Logic

Is there a fallacy where claim P is made, but the reply is to use radical people who have made claim P, but this usage of radical people is supposed to represent everyone who said claim P? I'll give an example below: 1. Suppose claim P is: 9/11 happened because of America's failed US foreign policy. 2. Jean Baudrillard has claimed a, b, and c to support P. Noam Chomsky has said d, e, and f to support P. (Note: Baudrillard and Chomsky are on the fringes of supporting P, meaning that they support P, but in very radical ways.) 3. However, a, b, c, d, e, and f are all false. 4. Therefore, P is false. Now, of course the fallacy is that one is only looking at two sources who argue for P, and by discounting those claims, there's a hasty generalization to say that P is false. So a hasty generalization, I believe is correct. However, my focus is on concentrating on the fringes. If one wants to argue against P, one doesn't argue against the fringes who argue for P. So it's sort of a straw-man, but at the same time, a, b, c, d, e, and f are true representations of Baudrillard and Chomsky. Specifically, is there a fallacy where one is discounting a claim where one only concentrates on the fringe groups that says P?

Comments

Whew! What you have here is a real smorgasbord of fallacies. Let's sort them out.

One fallacy here -- and I think this is the one you primarily have in mind -- is a fallacy called "attack ad hominem", which means "attacking the person." This is the fallacy of attacking the character or credentials of the person making the argument, instead of showing what's wrong with the argument itself. In the example you give, Chomsky claims that US foreign policy was partly responsible for the 9/11 attacks, and offers considerations d, e, and f. To attack Chomsky's argument, one would have to either give grounds for thinking that d, or e, or f was false -- that is, show that the argument contained a false or unsupported premise -- or else show that d, e, and f did not logically entail the conclusion (if the argument is meant to be deductive) or did not provide good evidential support for the conclusion -- that is, show that the argument was not valid (bad if the argument was supposed to be deductive) or not cogent (bad if the argument was meant to be non-deductive, or evidential). The evaluation of the argument does not depend on what kind of character Chomsky has; it doesn't even depend on whether or not he's sane.

The second fallacy that seems to be involved in the cases you are wondering about is "guilt by association." It goes like this: Joe Normal believes that P, but Crazy Fringe Person also believes that P, so Joe Normal must not be so normal after all. (Variant: Crazy Fringe Person argued for P thus: a, b, c, therefore P. Joe Normal believes that P. Therefore, Joe Normal must believe P for the same reasons Crazy Fringe Person believes P. ) If you put this fallacy together with attack ad hominem, you get this: Joe Normal argued for P, but Joe Normal is crazy, so I don't have to believe P. This sort of reasoning is, sadly, in evidence all the time. (Glenn Beck specializes in it) Lots of people share lots of beliefs with lots of other people -- just because people share one belief, they needn't (and typically don't) share all their beliefs. I am sure I share with almost every person in Massachusetts the belief that Boston is our capital, but I disagree with many of them about many other things. Furthermore, two people can share a belief without holding the belief for the same reasons. I may agree with Sally Republican that Obama has not done a good job, but Sally Republican believes this because she thinks he spent too much on the stimulus bill, while I believe it because I think he spent too little.

Those are the two fallacies that I think you were asking about. But there's a third that you seem to have committed yourself. Your inference from (3) to (4) is utterly invalid. Showing that someone has made a bad argument for P does not show that P is false. It only shows that the argument under consideration fails to demonstrate that P. But P can be true for all that, and there might be very good arguments to be made on behalf of P.

And by the way, don't fall victim to the other two fallacies. Watch out for the classification "fringe" or "radical". Such labels are often used by defenders of conventional opinion (like mainstream politicians and journalists) as weapons in ad hominem attacks on people whose ideas and observations challenge the comfortable, received opinion. I don't know enough about Baudrillard to defend him, but I think Chomsky's analysis of 9/11 was absolutely correct, and we ignore it at our (and the rest of the world's) peril. Look at the arguments, not the labels.

There was a nice post about this sort of argument on the Sojourner's blog recently: http://blog.sojo.net/2010/10/01/what-glenn-beck-and-alan-grayson-have-in-common/.

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