. Statistically speaking, however, you're far more likely to die in a car crash than a plane crash. One especially ugly plane crash doesn't detract from that fact.

Proof by verbosity - Have you ever seen huge walls of text when someone is arguing, so huge that you don't even know where to begin? That's an example of proof by verbosity. The idea is that you overload your opponent with a bunch of words so they feel overwhelmed. (Sometimes, however, people are just bad at being concise.)

Red herring - Red herrings are especially popular in politics. If you hear someone say something about a candidate and end up thinking to yourself, What does that have to do with anything? it's likely a red herring. Red herrings are introduced to an argument as being relevant to the discussion, but they're not really relevant at all. Their only purpose is to distract people from the actual issue being discussed. If you've ever watched a presidential debate, chances are you've seen your share of red herrings. Some of them are hard to spot. For example, if an apartment complex wanted to ban pets and people were debating on whether it could, and someone talked about how his/her grandmother's life was positively impacted by owning a dog, that's a red herring. It seems like it might be relevant, but the argument isn't over whether owning pets is a good thing. The argument is over whether the apartment complex can ban pets. Talking about how great pets are doesn't do anything for the argument.

Relativist fallacy - This is a tricky fallacy to spot sometimes, but oftentimes it goes like this: 1. Someone makes a claim. 2. Someone else says, "That might be true for most people, but I don't fit in that category, so I don't think it's really true," or, "Maybe for America, but nowhere else is like that." The reason why it's a hard fallacy is because oftentimes that's true; what is good for one person or culture is bad for another person or culture. The main way to combat this fallacy is to look at the claim being made and determine whether culture or personal experience really does affect the overall outcome. This is something that honestly takes life experience to get good at noticing. Some common examples I can think of are, "Spanking can't be bad for kids because I was spanked and I'm fine," and, "You might think God can't create a rock so heavy He can't lift it and then lift it because it's a contradiction, but I don't feel that way, so my opinion is right." Just because spanking didn't have a negative affect on you doesn't mean it didn't have a negative affect on other kids or that, as a whole, it's a bad practice. Just because you think contradictions are okay doesn't mean that they are.

Slippery slope - This fallacy, along with ad hominem attacks, are probably the most well-known and also the most misdiagnosed fallacies. For example, when the PATRIOT Act came out, some people said we would eventually all be rounded up and put into concentration camps, but in order for that to happen, a lot would have to change within our society. Another common slippery slope argument is that if gay marriage is allowed, the next thing we know, pedophilia will be okay. Again, a lot about society would have to change. In both of these examples, the "then" of the argument isn't really related to the "if" part of the argument. This is not always the case. Banning prayer from schools doesn't mean that the next course of action will be banning prayer from homes. Building one mosque on a street doesn't mean every street will eventually have a mosque. Raising taxes once doesn't mean that eventually all our money will go to taxes. I hope you get the idea. But sometimes an "if, then" argument isn't actually a slippery slope argument. Generally speaking, if a country's government begins to offer equal rights to a group, eventually the group begins to be seen as equals. It may take a very long time, but it does (again, generally speaking) tend to happen.

Special pleading - This is when someone applies circumstantial reasons (without proper backing) why (s)he (or someone else) is exempt from a sweeping statement. Someone saying (s)he isn't required to do his/her homework because (s)he already knows the material would be using special pleading. It's not a particularly good reason to not do the work assigned to him/her, especially since without the homework there's not much evidence (s)he knows the material until assessment time, which may be a big surprise for someone who was wrong about how much (s)he knew.

Spotlight - This fallacy is rather common and is closely tied to hasty generalizations. What happens when someone commits a spotlight fallacy is they assume that a popular member of a group is representative of the whole. What popular means here is not necessarily well-liked or well-supported, but rather anyone or anything that gets a lot of media attention. So if a woman who calls herself a feminist gets on television and spouts anti-male sentiments and someone watching it assumes all feminists are like that, (s)he is committing the spotlight fallacy. Not all feminists (very few, actually) have anti-male sentiments, but a common misconception of feminists is that they all hate men and want women to dominate society. Many groups suffer from this kind of erred categorization.

Straw man - "That's not what I said at all!" It's a common response to a straw man attack. If Person X says, "I think punishments for child porn should be steep," and Person Y says, "Do you hear that? Person X wants to ban porn and punish people who look at it! How fascist!" Person Y has just built up a straw man. Another example would be saying that someone who wants to scale back the number of troops deployed wants the country to run away with its tail between its legs. It's also known as the false attribution fallacy.

Two wrongs make a right - This is exactly what it sounds like. If Person X does something bad to Person Y, it doesn't justify Person Y doing something bad to person X. A common argument when dealing with capital punishment is that, "If the guy who killed all those people didn't care about the people he killed, why should we care about him dying?" While there are pros and cons to capital punishment, it's not a strong argument to say, "Well he killed so why can't we?" especially since it's already established that killing is wrong.

Weak analogy - Analogy is a commonly used and highly effective measure for getting your point across. However, it's possibly to make analogies out of just about any two objects. How effective the analogy is depends entirely on the two items being compared. If you compare the silence after announcing you found a cockroach in your food at a restaurant to the silence after the silence after the Challenger exploded, you likely have a weak analogy.



If I have misinterpreted a logical fallacy, or forgotten one, please PM me and let me know!



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