Argument

[JetLeg]

Hello everyone. What do you think of the following argument :

"
Drunk people make lots of bad arguments
X is a an argument said by a drunk person
Thus, (by inductive logic) it is probable that X is a bad argument.
".



The analogy here is that a person is like a box with a certain percentage of black pebbles. If it is known that one person usually makes bad arguments when he is drunk, this is analogous to a box having a higher percentage of black pebbles than white pebbles. You can predict that there is a higher probability of drawing black pebbles than white ones - and you can predict in the same way that X is prbably a bad argument. And so, you can dismiss the argument without looking at it, and ad hominem is justified up to a certain probability.

[babbits]

No, the truth value is undetermined. Even a stopped watch can be right once or twice a day.

[JetLeg]

No, the truth value is undetermined. Even a stopped watch can be right once or twice a day.

I agree that it can. That is why I do not say that the argument of a drunk person is neccessarily wrong, I just say that it is more probably wrong than right.

[arthwollipot]

It depends. Is the person drunk at the time he makes the argument, or is he generally known as a drunkard. In the former case I would say that it is (more or less) valid, but a weak argument. In the second, it is an ad hominem.

It also depends on whether you accept your first proposition. I've made many good arguments while drunk.

[Cavemonster]

Your first condition needs to be stronger to support your conclusion.

What counts as lots of bad arguments? Let's say an average person makes 1000 arguments over a day, and a for a drunk person, 200 of those are bad.

200 is certainly a lot, but your odds of getting a bad argument are still only 1/5.

I've had this same thought about right-wing radio. I've come to think of it more as a cost/benefit analysis than the pure likelyhood of truth.

A Rush Limbaugh or a will fill up the air with a huge amount of claims. Once you sort out from the work salad and the pure rhetoric what's actually being claimed, a good number of obviously false and poorly reasoned things jump out.

The question is, whether it is worth one's time to examine all these claims for truth. It is very likely that some of his claims are true, no one has a reason to lie with every word.

In the end though, when a source proves often unreliable, I ask myself, not if everything they say is likely to be false, but if those true things they could possibly say could be obtained from another, more reliable source.

In the case of right-wing radio, there are many more reliable sources where I can check the voting history of senate members for instance.

[Hokulele]

In vino veritas.

[rocketdodger]

Hello everyone. What do you think of the following argument :

"
Drunk people make lots of bad arguments
X is a an argument said by a drunk person
Thus, (by inductive logic) it is probable that X is a bad argument.
".


You need to know the numbers to make such an argument.

If the total number of bad arguments from drunk people is greater than the total number of good ones, then your conclusion is sound. If not, not.

In other words, you have to qualify "lots."

[KingMerv00]

To be fair to JetLeg, we make estimations like that all the time. For example, a statement from Kent Hovind about evolution is almost certainly wrong.

It isn't a logical certainty that Hovind is wrong but it is a good rule of thumb to consider the source a little.

[JetLeg]

You need to know the numbers to make such an argument.

If the total number of bad arguments from drunk people is greater than the total number of good ones, then your conclusion is sound. If not, not.

In other words, you have to qualify "lots."

I am interested not in the soundness, but in the validity of the argument.

To be fair to JetLeg, we make estimations like that all the time. For example, a statement from Kent Hovind about evolution is almost certainly wrong.

It isn't a logical certainty that Hovind is wrong but it is a good rule of thumb to consider the source a little.


But I do feel that there is something illogical in my example.

Consider this : Let's say that I am asking you "Is the claim P more probably true or false"? You will reject the question, since you do not know what P is. But if I tell you "A drunk person thinks that P is true", is that infinitely-unspecific piece of information enough for you to decide P is probably false???

[KingMerv00]

Consider this : Let's say that I am asking you "Is the claim P more probably true or false"? You will reject the question, since you do not know what P is. But if I tell you "A drunk person thinks that P is true", is that infinitely-unspecific piece of information enough for you to decide P is probably false???

The way you phrased that, I’d say “no“.

I think part of the problem is that being drunk may have no connection to the belief or non-belief in P. The person in question may also believe in P while sober. In order to make any real statistical judgments on the validity, you have to find a way to connect beliefs with drunkenness.

In any event, the truth of any matter is never solely determined by the nature of the messenger. The only reason we consider the speaker when considering an argument is for pragmatic reasons. We do not have all day and all night to research every piddling little fact in every inconsequential conversation.

Out of curiosity, is this really about drunkenness or are you using it as a metaphor for something else?

[JetLeg]

The way you phrased that, I’d say “no“.


But it seems that the conclusion from the argument in the OP is yes.


I think part of the problem is that being drunk may have no connection to the belief or non-belief in P. The person in question may also believe in P while sober. In order to make any real statistical judgments on the validity, you have to find a way to connect beliefs with drunkenness.

In any event, the truth of any matter is never solely determined by the nature of the messenger. The only reason we consider the speaker when considering an argument is for pragmatic reasons. We do not have all day and all night to research every piddling little fact in every inconsequential conversation.

Out of curiosity, is this really about drunkenness or are you using it as a metaphor for something else?


No, this is not about drunkness, I just chose a drunk person as an example of a person that would probably say lots of wrong statements / invalid arguments. My issue is with the logic of the claim, not its soundness, so you can substitute "drunk" for Kirk Cameron if you feel like it. Can Kirk Cameron merely by saying "P is true" make the probability of P being false higher?

[Roboramma]

But I do feel that there is something illogical in my example.

Consider this : Let's say that I am asking you "Is the claim P more probably true or false"? You will reject the question, since you do not know what P is. But if I tell you "A drunk person thinks that P is true", is that infinitely-unspecific piece of information enough for you to decide P is probably false???If we're just talking about any particular statement, I don't think it's valid. Drunk people may not be the best judges of things, but usually they can still tell the difference between a table and a ferrari, and if a drunk person says, "this is a table", and believes it, I think he's probably right.

[JetLeg]

So where is the fallacy in the OP then?

[KingMerv00]

The fallacy is that it is an ad hominem.

[JetLeg]

What about the analogy of taking a pebble out of a box with black pebbles <-> sampling a statement from a person who is usually wrong?

[Cavemonster]

So where is the fallacy in the OP then?

Your initial statement claims that drunks make lots of bad arguments. This only tells us that some non-trivial number of "black pebbles" exist. It doesn't give us any information on the ratio of black pebbles to white ones.

Your conclusion, that a statement from a drunk is more likely to be false, would need information about this ratio to be validated. Essentially your conclusion only holds true if the black pebble outnumber the white ones, when we really don't have that information.

The premise statement doesn't really address the neccessary conditions of the conclusion.

[JetLeg]

Your initial statement claims that drunks make lots of bad arguments. This only tells us that some non-trivial number of "black pebbles" exist. It doesn't give us any information on the ratio of black pebbles to white ones.

Your conclusion, that a statement from a drunk is more likely to be false, would need information about this ratio to be validated. Essentially your conclusion only holds true if the black pebble outnumber the white ones, when we really don't have that information.

The premise statement doesn't really address the neccessary conditions of the conclusion.

I am interested in the logic of my argument. IF the initial statement is true, does the conclusion follow, or it is invalid logically?

So, even though you are technically correct, I am interested just in the question whether such a line of thinking is fallacious or not.

Replace "drunk" with a person about whom it is GIVEN that most of his statements are wrong. Does then the conclusion follow? Can one make such a statistical argument from the claims to the person?

[paximperium]

I am interested in the logic of my argument. IF the initial statement is true, does the conclusion follow, or it is invalid logically?

So, even though you are technically correct, I am interested just in the question whether such a line of thinking is fallacious or not.

Replace "drunk" with a person about whom it is GIVEN that most of his statements are wrong. Does then the conclusion follow? Can one make such a statistical argument from the claims to the person?
This is interesting. Simply because it isn't just an ad hominem but also a statement about the person's mental state. It is similar to stating that person X is wrong about Y because he is a schizophrenic/mentally disabled etc.

The issue as already mentioned is that we do not have enough information to clarufy if a statement is true based solely in that alone. Your drunkard may be totally mentally sound even if drunk.

The only logical fallacy I could find it is a potential hasty generalization fallacy.

[JetLeg]

What I am really unsure about is the following : lets say a person is really mentally disabled. Can we disqualify/ignore his statements or is this a logical fallacy?

[Cavemonster]

I am interested in the logic of my argument. IF the initial statement is true, does the conclusion follow, or it is invalid logically?

So, even though you are technically correct, I am interested just in the question whether such a line of thinking is fallacious or not.

Replace "drunk" with a person about whom it is GIVEN that most of his statements are wrong. Does then the conclusion follow? Can one make such a statistical argument from the claims to the person?

I'm not sure if you read my post.
Accepting that drunks are wrong "a lot" doesn't tell you whether "most of their statements are wrong"

We can look at these as though they were math.
X=wrong statements Y=correct statement

1) A certain group of people are wrong a lot ------------------------- Y=? X= [some nontrivial fraction of X+Y]>0
2) This person is a member of that group ---------------------------- y=Y x=X
3) A particular statement from this person is likely to be wrong --- x> (x+y)/2

You don't seem to see the difference between being wrong "a lot" and being "mostly wrong". "Mostly" gives us valid clues about likelihood, "a lot" does not.

If your initial statement was that "A certain group of people are [B]most often wrong" then that would translate to X>[by a significant degree](X+Y)/2 and your chain of logic would actually work.

you dig?

[paximperium]

What I am really unsure about is the following : lets say a person is really mentally disabled. Can we disqualify/ignore his statements or is this a logical fallacy?
It is a logical fallacy.

While you may have a lower threshold to not believe in such a person's statement or claim, it is not valid to automatically disqualify or ignore said statement.

Their mental status says nothing about the statement itself so it does not automatically discredit their statement, just brings it into more doubt.

Edit: What cavemonster said...I miss my Logic 101...

[JetLeg]

I'm not sure if you read my post.
Accepting that drunks are wrong "a lot" doesn't tell you whether "most of their statements are wrong"

We can look at these as though they were math.
X=wrong statements Y=correct statement

1) A certain group of people are wrong a lot ------------------------- Y=? X= [some nontrivial fraction of X+Y]>0
2) This person is a member of that group ---------------------------- y=Y x=X
3) A particular statement from this person is likely to be wrong --- x> (x+y)/2

You don't seem to see the difference between being wrong "a lot" and being "mostly wrong". "Mostly" gives us valid clues about likelihood, "a lot" does not.

If your initial statement was that "A certain group of people are [B]most often wrong" then that would translate to X>[by a significant degree](X+Y)/2 and your chain of logic would actually work.

you dig?



Al right, then I should have said "most". Mentally replace this.

[Cavemonster]

Al right, then I should have said "most". Mentally replace this.

Ok,
1) If you know that someone is a member of a group whose statements are actually and verifiably most often wrong
2) And a person from that group makes a statement
3)and I know nothing about that statement rather than it was made by a member of that group.

Then I can assume that the statement is likely to be wrong.

However, in practice, even the mentally disabled or right wing radio hosts who are both wrong about many things are not wrong in more than 50% of their statements as a group. Mentally disabled people I know make many more mundane statements about, say being hungry or tired or just daily functional stuff.

The other issue is that this only hold true when we have no other information about the group, the individual or the statement which is never the truth in practice.

[my_wan]

As a technicality the may be truth to some slanting of the odds, maybe. Yet a debate that is logically decidable has at least one member of the pair arguing falsely anyway. That 50% doesn't change for the sober party on account of the opponent being drunk. It just makes it easier to appear to win a losing debate.

[JetLeg]

The fallacy is that it is an ad hominem.

Ok, now prove that this argument is fallacious. Give an example of an absurdity that can be proven using this line of thinking.

[Egg]

Hello everyone. What do you think of the following argument :

"
Drunk people make lots of bad arguments
X is a an argument said by a drunk person
Thus, (by inductive logic) it is probable that X is a bad argument.
".



The analogy here is that a person is like a box with a certain percentage of black pebbles. If it is known that one person usually makes bad arguments when he is drunk, this is analogous to a box having a higher percentage of black pebbles than white pebbles. You can predict that there is a higher probability of drawing black pebbles than white ones - and you can predict in the same way that X is prbably a bad argument. And so, you can dismiss the argument without looking at it, and ad hominem is justified up to a certain probability.

It looks to me like there's a confusion happening between an argument and a statement.

If we're just looking at statements then the pebble analogy might be a reasonable manner to assess the probable truth of a statement assuming that we have no other information to go on. This is just a matter of probability and therefore not an ad hom.

For an argument (which is what the OP seems to be about) then we would assess the merit of the argument. To make any judgement on the argument based on the person arguing (even if previous argument had been poor) would be an ad hom fallacy.

[JetLeg]

It looks to me like there's a confusion happening between an argument and a statement.

If we're just looking at statements then the pebble analogy might be a reasonable manner to assess the probable truth of a statement assuming that we have no other information to go on. This is just a matter of probability and therefore not an ad hom.

For an argument (which is what the OP seems to be about) then we would assess the merit of the argument. To make any judgement on the argument based on the person arguing (even if previous argument had been poor) would be an ad hom fallacy.


I think it holds with arguments as well.

X claims illogical arguments most of the time
X said the argument P
It is probable that the argument P is illogical

[Cavemonster]

I think it holds with arguments as well.

X claims illogical arguments most of the time
X said the argument P
It is probable that the argument P is illogical

This is true, but only in the absence of other information and only if the first statement is true of X, but I can't think of a set of people X where it really does hold true.

[Egg]

I think it holds with arguments as well.

X claims illogical arguments most of the time
X said the argument P
It is probable that the argument P is illogical

That's true, and it might well be reason enough not to bother listening to any more of X's arguments, but I would think that dismissing the argument based on that rather than the merit of the argument itself would be fallacious.

[paximperium]

This is true, but only in the absence of other information and only if the first statement is true of X, but I can't think of a set of people X where it really does hold true.
Creationist.

[JetLeg]

__

[Cavemonster]

Creationist.

:P

That only works if you confine us to a certain subject, the origins of life on this planet. And yes a specific group or individual can be overwhelmingly wrong about a specific subject, but the OP is much more general than that


If you counted up all the arguments made by... even Ted Haggard, even someone who spouts bull for a living, over the course of a year, I think you'd have a hard time finding a majority of arguments that can be discounted. Because there are so many mundane things...
"I need to buy more toothpaste, because I have run out"
"We should push these tables together, because there are 8 of us"

If you limited it to a specific area, or dropped all mundane statements and arguments from both the original count and consideration at the end, then you'll get some groups with >50% bad arguments/statements.

[paximperium]

Bad example.

I consider any statement from Ted Haggard to be dubious. If he said he wanted to pee or needs toothpaste, I'd doubt that claim.

But then, "Ted Haggard's completely Heterosexual." Sing along!!!:D

[Cavemonster]

Bad example.

I consider any statement from Ted Haggard to be dubious. If he said he wanted to pee or needs toothpaste, I'd doubt that claim.

But then, "Ted Haggard's completely Heterosexual." Sing along!!!:D

You may be right. But luckily, the Ted Haggards of the world are exceedingly rare.

[westprog]

It looks to me like there's a confusion happening between an argument and a statement.

If we're just looking at statements then the pebble analogy might be a reasonable manner to assess the probable truth of a statement assuming that we have no other information to go on. This is just a matter of probability and therefore not an ad hom.

For an argument (which is what the OP seems to be about) then we would assess the merit of the argument. To make any judgement on the argument based on the person arguing (even if previous argument had been poor) would be an ad hom fallacy.

I think this shows the difference between the idealised way we make judgements, and how we do it in reality.

Almost any argument will rest on certain facts which we could check if we wanted, but in practice will mostly accept. If we are in a lecture theatre at university, and the professor makes an argument, we'll be far more disposed to even listen to it than if a drunk approaches us in a pub trying to incoherently tell us what might be exactly the same thing. That's a perfectly sensible way to behave.

[JetLeg]

To make any judgement on the argument based on the person arguing (even if previous argument had been poor) would be an ad hom fallacy.

How do you prove that ad hom is a fallacy anyway?

[paximperium]

How do you prove that ad hom is a fallacy anyway?
Here's an example.

Paximperium: The sky is blue because of X
Bob: Paximperium is a doo doo head therefore he is wrong.

[JetLeg]

__

[Mobyseven]

I am interested in the logic of my argument. IF the initial statement is true, does the conclusion follow, or it is invalid logically?

That one's easy. Your argument is invalid - the premises do not entail the conclusion.

Well, this was an easy thread. What do I win?

[joobz]

It also depends on whether you accept your first proposition. I've made many good arguments while drunk.

Arthwollipot: Joobz, please. Turn of the computer. Don't post on the forum.
Joobz: Whhhhhyyz notshhh?
Arthwollipot: Because, your drunk. you'll make a fool of yourself.
Joobz: Ohhhh yeahh.... I arghhue better when I'm drunkk.;sd
Arthwollipot: :nope:
Joobz: tergiversate!111!!!!!!!

[linusrichard]

Ok, now prove that this argument is fallacious. Give an example of an absurdity that can be proven using this line of thinking.

Okay.

India has a lot of people (true).
X is a person, chosen at random from the entire human population.
Therefore, by inductive logic, it is probable that X is Indian.

A lot of numbers are multiples of 7 (indisputably true).
X is an integer chosen at random.
Therefore, by inductive logic, it is probable that X is a multiple of 7.

Etc.


(Note: this is a response to the original argument as you put it in the OP, which is what Merv was talking about. As you later amended it, it's fine.)

[Mashuna]

Arthwollipot: Joobz, please. Turn of the computer. Don't post on the forum.
Joobz: Whhhhhyyz notshhh?
Arthwollipot: Because, your drunk. you'll make a fool of yourself.
Joobz: Ohhhh yeahh.... I arghhue better when I'm drunkk.;sd
Arthwollipot: :nope:
Joobz: tergiversate!111!!!!!!!

Hey, you do argue better when you're drunk!




:duck:

[westprog]

Here's an example.

Paximperium: The sky is blue because of X
Bob: Paximperium is a doo doo head therefore he is wrong.

But if PI is, in fact, a doo doo head, then why should we bother examining his arguments? It might be fallacious to reject an argument based on the person offering it, but it's quite a sensible thing to do.

In fact, saying PI is a DDH and that makes his argument invalid is fallacious, but the similar argument that because PI is a DDH that we are going to treat his argument as fallacious whether it is or not, is probably the right thing to do.

(I hasten to say that no implications of PI's doo doo headedness are meant).

[JetLeg]

But if PI is, in fact, a doo doo head, then why should we bother examining his arguments? It might be fallacious to reject an argument based on the person offering it, but it's quite a sensible thing to do.

In fact, saying PI is a DDH and that makes his argument invalid is fallacious, but the similar argument that because PI is a DDH that we are going to treat his argument as fallacious whether it is or not, is probably the right thing to do.

(I hasten to say that no implications of PI's doo doo headedness are meant).

Maybe we can say that if PI is a DDH we are not going to be interested in his arguments, but in case that we do look into them, we will look with the same type of objectivity as we would with Q?


An additional point is that if PI is a liar, then not the logic of his arguments, but the truthof his premises can be doubted - and that would not be fallacious.

[westprog]

Maybe we can say that if PI is a DDH we are not going to be interested in his arguments, but in case that we do look into them, we will look with the same type of objectivity as we would with Q?


And even a complete DDH might come up with a well constructed argument by accident.

An additional point is that if PI is a liar, then not the logic of his arguments, but the truthof his premises can be doubted - and that would not be fallacious.

I think the "Life's too short" principle applies. Certainly we shouldn't assert that the DDH's arguments are necessarily faulty, or that the LDDH is always lying, but we may assume as much.

[slingblade]

Ok, now prove that this argument is fallacious. Give an example of an absurdity that can be proven using this line of thinking.

www.nizkor.org:

Translated from Latin to English, "Ad Hominem" means "against the man" or "against the person."

An Ad Hominem is a general category of fallacies in which a claim or argument is rejected on the basis of some irrelevant fact about the author of or the person presenting the claim or argument. Typically, this fallacy involves two steps. First, an attack against the character of person making the claim, her circumstances, or her actions is made (or the character, circumstances, or actions of the person reporting the claim). Second, this attack is taken to be evidence against the claim or argument the person in question is making (or presenting). This type of "argument" has the following form:

Person A makes claim X.
Person B makes an attack on person A.
Therefore A's claim is false.


The reason why an Ad Hominem (of any kind) is a fallacy is that the character, circumstances, or actions of a person do not (in most cases) have a bearing on the truth or falsity of the claim being made (or the quality of the argument being made).

It is a mistake to decide one will disregard the arguments of a certain person, like yourself for example, simply because of character, circumstance, or actions.

I remember you, you see. And I remember you're not the best at argumentation. But for my own benefit, I know I ought to examine your posts and not dismiss them out of hand, based on your past history here. You might have improved at arguing, or you might have been faking ignorance when last you posted, or I might have simply misunderstood you.

But none of that precludes your coming up with a good argument, or making sense now, or being willing to learn now.

So, an ad hom against you, again for example, might be:

"Don't anyone listen to JetLeg. The last time he was here, he made a proper fool of himself, and didn't say anything worth reading."

This is an attack against you, as a person, not your arguments. I have just poisoned the well against you, and given at least some people reason to doubt you and your words, before you've really said anything.

This is unfair, and is lousy logic.

Now, let me take your drunk man argument.


You are at a drinking establishment with friends. There is also a man there who you know for a fact is a notorious drunkard and liar. You and your friends are outside on the patio, enjoying a cocktail and watching the sun set.

Suddenly, here comes Drunken Guy, who is indeed drunk, hollering that there's a fire in the basement, and the bar's owner has stored a drum of gasoline down there.

Do you ignore Drunken Guy because he is Drunken Guy and you consider him unreliable?

Or do you get everyone out of the bar and call the fire department?

[quarky]

My friend has a collection of old clocks; none running; all stopped at different times.
Each is correct twice a day.

If he took the average time, at any moment, of all the times stated by the dials, they would be more accurate than any of the individual clocks.

(Or would they?)

[JetLeg]

Slingblade, I would call the fire department. But again, you give a counter example to

person X is a drunkard and a liar
therefore everything he says must be false

But the OP says

person X is a drunkard and a liar
thus there is a high probability that his arguments are invalid/unsound

[Cavemonster]

www.nizkor.org:
Suddenly, here comes Drunken Guy, who is indeed drunk, hollering that there's a fire in the basement, and the bar's owner has stored a drum of gasoline down there.

Do you ignore Drunken Guy because he is Drunken Guy and you consider him unreliable?

Or do you get everyone out of the bar and call the fire department?

You leave out the option of going down to the basement to check for yourself.

But how about this one. Drunken Guy routinely staggers into the bar tells everyone there is a fire and drinks directly from the tap as everyone runs for their lives. After the twentieth time or so, is it illogical to dismiss his argument without checking into it?

It is not a fallacy to ignore an information source based on the unreliability of that information source whether it be a human or a stopped clock. It is fallacy to imagine that we know whether a statement is true based on who said it, but it is very logical to use the past behavior of an information source to gauge whether it's worth the time to listen to it.

Just because a clock is stopped doesn't mean it never gives the correct time, it does, in fact twice a day! It would be fallacious to assume the time it gives is necessarily wrong, but it would be foolish not to ignore it as a timekeeper.

[JetLeg]

My friend has a collection of old clocks; none running; all stopped at different times.
Each is correct twice a day.

If he took the average time, at any moment, of all the times stated by the dials, they would be more accurate than any of the individual clocks.

(Or would they?)

I think they would not be. An individual clock is "right" exactly twice a day. ANY average time is the "right" time also exactly twice a day.

[linusrichard]

person X is a drunkard and a liar
thus there is a high probability that his arguments are invalid/unsound

You're still using undefined terms. What is a "liar"? What is a "high probability"?

If someone lies n% of the time, then for any given statement of theirs (about which we have no other information), there is an n% probability it is a lie. If n is .1, or 80, then it works. But if n is 10, I don't think it holds up. Maybe you consider 10% a high probability. That's okay - I wouldn't criticize you for that. But it shows that we can't really discuss this until we set some parameters.

[slingblade]

Slingblade, I would call the fire department. But again, you give a counter example to

person X is a drunkard and a liar
therefore everything he says must be false

But the OP says

person X is a drunkard and a liar
thus there is a high probability that his arguments are invalid/unsound

I know that. But how do you know if the probability holds in every case, for each argument he makes, unless you weigh and evaluate every argument he makes?

You cannot simply take his past reputation and apply it in the future, because there always exists the possibility his argument is sound and valid this time. You said it yourself: that it is probably wrong, doesn't make it certainly wrong. How are you to know? By weighing the argument itself, instead of the individual making the argument.

What else can I tell you? That answers your question.

It is an ad hominem fallacy to reject an argument because of who is making it.
The argument itself, regardless of the arguer, must be evaluated, or else you fall into this fallacy.

[paximperium]

You are mixing two complete different issues which relate to the truth of a claim.
1)Logical validity of an argument.
2)Probability of what being said argument is true.

Using an ad hominem is logical fallacious since it does not address 1) but may be completely relevant to the probability if the statement is true as linked to 2).

Drunk: I did not steal this bottle of rum because I only drink vodka.
1)This is logically valid.
2)However the truth if this claim is suspect.

[Cavemonster]

It is an ad hominem fallacy to reject an argument because of who is making it.
The argument itself, regardless of the arguer, must be evaluated, or else you fall into this fallacy.

Let's say my uncle Jimmy only says the words "Apple Cobbler" no matter what anyone asks him.

Is it illogical if I ask him what the weather is like and I don't consider that it actually might be apple cobblering?

[slingblade]

You leave out the option of going down to the basement to check for yourself.

Yes, but no. I wouldn't, myself. Gasoline's dangerous. :)
But yes, that is also an option, and there are others. Ask the bar owner if there really is gas down there, and so on.

But how about this one. Drunken Guy routinely staggers into the bar tells everyone there is a fire and drinks directly from the tap as everyone runs for their lives. After the twentieth time or so, is it illogical to dismiss his argument without checking into it?

Yes, because the fourth time the Little Boy cried "wolf!" it ate him. :p

It is not a fallacy to ignore an information source based on the unreliability of that information source whether it be a human or a stopped clock. It is fallacy to imagine that we know whether a statement is true based on who said it, but it is very logical to use the past behavior of an information source to gauge whether it's worth the time to listen to it.

Logically, no, it's still an ad hom. You're still weighing the person and not the argument. You can only weigh the argument by hearing it.

Emotionally, you may be justified in ignoring that drunken, loudmouthed sod, but logically, no.

Just because a clock is stopped doesn't mean it never gives the correct time, it does, in fact twice a day! It would be fallacious to assume the time it gives is necessarily wrong, but it would be foolish not to ignore it as a timekeeper.

The stopped clock analogy has limited usefulness. A broken clock isn't likely to repair itself, to start up on its own once stopped, or to set itself to the correct time once started.

A person, however, is capable of making correct arguments amongst his invalid, unsound ones. The only way you know that is to evaluate them individually. Judging the arguer instead of the argument is an ad hominem fallacy.

[slingblade]

Let's say my uncle Jimmy only says the words "Apple Cobbler" no matter what anyone asks him.

Is it illogical if I ask him what the weather is like and I don't consider that it actually might be apple cobblering?

You have a retarded uncle?

I'm not talking to you anymore. That sort of thing is inherited and for all I know, you're retarded, too.

[Cavemonster]

Slingblade,
This a fairly important to clarify.
It is not an ad hominem fallacy to regard the reliability of the source as evidence for or against a claim.

http://en.wikipedia.org/wiki/Ad_hominem

The ad-hominem fallacy is based on an unstated and false premise regarding the reliability of the source.

Stated premise- X person is a (unsavory quality) true
Unstated premise- Those with (unsavory quality) are likely to lie false
Conclusion- X person's statement is likely to be a lie false

It's that unstated and false assumption that makes it a fallacy, not the changing and uncertain nature of humans. If there is a stated and true premise about a person's reliability, then it is reasonable and not fallacious to use that information to reach your conclusion.

Therefore:
Stated premise- X person is a (unsavory quality) true
Stated premise- Those with (unsavory quality) are likely to lie true
Conclusion- X person's statement is likely to be a lie true

If the middle premise is both stated and true, then the logic is sound.

[Roma]

So what is the definition of "drunk" anyway?
More intoxicated than an airlines pilot, less intoxicated than a fraternity brother after exams?

[Hokulele]

Therefore:
Stated premise- X person is a (unsavory quality) true
Stated premise- Those with (unsavory quality) are likely to lie true
Conclusion- X person's statement is likely to be a lie true

If the middle premise is both stated and true, then the logic is sound.


Sure, but JetLeg has muddied the water by introducing two unsavory qualities and has not established that drunkards are more likely to lie (or be wrong). For example, a drunk physicist is more likely to be correct about physics than a sober layman. It just takes a bit longer for him/her to get the equations written down.

[Cavemonster]

Sure, but JetLeg has muddied the water by introducing two unsavory qualities and has not established that drunkards are more likely to lie (or be wrong). For example, a drunk physicist is more likely to be correct about physics than a sober layman. It just takes a bit longer for him/her to get the equations written down.

Well, what we ended up with was.

Drunk people make mostly bad arguments
X is a an argument said by a drunk person
Thus, (by inductive logic) it is probable that X is a bad argument.

If you accept the first statement as true (which in a real world sense it isn't) and you have no other information about the speaker or the argument (which is highly unlikely in any real world scenario) then the argument is sound. It doesn't map well onto reality, but it's internally consistent.

[Hokulele]

I agree, I just wanted to make it clear to JetLeg (who seemed to be confused) that logical consistency doesn't always lead to the correct answer. False premises are false premises.

[GStan]

What if Jetleg was drunk the whole time he was arguing this thread?:jaw-dropp
Would that support his position or refute it?

[JetLeg]

In another post, called "When is Ad Hom a fallacy" (moderator, can you mend the two posts into one? ) Greedy Algorythm actually made a really good point, and I think it resolves the question.

The argument

The vast majority of X's arguments are invalid
P is an argument by X
---
It is probable that P is invalid.

Is a valid inductive argument, and not an ad hom. However, when one actually judges the specific argument P, since it is possible that it is valid, then one has to judge by its own merit, and not by association with X. It is a bit complicated to put in words, but can be easily explained using the analogy of black and white balls :


If there is a box with 99% black balls, there is a 99% probability that a randomly taken out ball will be black. However, when you take a ball, and try to determine whether it is a black ball or not, you use your sight - you do nto use the probability. You cannot take out a ball, and not judge whether it is black or white "on its own merit". You cannot take a white ball, look at it and declare "there is 99% probability that this ball is black"!!

And linusrichard has a sound point as well, with regards to the premises.

[Egg]

I'm not quite sure how you think that differs from what has already been said in this thread, but if it works for you, great! :)

So, how might you use some kind of probability like this practically (assuming you could gather enough information to calculate such a thing) ?

[JetLeg]

Well, it works more simply and more practically than statistics : "This person's arguments are lousy ones. There is no reason I should go on and listen to this ********. " Which is a valid way of thinking, and was demonstrated above slightly more rigourously.