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Fallacies: Ad Hominem

In this video, Paul Henne describes the ad hominem fallacy, which is an informal fallacy that arises when someone attacks the person making the argument rather than their argument. He also describes the four subtypes of this fallacy.

Speaker: Paul Henne, Duke University.
Created by Gaurav Vazirani.

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  • old spice man green style avatar for user Alf Lyle
    Since Paul doesn't have any friends after this video, why should we consider anything he has to say as valid?
    (15 votes)
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  • leaf grey style avatar for user Michœl
    Can Ad hominem work the other way? As in, someone can support someone's argument purely based on their GOOD character?
    (6 votes)
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  • leafers ultimate style avatar for user Josh Brooks
    Is this the most misused and misunderstood fallacy of all time?
    (3 votes)
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    • leaf green style avatar for user David Greene
      I doubt there is any research determining that, but it has been the one I have personally found to be the most grossly misused. The most common mistake I notice people make when accusing another of committing an ad hominem fallacy is misidentifying an insult as such. While an insult might be unpleasant, if it is merely appended to an argument as opposed to being used as a substitute for an argument, then that insult is not strictly an instance of an_ad hominem_ fallacy. An argumentum ad hominem is when someone uses a personal attack as a substitute for an argument, or utilizes the personal attack as a premise supporting an argument, not when someone makes an argument and so happens to insult the person as well.

      The second most common mistake I notice is people believing that an accusation of ad hominem is itself an argument, or itself sufficient to discredit another's argument. The irony here is that the accuser is actually committing a different fallacy in the process, namely the argument from fallacy (also known as the fallacy fallacy or argumentum ad logicum). If the person does not logically prove the fallacy, either, they are also begging the question by accusing another of being fallacious without presenting an argument which proves it.
      (2 votes)
  • hopper cool style avatar for user MickeyRich
    Question: If a specific person's behaviors are the subject of your argument, are you still committing an ad hominem fallacy if you attack them because their behaviors are the subject of your argument?
    (3 votes)
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  • spunky sam blue style avatar for user josefrichardtyler
    This video doesn't mention the genetic fallacy as a subset of Ad Hominem attacks. Is that still it's own thing, or can it be subsumed by one of the four categories mentioned here?
    (2 votes)
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    • leaf green style avatar for user David Greene
      I have seen argumentum ad hominem categorized as a specific instance and subset of the genetic fallacy category, which is itself a subcategory of fallacies of irrelevance. I'm not certain of the exact taxonomy of logical fallacies, if there even is one, but I would personally consider ad hominem to be a subset of genetic fallacies rather than contrariwise.
      (1 vote)
  • aqualine tree style avatar for user Daniel Alessi
    Is this image an example of circumstantial ad hominem, despite the fact that the person's circumstances are being used to support the argument instead of attack it? http://goo.gl/OTkcZX
    (2 votes)
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    • leaf green style avatar for user David Greene
      I believe that would be an example of an appeal to emotion (argumentum ad passiones) rather than a personal attack (argumentum ad hominem). The defense attorney is not attacking his defendant for being an orphan; rather, he is appealing to the emotions of the jury so that they do not convict his defendant of the murder.

      It may also be an example of fallacy of irrelevance, since the fact that the defendant is an orphan is usually irrelevant to whether he committed the murder (and, consequently, whether he should be convicted of murder). The ad hominem fallacy is a subset of genetic fallacies, which is itself a subcategory of fallacies of irrelevance, hence why the argument may seem to be related to the ad hominem fallacy.
      (1 vote)
  • purple pi teal style avatar for user Maria
    Let's say that Catherine said "Nobody should ever eat animals." If I were to point out "Catherine, you eat animals," would I be committing the Ad Hominem fallacy?
    Or what if she said "If people are all vegetarian, there would be no war," and I responded "Hitler was a vegetarian." Would that be the Ad Hominem fallacy, or not, because I was attacking a claim?
    (1 vote)
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  • mr pink red style avatar for user okemos
    What is the opposite of Ad Hominem? Is it similar to it or what ?
    (1 vote)
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  • blobby green style avatar for user lxndr.rvs
    Are ad hominem attacks justifiable if we couch the attack differently? Like,

    "Jon has made many bad suggestions in the past
    Jon has made a new suggestion
    This new suggestion is probably a bad one."
    (1 vote)
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  • mr pants teal style avatar for user Joe Adams
    Is there a converse to an Ad hominem fallacy? (e.g. claiming an argument must be true because someone great/well-renowned made a similar argument) Maybe this is what was hinted at the end about philosophers weighing it; after all, our study seems to be 'standing on the shoulders of Giants.'
    (1 vote)
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Video transcript

(intro music) Hello. I'm Paul Henne, and I'm a philosophy graduate student at Duke University. And in this video, I'm gonna talk to you about an informal fallacy called "ad hominem." The phrase "ad hominem" might sound a bit bombastic, but I assure you that it's an interesting and useful critical thinking tool. The latin phrase roughly means "to the person," and that's exactly what this fallacy is. It's an attack against the person making the argument, rather than an attack against the argument itself. But let's see if we can pin down exactly what this means by using an example. Suppose that my friend Vlad made the following argument. "Cats stay indoors and use a litter box, "while dogs need to be walked "and they have to run outside. "Dogs are just more work. "Therefore, cats are better domestic pets than dogs." And then I reply, "Yeah, Vlad, but you're a total jerk." So I disregard Vlad's argument in favor of cats and decide to get a dog. So let's think about my reply to Vlad's argument. Maybe you think that my reply is a completely good response to Vlad. Suppose it's true that Vlad is a total jerk and that I think no one should respect him or listen to what he says. I think Vlad has bad character in some way. Therefore, his argument should be rejected. So my response is good, right? If this example doesn't convince you, suppose that Vlad is really Hitler. Hitler is a total jerk, so his conclusion is false, or his argument isn't valid. Does that sound good? But let's represent my argument more generally, to see why this reasoning is actually flawed. Premise (1): Person P makes claim C, "cats rule, dogs drool." Premise (2): Person P has unsatisfactory standing or circumstance ("Vlad is a total jerk.") Conclusion: Therefore, claim C is false. (it's false that cats are better domestic pets.) While it might seem appealing in some cases to say that this is a good argument form, it would be generally wrong to think so. The standing of the person making the argument in most cases will be irrelevant to the validity or the soundness of the argument. And this is the misconception that I would like to correct in this video. Simply because Vlad is a total jerk doesn't mean that his claim about cats as better domestic pets is false. He could be a complete jerk, yet still make a good argument in favor of cats as domestic pets. So let's look more closely at this fallacy and at its four sub-types. The first type of ad hominem fallacy is the abusive type. To understand this type, let's return to our first example where I called Vlad a jerk. In this case, I've committed the abusive ad hominem fallacy. In other words, I've attacked or abused the person making the argument. I haven't criticized the argument itself. More specifically, I've abused Vlad by simply attacking his character, and then I equated his poor character with his argument. This is a fallacy because, while the speaker, Vlad, might not have good standing as I see him, his argument may still be valid, that is, cats might be better domestic pets. Another type of Ad Hominem fallacy is the circumstantial type. Let's suppose that, when I'm talking to my friend Catherine, she makes the following argument. Premise (1): Animals are sentient beings. Premise (2): If a being is sentient, then killing it for food is immoral. Conclusion: Therefore, killing animals for food is immoral. Suppose then that I make the following statement in reply: "Yeah, but Catherine, you work for a vegan food company. "So your argument must be invalid." In this case, I attack Catherine's circumstance, that she works for a vegan food company, instead of her argument. Maybe I thought that she may have a conflict of interest in making her argument, that is, she wants to sell more vegan food products. So she may be motivated to give a faulty argument in favor of veganism. Despite this potential conflict of interest, my reply to her argument does not effectively criticize her argument. Although she works for a vegan food company and may have a conflict of interest, she may also have a perfectly valid and sound argument supporting her conclusion that killing animals for food is immoral. If I wanted to effectively combat her argument, I could maybe argue that animals aren't sentient, or attack some other premise in her argument. The third type of ad hominem fallacy is called "tu quoque," which roughly means "you also." To explore this variation of the fallacy, let's return to our previous example. But suppose that my reply to Catherine's argument were "Yeah, Catherine, but you eat meat. "So you support the killing of animals for food. "Your argument must be invalid." In this case, I highlight Catherine's standing, in that she doesn't act in a way that's consistent with her conclusion. I take her hypocrisy to invalidate her argument, or at least to be a reason to reject her conclusion. But again, my reply doesn't effectively critique Catherine's argument. I've not even mentioned any problems with the premises or the conclusion at hand. So despite her purported hypocrisy, Catherine might have an effective argument and just think that it's immoral that she eats meat. The last type of ad hominem fallacy is the guilt by assocation type. Let's suppose now that my response to Catherine's argument is this: "Yeah, Catherine, but towards the end of his life, "Hitler was a vegetarian. "So, you might have made a similar argument. "Since we'd reject his argument simply because he's Hitler, "the most evil person in the world, "we should obviously reject your argument, too." What have I done in this case? Well, I've associated Catherine with a person of very poor character, and then I've suggested that it is a reason to reject Catherine's argument. This, however, is fallacious, because while Hitler was a terrible person who committed some of the most atrocious acts in history, he still may have made a valid and sound argument about the morality of eating animals. Moreover, Catherine's slight association with Hitler does not invalidate her argument. And by discussing her character, I have not even addressed the issue at hand, veganism. Let's look at the fallacy in our general schema. The arguments that I've been making against Catherine are of the following form. Premise (1): Catherine claimed that killing animals for food is immoral. Premise (2): But she has poor standing or circumstances. Conclusion: Therefore, it is not the case that killing animals for food is immoral. Have I committed an informal fallacy in these cases? Yes! I have not invalidated or even addressed the subject of Catherine's argument. Rather, I have personally attacked her standing and character. This is the ad hominem fallacy, and you will see it often. It is important to note, also, that philosophers have many questions and concerns about this fallacy and when a person's standing and character are relevant to an argument. But we will have to save these questions for another video. Subtitles by the Amara.org community