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14. Ad Hominem

 

Wireless Philosophy, Fallacies, 8:11. Original title: CRITICAL THINKING - Fallacies: Ad Hominem [HD]

Summary​

Paul Henne (Duke University) explores the ad hominem fallacy, Latin for "to the person": an attack on the person making an argument rather than on the argument itself. He introduces it through a running dispute with his friend Vlad.

The basic move​

Vlad argues that cats are better pets than dogs because cats stay indoors and use a litter box, while dogs need walking and are more work. Henne replies, "Yeah, Vlad, but you're a total jerk", dismisses the argument, and gets a dog. Generalised, the reasoning runs:

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.

Henne argues this form is generally wrong: the standing of the person making an argument is in most cases irrelevant to whether the argument is valid or sound. Vlad, however unpleasant, or even a Hitler, as Henne puts it, could still make a good argument in favour of cats.

Four sub-types​

The abusive type attacks the person's character directly, as in the Vlad example. The remaining three types turn on a second running example: Henne's friend Catherine argues that because animals are sentient, and killing a sentient being for food is immoral, killing animals for food is immoral.

The circumstantial type attacks the arguer's situation instead of her argument: "Yeah, but Catherine, you work for a vegan food company, so your argument must be invalid", pointing to a possible conflict of interest without touching her premises.

Tu quoque ("you also") points to the arguer's own inconsistency: "Yeah, Catherine, but you eat meat, so you support the killing of animals for food; your argument must be invalid", again without addressing her premises or conclusion.

Guilt by association links the arguer to someone disreputable: "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, we should obviously reject your argument, too."

All three share the same general 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.

Key takeaway​

None of these replies engage Catherine's or Vlad's premises or conclusion; they attack standing and character instead, which in most cases has no bearing on whether an argument is valid or sound. Henne notes that philosophers still debate when a person's standing and character are relevant to an argument, a question he leaves for another video.