TUTORIAL - Informal Logical Fallacies

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Sentzeu
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Post by Sentzeu »

It should be a fallacy... "appeal to ignorance of big words" or something like that
I don't agree. Even if it’s needlessly complex, almost too the point of making it incomprehensible, it would still hold true if the logic was sound. Making an argument needlessly complex being bad is a matter of etiquette.

However an argument based on the notion that an opponents wording are of such obfuscated a nature that they cannot hold true would be wrong.

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gnome
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Re: TUTORIAL - Informal Logical Fallacies

Post by gnome »

Abdul Alhazred wrote:
Pyrrho wrote: tu quoque or "You're Another" - an argument is answered by responding with the same or similar arguments which are irrelevant to the conclusion. Example: “Yes, I use foul language, but so do you.”
There is a variant to this common in politics. I call it "pre-emptive you're another". This consists of falsely accusing your opponent of the malfeasance you yourself are doing. That way, when your opponent accuses you, it looks like a lame "you're another".
Ahh here's the rub... in politics the "you're another" argument is often relevant to the conclusion, often unstated, which is "... therefore vote for me instead." ... an invalid conclusion if you are guilty of the same malfeasance you are accusing your opponent of.

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Pyrrho
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Post by Pyrrho »

Chaos wrote:
"Appeal to Authority" - committed when one attempts to support a conclusion by citing a person or persons who already assert the same conclusion, but who are not qualified to assert that conclusion. Often occurs when a person claims to be an authority when they are not. Note: if the authority cited is a reliable, qualified authority concerning the conclusion, this can be a valid argument. The fallacy lies in citing an authority that is not reliably qualified to assert the conclusion. Example: “Joe the plumber says that ghosts are electromagnetic plasma produced by the spirit.”
I have a problem with that fallacy. How exactly is it decided who is
a reliable, qualified authority concerning the conclusion?

For example - and I´m talking strictly as advocatus diaboli here -, are creationist biologists (and I guess there are some) still reliable, qualified authorities on the creation vs. evolution controversy? If so, why are you still so sure they are wrong? Why do you not accept what they say? If they are not authorities, what makes them different from evolutionist authorities? Why do you believe these, but not creationists?

Appeal to authority is a fallacy, all right, but that exception you make does not hold up to close scrutiny.
The actual text in my source book reads as follows:

Code: Select all

It is not infrequent for one to attempt to support a conclusion by citing some person(s) who asserts the conclusion. This type of argument has the form (where p represents some statement):

A asserts p.
Therefore p.

Just because A asserts p it does not follow that p is true. However, if A is a reliable authority concerning p, that A asserts p is good grounds for concluding that p. In other words:

A is a reliable authority concerning p.
A asserts p.
Therefore p.

is a correct argument pattern. How can we determine that A is a reliable authority in a field? The answer is simple: If a very high percentage of the assertions he makes with respect to the field in question are true, then he is an authority in the field in question.
The flash of light you saw in the sky was not a UFO. Swamp gas from a weather balloon was trapped in a thermal pocket and reflected the light from Venus.

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ceptimus
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Post by ceptimus »

People (skeptics even) often say, "Absence of evidence is not evidence of absence."

Sounds neat, but when you think about it, it's wrong. What they mean is, "Absence of evidence is not proof of absence."

If absence of evidence were not evidence of absence, we should all continue to believe in the existence of Bigfoot, lake monsters and the like.

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DrMatt
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Post by DrMatt »

Sundog wrote:I've always wondered why "appeal to pity" is listed as a logical fallacy. It would be, of course, were someone to actually use it to try to justify the logic of a position. By far the more common usage, it seems to me, is an appeal to "put aside" the train of logic for a moment and balance it against certain consequences.

Used this way it isn't a logical fallacy at all, and it isn't reasonable to dismiss it on this pretext. For example:

Bob lays out a very logical argument for Bush's rewriting of the regulations pertaining to overtime.

Alice says, "But millions of people rely on this extra money to get by!"

Bob rejects Alice's statement, citing appeal to pity. He's wrong; Alice isn't attempting to refute Bob's logic, she's simply saying that logic is not the only thing to be taken into account when making decisions like this.
That would be a misapplication of Appeal To Pity. Appeal to Pity occurs when the argument attempts to call a sentence S true because the person asserting S is pityable.

E.g. "Laetrile must be a good drug, after all it's for cancer and cancer patients shouldn't be denied any treatments!"

In fact, whether or not cancer patients should be denied any treatments has no bearing at all on the medical value of Laetrile. Laetrile turns out to be cyanide derived from peach pits.
Grayman wrote:If masturbation led to homosexuality you'd think by now I'd at least have better fashion sense.

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DrMatt
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Post by DrMatt »

ceptimus wrote:People (skeptics even) often say, "Absence of evidence is not evidence of absence."

Sounds neat, but when you think about it, it's wrong. What they mean is, "Absence of evidence is not proof of absence."

If absence of evidence were not evidence of absence, we should all continue to believe in the existence of Bigfoot, lake monsters and the like.
I'd like to emphasize this, as it is quite correct. Absence of evidence for sentence S asserting the existence of X very much IS evidence of the nonexistence of X. We call this principle Occam's Razor, and it helps save us from spinning our wheels endlessly on blind alleys (and mixed metaphors).
Grayman wrote:If masturbation led to homosexuality you'd think by now I'd at least have better fashion sense.