What is the difference between a fallacious argument and an invalid arguement?

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kennethamy
 
Reply Mon 1 Mar, 2010 07:00 am
@Emil,
Emil;134013 wrote:
Not all invalid arguments are fallacious. And not all fallacious arguments are invalid.


And it would be fallacious to argue from either proposition to the other proposition too.
 
Doubt doubt
 
Reply Sat 13 Mar, 2010 02:24 am
@Deckard,
my understanding of fallacious arguments is that they use a premise that can or cant be true but cant be true consistently. a good example would be fallacious via generalization or fallacious via confusing correlation or causation. it seams to me that a fallacious argument is not an argument at all as it can not be valid in the sense that the premises have no bearing on whether the conclusion is true or false. with via confusing coralation or causation it is fallacious because there are multiple interpretations of the conclusion the premise is being used to prove.

example

When sales of hot chocolate go up, street crime drops.

this could very well be true but the premise does not prove it. id assume it was because when it gets cold more people buy hot chocolate, and less people hang out outside thus less crime. even if the criminals are still all out, there would be less potential victims.

Ill read more posts now to find an example of a fallacious argument that is valid because it seams to me you dont even finish reading it once the fallacy is apparent.
 
kennethamy
 
Reply Sat 13 Mar, 2010 07:22 am
@Doubt doubt,
Doubt doubt;139252 wrote:
my understanding of fallacious arguments is that they use a premise that can or cant be true but cant be true consistently. a good example would be fallacious via generalization or fallacious via confusing correlation or causation. it seams to me that a fallacious argument is not an argument at all as it can not be valid in the sense that the premises have no bearing on whether the conclusion is true or false. with via confusing coralation or causation it is fallacious because there are multiple interpretations of the conclusion the premise is being used to prove.

example

When sales of hot chocolate go up, street crime drops.

this could very well be true but the premise does not prove it. id assume it was because when it gets cold more people buy hot chocolate, and less people hang out outside thus less crime. even if the criminals are still all out, there would be less potential victims.

Ill read more posts now to find an example of a fallacious argument that is valid because it seams to me you dont even finish reading it once the fallacy is apparent.


A fallacy is an argument whose premises fail to support their conclusion. This is the logical dimension of fallacies. There is also a psychological dimension. The premises appear to support the conclusion, so people are sometimes deceived into thinking that the argument is a good argument. On account of this psychological dimension, fallacies are often called, "counterfeit arguments", because people are apt to take the fake thing for the real thing.

You will probably have to look for a long time to find a valid fallacy, since if an argument is valid, it cannot be a fallacy, and if it is a fallacy, it cannot be valid.
 
Doubt doubt
 
Reply Sat 13 Mar, 2010 10:51 am
@kennethamy,
Doubt doubt;139252 wrote:
my understanding of fallacious arguments is that they use a premise that can or cant be true but cant be true consistently. a good example would be fallacious via generalization or fallacious via confusing correlation or causation. it seams to me that a fallacious argument is not an argument at all as it can not be valid in the sense that the premises have no bearing on whether the conclusion is true or false. with via confusing coralation or causation it is fallacious because there are multiple interpretations of the conclusion the premise is being used to prove.

example

When sales of hot chocolate go up, street crime drops.

this could very well be true but the premise does not prove it. id assume it was because when it gets cold more people buy hot chocolate, and less people hang out outside thus less crime. even if the criminals are still all out, there would be less potential victims.

Ill read more posts now to find an example of a fallacious argument that is valid because it seams to me you dont even finish reading it once the fallacy is apparent.





kennethamy;139282 wrote:
A fallacy is an argument whose premises fail to support their conclusion. This is the logical dimension of fallacies. There is also a psychological dimension. The premises appear to support the conclusion, so people are sometimes deceived into thinking that the argument is a good argument. On account of this psychological dimension, fallacies are often called, "counterfeit arguments", because people are apt to take the fake thing for the real thing.

You will probably have to look for a long time to find a valid fallacy, since if an argument is valid, it cannot be a fallacy, and if it is a fallacy, it cannot be valid.


seams to me we both said the same thing.

Deckard;130594 wrote:
I don't think that the presence of fallacy invalidates an argument. An ad homenum attack for example:

Al Gore tells only lies
Al Gore says that global climate change is a real problem
Therefore global climate change is a lie

If the premises were true then the conclusion would have to be true.
Yet to say that Al Gore tells only lies is an ad homenum attack so this is a fallacious argument.

I can see that not all fallacious arguments are invalid arguments.

But are all invalid arguments fallacious arguments?
That's the part I'm stuck on. By the definition I provided for fallacious arguments it would seem so but I think that definition may not be technical enough for our purposes.



this is why i was looking for a fallacious argument that was valid. i thought there was no such thing and you seam to be saying that too.
 
Pyrrho
 
Reply Mon 15 Mar, 2010 12:44 pm
@Doubt doubt,
Emil;134013 wrote:
Not all invalid arguments are fallacious.



Please explain. If we use the definition of fallacy as "Incorrectness of reasoning", then all invalid arguments are fallacious. See:

Fallacy | Define Fallacy at Dictionary.com

What idea of "fallacy" are you using?

Or are you using "valid" in a narrow sense, only applying it to deductive reasoning? In which case, inductive reasoning that is "good" is not fallacious, but it would still be deductively invalid.


Emil;134013 wrote:
Not all fallacious arguments are invalid.

That's pretty much it.


Yes. The fallacy known as petitio principii, or "begging the question", is deductively valid, but it is a fallacy. And if the premises happen to be true, it is even sound. But it is still a fallacy.
 
Emil
 
Reply Mon 15 Mar, 2010 05:03 pm
@Pyrrho,
Pyrrho;139970 wrote:
Please explain. If we use the definition of fallacy as "Incorrectness of reasoning", then all invalid arguments are fallacious. See:

Fallacy | Define Fallacy at Dictionary.com

What idea of "fallacy" are you using?

Or are you using "valid" in a narrow sense, only applying it to deductive reasoning? In which case, inductive reasoning that is "good" is not fallacious, but it would still be deductively invalid.




Yes. The fallacy known as petitio principii, or "begging the question", is deductively valid, but it is a fallacy. And if the premises happen to be true, it is even sound. But it is still a fallacy.


All good inductive arguments are invalid, but they are not fallacious.

I apply the term "valid" to all arguments. For any argument, it is either valid or invalid. Some people (e.g. Fast) think that the term only applies to deductive arguments but I no of no reason to believe that.

Circular reasoning and begging the question are not the same but are related. Begging the question is more broad. All arguments that are circular beg the question, but not all arguments that beg the question are circular. Circularity is easy to define. An argument is circular iff the conclusion is also a premise.
 
fast
 
Reply Thu 1 Apr, 2010 08:29 am
@Emil,

[QUOTE=Emil;140039]All good inductive arguments are invalid, but they are not fallacious.

I apply the term "valid" to all arguments. For any argument, it is either valid or invalid. Some people (e.g. Fast) think that the term only applies to deductive arguments but I no of no reason to believe that.

Circular reasoning and begging the question are not the same but are related. Begging the question is more broad. All arguments that are circular beg the question, but not all arguments that beg the question are circular. Circularity is easy to define. An argument is circular iff the conclusion is also a premise.[/QUOTE]

If an argument is invalid, then an argument is not valid, but just because an argument is not valid, that does not mean that an argument is invalid.

Inductive arguments are not valid, but not because they are invalid, as no inductive argument is invalid. Inductive arguments are neither valid nor invalid, yet they are all not valid.

Deductive arguments, however, are valid or invalid, and if a deductive argument is invalid, then the argument is not valid.

In analogy, it's like differentiating between true, false, and not true. If p is false, then p is not true, but we shouldn't jump to the conclusion that p is false just because p is not true, as being not true does not imply being false, just as an argument being not valid does not imply that an argument is invalid.

People make mistakes, and one mistake people make is to think that because p is not true, p is therefore false, and the mistake that you and many broke dick sources on the internet are making is that because inductive arguments are not valid that they are therefore invalid.
 
kennethamy
 
Reply Thu 1 Apr, 2010 08:46 am
@fast,
fast;147076 wrote:



If an argument is invalid, then an argument is not valid, but just because an argument is not valid, that does not mean that an argument is invalid.

Inductive arguments are not valid, but not because they are invalid, as no inductive argument is invalid. Inductive arguments are neither valid nor invalid, yet they are all not valid.

Deductive arguments, however, are valid or invalid, and if a deductive argument is invalid, then the argument is not valid.

In analogy, it's like differentiating between true, false, and not true. If p is false, then p is not true, but we shouldn't jump to the conclusion that p is false just because p is not true, as being not true does not imply being false, just as an argument being not valid does not imply that an argument is invalid.

People make mistakes, and one mistake people make is to think that because p is not true, p is therefore false, and the mistake that you and many broke dick sources on the internet are making is that because inductive arguments are not valid that they are therefore invalid.


I suppose that what he means is that if the argument were thought to be deductive, then it would be thought to be invalid. We have to decide what kind of argument it is, before we can decide on how to evaluate it.
 
Pyrrho
 
Reply Thu 1 Apr, 2010 09:03 am
@fast,
fast;147076 wrote:



If an argument is invalid, then an argument is not valid, but just because an argument is not valid, that does not mean that an argument is invalid.

Inductive arguments are not valid, but not because they are invalid, as no inductive argument is invalid. Inductive arguments are neither valid nor invalid, yet they are all not valid.

Deductive arguments, however, are valid or invalid, and if a deductive argument is invalid, then the argument is not valid.

In analogy, it's like differentiating between true, false, and not true. If p is false, then p is not true, but we shouldn't jump to the conclusion that p is false just because p is not true, as being not true does not imply being false, just as an argument being not valid does not imply that an argument is invalid.

People make mistakes, and one mistake people make is to think that because p is not true, p is therefore false, and the mistake that you and many broke dick sources on the internet are making is that because inductive arguments are not valid that they are therefore invalid.



"Invalid" means "not valid". The prefix "in-" in this case means "not". This is also the meaning of the prefix "in-" in words like "ineligible" and "incorrigible".

Since Emil defines "valid" in terms of deduction, where the conclusion follows absolutely from the premises, all inductive arguments are invalid (in his use of the term). I have, however, seen the word "valid" applied to inductive arguments, which roughly means good inductive arguments (let us not digress into what that means). With such a use, not all inductive arguments would be invalid, but that is due to a different meaning for the term "valid". Regardless of what one means by the term "valid", the term "invalid" means "not valid".
 
kennethamy
 
Reply Thu 1 Apr, 2010 10:00 am
@Pyrrho,
Pyrrho;147085 wrote:
"Invalid" means "not valid". The prefix "in-" in this case means "not". This is also the meaning of the prefix "in-" in words like "ineligible" and "incorrigible".

Since Emil defines "valid" in terms of deduction, where the conclusion follows absolutely from the premises, all inductive arguments are invalid (in his use of the term). I have, however, seen the word "valid" applied to inductive arguments, which roughly means good inductive arguments (let us not digress into what that means). With such a use, not all inductive arguments would be invalid, but that is due to a different meaning for the term "valid". Regardless of what one means by the term "valid", the term "invalid" means "not valid".


Would you say that " caution, inflammable" means "caution, not flammable"?

The trouble is that the negative operator may mean either, "non" as in, "non-intelligent" or "not" as in, "not-intelligent". Chairs and table are not intelligent in the sense of "non-intelligent" since they are not able to be intelligent either. In the same way, inductive argument are not valid in the sense of non-valid, since they are not capable of being valid either. If an argument is not capable of being valid, to say it is not valid does not mean it is invalid, but means that it is non-valid.

Medieval philosopher use to make the distinction in terms of the notions of negation and privation. A stone cannot see, but that does not mean it is blind. Not being able to see is a negation. But blindness is a privation.
 
Pyrrho
 
Reply Thu 1 Apr, 2010 11:15 am
@kennethamy,
kennethamy;147096 wrote:
Would you say that " caution, inflammable" means "caution, not flammable"?

The trouble is that the negative operator may mean either, "non" as in, "non-intelligent" or "not" as in, "not-intelligent". Chairs and table are not intelligent in the sense of "non-intelligent" since they are not able to be intelligent either. In the same way, inductive argument are not valid in the sense of non-valid, since they are not capable of being valid either. If an argument is not capable of being valid, to say it is not valid does not mean it is invalid, but means that it is non-valid.

Medieval philosopher use to make the distinction in terms of the notions of negation and privation. A stone cannot see, but that does not mean it is blind. Not being able to see is a negation. But blindness is a privation.


I did not say the prefix "in-" invariably meant "not"; I said "in this case" it means "not".

If you believe that "invalid" means something other than "not valid", please explain what you think it means. I have never in a logic class or logic book seen it defined any other way than simply "not valid". But as you evidently think it means something else, please tell us what that something else is.
 
kennethamy
 
Reply Thu 1 Apr, 2010 12:09 pm
@Pyrrho,
Pyrrho;147115 wrote:
I did not say the prefix "in-" invariably meant "not"; I said "in this case" it means "not".

If you believe that "invalid" means something other than "not valid", please explain what you think it means. I have never in a logic class or logic book seen it defined any other way than simply "not valid". But as you evidently think it means something else, please tell us what that something else is.


But, "not valid" can mean either "invalid", or incapable of being either valid or invalid. So an inductive argument is, I suppose, not valid in the same way that numbers are not purple.But not in the same way that an argument that is deductively fallacious is not valid, i.e. invalid. The view that inductive arguments are not valid leads to the view that inductive arguments are just failed deductive arguments, which is simply wrong. And which leads to the pseudo-problem of the justification of induction. That is why Hume believed that induction needed justification. It was because he believed that inductive arguments are just invalid (deductive) arguments. Emil and I have had this discussion before, and I thought he agreed with me. Apparently he has had a relapse. Or he doesn't recall.
 
Pyrrho
 
Reply Thu 1 Apr, 2010 12:16 pm
@kennethamy,
kennethamy;147130 wrote:
But, "not valid" can mean either "invalid", or incapable of being either valid or invalid. So an inductive argument is, I suppose, not valid in the same way that numbers are not purple.But not in the same way that an argument that is deductively fallacious is not valid, i.e. invalid. The view that inductive arguments are not valid leads to the view that inductive arguments are just failed deductive arguments, which is simply wrong. And which leads to the pseudo-problem of the justification of induction. That is why Hume believed that induction needed justification. It was because he believed that inductive arguments are just invalid (deductive) arguments. Emil and I have had this discussion before, and I thought he agreed with me. Apparently he has had a relapse. Or he doesn't recall.


But you still have not said what you mean by "invalid". If it means something other than "not valid", what is it that it means?
 
kennethamy
 
Reply Thu 1 Apr, 2010 12:22 pm
@Pyrrho,
Pyrrho;147136 wrote:
But you still have not said what you mean by "invalid". If it means something other than "not valid", what is it that it means?


It means that the argument is a. deductive, and d. that the premises fail to support the conclusion. We can say that a and b together make the argument not valid. But since an inductive argument is not deductive, it cannot be not valid in the same sense. There are two senses of "not valid". In one sense it just means, "invalid", in the other, it doesn't.
 
Pyrrho
 
Reply Thu 1 Apr, 2010 01:34 pm
@kennethamy,
kennethamy;147138 wrote:
It means that the argument is a. deductive, and d. that the premises fail to support the conclusion. We can say that a and b together make the argument not valid. But since an inductive argument is not deductive, it cannot be not valid in the same sense. There are two senses of "not valid". In one sense it just means, "invalid", in the other, it doesn't.


I am not sure that that will be sufficient to explain it. The concept of a deductive valid argument is clear enough, but what makes an argument deductive that is not valid?
 
kennethamy
 
Reply Thu 1 Apr, 2010 02:29 pm
@Pyrrho,
Pyrrho;147156 wrote:
I am not sure that that will be sufficient to explain it. The concept of a deductive valid argument is clear enough, but what makes an argument deductive that is not valid?


That is an interesting question, but why is it relevant to this discussion?
 
logicalroy
 
Reply Wed 2 Mar, 2011 07:29 pm
@Deckard,
Hello,

Many people on here seemed to express too many emotions as if this was a psychology thread. Kennethamy was correct though. All invalid arguments are fallacious and All fallacious arguments are unsound. ALL fallacious arguments use an invalid inference rule. If the argument is unsound you know it is not valid. Valid means there is no interpretation where the premises are true and the conclusion can be false simultaneously. Yes if an argument commits a fallacy you can ignore it and try to grasp the meaning still. If an argument is unsound you have a right to ignore it.
Many people think of validity in form alone which if that is the case why not state it that way? Too many focus on validity when SOUNDness is the most important! All Sound arguments MUST be valid! Consider a bad answer given by Krumple:
p1. Birds have wings.
p2. Things that have wings can fly.
c1. All birds fly.

The conclusion is false, because not all birds actually can fly.
-----------------------------
THIS COMMITS A FALLACY and is not valid. [commits the undistributed middle fallacy]

Krumple give more false advice: "Typically a logical fallacy is one where at least one of the premises and the conclusion are both determined to be false." A fallacy does not alway contain a false premise!

Many people did not learn the correct Ad Hom fallacy: there was a person who gave a horrible example of Al Gore lying. Just because the statement is a negative statement about a person that DOES NOT mean it is an AD HOM fallacy in the academic sense. An Ad Hom fallacy is to disregard a conclusion to an argument because a person has the quality of x (where x is a variable that is irrelevant to the conclusion). Person B has the quality of x; thus person B should be ignored. That is what the Ad Hom fallacy is. The Ad Hom people use in chatrooms is NOT in the academic sense and people need to be aware there is a difference between the legit Ad Hom fallacy and nonsense found in chatrooms.
 
bahali
 
Reply Thu 22 Jan, 2015 11:49 am
go here it is all explained.
http://wsuonline.weber.edu.education2020.us/wrh/recfallacies.htm?date=MS8yMi8yMDE1IDY6MDg6MjEgUE0%3d&u=OTcxNmFiYWItZTk1ZS1lNDExLTgwYmYtMDAxNTE3ZjA5ODk1&tbopt=MTExMDAwMTAwMDAw&preflang=RW5nbGlzaA%3d%3d&hash=ZwDLfYWeIotmZsi1l43IVQ%3d%3d
 
 

 
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