Comments on: The Fallacy Fallacy

By: Vichy

Vichy — Mon, 01 Jun 2009 22:08:54 +0000

I typically like to explain the exact error, partially because I can’t always remember the name or spelling of a particular fallacy.

And I think sometimes it is just personal laziness and a presumption of knowledge in the audience.

By: A Second Hand Conjecture

A Second Hand Conjecture — Sat, 28 Apr 2007 20:12:28 +0000

Questioning fallacies, begging for answers

At Overcoming Bias Robin Hanson points out that logically many fallacious forms of argument are not necessarily so. So is question begging inherently fallacious? It seems context matters. The comments are juicy.
Much more here. Conclusio…

By: Ann

Ann — Sat, 28 Apr 2007 18:52:29 +0000

The weakness of the ad hominem argument even “when used correctly” is suggested from Doug S’s description of it, fleshed out a little.
Someone asserts x.
Anyone who asserts x probably has some reason for doing so, which reason might derive from a characteristic that would cause him to make the assertion even if it were false.
Therefore, no one’s assertion of x is evidence that x is true.

An argument that hinges entirely on the credibility of its declarant is a weak one, and should be considered only when no better form of evidence is available. However, opposition to an argument that hinges entirely on an attack on the credibility of its declarant suggests a lack of interest in the evidence upon which the declarant may be basing his assertion.

“I will ignore your statement when considering the issue of whether cell phones cause brain cancer because you are a spokesperson for a cell phone manufacturer” may superficially sound more reasonable than the fallacious “I will conclude your statement is false for the same reason,” but if the goal is truth, no assertion can be dismissed out of hand, merely because of its declarant’s possible bias.

By: Doug S.

Doug S. — Sat, 28 Apr 2007 17:03:59 +0000

“Ad hominem” when used correctly is an attack on the credibility of the speaker of an assertion.

I think the structure of the argument, when used correctly, is something like this:

You have asserted X.
You have some characteristic that would cause you to assert X whether it is true or not.
Therefore, your assertion of X is not evidence that X is true.

Example:
You assert that cell phones do not cause brain cancer.
You are a spokesperson for a cell phone manufacturer, so you would be likely to say that even if it were false.
Therefore, I will ignore your statement when considering the issue of whether cell phones cause brain cancer.

Where the “ad hominem” argument becomes a fallacy is when you use it to claim that because a person with particular attributes says X, X must therefore be false. After all, a stopped clock is right twice a day!

By: Eliezer Yudkowsky

Eliezer Yudkowsky — Sat, 28 Apr 2007 07:03:16 +0000

You’re certainly going to have problems if you think of bias-resemblance as being deontologically prohibited as bad conduct, like flashing yourself in a public area. Certainly an argument can exhibit bias and yet come to a correct conclusion – the world’s stupidest man may say the sun is shining, but that doesn’t make it dark out. The question is whether that kind of argument reliably produces good answers, and at what degree of reliability.

Some “fallacies” are bad ideas not because they are totally nonfunctional, but because of their side effects or their very weak reliability. Ad hominem short-circuits a more rigorous process of argument; appeal to authority may not be sufficiently reliable.

By: Bruce Britton

Bruce Britton — Sat, 28 Apr 2007 01:51:27 +0000

Many of the cognitive biases have directly opposing cognitive biases. For a particularly good example, look at the opposition of the Ludic Fallacy against the probabliity biases (gambler’s fallacy, etc). In any particular case, either one or the other of the pair of biases may be a correct description of the situation, but not both, because they are mutually exclusive. So with cognitive biases, just like ‘logical fallacies,’ you have to look at the subject matter context in order to come to a correct judgement about whether the arguement is a good one.

By: Bruce Britton

Bruce Britton — Sat, 28 Apr 2007 01:38:19 +0000

Isn’t this problem also true about the lists of cognitive biases? We love to collect lists of cognitive biases, which we use to club opponents. And in many cases we can’t tell that an arguement is bad just by looking at whether its form matches the form of a cognitive bias. For example, there are arguements that are based on the availability heuristic, but have true conclusions, and ones that are false. Similarly for the representativeness heuristic: sometimes the conclusions based on it are true, and sometimes they are false. It is true that the Aristotelian-type logical approach to arguement has shortcomings, but the work of Chaim Perelman provides a corrective to many of the problems. Perhaps a post on his work would be useful.

By: Barkley Rosser

Barkley Rosser — Fri, 27 Apr 2007 17:44:21 +0000

Well, it should be kept in mind that one can “know” something is “true,” even if it cannot be proven, or, to be more precise, is associated with a logical contradiction within the logical sytem out of which it comes. This is deeply connected to the Godel problem.

By: TGGP

TGGP — Fri, 27 Apr 2007 17:40:58 +0000

A google search for "circularpetitio principii" or even just "circularpetitio" returns no results. Is that begging the question? Since logic was supposedly invented by the greeks, shouldn't we be using greek terminology rather than latin? As an added bonus, the former is not a dead language! One of my favorite bloggers used to be Ilkka Kokkarinen of Sixteen Volts (after his university got wind of it he shut it down and switched to the Fourth Check Raise) had a good post on how logical fallacies resemble many perfectly good arguments.

By: Acksiom

Acksiom — Fri, 27 Apr 2007 15:40:04 +0000

“In each case, the argument type is shown to match structurally arguments which are widely accepted. This suggests that it is not the form of the arguments as such that is problematic but rather something about the content of those examples with which they are typically justified.”

Wait — isn’t that itself an example of the fallacy of the Appeal to Belief?

Such structural matching rather suggests to me that these widely accepted arguments are merely similarly fallacious, and that instead it is indeed their abstract form that is problematic, and their specific content which is being relied upon to conceal their lack of validity.