Abbreviate Argumentum ad Hominem to AAH and ad Hominem Abusive to AAHA.

Source: p 132, A Concise Introduction to Logic (12 Ed, 2014) by Patrick Hurley

Keep in mind that the purpose of an ad hominem argument is to discredit another person’s argument by placing its author in a bad light. Thus, for the fallacy to be committed, there must always be two arguers (at least implicitly). If it should turn out that the person being attacked is not an arguer, then the personal comments made by the attacker may well be relevant to the conclusion that is drawn. In general, personal observations are relevant to conclusions about what kind of person someone is (good, bad, stingy, trustworthy, and so forth) and whether a person has done something. [...]

[1.] Joseph Kony, leader of the Lord’s Resistance Army, has kidnapped thousands of children from villages in central Africa, murdered their parents and relatives, and forced them into military service. He has also killed thousands of elephants and sold their ivory to fund his operation. Kony is therefore a thoroughly disgusting and despicable human being.

[2.] The conclusion is not that Kony’s argument is bad but that Kony himself is bad. Because the premises give relevant support to this conclusion, the argument commits no fallacy. Another example:

[3.] Shakespeare cannot possibly have written the thirty-six plays attributed to him, because the real Shakespeare was a two-bit country businessman who barely finished the fourth grade in school and who never left the confines of his native England.

[4.] The conclusion is not that some argument of Shakespeare’s is bad but that Shakespeare did not write certain plays. Again, since the premises are relevant to this conclusion, the argument commits no ad hominem fallacy.

I see that 1 attacks Kony's actions and 3 Shakespeare's scarce education; so 1 and 3 attacks no argument whatsoever. But I do not comprehend the importance of this distinction between attacking someone and attacking this person's arguments, for the status of AAH as a fallacy.

If AAH is NOT fallacious when used to attack someone, then why does it become fallacious when used to attack this same person's arguments?

  • Short answer: because "fallacious" necessarily (by definition) refers to argument/(purported)reasoning/persuasion. If there is none of the latter to begin with, there cannot be the former. More of a terminology quibble than anything substantive maybe.
    – Jeff Y
    Jan 12, 2016 at 19:54

2 Answers 2


You get an ad hominem fallacy, if person X makes a claim, and you try to say that the claim must be false because X has some fault.

Kony didn't make any claims, and nobody tries to discredit his claims. Shakespeare didn't make any claims and nobody tries to discredit his claims. Therefore no ad hominem fallacy.

Now if Kony made the claim that he loves children and elephants, we would still have no ad hominem fallacy, because the attack against his character directly implies that he is lying. But if he claimed that the earth circles around the sun, then saying "this must be false because he is an evil man" is an ad hominem fallacy. (If he said the sun circles around the earth, it would also be an ad hominem fallacy. It doesn't matter for the fallacy whether the claimed fact is true or false).

The fact that Kony is evil as claimed doesn't make his arguments true or false. If he said "2 plus 2 is 4", claiming this is false because he is evil would make you look stupid. If the pope said "2 plus 2 is 5", claiming this is true because he has a good character would make you look equally stupid.


If AAH is NOT fallacious when used to attack someone, then why does it become fallacious when used to attack this same person's arguments?

The negative statements about the person's character (AAH) are directly relevant to the conclusion about the person's character, but they are NOT relevant to the truth of an unrelated statement that the person is arguing for.

For example, if Joseph Kony were declaring that "bumblebees can see ten shades of green," it would be fallacious to respond by pointing out the evil things Kony has done, because his past does not provide any evidence for or against the assertion about how many shades of green bumblebees can see.

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