The logical fallacies thread

[chefencer]

Originally Posted by rcmatthews

Because most people are stupid. Therefore, if most people belive something, it doesn't increase the probability that it is a truth.

I'll drink to that...

[Inquartata]

Originally Posted by jBirch

"The more popular a belief the more likely it is to be true" is a true statement.

Ah, no. It is not.

This is an appeal to statistics which takes as base that the more often something is observed to be true 'the more likely it is to be true'.

We are not talking about observations of fact, we are talking about the beliefs of people.

Many people believe in ghosts. Does this make any sort of case for the existence of ghosts? No.

Many people belive in God, Allah, Jehovah, an afterlife, etc. Does the widespread nature of this view make any sort of case for the actual existence of any of these? No.

We are talking about opinions, not facts.

Further, the standard distinction between argumentum ad numerum and argumentum ad populum is that populum appeals to the general area (ie// it is true because the people engaging in the discourse assert it is true) while ad numerum appeals to the statistics of a broader population (lots of people believe in God, therefor, God must exist).

Regardless of the semantical difference, the fallacy argumentum ad numerum is that because a belief is widely held to be true it is therefor absolutely true.

James.

ARGUMENTUM AD NUMERAM

"This fallacy is closely related to the argumentum ad populum. It consists of asserting that the more people who support or believe a proposition, the more likely it is that that proposition is correct. For example:

'The vast majority of people in this country believe that capital punishment has a noticeable deterrent effect. To suggest that it doesn't in the face of so much evidence is ridiculous.'

'All I'm saying is that thousands of people believe in pyramid power, so there must be something to it.'"

Note the wording: "more likely", and the absence of "absolutely".

ARGUMENTUM AD POPULAM

"This is known as Appealing to the Gallery, or Appealing to the People. You commit this fallacy if you attempt to win acceptance of an assertion by appealing to a large group of people. This form of fallacy is often characterized by emotive language. For example:

'Pornography must be banned. It is violence against women.'

'For thousands of years people have believed in Jesus and the Bible. This belief has had a great impact on their lives. What more evidence do you need that Jesus was the Son of God? Are you trying to tell those people that they are all mistaken fools?'"

And finally, the fallacy which most closely matches the statement in question:

FALLACY OF COMPOSITION

"The Fallacy of Composition is to conclude that a property shared by a number of individual items, is also shared by a collection of those items; or that a property of the parts of an object, must also be a property of the whole thing."

Ie, because one member of the class of Mexicans is "messy", all members of the class are messy. This is the suppressed premise in the statement "They should all go home ( because they are messy ).

[rcmatthews]

I think (because most people are stupid) that these fallacies are not necessarily fallacies, but arguing tools. Just because an argumentum ad populam is a logical fallacy doesn't make it an less of a persuasive tool, to most people.

[Inquartata]

That's why eternal vigilance is needed. The fallacies are so well understood because they are so appealing and come so naturally to most people's rhetoric. They work, and when they do they perpetuate error, so exposing them is an obligation for the logically minded...

[Epee_Pox]

An obligation for the logical, but a pleasure for the snarky.

Give me pleasure over obligation any day.

[Inquartata]

Obviously, you are not Japanese...

[TrainingDummy]

Why argue with them? It's the "logical fallacies" thread! Oh wait, you fence sabre, right Inquartata? THAT explains it!

[jBirch]

Inq,

Originally Posted by Inq

Ah, no. It is not.

Assertion without proof.

The statistical method for determining liklihood of truth rests entirely on the distribution of observation in a representative population. The more often an observation occurs, the more likely the underlying phenomenon is to be true.

Ie// if everyone observes ghosts then the probability that ghosts exist is high. If few people observe ghosts then the probability that ghosts exist is low.

You're arguing the opposite: that if few people observe ghosts then the probability of their existance is high while if many people observe ghosts their probability is low. This is patently absurd.

Noodle is the one who actually made a valid observation of the problem, that the sample of everyone is biased toward certain beliefs and I accept that when we apply the argument to certain exceptions, we need to take care to take a truly unbiased sample. But still, if you take a poll amongst an unbiased sample, the more prevelent a belief in the sample the more likely to be true that belief is.

Originally Posted by Inquartata

That's why eternal vigilance is needed. The fallacies are so well understood because they are so appealing and come so naturally to most people's rhetoric. They work, and when they do they perpetuate error, so exposing them is an obligation for the logically minded...

Actually, Aristotle meant for them to be used in identifying weakness in one's own argument, not in the arguments of others (which essentially just turns them into ad hominem tools).

His comments on Persuasion - Ethos, Pathos, Logos - is more applicable to general rhetorical style with fallacies being used to break down an opponent's appeal to ethos.

Most discussions aren't really a search for truth at any rate, but the ideological struggle for belief.

James.

[jBirch]

Originally Posted by Inquartata

ARGUMENTUM AD NUMERAM

"This fallacy is closely related to the argumentum ad populum. It consists of asserting that the more people who support or believe a proposition, the more likely it is that that proposition is correct. For example:

'The vast majority of people in this country believe that capital punishment has a noticeable deterrent effect. To suggest that it doesn't in the face of so much evidence is ridiculous.'

'All I'm saying is that thousands of people believe in pyramid power, so there must be something to it.'"

Note the wording: "more likely", and the absence of "absolutely".

Well then, your definitional source is wrong.

ARGUMENTUM AD NUMERAM (argument or appeal to numbers)
This fallacy is the attempt to prove something by showing how many people think that it's true. But no matter how many people believe something, that doesn't necessarily make it true or right.

Originally Posted by Wikipedia

Although Argumentum ad populum makes few concessions about the relationship between truth and widespread acceptence, according to the Law of large numbers, as the sample population gets bigger, truth becomes more likely.

James.

[mrbiggs]

How about the fallacy of watching Fox News?

[Inquartata]

Originally Posted by TrainingDummy

Why argue with them? It's the "logical fallacies" thread! Oh wait, you fence sabre, right Inquartata? THAT explains it!

Why argue with who, the Japanese?

[Inquartata]

Originally Posted by jBirch

Assertion without proof.

Not a fallacy. Just bad form.

However, inasmuch as you made the original assertion, the burden of proof lies upon you, not me. Trying to shift it to me IS fallacious. ( AND bad form. )

The statistical method for determining liklihood of truth rests entirely on the distribution of observation in a representative population. The more often an observation occurs, the more likely the underlying phenomenon is to be true.

Ah...no. Statistics do not determine "truth", they only support conclusions to a given degree of probability. That requires analysis, not mere number-crunching.

If I tell a lie a thousand times and the truth only once, the lie does not become the truth because of the frequency of its occurrence.

Ie// if everyone observes ghosts then the probability that ghosts exist is high. If few people observe ghosts then the probability that ghosts exist is low.

Actually, the correlation between the observations and the "truth" is zero there. Truth does not depend on how many people affirm it. It can be truth even if no one affirms it, and it can be howling error if everyone affirms it.

You're arguing the opposite: that if few people observe ghosts then the probability of their existance is high while if many people observe ghosts their probability is low. This is patently absurd.

No. I'm arguing that in both cases the correlation between the number of people how report seeing ghosts and the actual, demonstrable existence of ghosts is zero.

But still, if you take a poll amongst an unbiased sample, the more prevelent a belief in the sample the more likely to be true that belief is.

This is why logical fallacies are so hard to kill off: they are so superficially attractive to the human mind. They just SEEM so darned rational and appealing.

That statement of yours is the very embodiment of the fallacy we're discussing. But I'll bet you'll never be convinced of it...

Actually, Aristotle meant for them to be used in identifying weakness in one's own argument, not in the arguments of others (which essentially just turns them into ad hominem tools).

Eh...Aristotle's discussion and classification of the inductive fallacies occurs in a work which translates to "Sophistical Refutations". You assert that he meant to refute his OWN arguments?

Ari was concerned with debate, argument, rhetoric and winning arguments the better to bring truth to victory over error. Consider this passage:

"As to the number, then, and kind of sources whence fallacies arise in discussion, and how we are to show that our opponent is committing a fallacy and make him utter paradoxes; moreover, by the use of what materials solescism is brought about, and how to question and what is the way to arrange the questions; moreover, as to the question what use is served by all arguments of this kind, and concerning the answerer’s part, both as a whole in general, and in particular how to solve arguments and solecisms-on all these things let the foregoing discussion suffice. It remains to recall our original proposal and to bring our discussion to a close with a few words upon it."

That is not the only passage in which he mentions showing the arguments of opponents to be fallacious.

He says that they ought not be used spitefully or with malice, not to make others seem to be buffoons, only to expose error and make them see the truth. He does not say they should be used only on one's own arguments, and he does not say that they constitute personal insults.

Most discussions aren't really a search for truth at any rate, but the ideological struggle for belief.

James.

Boy, ain't THAT the truth!

[Inquartata]

Originally Posted by jBirch

Well then, your definitional source is wrong.

"Assertion without proof".

Seriously, you're using Wikipedia to counter my source?

[Jason]

Originally Posted by Inquartata

"Assertion without proof".

Seriously, you're using Wikipedia to counter my source?

But EVERYBODY uses Wikipedia!

[Neil]

I don't see the point of continuously quoting these fallacies. It's obvious (if you think about it for a second) that it's wrong to extrapolate the behaviour of one person to an entire group that they happen to be part of; you don't need to learn that it's an example of the *whatever* fallacy. We don't need unnecessary jargon for every commonly-encountered piece of dodgy reasoning.

Another thing that annoys me is that people often use these fallacies as a type of point-scoring. Instead of engaging in constructive argument with the other person, they point out a fallacy and then act all smug - on a par with criticising their grammar/typos.

[Inquartata]

Meh, when they invent that time machine maybe you can go back and scold old Aristotle for his obvious shortcomings.

[Dr. Pfleschbach]

[quote=Neil
Another thing that annoys me is that people often use these fallacies as a type of point-scoring. Instead of engaging in constructive argument with the other person, they point out a fallacy and then act all smug - on a par with criticising their grammar/typos.[/QUOTE]

You must be referring to Inquartata. He does that because he has no constructive argument to contribute.

[jBirch]

Originally Posted by Inquartata

Not a fallacy. Just bad form.

However, inasmuch as you made the original assertion, the burden of proof lies upon you, not me. Trying to shift it to me IS fallacious. ( AND bad form. )

No, actually, it was your original assertion that needs to be proven. That the more often something is observed to be true has no bearing on whether it is more likely to be true or not.

Ah...no. Statistics do not determine "truth", they only support conclusions to a given degree of probability. That requires analysis, not mere number-crunching.

Right. And the more statistical points that support a certain conclusion, the more likely that conclusion is to be the correct one. When P = 1, then you have an absolute truth. The point of the ad numerum fallacy is that P ~= 1.

If I tell a lie a thousand times and the truth only once, the lie does not become the truth because of the frequency of its occurrence.

No, but if everyone tells the same lie a thousand times and one guy tells the truth once, the lie is more probably truth then the actual truth is. I didn't say the lie WAS truth, merely that it was more probably true then the actual truth (since we have no other way to determine truth in this case).

Actually, the correlation between the observations and the "truth" is zero there. Truth does not depend on how many people affirm it. It can be truth even if no one affirms it, and it can be howling error if everyone affirms it.

Right, but it is less likely to be true if no one affirms it and more likely to be true if everyone does.

No. I'm arguing that in both cases the correlation between the number of people how report seeing ghosts and the actual, demonstrable existence of ghosts is zero.

So then, how does one prove the existence of ghosts?

This is why logical fallacies are so hard to kill off: they are so superficially attractive to the human mind. They just SEEM so darned rational and appealing.

Yeah, they do, don't they?

That statement of yours is the very embodiment of the fallacy we're discussing. But I'll bet you'll never be convinced of it...

I certainly am open to being convinced. So far you've merely engaged in hand waving and counter-factual argument. Give me any example where the increased observation of an event does not go directly to its probability of existing.

Eh...Aristotle's discussion and classification of the inductive fallacies occurs in a work which translates to "Sophistical Refutations". You assert that he meant to refute his OWN arguments?

Ari was concerned with debate, argument, rhetoric and winning arguments the better to bring truth to victory over error. Consider this passage:

"As to the number, then, and kind of sources whence fallacies arise in discussion, and how we are to show that our opponent is committing a fallacy and make him utter paradoxes; moreover, by the use of what materials solescism is brought about, and how to question and what is the way to arrange the questions; moreover, as to the question what use is served by all arguments of this kind, and concerning the answerer’s part, both as a whole in general, and in particular how to solve arguments and solecisms-on all these things let the foregoing discussion suffice. It remains to recall our original proposal and to bring our discussion to a close with a few words upon it."

That is not the only passage in which he mentions showing the arguments of opponents to be fallacious.

He says that they ought not be used spitefully or with malice, not to make others seem to be buffoons, only to expose error and make them see the truth. He does not say they should be used only on one's own arguments, and he does not say that they constitute personal insults.

When I was studyiing them in university, the professor interpreted "not spitefully or with malice, not to make others seem to be buffoons" to be directing one to use fallacies to construct one's own arguments in a more efficient manner in order to expose the weakness in your opponent's arguments. This was to be done to give your own points more suasion in the debate, not to give your opponent less.

You keep committing the same fallacy over and over here. I am not saying that a certain number of observations pointing to a conclusion cross a threshold and make that conclusion true. I am saying that the more observations supporting a conclusion, the more likely to be true that conclusion is. Since we are dealing with probability it is important to note that we are talking about probability of truth, not the arbitration of absolute truth (to come back to the original point I made about your definition of ad numerum and ad populum).

Originally Posted by Inquartata

"Assertion without proof".

Seriously, you're using Wikipedia to counter my source?

Since you've posted no source but your own opinion, yeah. *grin* It's called an "appeal to authority". Goes to Ethos. Got a better one?

James.