Author Topic: Logical Fallacy Thread?  (Read 1447 times)

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Online The Latinist

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Re: Logical Fallacy Thread?
« Reply #30 on: September 05, 2018, 07:17:56 PM »
Here’s a syllogism for you, CarbShark:

All cars are green.
My Volkswagen is a car.
Therefore, my Volkswagen is green.

The form of the above syllogism is entirely valid.  It’s a type of argument called modus ponens, and it obeys all of the rules of formal deductive reasoning.  It is therefore formally valid.

But of course the conclusion is wrong, because the premise that all cars are green is incorrect.  That does not in any way invalidate the logic of the argument, however; its form is still 100% correct.  There is no formal fallacy there at all.  If I changed the word “green” in both premise and conclusion to “vehicle,” the form of the argument would not have changed, but the correctness of the conclusion would have.  That’s because the incorrectness of the conclusion was not due to the form of the argument, but to the faulty premise.  The argument is therefore formally sound in both cases.

It’s the same with the argument from authority.  If the premise of my argument were “My dad says all cars are green,” the argument would still have the same form.  The conclusion would be faulty because the (unstated) assumption that my dad’s assertion about cars is necessarily correct is fallacious.  But the argument in form remains modus ponens, and it remains formally correct.

So what kind of fallacy is that?  It’s not a formal fallacy because it has nothing to do with the form of he argument.  It’s an informal fallacy.  Get it?  Formal = relating to form; informal = not relating to form.  An argument can be formally valid even if it is riddled with informal fallacies.

Do you understand the difference now, and can you see that the one has nothing to do with the other?
I would like to propose...that...it is undesirable to believe in a proposition when there is no ground whatever for supposing it true. — Bertrand Russell

Online CarbShark

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Re: Logical Fallacy Thread?
« Reply #31 on: September 05, 2018, 07:55:36 PM »
I also want to point out that the concept of Appeal to Authority is the original fallacy. There was no modifier. There was no "appeal to false authority." That is a fairly recent modifier that's been added to the lexicon.

Just to be clear, what I am saying is:

Authority is not a logical value. Authority may be valid concept in other avenues of critical thinking and learning but in and of itself if offers no proof and is always fallacious.

Fallacious does not mean false. It doesn't even mean unlikely, and the conclusion of a fallacious argument may very well be true, and in many cases will be true, but the form of the argument:

x is true because y says it is true

is always fallacious.

Similarly

x is false because y says it's true

Always fallacious.

« Last Edit: September 05, 2018, 08:06:03 PM by CarbShark »
and Donald Trump is President of the United States.

I'm not a doctor, I'm just someone who has done a ton of research into diet and nutrition.

Online CarbShark

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Re: Logical Fallacy Thread?
« Reply #32 on: September 05, 2018, 08:09:01 PM »
Here’s a syllogism for you, CarbShark:

All cars are green.
My Volkswagen is a car.
Therefore, my Volkswagen is green.x

The form of the above syllogism is entirely valid.  It’s a type of argument called modus ponens, and it obeys all of the rules of formal deductive reasoning.  It is therefore formally valid.

But of course the conclusion is wrong, because the premise that all cars are green is incorrect.  That does not in any way invalidate the logic of the argument, however; its form is still 100% correct.  There is no formal fallacy there at all.  If I changed the word “green” in both premise and conclusion to “vehicle,” the form of the argument would not have changed, but the correctness of the conclusion would have.  That’s because the incorrectness of the conclusion was not due to the form of the argument, but to the faulty premise.  The argument is therefore formally sound in both cases.

It’s the same with the argument from authority.  If the premise of my argument were “My dad says all cars are green,” the argument would still have the same form.  The conclusion would be faulty because the (unstated) assumption that my dad’s assertion about cars is necessarily correct is fallacious.  But the argument in form remains modus ponens, and it remains formally correct.

So what kind of fallacy is that?  It’s not a formal fallacy because it has nothing to do with the form of he argument.  It’s an informal fallacy.  Get it?  Formal = relating to form; informal = not relating to form.  An argument can be formally valid even if it is riddled with informal fallacies.

Do you understand the difference now, and can you see that the one has nothing to do with the other?

That is an argument from a false premise. That is a logical fallacy. That syllogism is invalid.

 (I hope this isn't a double post)
and Donald Trump is President of the United States.

I'm not a doctor, I'm just someone who has done a ton of research into diet and nutrition.

Online The Latinist

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Re: Logical Fallacy Thread?
« Reply #33 on: September 05, 2018, 09:28:11 PM »
It is not formally invalid, though. False premise is an informal fallacy, and does not invalidate the argument.  You seem to fail to appreciate the distinction.
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Offline John Albert

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Re: Logical Fallacy Thread?
« Reply #34 on: September 06, 2018, 02:56:49 PM »
Please, click these links and read them: (1, 2, 3, 4, 5, 6, 7).

They explain the appeal to authority fallacy in sufficient detail. That should clear up any misunderstandings about the informal fallacy.

I'll be happy to, but you first. I asked for examples of appeals to authority that are not fallacious arguments.

I already gave you an example of an appeal to authority that is not a logical fallacy. Besides, I asked you to look at those links first.

And it's really necessary for you to look at those links first, because they explain the meaning of the "appeal to authority" fallacy. Until you learn that, you won't be able to accurately judge whether a given example is fallacious, and will just remain trapped in a catch-22 of your own ignorance.
« Last Edit: September 06, 2018, 02:59:14 PM by John Albert »

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Re: Logical Fallacy Thread?
« Reply #35 on: September 06, 2018, 03:24:14 PM »
Please, click these links and read them: (1, 2, 3, 4, 5, 6, 7).

They explain the appeal to authority fallacy in sufficient detail. That should clear up any misunderstandings about the informal fallacy.

I'll be happy to, but you first. I asked for examples of appeals to authority that are not fallacious arguments.

I already gave you an example of an appeal to authority that is not a logical fallacy. Besides, I asked you to look at those links first.

And it's really necessary for you to look at those links first, because they explain the meaning of the "appeal to authority" fallacy. Until you learn that, you won't be able to accurately judge whether a given example is fallacious, and will just remain trapped in a catch-22 of your own ignorance.

I looked at them and I have two takeaways.

First, you don't know what an authoritative source is, second you probably didn't read them yourself, or if you did, didn't understand them or just remember the part you think supports your position.

Still waiting for an example (Not sure which one of your posts you imagine was an non-fallacious argument from authority, but I'd like to see it.
and Donald Trump is President of the United States.

I'm not a doctor, I'm just someone who has done a ton of research into diet and nutrition.

Offline John Albert

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Re: Logical Fallacy Thread?
« Reply #36 on: September 06, 2018, 05:02:59 PM »
First, you don't know what an authoritative source is

Okay, that's just a weak ad hominem fallacy.


second you probably didn't read them yourself

Yes, I did. Every single one of them. That's why I posted them as explanations of what "appeal to authority" means.


or if you did, didn't understand them or just remember the part you think supports your position.

No, if you go back and read what I said, you'll find that it's in fairly exact accordance with every one of those descriptions.

In fact, Steven Novella has addressed this fallacy a number of times on the SGU podcast and in his blog, and he's said essentially the same thing I said.

There, that's an appeal to authority right there.

Is it a fallacious one?  I'd say it's not a fallacy because I'm not arguing that I'm right because Dr. Novella's definition is the same as mine; I'm just citing him as an authority. As a recognized leader in the scientific skepticism movement who often writes and speaks on the subject of logical fallacies, I'd expect you to agree that he's a legit authority. If you don't agree, then we could have a further discussion about what would constitute an acceptable authority. That's the proper, reasonable way to appeal to authority in a respectful discourse.

Meanwhile, The Latinist has patiently been trying to explain to you the concept of formal logic. Yet in your quest to maintain the illusion of your own eminent correctness, you just keep talking right past his points to reiterate the same irrelevancies. 

Clearly, you're not here to learn or to have a civil discussion with other people. You're only interested in lecturing and pontificating on subjects you don't really know very much about. As such, you're not only a chore to have a conversation with, but you're unwilling to admit when you're wrong or mistaken.

That makes you unteachable, a lost cause. I can see nothing more can be gained by continuing this conversation.
« Last Edit: September 06, 2018, 05:05:40 PM by John Albert »

Offline Desert Fox

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Re: Logical Fallacy Thread?
« Reply #37 on: September 06, 2018, 06:34:39 PM »
Quantum mechanics is almost impossible for many posters here to understand. . . Me included.
In many cases the best we can do as far as arguing something in quantum mechanics is to quote an authority.
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Online CarbShark

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Re: Logical Fallacy Thread?
« Reply #38 on: September 06, 2018, 07:14:43 PM »
First, you don't know what an authoritative source is

Okay, that's just a weak ad hominem fallacy.

 
Quote
second you probably didn't read them yourself
Yes, I did. Every single one of them. That's why I posted them as explanations of what "appeal to authority" means.

OK, then you probably don't understand them because some contradict what you've said and several contradict each other.
Quote

or if you did, didn't understand them or just remember the part you think supports your position.

No, if you go back and read what I said, you'll find that it's in fairly exact accordance with every one of those descriptions.
Impossible, since they are not in accordance with each other on the exact issue.
Quote

In fact, Steven Novella has addressed this fallacy a number of times on the SGU podcast and in his blog, and he's said essentially the same thing I said.
There, that's an appeal to authority right there.

Is it a fallacious one?  I'd say it's not a fallacy because I'm not arguing that I'm right because Dr. Novella's definition is the same as mine; I'm just citing him as an authority.

Well that's wrong, on several levels. First, yes, it is an appeal to authority and yes it is a fallacy, because it's being used to support your claim.

We're actually not arguing if you are right. We are arguing over whether and appeal to authority is always a logical fallacy. You are using an appeal to authority (Novella) to support the proposition that sometimes appeals to authority are not always logical fallacies.

The fact that his definition is the same as yours is irrelevant. The idea that you are "just citing him as an authority." does not change the context that it is an appeal to authority.

Quote
As a recognized leader in the scientific skepticism movement who often writes and speaks on the subject of logical fallacies, I'd expect you to agree that he's a legit authority. If you don't agree, then we could have a further discussion about what would constitute an acceptable authority. That's the proper, reasonable way to appeal to authority in a respectful discourse.

He is a legitimate authority.  Yes.

An appeal to a legitimate authority is an appeal to an authority and is a logical fallacy.

(Actually, an appeal to an authority who is not a legitimate authority is not an appeal to authority, it's a non-sequitur.)


Quote
Meanwhile, The Latinist has patiently been trying to explain to you the concept of formal logic. Yet in your quest to maintain the illusion of your own eminent correctness, you just keep talking right past his points to reiterate the same irrelevancies. 

Yeah, I'll respond to that appropriately. For now, as I said, I see I've made a mistake and I'll explain.

 
and Donald Trump is President of the United States.

I'm not a doctor, I'm just someone who has done a ton of research into diet and nutrition.

Offline jt512

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Logical Fallacy Thread?
« Reply #39 on: September 07, 2018, 05:16:42 PM »
Please, click these links and read them: (1, 2, 3, 4, 5, 6, 7).

They explain the appeal to authority fallacy in sufficient detail. That should clear up any misunderstandings about the informal fallacy.

Ironically, the authorities to which you appeal disagree on when an appeal to authority is fallacious (as CS pointed out).  And one explicitly states that there is no consensus:

„Historically, opinion on the appeal to authority has been divided: it is listed as a valid argument as often as a fallacious argument in various sources,[4] with some holding that it is a strong argument[5][6][7] which "has a legitimate force",[8] and others that it is weak or an outright fallacy[9][10][11][12] where, on a conflict of facts, "mere appeal to authority alone had better be avoided".[13]“

Quote
As for formal logic, appeals to authority are irrelevant because formal logic does not address the veracity of premises; formal logic only deals with the validity of the logical operations in a syllogism.

One of your own sources contradicts you, stating that the argument from authority is „always deductively fallacious.“

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« Last Edit: September 07, 2018, 05:28:42 PM by jt512 »
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Offline John Albert

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Re: Logical Fallacy Thread?
« Reply #40 on: September 09, 2018, 12:52:03 PM »
Please, click these links and read them: (1, 2, 3, 4, 5, 6, 7).

They explain the appeal to authority fallacy in sufficient detail. That should clear up any misunderstandings about the informal fallacy.

Ironically, the authorities to which you appeal disagree on when an appeal to authority is fallacious (as CS pointed out).  And one explicitly states that there is no consensus:

„Historically, opinion on the appeal to authority has been divided: it is listed as a valid argument as often as a fallacious argument in various sources,[4] with some holding that it is a strong argument[5][6][7] which "has a legitimate force",[8] and others that it is weak or an outright fallacy[9][10][11][12] where, on a conflict of facts, "mere appeal to authority alone had better be avoided".[13]“

Of course they disagree, because there is no universal consensus as to exactly when an appeal to authority is fallacious. It's determined on a case-by-case basis.

How do you reckon this is my problem?


Quote
As for formal logic, appeals to authority are irrelevant because formal logic does not address the veracity of premises; formal logic only deals with the validity of the logical operations in a syllogism.

One of your own sources contradicts you, stating that the argument from authority is „always deductively fallacious.“

Yeah, it's always fallacious when used as a basis for deductive reasoning. (ie. "x is true because y said it") So what?

That doesn't mean it's a formal fallacy. By definition, formal fallacies identify specific errors in formal logic. They don't deal at all with the veracity of premises.
« Last Edit: September 09, 2018, 01:11:03 PM by John Albert »

Offline John Albert

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Re: Logical Fallacy Thread?
« Reply #41 on: September 09, 2018, 01:04:47 PM »
OK, then you probably don't understand them because some contradict what you've said and several contradict each other.

Not really. They don't contradict each other on the major features. They all state that citing an authority is not necessarily a fallacy. It's only a fallacy under two conditions: when the authority is illegitimate, and/or when one argues that the premise is true because the authority said it.


Quote
In fact, Steven Novella has addressed this fallacy a number of times on the SGU podcast and in his blog, and he's said essentially the same thing I said.
There, that's an appeal to authority right there.

Is it a fallacious one?  I'd say it's not a fallacy because I'm not arguing that I'm right because Dr. Novella's definition is the same as mine; I'm just citing him as an authority.

Well that's wrong, on several levels. First, yes, it is an appeal to authority and yes it is a fallacy, because it's being used to support your claim.
We're actually not arguing if you are right. We are arguing over whether and appeal to authority is always a logical fallacy. You are using an appeal to authority (Novella) to support the proposition that sometimes appeals to authority are not always logical fallacies.

The fact that his definition is the same as yours is irrelevant. The idea that you are "just citing him as an authority." does not change the context that it is an appeal to authority.

No, you're wrong. If we both agree that Steve Novella is a legit authority on the subject, then it's not a fallacy.

You obviously don't understand what an appeal to authority means. Which is not surprising given the way you tend to frame your arguments on other subjects, especially health and nutrition. You often cite known crackpots as authorities, and dismiss legitimate authorities with flimsy conspiracy theories.


He is a legitimate authority.  Yes.

An appeal to a legitimate authority is an appeal to an authority and is a logical fallacy.

Not always. Go reread the definition of the fallacy/


(Actually, an appeal to an authority who is not a legitimate authority is not an appeal to authority, it's a non-sequitur.)

It's an attribution problem, not a non-sequitur. You obviously don't understand what a non-sequitur is, either. 

Offline RubyDuckman

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Re: Logical Fallacy Thread?
« Reply #42 on: September 10, 2018, 12:49:27 PM »
RubyDuckman: I do not believe I used the term “sound,” and I am pretty sure I used the term “valid” correctly everywhere I used it.
The quote in question

Quote
Of course the conclusion is not necessarily true, because the the premises are not valid. They contain an argument from false authority.


In formal logic,  the term "valid" refers to the argument,  not the truth of the premises.

Quote
But that has nothing whatsoever to do with the form of the argument, which is sound.  That's why such fallacies are called informal.


The form of the argument is valid but it is not sound , because the premises are false.



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