Picking Apart Arguments With Logical Fallacies

Whether reading the editorial section of a newspaper, or perhaps an opinionated blog post, it is important to have a lookout for common logical mistakes in order to see if the argument has merit.

Logical mistakes, or logical fallacies, are a death sentence for any argument. An argument based on a logical fallacy is an argument built upon no foundation. There is no point in continuing the argument if the argument cannot at least be argued logically.

This post will point out the common fallacies I come across and give an example of the fallacy in use.

Red Herring

Tom: “I would like to build a fence on the United States and Mexican border.”
Jason: “Do you not realize the environmental impact of building a fence? And you people wonder why global warming is so bad?”

This fallacy is characterized by someone diverting the argument from one to another. For example, Tom is talking about illegal immigration. Jason, however, shifts the argument towards the environment.

Straw Man

Jessica: “I am for abortion.”
Amanda: “I’m pregnant. So are you saying you want to kill my child?”

In this example, Jessica is stating her position. However, Amanda distorts Jessica’s position and takes it to an extreme. Straw Man arguments take an argument to an extreme and try to make it personal.

Hasty Generalization

Amanda: “The majority of people at work want to be part of a new union.”
May: “Why do you think that?”
Amanda: “I was talking to a few of them at lunch.”

Hasty Generalization is making an argument seem valid when too few people have been consulted. The Hasty Generalization fallacy could have been true in this case if Amanda had talked to a few more of the workers. In this case, however, the sample size was too small to come to a conclusion that the workforce wanted to shift to a new union.

Poisoning the Well

Jill: “My boyfriend is such an idiot. You’ll see why when you meet him.”

Poisoning the Well is presenting negative information about a person before that person even has a chance to defend himself or his position. In the example, Jill poisoned the well to the friend listening by declaring that her boyfriend was an idiot before the other friend had a chance to meet him.

Ad Hominem

Tom: “I think marriage should be between man and a woman.”
Jason: “How can you say that? You’ve been divorced and remarried twice. So evidently, you think that marriage should be between man and three women.”
Tom: “I didn’t say that.”
Jason: “Whatever. You’re a moron.”

The Ad Hominem fallacy is a form of a personal attack. In this example, Tom is making a point that marriage should be between man and a woman. Rather than listen to Tom’s points supporting the argument, Jason attacks Tom personally in order to prove that Tom’s argument is false.

Division

Tom: “You must be a republican.”
Jason: “Why do you say that?”
Tom: “Because you live in Texas.”

Just because Tom lives in Texas doesn’t automatically make him a republican. The Division fallacy is committed when someone assumes what is true of the whole is also true of parts of the whole.

Composition

Amanda: “I think all bikers are scary. They all have tattoos, long beards, and leather jackets.”

A stereotype is a form of composition fallacy. Just because some bikers share a common characteristic does not mean that all bikers share that same characteristic.

Post Hoc (Superstition)

Amanda: “You broke my computer!”
Joey: “What makes you think that?”
Amanda: “You used it last. The next time I got on the computer, the screen just went blank and the computer started smoking.”

The Post Hoc fallacy is another term for superstition. Just because Joey got on the computer right before the computer fried does not mean that Joey caused the computer’s failure.

Appeal to Emotion

Jessica: “Please buy these magazines from me. I’ll be able to go on my trip and work my way through college.”

Please note that in the above argument, the person isn’t really arguing a point. The person is using emotion to win you over. Appeal to Emotion tries to persuade you using emotions rather than logic.

Begging the Question

Trevor: “Why do you think Bush invaded Iraq?”
Anthony: “Because he wanted to plunge this country into war.”

A person arguing using the Begging the Question fallacy does not really answer the question. Notice that Anthony didn’t really answer Trevor’s question. Anthony more or less reworded Trevor’s question into a phrase.

Two Wrongs Don’t Make a Right

Tom: “I’m not going to give my girlfriend a birthday present because she didn’t give me one.”

This fallacy is pretty self-explanatory on the basis that you can’t justify a position because you have been wronged in the past.

Appeal to Majority

Jason: “We should pull out of Iraq.”
Ashley: “Why?”
Jason: “Because most Americans do not support the war.”

The Appeal to Majority fallacy points out that you can’t base an argument on the amount of people behind it. It’s the same fallacy when some company declares, “10 million customers can’t be wrong.” The amount of customers (or downloads, or visits) does not determine the quality of a product and/or service alone.

Conclusion

Please note that the examples to each fallacy are in a vacuum and are out of context. In an argument, there are usually more factors that you have to gauge such as temperament, credibility, and bias. Even intuition can come in handy.

If you would like to read more on fallacies, please check out these two links:

5 Comments

  1. Wow, I really like what you have here. 🙂

    "Poisoning the Well", you should be in Orange County, Southern California. You will hear such things every hour by both girls and guys, if not every 30 minutes.

    About "Post Hoc", I think the information that Amanda has can be used to track down the real reason instead of using it as a final judgment, the way she did in the example.

    "Appeal to Emotion": this one happens almost everyday in many places. I think it depends on the person being told such a quote whether or not they wish to let their emotions control their money. Same thing with so many kids I sometimes see outside banks selling chocolate to support their education.

    "Two Wrongs Don't Make a Right"; are you saying boyfriends and girlfriends are obligated to give each other presents? 😀 Also, if such an act is voluntary, either person may avoid doing it to prove a point in case there is a disagreement somewhere in the relationship.

    "Appeal to Majority"; I heard this one a lot, almost everyday. This applies to both sides of the arguments [e.g., those who support and those who oppose "the" war or any war]. I like your example of many people visiting or downloading something. That does not determine the quality of a product or a service, yes. More people go into Kmart compared to Target. Does that mean Target is not as good as Kmart?

    "Begging the question"; I love this a lot, as I see it everyday. And it is also annoying in many cases. I would like to post more on this specific point if I have your permission. 😀 I may have already posted something on this.

    Should I guess here that the examples used here show things you support and do not support? 😀

    Good work Ronald! I am hoping to see more posts like this one. 🙂

  2. I think our knowledge of fallacies is pretty much at the same level, so I’m just going to put in some examples that are clearer in my head. 🙂

    Straw Man – it doesn’t necessarily have to make the argument personal (although the example does). The Straw Man just takes an argument and takes it to an indefensible extreme. I heard this one recently. A coworker has a dog which is his “baby” (or his wife’s, I forget). This dog just went through surgery on its knee and has a cast that costs about $700 to change. We wondered why he didn’t just put the dog down and he said “You wouldn’t shoot your kid, would you?” Classic Straw Man.

    Composition – it is a little clearer to me if Amanda had said “I think all bikers are scary. Those ones at the bar down the street all have tattoos, long beards, and leather jackets.” Hmm. I just checked out this logical fallacy page and this example seems to be more of a Hasty Generalization than Composition. I have a hard time getting the two straight, but Composition takes a characteristic of one or more parts (sodium is toxic, chloride is toxic) and drawing a conclusion about the whole from that (anything with sodium and chloride in it is toxic). Hasty Generalization is the sampling error about drawing a conclusion when having seen only a few representative members of a group.

    Begging the Question – Your favorite one, right Ronalfy? 😛 I like the example from our old textbook. “Why do you think OJ Simpson is guilty?” “Because he killed Nicole” This is Begging the Question because the question is asking “Why do you think OJ Simpson is guilty of killing Nicole?” and the answer is parroting back the question.

    Finding logical fallacies to an argument will help in deconstructing an opponents viewpoint, but convincing them that their argument is fallacious may be another challenge. 🙂

    cetroyer

  3. Cetroyer,

    After looking at the composition example, I think it can fall in both categories. Thanks for your examples.

    Bes,

    I wasn't trying to show examples of what I support and don't support. I was trying to give relevant, present-day examples of issues.

    You're allowed to expand, quote, or use anything I write about. I have my work under Creative Commons.

  4. Nice work on this article. BTW, I like the new look on the archives and website; I typically just like to look at content through the google reader. –clau

  5. Thank you Claudia for the comment and for being a subscriber. Muchas gracias.

    I appreciate your feedback on the archives and website as well. I am forever tweaking this thing that I call a website. 🙂

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