Ad Hominem is Latin for "to the man." This is when we try to disprove a conclusion by criticizing the person or the person's circumstances instead of the argument.
1) Some argue Catholic Priests are pedophiles, so their beliefs about God must be false.
2) “Your argument against eating meat is bad because you hypocritically eat meat.”
This is an ad hominem fallacy because your hypocrisy has nothing to do with the logical structure and content of your vegetarian argument.
3) One of my students dismissed a conclusion by observing that environmentalists are “long-haired potheads who live in carbon-emitting Volkswagon campers.”
It is important to understand that an insult is not an ad hominem fallacy. The insult becomes a fallacy only when we erroneously infer a conclusion from the insult. For example, if I argue "Clinton’s law is bad because he is a jerk who cheated on his wife," then I argued in a fallacious way. The problem is his cheating has nothing to do with the law. In general, the problem with the ad hominem fallacy is “the attacked person's circumstances or actions do not usually affect the conclusion” (Parker & Moore, 2009).
There are various types of ad hominem arguments (e.g. circumstantial, abusive, guilt by association, poisoning the well, ad feminin, Tu quoque), but what they have in common is they illegitimately focus on the person instead of the argument.
How to Avoid
Focus on the evidence and argument, not the person’s negative (or positive) qualities.
- Identify ad hominem fallacies in a political debate. Remember, not every insult is fallacious.
- When is an ad hominem approach not fallacious? That is, when is a person's character or circumstances relevant to the conclusion?
- Answers will vary.
- In a courtroom, the character of the witness is relevant because the jurors need to know whether they can trust the witness’ testimony. Focusing on character defects weakens any claim based on the trustworthiness of a person.