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The Rat
SFN Regular
Canada
1370 Posts |
 Posted - 08/05/2009 : 18:50:56
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As I see it there are three kinds of ad hominems, so in a stroke of originality I'll call the Type 1, 2, and 3.
A Type 1 ad hominem is the one which I think we should all avoid, and here's an example - "Why should we listen to that asshole/nutcase/idiot/...?" Well, maybe that person has come up with a legitimate argument or idea, what you think of them is not important. All people should be accorded the dignity of at least being heard, even if the only good idea they have ever had is a recommendation for a good burger joint.
Type 2 is the simple "He's an idiot." Yes, in the strictest sense it's an ad hominem, but in my opinion it's nowhere near as bad as Type 1. All you're doing is giving a personal assessment of the person without necessarily disparaging their idea.
Type 3 is the unavoidable ad hominem. Yes, you heard me correctly, unavoidable. If someone says to you "I just heard Fred Phelps say...", then I can guarantee that most will roll their eyes (even if you keep a straight face you might do it mentally), let out a snort, and say, mutter, or think "Oh crap, what's that dork saying now?!" This is unavoidable because you have elicited an ad hominem merely by mentioning someone's name. Phelps would be only one example, Bart Sibrel would be another, at least for me. While the first two are fairly clear cut, Type 3s are interesting because you could probably make a fair sized list of names for which you would react that way.
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Bailey's second law; There is no relationship between the three virtues of intelligence, education, and wisdom.
You fiend! Never have I encountered such corrupt and foul-minded perversity! Have you ever considered a career in the Church? - The Bishop of Bath and Wells, Blackadder II
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Dude
SFN Die Hard
USA
6891 Posts |
Posted - 08/05/2009 : 22:04:55 [Permalink]
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You have it wrong Rat! Just sayin.
It is not argumentum ad hominem to reject claims from a well documented crackpot out of hand. It is not ad hom to reject expert advice from a non-expert. And so on. You are not committing a logical fallacy in those cases.
If your cab driver tells you that you need heart surgery or a prescription medicine it is not an ad hom fallacy to reject that advice because he is a cab driver.
Same with the Phelps clan and anything they have to say. They have a solid and well documented history of hysterical hyperbole and harsh hateful rhetoric. The default position for any claim from a person or group like this has to be extreme skepticism, because of the source.
As for your #2, that is just name calling. See the other thread for why it isn't argumentum ad hominem.
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Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson
"god :: the last refuge of a man with no answers and no argument." - G. Carlin
Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth |
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Simon
SFN Regular
USA
1992 Posts |
Posted - 08/06/2009 : 07:44:22 [Permalink]
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I could be 'poisoning the well', no?
I mean, it's not because a person is a crackpot with a poor track record that this one particular argument is invalid.
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Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.
Carl Sagan - 1996 |
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Dude
SFN Die Hard
USA
6891 Posts |
Posted - 08/06/2009 : 09:12:47 [Permalink]
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Originally posted by Simon
I could be 'poisoning the well', no?
I mean, it's not because a person is a crackpot with a poor track record that this one particular argument is invalid.
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True, but it is still not ad hom to reject an argument/claim from the crackpot because they are a crackpot. At least in instances where the person/group is well documented as a crackpot.
Say that a creationist is making a claim about evolution. It would be an ad hominem to reject the claim from some random person because they are a creationist. It would not be ad hom to reject claims about evolution from Ken Ham/AiG because he is a creationist, or because he is Ken Ham/AiG.
I'm probably not explaining this all that well.
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Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson
"god :: the last refuge of a man with no answers and no argument." - G. Carlin
Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth |
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Simon
SFN Regular
USA
1992 Posts |
Posted - 08/06/2009 : 13:56:28 [Permalink]
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No, no, I see your point and it certainly makes a lot of sense as a shortcut in real life.
But from a purely mechanically logic point of view, I believe that it is probably incorrect. |
Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.
Carl Sagan - 1996 |
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Dave W.
Info Junkie
USA
26022 Posts |
Posted - 08/06/2009 : 14:34:56 [Permalink]
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Yeah, it's always possible that Ken Ham (for example) will come up with a good point sometime. Which is why a dissmisive attitude upon hearing someone's name isn't the same as a dismissal of whatever it is they go on to say.
In other words, #3 is easily avoidable. Someone says to you, "Ken Ham says blah-blah-blah." You roll your eyes and think, "not again!" but you go and check "blah-blah-blah" for veracity, anyway, because 999 times out of 1000, you'll get a chuckle at Ham's newest lie, and the other 0.1% of the time you'll learn something fascinating purely by accident. #3 is only a problem if you don't check. |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
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Dude
SFN Die Hard
USA
6891 Posts |
Posted - 08/06/2009 : 15:16:56 [Permalink]
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No, really, it is not a fallacy of logic to reject (out of hand) medical advice from a cab driver because they are a cab driver.
Expert advice or knowledge comes from, well, experts.
let me see if I can explain better.
argumentum ad hominem:
"Ken Ham is a well documented crackpot, liar, a preacher, and has no degree of any level in biology, and has a personal agenda that requires him to attempt to discredit evolution, therefore his claim about evolution (insert claim here) is wrong."
Not ad hom:
Ken Ham is a well documented crackpot, liar, a preacher, has no degree of any level in biology, and has a personal agenda that requires him to attempt to discredit evolution, therefore anything he says about evolution should be rejected out of hand.
In a less extreme case than Ken Ham the rejection could be tentative.
Source credibility for expert or scientific data is an important consideration. Anyone who has ever written an academic paper should be able to attest to this. Just think about listing wikipedia as a reference for anything except a paper about wikipedia...
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Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson
"god :: the last refuge of a man with no answers and no argument." - G. Carlin
Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth |
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Dave W.
Info Junkie
USA
26022 Posts |
Posted - 08/06/2009 : 17:45:17 [Permalink]
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I don't see a distinction between the conclusions. How are "thus-and-such is wrong" and "thus-and-such should be rejected out of hand" different in any logical (or practical) sense?
Besides, let's say that Joe gets into a cab, bleeding from the eyes. Generally, he would be a fool to reject the cabdriver's advice to take Joe to a hospital.
Fallacies aren't always false. Taking the cabbie's medical advice isn't logically sound, because he's not an appropriate expert, but logically unsound arguments can still have true conclusions.
For another example, "Because the cabbie said so, evolution is a correct theory." It's a piss-poor logical argument, but the conclusion is still true.
And the reason Wikipedia is shunned by teachers and professors is that it's a known-to-be-unreliable source and they don't have the time to check the references. Writing a paper on evolution using nothing but books by Discovery Institute hacks would be much, much worse for the truth of your paper than using Wikipedia for the same task. But since Wikipedia is known to almost every teacher, but Jonathan Wells isn't, a reference to Icons of Evolution could pass the sniff test even in some biology classes, but Wikipedia would be (mostly) incorrectly rejected out-of-hand. |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
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Simon
SFN Regular
USA
1992 Posts |
Posted - 08/06/2009 : 20:28:32 [Permalink]
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Technically; 'because PZ Myers thinks so, Evolution is a correct theory' is not really logical either.
I guess, you can expect a specialist in the field to be familiar with all the evidences and be more trustworthy than a neophyte but even a neophyte's opinion has some value, just, less than a specialist.
So, it is not necessarilly illogical to listen to the cabbie (or that of a playmate), but it would be to listen to his advice against that of a known health specialist. |
Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.
Carl Sagan - 1996 |
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Dude
SFN Die Hard
USA
6891 Posts |
Posted - 08/06/2009 : 21:10:19 [Permalink]
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Originally posted by Dave W.
I don't see a distinction between the conclusions. How are "thus-and-such is wrong" and "thus-and-such should be rejected out of hand" different in any logical (or practical) sense?
Besides, let's say that Joe gets into a cab, bleeding from the eyes. Generally, he would be a fool to reject the cabdriver's advice to take Joe to a hospital.
Fallacies aren't always false. Taking the cabbie's medical advice isn't logically sound, because he's not an appropriate expert, but logically unsound arguments can still have true conclusions.
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The distinction is really quite clear I think. In one you are claiming the person is wrong because of (insert reason here). In the other example, where you simply reject their claim, you are not addressing the specific truth value of their claim. The first is a fallacy of logic, the second is not.
In the simplistic "bleeding" scenario you suggest the cabbie's advice could be accepted, provisionally, based a legitimate appeal to common knowledge (bleeding is generally bad) and the advice is to seek expert advice!(go to a hospital)
But what if the cab driver diagnosed Joe and offered him specific medical treatment? Even if the cabbie was correct in the diagnosis and offered an accepted medical treatment for the problem, it is not a failure of logic to reject the cabbie's advice because he is a cabbie.
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Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson
"god :: the last refuge of a man with no answers and no argument." - G. Carlin
Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth |
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Dave W.
Info Junkie
USA
26022 Posts |
Posted - 08/07/2009 : 07:20:17 [Permalink]
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Originally posted by Dude
The distinction is really quite clear I think. In one you are claiming the person is wrong because of (insert reason here). In the other example, where you simply reject their claim, you are not addressing the specific truth value of their claim. The first is a fallacy of logic, the second is not. |
Rejecting a proposition without assessing its truth value is done because you have decided that some part of the logic is wrong, so there is still "wrongness" involved.
"Because it was proposed by a creationist, we should refuse to assess the truth of hydroplate theory" is just as logically weak as "because it was proposed by a creationist, hydroplate theory is wrong." The fact that the person making the argument is a creationist is neither a necessary nor sufficient reason to reject the proposition, and to claim otherwise is to claim that ideas cannot exist independently of the people who propose them.In the simplistic "bleeding" scenario you suggest the cabbie's advice could be accepted, provisionally, based a legitimate appeal to common knowledge (bleeding is generally bad) and the advice is to seek expert advice!(go to a hospital)
But what if the cab driver diagnosed Joe and offered him specific medical treatment? Even if the cabbie was correct in the diagnosis and offered an accepted medical treatment for the problem, it is not a failure of logic to reject the cabbie's advice because he is a cabbie. |
Yes, it is. The logic requires that the correlation between "cab driver" and "lack of medical knowledge" is complete. But as soon as you run into a bona fide medical doctor who happens to enjoy driving a cab in his spare time, that correlation fails.
In that sense, such ad hominem arguments are the precise converse of arguments from incorrect authority. The ad hom is "we shouldn't listen to X because he is a Y," while the authority argument is "we should listen to X because he is a Y." They're both fallacious for much the same reason: people do not always have all the qualities one might associate with the stereotype of whatever group Y represents. Only when the Y group is supposed to be authorities on the subject of X are such appeals to authority not generally considered fallacious (such as appealing to Ken Miller on evolution because he's a biologist).
In other words, both "we should listen to Ken Miller about evolution because he's a Catholic" and "we should ignore Ken Miller about evolution because he's a Catholic" are fallacious arguments because Miller's Catholicism has nothing to do with whether or not his ideas about evolution are correct or not. Replace "Catholic" with "cab driver" (were Miller a cabbie) and both propositions still include fallacious logic, and the truth value of Miller's statements about evolution is irrelevant. |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
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Dude
SFN Die Hard
USA
6891 Posts |
Posted - 08/07/2009 : 16:46:51 [Permalink]
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Dave_W said:
Rejecting a proposition without assessing its truth value is done because you have decided that some part of the logic is wrong, so there is still "wrongness" involved.
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No, it is a source credibility issue. Once a source has been demonstrated unreliable it only makes sense to reject further data from that source. Could you be rejecting accurate data? Sure. But if experience tells you that a source historically produces unreliable data you have no obligation to parse anything they say in the future just because it might be accurate.
Yes, it is. The logic requires that the correlation between "cab driver" and "lack of medical knowledge" is complete. But as soon as you run into a bona fide medical doctor who happens to enjoy driving a cab in his spare time, that correlation fails.
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I'm sure you are well aware of the problems with your example here. If the cab driver identifies himself as a doctor also, then you'd be right. But if all they are is a cab driver, and all they identify themselves as is a cab driver, it is not an ad hom to reject expert advice from them because they are a cab driver.
| In other words, both "we should listen to Ken Miller about evolution because he's a Catholic" and "we should ignore Ken Miller about evolution because he's a Catholic" are fallacious arguments because Miller's Catholicism has nothing to do with whether or not his ideas about evolution are correct or not. Replace "Catholic" with "cab driver" (were Miller a cabbie) and both propositions still include fallacious logic, and the truth value of Miller's statements about evolution is irrelevant. |
Yes, as you have written those, I'd agree they are logical fallacies. Especially considering we know Miller is a knowledgeable and credible expert in biology.
With regard to expert knowledge it is not a fallacy to say, "We should ignore Tom Cruise about brain chemistry because he is an actor and lacks any education in the field of neuroscience."
Thats the party I wasn't vocalizing... its the combination of a non-expert "job" and the implied lack of expertise that render it a non-fallacy to reject such advice. More so when the source has a history of credibility problems. Ken Ham is not qualified to dispute geological and biological conclusions about the age of the earth. Tom Cruise is not qualified to make expert claims about brain chemistry. They lack credibility as sources.
I guess in the strictest sense it is a fallacy to reject or assert the falsity of a claim (as in my last couple posts in this thread) without also including something like "because he is a cab driver with no formal or informal medical training."
But seriously, who in their right mind would accept expert medical advice from a cab driver?
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Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson
"god :: the last refuge of a man with no answers and no argument." - G. Carlin
Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth |
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HalfMooner
Dingaling
Philippines
15831 Posts |
Posted - 08/07/2009 : 17:30:59 [Permalink]
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The way I think about the example of a cab driver giving medical advice is this:
Any layman may give good or bad medical advice, though it's usually wrong or dangerously incomplete. If the cab driver is a sharp cookie, and has just survived a serious cancer, he may be in a position to give you some information about the treatments for that particular cancer from a patient's viewpoint.
An intelligent, experienced cab driver is probably more likely to tell you honestly about some of the shitty side-effects from the chemotherapy, surgery, and/or radiation therapy for that cancer than a doctor might. Doctors do, in my personal experience, habitually brush over such things. That's probably for two reasons: To save themselves precious time, and to avoid scaring a patient off from lifesaving (and painful) therapy. This really happens, and assures there will be many scary -- and avoidable -- surprises to patients.
Still, an opinion from any layman should be taken with a grain of salt. At most, their words should inspire a patient to ask the right questions of their physicians.
So, is saying not to pay attention to cab drivers for medical opinion an ad hom fallacy? Yes and no, though usually it isn't a fallacy.
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“Biology is just physics that has begun to smell bad.” —HalfMooner
Here's a link to Moonscape News, and one to its Archive. |
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Dave W.
Info Junkie
USA
26022 Posts |
Posted - 08/07/2009 : 17:44:19 [Permalink]
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Originally posted by Dude
Dave_W said:
Rejecting a proposition without assessing its truth value is done because you have decided that some part of the logic is wrong, so there is still "wrongness" involved.
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No, it is a source credibility issue. Once a source has been demonstrated unreliable it only makes sense to reject further data from that source. Could you be rejecting accurate data? Sure. But if experience tells you that a source historically produces unreliable data you have no obligation to parse anything they say in the future just because it might be accurate. |
But that's a common-sense rule-of-thumb, and doesn't excuse or justify faulty formal logic.| I'm sure you are well aware of the problems with your example here. If the cab driver identifies himself as a doctor also, then you'd be right. But if all they are is a cab driver, and all they identify themselves as is a cab driver, it is not an ad hom to reject expert advice from them because they are a cab driver. |
Again, we're talking about rejecting propositions based upon someone's name and our previous experience with that person alone. It's always possible that Ken Ham will crack a textbook open and start learning between now and the next time you hear his name.| Yes, as you have written those, I'd agree they are logical fallacies. Especially considering we know Miller is a knowledgeable and credible expert in biology. |
No, I specifically said that the truth value of Miller's statements about evolution are irrelevant to whether the propositions I offered included fallacious ad hominem arguments. His expertise in biology doesn't matter when examining those logical chains.With regard to expert knowledge it is not a fallacy to say, "We should ignore Tom Cruise about brain chemistry because he is an actor and lacks any education in the field of neuroscience."
Thats the party I wasn't vocalizing... its the combination of a non-expert "job" and the implied lack of expertise that render it a non-fallacy to reject such advice. More so when the source has a history of credibility problems. Ken Ham is not qualified to dispute geological and biological conclusions about the age of the earth. Tom Cruise is not qualified to make expert claims about brain chemistry. They lack credibility as sources.
I guess in the strictest sense it is a fallacy to reject or assert the falsity of a claim (as in my last couple posts in this thread) without also including something like "because he is a cab driver with no formal or informal medical training."
But seriously, who in their right mind would accept expert medical advice from a cab driver? |
Again, the fallacy is one of formal logic, and appealing to common-sense heuristics cannot break the fallacy. Ken Miller's, Ken Ham's, Tom Cruise's and the random cab driver's ideas can be examined on their own merits, without reference to the person stating them. We could even pick neuroscience propositions at random, blindly test them for veracity and learn that the source of the most incorrect statements is Tom Cruise, but that gives us no more a logical basis for rejecting all subsequent statements of his than seeing 1,000 white swans in a row allows us to logically state that all swans are white.
In other words, empiricism doesn't allow us to escape the ad hominem fallacy because empiricism isn't a tool or principle of formal logic.
Would I accept medical advice from a cabbie? Of course not. But I'm more than willing to sacrifice the ideal of a Spock-like avoidance of logical fallacies in favor of my health. Just like I'm going to form a not-strictly-logical conclusion if I find a stranger in my home with a baseball bat. I won't take the risk involved in logically ruling out the idea that he's trying to save me and my family from a rabid raccoon before I leap to a much less-favorable conclusion and act against the intruder. |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
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Dude
SFN Die Hard
USA
6891 Posts |
Posted - 08/07/2009 : 21:53:53 [Permalink]
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Before I argue myself completely into a locked box...
Yes, any argument that says says person X is wrong because they are a cab driver (or whatever) is technically an ad hominem argument. When you assign a truth value to a claim you should do it based on the merit of the claim, if your syllogism is "you are wrong because you are a cabbie" there is no question you have committed a logical fallacy.
Let me take a different approach.
When you are confronted with the situation "Ken Ham says X about evolution" and you roll your eyes... You are not actually committing a fallacy of logic. You are quickly making an inductive argument in your head that goes like this: Ken Ham was wrong about his claim that evolution is A, B, C, D, E, F, G, H, I, J, K,.... so he is probably wrong when he says X about evolution. That is a cogent argument. As with all induction there is, obviously, some probability your conclusion is wrong. But in instances like this where source credibility is well established, you end with strong induction.
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Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
-- Thomas Jefferson
"god :: the last refuge of a man with no answers and no argument." - G. Carlin
Hope, n.
The handmaiden of desperation; the opiate of despair; the illegible signpost on the road to perdition. ~~ da filth |
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Dave W.
Info Junkie
USA
26022 Posts |
Posted - 08/07/2009 : 23:37:51 [Permalink]
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Originally posted by Dude
When you are confronted with the situation "Ken Ham says X about evolution" and you roll your eyes... You are not actually committing a fallacy of logic. You are quickly making an inductive argument in your head that goes like this: Ken Ham was wrong about his claim that evolution is A, B, C, D, E, F, G, H, I, J, K,.... so he is probably wrong when he says X about evolution. That is a cogent argument. As with all induction there is, obviously, some probability your conclusion is wrong. But in instances like this where source credibility is well established, you end with strong induction. |
And what I'm saying is that if you leave it at that, and don't bother checking claim X simply because it's Ken Ham and you're sure of your induction, then you've still proposed an ad hominem argument within the context of what "an ad hominem argument" means. That particular fallacy (and the argument from authority) both reject induction.
And it's all because the converse (authority) argument suggests that if Francis Collins has been correct about claims that the human genome is A, B, C, D, E, F, G, H, I, J, K, etc., then he's inductively correct when he says the human genome is evidence of God's handiwork. I'm sure you'll agree that he's got a fairly high degree of expertise in both human genetics and theology (at least as much as the next man), but I'm equally sure that you'll reject the induction.
What my argument boils down to is that people, skeptics included, commit Rat-type-3 ad hominem arguments all the time, but they only remain so if we don't actually do the checking that would be required if the propositions came from any other source: a person who has not lied to us a zillion times.
In other words, it's an ad hom so long as you say something like, "Ken Ham said it, so why should I bother checking?" Hell, I once told Mozina that if he said the sky is blue, I'd go check the veracity of his statement. But if I ever copped an "it's Mozina, so why exert the effort?" attitude, I would have been commiting the type of fallacy that The Rat was talking about. |
- Dave W. (Private Msg, EMail)
Evidently, I rock!
Why not question something for a change?
Visit Dave's Psoriasis Info, too. |
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Ad hominems, again
