Logical Fallacy Friday: Ad Hominem

I dare you to wear this to your next debate team competition.

Along with the Straw Man, the Ad Hominem fallacy is probably quite familiar. Ad hominem is Latin for “to the person,” but I like to the think of it as the “So’s your face” fallacy. This is where you suggest that an argument is invalid due to some personal characteristic or behavior of whoever is making that argument.  In other words, ad hominem isn’t just name calling or using insulting language, nor is it simply focusing on personal characteristics in order to avoid substantive debate–though ad hominem can often have that effect.  This fallacy is an attempt to prove an argument invalid on the basis of who made it.

The classic ad hominem (ad hominem abusive) goes more or less like this:

X argument made by Y must be false because Y is a terrible person.

I firmly believe that Tom Delay is a terrible person.  In addition to being a corrupt politician, he totally ruined Dancing with the Stars for me, an offense I can never forgive.  But I am also pretty certain that Tom Delay is, from time to time, capable of making a true statement.  Therefore, my preferred assertion that whatever Tom Delay says must be a lie because Tom Delay is terrible is a classic logical fallacy. I would never, ever vote for him, even if he were running against a wet mop.  But if I were standing opposite him in a political debate, I couldn’t expect to just keep saying “It’s Tom Delay people, Tom Delay, I mean seriously, people, TOM EFFING DELAY,” and expect to get very far.

Ok, so that one is kind of easy.  Let’s move on.

X person, who belongs to Y marginalized group is incorrect when zie speaks on Z issue that affects Y group, because zie is too close to the issue and is therefore biased.

This rests on the logic that all members of Y marginalized group think alike about issues that affect that group. We saw this with Sonia Sotomayor, as opponents of her nomination suggested that she couldn’t possibly be objective about issues that affect Latin Americans. We’re seeing it now when  opponents suggest that if Elena Kagan is a lesbian (which we don’t actually know), she must think [insert reductive summary of a gay-friendly position here] about issues that affect the LGBTQI community.  It also suggests that marginalized groups are incapable of being “objective” about that particular issue because they are too close to it, making the dominant, privileged group the de facto authority by default, concealing the fact that members of that privileged group have something substantial to gain by perpetuating the systems and institutions that grant them that privilege.

This particular ad hominem (ad hominem circumstantial) assumes that individuals who have personal investment in a particular issue are not qualified to speak credibly about it often takes the form of an “objectivity” argument.  Consider the following:

X must be untrue because it was said by Y, who has money invested in industries that stand to gain from X.

This one is tricky.  Remember, however, that in order for this to be a true ad hominem fallacy, the speaker has to be attacking not just the credibility of Y but indicating that because Y stands to gain from X, X must be untrue. For example, I was recently having an argument with a Libertarian.  I do not recommend this as a fun activity.  This Libertarian, who had been reading all sorts of neat stuff from Regnery Publishing was convinced that global warming could not possibly be factual because Al Gore has a lot of money invested in green technology.  You can hear similar arguments from the left as well:  “This particular statement about energy can’t possibly be true, because the CEO of an oil company said it.”

This fallacy is problematic because it axiomatically posits that people who have spent considerable time and energy learning about an issue, people who might actually be experts on that issue, are somehow always wrong because they have something to gain if their position is proven to be valid.  I am quite certain that both Al Gore and oil company executives have said many true things about energy, but do I take their stances at face value?  No.  It is not an ad hominem fallacy to say, “Given Y’s closeness to X, I think we need to get more information and hear from additional experts.”

Let’s try another one.

X conservative evangelical must be wrong about Y moral issue because X was caught participating in Z act considered immoral by people like X.

Ok, here’s the bald uncomfortable truth.  Sometimes people act in ways that are entirely inconsistent with their stated values.  Is it hypocritical?  Yes.  Does that by default make anything they have to say about those values inherently untrue?  No, not really.  As much as I would like to say that the sexual foibles of certain conservative politicians make their arguments about sexual mores automatically invalid, it just isn’t right to do so.  If I want to rebut X’s argument about Y, I have to do more than just point out that X hired a male prostitute and took him to Europe (though that would be pretty damaging to X, for sure).

This is known at the ad hominem tu quoque (“you too”) fallacy.  A more benign example (I got this one from Wikipedia) would be a father telling his son that smoking is harmful and the son pointing out that the father used to smoke. The father’s past does not mean that smoking is not harmful.

And now for the final example:

X holds Y position, which is also held by Z disreputable group, therefore X must be sympathetic with everything Y stands for.

My favorite example of this (guilt by association) from the 2008 Presidential election was when the McCain/Palin campaign was all “WEATHER UNDERGROUND” any time Obama supported anything that sort of sounded like something a member of the Weather Underground might have supported.  Glenn Beck does this all the time too with Nazis and Communists.  I could write a lengthy analysis of how this works, or I could just let Jon Stewart demonstrate and wish you all a good weekend:

The Daily Show With Jon Stewart	Mon – Thurs 11p / 10c
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Note: this clip demonstrates a bunch of other fallacies too, including the straw man and the slippery slope.

LFF Posts: Straw Man