question: what is this failure of logic called?

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Reply Sat 12 Sep, 2009 05:30 pm
I'm rebutting an argument. Can you tell me what is wrong here?

- Louise claims that Virginia was sexually abused as a child.
- Virginia made no such claims.
- Louise explains Virginia's silence as indicating that she is in denial about the sexual abuse.

Would we call this circular reasoning?

Thanks very much for your help.
 
Octal
 
Reply Sat 12 Sep, 2009 05:34 pm
@lidarose9,
I would call this Mathematics: it's just a bunch of irrefutable errors!
 
Zogg the Demon
 
Reply Sat 12 Sep, 2009 06:00 pm
@lidarose9,
I would say it's rather a case of affirming the consequent. The general structure of this kind of fallacy is:

  1. If P, then Q.
  2. Q.
  3. Therefore, P.

In this case, this would be

  1. If Virginia was sexually abused as a child, then she would (possibly) deny it.
  2. Virginia denies it.
  3. Therefore, Virginia was sexually abused.
 
Emil
 
Reply Sat 19 Sep, 2009 02:27 pm
@Zogg the Demon,
Zogg the Demon;89911 wrote:
I would say it's rather a case of affirming the consequent. The general structure of this kind of fallacy is:

  1. If P, then Q.
  2. Q.
  3. Therefore, P.

In this case, this would be

  1. If Virginia was sexually abused as a child, then she would (possibly) deny it.
  2. Virginia denies it.
  3. Therefore, Virginia was sexually abused.



I think this analysis is false. She did not make an argument, so there is no AtC argument being made. She merely explained something. A proposition being explained by another proposition is not an argument.

---------- Post added 09-19-2009 at 09:29 PM ----------

lidarose9;89900 wrote:
I'm rebutting an argument. Can you tell me what is wrong here?

- Louise claims that Virginia was sexually abused as a child.
- Virginia made no such claims.
- Louise explains Virginia's silence as indicating that she is in denial about the sexual abuse.

Would we call this circular reasoning?

Thanks very much for your help.


Her remark is question begging but it is not an argument. It is question begging in the sense that it assumes what is under discussion, that is, that Virginia was sexually abused as a child.

It's a form of explaining other people's utterances psychologically instead of evaluating their reasoning. One should always evaluate reasoning before explaining it. There are many things which are false but are yet explainable.
 
kennethamy
 
Reply Sat 19 Sep, 2009 03:07 pm
@Emil,
Emil;91965 wrote:
I think this analysis is false. She did not make an argument, so there is no AtC argument being made. She merely explained something. A proposition being explained by another proposition is not an argument.

---------- Post added 09-19-2009 at 09:29 PM ----------



Her remark is question begging but it is not an argument. It is question begging in the sense that it assumes what is under discussion, that is, that Virginia was sexually abused as a child.

It's a form of explaining other people's utterances psychologically instead of evaluating their reasoning. One should always evaluate reasoning before explaining it. There are many things which are false but are yet explainable.



Well, it is implicitly question question-begging, since it is being assumed that Virginia has been sexually abused by saying that she is in denial (about being sexually abused).
 
Emil
 
Reply Sat 19 Sep, 2009 05:02 pm
@kennethamy,
kennethamy;91973 wrote:
Well, it is implicitly question question-begging, since it is being assumed that Virginia has been sexually abused by saying that she is in denial (about being sexually abused).


Right.


(random characters.)
 
kennethamy
 
Reply Sat 14 Nov, 2009 05:23 pm
@lidarose9,
lidarose9;89900 wrote:
I'm rebutting an argument. Can you tell me what is wrong here?

- Louise claims that Virginia was sexually abused as a child.
- Virginia made no such claims.
- Louise explains Virginia's silence as indicating that she is in denial about the sexual abuse.

Would we call this circular reasoning?

Thanks very much for your help.


Begging the question. Assuming what we need to prove.
 
Emil
 
Reply Sat 14 Nov, 2009 07:27 pm
@kennethamy,
kennethamy;103540 wrote:
Begging the question. Assuming what we need to prove.


You must be getting old. You already answered this thread. :p
 
kennethamy
 
Reply Sat 14 Nov, 2009 10:36 pm
@Emil,
Emil;103561 wrote:
You must be getting old. You already answered this thread. :p


"Getting?".............
 
leafy
 
Reply Sun 15 Nov, 2009 01:44 am
@lidarose9,
It's a non-sequitur, just like all failures of logic. Any fallacy is simply an inference for which there is no other rule to justify it. Naming them is just pointing out the background to the fallacy.
 
kennethamy
 
Reply Sun 15 Nov, 2009 05:08 am
@leafy,
leafy;103589 wrote:
It's a non-sequitur, just like all failures of logic. Any fallacy is simply an inference for which there is no other rule to justify it. Naming them is just pointing out the background to the fallacy.


No. Naming them details the reason for the non-sequitur. But, as Emil and I have been discussing, the fallacy of begging the question is not really a non-sequtur, or at least, not in the ordinary sense. In fact, a technically sound argument may commit the fallacy of begging the question. So, something else is going on.
 
Emil
 
Reply Sun 15 Nov, 2009 07:59 am
@kennethamy,
kennethamy;103602 wrote:
No. Naming them details the reason for the non-sequitur. But, as Emil and I have been discussing, the fallacy of begging the question is not really a non-sequtur, or at least, not in the ordinary sense. In fact, a technically sound argument may commit the fallacy of begging the question. So, something else is going on.


Leaf should have written: "formal fallacies". All formal fallacies are non-sequiturs.
 
catfood phil
 
Reply Sun 15 Nov, 2009 08:26 am
@leafy,
Almost seems like an 'Argumentum ad Ignorantian' but 'Affirming the consequent' is the one I would go for.
People who have been abused deny their abuse, she denies that she was abused so she must have been.
Hope this helps.
 
Emil
 
Reply Sun 15 Nov, 2009 08:55 am
@catfood phil,
catfood;103617 wrote:
Almost seems like an 'Argumentum ad Ignorantian' but 'Affirming the consequent' is the one I would go for.
People who have been abused deny their abuse, she denies that she was abused so she must have been.
Hope this helps.


Please explain why you think it is an instance of affirming the consequent.

It seems to me that people often call arguments for various fallacies for no particular reason. Perhaps as part of the fallacy fallacy.
 
catfood phil
 
Reply Sun 15 Nov, 2009 11:19 am
@Emil,
Emil;103621 wrote:
Please explain why you think it is an instance of affirming the consequent.

It seems to me that people often call arguments for various fallacies for no particular reason. Perhaps as part of the fallacy fallacy.


It fallacious because instead of affirming the antecedents to prove or credit the consequent e.g. People who have been abused deny their abuse. She was abused so it is only natural that she would deny it.
In this case the consequent is used to prove the antecedents: People who have been abused deny their abuse, she denies that she was abused so she must have been.
There could be more possibilities to explain this consequent, the most notable would be that she has not been abused.
 
Emil
 
Reply Sun 15 Nov, 2009 11:38 am
@catfood phil,
catfood;103638 wrote:
It fallacious because instead of affirming the antecedents to prove or credit the consequent e.g. People who have been abused deny their abuse. She was abused so it is only natural that she would deny it.
In this case the consequent is used to prove the antecedents: People who have been abused deny their abuse, she denies that she was abused so she must have been.
There could be more possibilities to explain this consequent, the most notable would be that she has not been abused.


Consider this analysis:
[INDENT]1. Virginia was sexually abused as a child.
2. If Virginia is silent about it, then Virginia is in denial about it.
[/INDENT]An additional premise is needed for this analysis:
[INDENT]3. If Virginia is in denial about it, then Virginia was sexually abused as a child.
[/INDENT]From (2) and (3) it follows by HS that:
[INDENT]4. If Virginia is silent about it, then then Virginia was sexually abused as a child.
[/INDENT]And given the fact that she is silent:
[INDENT]5. If Virginia is silent about it.
[/INDENT]It follows from (5) and (4) that she was sexually abused, that is, (1). Thus no fallacy.

The problem with this explanation is that it does not account for the "explain" mentioned in the OP. That "explain" is accounted for by the begging the question analysis. Hence why I prefer that theory.

But then again we are operating with very, very limiting information. From the information given in the OP, it is not possible to be sure about it.
 
ACB
 
Reply Sun 15 Nov, 2009 06:37 pm
@Emil,
My analysis would be as follows:

1. Louise claims that Virginia was sexually abused as a child.
2. Virginia is silent about it.
3. If someone is silent about it, they are denying it.
4. If someone has been sexually abused as a child, they deny it.
5. (from 2 and 3) Virginia denies it.
6. (from 4 and 5) Therefore Virginia was sexually abused as a child.
7. Therefore Louise's claim in (1) is true.


As I see it, steps (4)-(6) are a clear case of affirming the consequent. Note that Louise's claim may actually be false. (Step 3 also looks very dubious.)
 
kennethamy
 
Reply Sun 15 Nov, 2009 06:44 pm
@ACB,
ACB;103689 wrote:
My analysis would be as follows:

1. Louise claims that Virginia was sexually abused as a child.
2. Virginia is silent about it.
3. If someone is silent about it, they are denying it.
4. If someone has been sexually abused as a child, they deny it.
5. (from 2 and 3) Virginia denies it.
6. (from 4 and 5) Therefore Virginia was sexually abused as a child.
7. Therefore Louise's claim in (1) is true.

As I see it, steps (4)-(6) are a clear case of affirming the consequent. Note that Louise's claim may actually be false. (Step 3 also looks very dubious.)


3. and 4. are just unsupported assumptions, neither of which would be made by someone who did not believe the conclusion of the argument, 7. in the first place. That is why the argument begs the question. It assumes exactly what requires proof.
 
Emil
 
Reply Mon 16 Nov, 2009 01:50 am
@ACB,
ACB;103689 wrote:
My analysis would be as follows:

1. Louise claims that Virginia was sexually abused as a child.
2. Virginia is silent about it.
3. If someone is silent about it, they are denying it.
4. If someone has been sexually abused as a child, they deny it.
5. (from 2 and 3) Virginia denies it.
6. (from 4 and 5) Therefore Virginia was sexually abused as a child.
7. Therefore Louise's claim in (1) is true.


As I see it, steps (4)-(6) are a clear case of affirming the consequent. Note that Louise's claim may actually be false. (Step 3 also looks very dubious.)


I see.

Technically (3) is not a step. A step in an argument is usually understood as an inference. (3) is a premise and it is false, and I think that was what you were getting at.

Anyway it requires a lot of speculation.

---------- Post added 11-16-2009 at 08:52 AM ----------

kennethamy;103693 wrote:
3. and 4. are just unsupported assumptions, neither of which would be made by someone who did not believe the conclusion of the argument, 7. in the first place. That is why the argument begs the question. It assumes exactly what requires proof.


I don't think (4) is entirely unsupported, but (3) clearly only works if one believes that the individual in question has been sexually abused. Hence the question begging.
 
kennethamy
 
Reply Mon 16 Nov, 2009 03:07 am
@Emil,
Emil;103751 wrote:
I see.

Technically (3) is not a step. A step in an argument is usually understood as an inference. (3) is a premise and it is false, and I think that was what you were getting at.

Anyway it requires a lot of speculation.

---------- Post added 11-16-2009 at 08:52 AM ----------



I don't think (4) is entirely unsupported, but (3) clearly only works if one believes that the individual in question has been sexually abused. Hence the question begging.


But the arguer has no business assuming either 3 or 4, and does so only if he already has accepted 7. And, you are right. Neither 3 nor 4 are "steps" in the argument. Both are premises, and 3. is there only so that the conclusion can be drawn. And that is why it begs the question. It violates Aristotle's prescription that the premises should be better known than the conclusion.
 
 

 
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