The opposite of ad hominem

[ciao_yall]

Two questions:

1)  I get that there are several verrrryyy similar fallacies that get subsumed under variations of the name 'ad hominem'-- this fallacy, like many others, is also something which gets named various other things in different texts and other sources.   Is there an Oxford English Dictionary-style authoritative list of fallacies and the names thereof somewhere?

2) Am I the only one that wonders whether the ad hominem is always exactly fallacious?  IOW, attacking the man rather than the idea is fallacious only when the idea itself cannot be legitimately attacked, so the critic defaults to ad hominem personal attacks, but pointing out various negative things about someone is necessary on occasion-- take the process of voir dire in jury selection: if I am the defense attorney defending a black guy accused of raping a little white girl, I will directly challenge prospective juror X if it is determined he's a KKK member.   I need know nothing else to know he should not be seated on this jury.   And when I am reading information about religion x, I do need to know what if any relationship the author has had to said religion.  Certainly,  if he is an excommunicated member thereof....   I need not be able to prove that his claims are false, before I say I will not credit them without independent verification.

The whole point of ad hominem attacks is that the attacker does not have facts on their own side, so they attack the person. Whether or not a person is a member of the KKK or an excommunicated member of a church does not impact the facts of whether the accused is guilty or the claims are wrong.

A part of ad hominem attacks might be to claim that the speaker does not have the right to opine on a subject. Again, not about what they are saying, just about who they are.

[Parasaurolophus]

Two questions:

1)  I get that there are several verrrryyy similar fallacies that get subsumed under variations of the name 'ad hominem'-- this fallacy, like many others, is also something which gets named various other things in different texts and other sources.   Is there an Oxford English Dictionary-style authoritative list of fallacies and the names thereof somewhere?

Not really. Most introductory logic or critical thinking textbooks include a small pile of the more common or important ones (there are tons of free ones out there; I like this one for my own students; the fallacies are in Chs. 3 and 4). A good internet resource is the Fallacy Files website, which has a good taxonomy of quite a few more fallacies than you'll usually see in a textbook (scroll right for the informal ones). (The site is a great source of examples, too.)

Really, though, it's not really worth anyone's time to try to come up with a comprehensive list (as I said, there are infinitely many possibilities, and they're not all going to be useful for thinking about the quality of arguments).

2) Am I the only one that wonders whether the ad hominem is always exactly fallacious?

It is only ever fallacious when the attack is irrelevant to the issue at hand. Pointing out a conflict of interest, for example, is an ad hominem--but not a fallacious one.

The only fallacies which are fallacious every time are formal fallacies. That's because they name invalid arguments (validity is a property of the structure of an argument, not of its content). Informal fallacies, on the other hand, are determined based on the content of the argument (and the content, obviously, is going to vary from case to case; incidentally, many informal fallacies are perfectly valid arguments--validity is not the gold standard of argumentation!).

[kaysixteen]

Excellent explanation of the elements needed for an ad hominem or other informal fallacies to be, ahem, actually fallacious, para.

I recall teaching a junior high informal logic class many years ago, and finding it very very useful for the students.  IMO, much more so than the corresponding formal logic class for kids that age.  I was wondering if you had any strategies for teaching informal fallacies?

[FishProf]

To add to Para:

The example of the juror being in the KKK isn't even necessarily an ad hominem.  In the example given, the question of whether the juror can be impartial IS an argument about the person.  Saying they cannot be impartial in this case because of the bias implicit (or explicit if the robes are on) in being a KKK member is directly addressing the claim (i.e. that this person would make a suitably impartial juror).

The ex-communicated member case IS an ad hominem because the CLAIMS the person makes about the religion stand or fall on their own merits.   If an atheist and an ex-pope* make the SAME claim about Catholic doctrine, it doesn't become more or less true depending on who is making the argument.

*assume these are two different people, which isn't automatically true.

[Parasaurolophus]

I recall teaching a junior high informal logic class many years ago, and finding it very very useful for the students.  IMO, much more so than the corresponding formal logic class for kids that age.  I was wondering if you had any strategies for teaching informal fallacies?

Not really, except insofar as I think students get more out of them when they understand the basics of validity and soundness, and so understand why the informal fallacies are informal. But I've never tried teaching at the HS level.

I have my students bring in real-world examples of arguments they think are bad, and we pick them apart together. I wouldn't call that a strategy per se, nor is it particular to informal fallacies, but it's fun for everyone.

[financeguy]

There are a lot of logical fallacies that behavioral economics can point out. $15 for lunch "feels" better than $10 for lunch and $4 to park. Paying off a 0% loan with a balance earning interest elsewhere "feels" better than continuing to make payments on the loan. Both stem from the fact that we look at the number of transactions vs their magnitude. (People say I have so many bills, not that the net amount is so high.)

A term that I think is very useful is "cognitive error" as opposed to mistake. If I ask what is 7x7 and you say 42, you can recognize it is actually 49 once this is pointed out and "see" it as such going forward. It was a mistake. A cognitive error can be recognized as a mistake ($15 for lunch is NOT better than $10 for lunch and $4 to park) but will never be seen as such. (If in this example "seen" is synonymous with one's intuitive recognition of the situation.)

I bring this up to point out that just because a logical falicy is pointed out does not mean that it ceases to work. It may have no effect at all. An Ad Hominem can likewise be pointed out as such and still remain highly effective.

[Anselm]

Fallacies are found everywhere and invented by the hyper-skeptics.  We all use ad hominem attacks.  I maintain it is only a fallacy when you throw in therefore and try to make a watertight proof.