Is this a recognized fallacy or tactic?

[swansont]

A premise is offered, and then an argument follows without establishing the veracity of the premise. If the premise is false the conclusion is invalid, but the poster is proceeding as if it were true.

Such as an argument based on the moon being made of cheese, and concluding the moon landings were faked because they would have noticed the cheese if they’d landed there. (the conclusion is not being used to support the premise, so it’s not begging the question/circular logic)

Seems like this happens a fair amount, and it’s a failure of logic, but is there a recognized name for it?

 

[iNow]

Fallacy of unwarranted assumption 

https://onlinelibrary.wiley.com/doi/abs/10.1002/9781119165811.ch100

[swansont]

Thank you

[TheVat]

Have heard something similar called a false premise fallacy.  But unwarranted assumption would cover a wider swath, including both false premises and also premises that are unsupported, ergo not established as true.  

[studiot]

2 hours ago, swansont said:

A premise is offered, and then an argument follows without establishing the veracity of the premise. If the premise is false the conclusion is invalid, but the poster is proceeding as if it were true.

Such as an argument based on the moon being made of cheese, and concluding the moon landings were faked because they would have noticed the cheese if they’d landed there. (the conclusion is not being used to support the premise, so it’s not begging the question/circular logic)

Seems like this happens a fair amount, and it’s a failure of logic, but is there a recognized name for it?

 

 

In my experience most problems arise when combinations of statements are made, the results depend upon the connective employed.

Here is a good set of truth tables for first order logic about this.

A disjunction of a false statement (premise) with a true statement  has a truth value of true.

 

https://docs.oracle.com/html/E79061_01/Content/Reference/Truth_tables.htm

[iNow]

2 hours ago, swansont said:

Thank you

Sometimes is simplified as an assumption fallacy 

[swansont]

18 minutes ago, studiot said:

 

In my experience most problems arise when combinations of statements are made, the results depend upon the connective employed.

Here is a good set of truth tables for first order logic about this.

A disjunction of a false statement (premise) with a true statement  has a truth value of true.

 

https://docs.oracle.com/html/E79061_01/Content/Reference/Truth_tables.htm

It’s true that there are these issues, and also conditionals cause problems with some, but the examples I’m thinking of look to be simple false/unwarranted assumptions. But the wonderful world of search engines employing AI kept pointing me to begging the question, which isn’t it.

[StringJunky]

3 hours ago, TheVat said:

Have heard something similar called a false premise fallacy.  But unwarranted assumption would cover a wider swath, including both false premises and also premises that are unsupported, ergo not established as true.  

'False premise' is what I call it.

[dimreepr]

16 hours ago, swansont said:

A premise is offered, and then an argument follows without establishing the veracity of the premise. If the premise is false the conclusion is invalid, but the poster is proceeding as if it were true.

Such as an argument based on the moon being made of cheese, and concluding the moon landings were faked because they would have noticed the cheese if they’d landed there. (the conclusion is not being used to support the premise, so it’s not begging the question/circular logic)

Seems like this happens a fair amount, and it’s a failure of logic, but is there a recognized name for it?

 

Philosophically speaking, language's can be misinterpreted, maybe the premise offered is valid, even when both appear to be speaking the same language, the smallest nuance can be the switch between the truths.

If memory serves, it a Wittgenstein type question.

[swansont]

1 hour ago, dimreepr said:

Philosophically speaking, language's can be misinterpreted, maybe the premise offered is valid, even when both appear to be speaking the same language, the smallest nuance can be the switch between the truths.

If memory serves, it a Wittgenstein type question.

Maybe it is, but that’s not the point of contention here. The issue is that it’s unsupported. Nothing offered to show that it’s true. 

[sethoflagos]

19 hours ago, swansont said:

Seems like this happens a fair amount, and it’s a failure of logic, but is there a recognized name for it?

Is it truly a failure of logic? Bad arguments based on false premises can still be logically flawless.

We get a bit challenged in our definitions when assuming all arguments are presented in good faith. Sometimes they are not. The problems can lie in ethos or pathos rather than logos.

[swansont]

1 hour ago, sethoflagos said:

Is it truly a failure of logic? Bad arguments based on false premises can still be logically flawless.

The subsequent steps could be flawless, but not the premise if it's false. i.e. the failure is thinking the conclusion is valid.

1 hour ago, sethoflagos said:

We get a bit challenged in our definitions when assuming all arguments are presented in good faith. Sometimes they are not. The problems can lie in ethos or pathos rather than logos.

It's an informal fallacy; the conclusion is invalid if the premise is false, and the burden of proof is on the presenter. They own the obligation to ensure the premise is true, so if there is a question, their argument is incomplete. I don't think it's necessarily an issue of good faith or not. 

I just wanted to know what to call it when it comes up. No need to debunk such an argument until the premise has been verified.

[Eise]

Maybe this distinction can help others to clarify what you want to say to them: the difference between a valid argument and a sound argument:

Quote

 

A deductive argument is said to be valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false. Otherwise, a deductive argument is said to be invalid.

A deductive argument is sound if and only if it is both valid, and all of its premises are actually true. Otherwise, a deductive argument is unsound.

 

From here.

[studiot]

40 minutes ago, Eise said:

Maybe this distinction can help others to clarify what you want to say to them: the difference between a valid argument and a sound argument:

From here.

Thank you for this link.

Quite a good presentation.

I do note however, that the examples given are examples of what I was talking about, namely fallacies that arise from combinations of premises.

swansont has already pointed out that he specified a single premise only.

[dimreepr]

22 hours ago, swansont said:

Maybe it is, but that’s not the point of contention here. The issue is that it’s unsupported. Nothing offered to show that it’s true. 

It's still basically the same question, in that nothing offered that you consider to be true. 

[swansont]

4 hours ago, studiot said:

Thank you for this link.

Quite a good presentation.

I do note however, that the examples given are examples of what I was talking about, namely fallacies that arise from combinations of premises.

swansont has already pointed out that he specified a single premise only.

Your previous objection, as I read it, was that it was how the combination was connected - “and” vs “or” - and that’s not the issue. It’s the dubious veracity of a premise, like in the example “all toasters are made of gold” *

More than one premise could be false, but that’s irrelevant. You can’t assert the conclusion is true until the dubious premise is confirmed. The link calls the toasters example a a valid argument but not a sound argument. My wording was that the conclusion was invalid, i.e. the truth value is still in question.

*all toasters contain 6 oz of gold
6 oz of gold is worth at least $10,000
Therefore, all toasters are worth at least $10,000

One premise is of dubious veracity. There is no connection confusion. The conclusion can’t be offered as being true.

 

[studiot]

3 hours ago, swansont said:

Your previous objection, ...

That wasn't an objection that was an attempt to supply additional information.

If there is more than one premise either the premises are totally independent from each other or they are not.

This has a bearing on the deductive process.

All I was offering was a link to some well presented tables tabulating possibilities.

[sethoflagos]

9 hours ago, Eise said:

Maybe this distinction can help others to clarify what you want to say to them: the difference between a valid argument and a sound argument:

From here.

Thank you, yes. That's the distinction I was attempting to refer to.

[MSC]

On 9/28/2024 at 3:15 PM, iNow said:

Fallacy of unwarranted assumption 

https://onlinelibrary.wiley.com/doi/abs/10.1002/9781119165811.ch100

So this is why I hate when other philosophers say "we need to make some baseline assumptions in order to..." Or something similar.

[swansont]

2 hours ago, MSC said:

So this is why I hate when other philosophers say "we need to make some baseline assumptions in order to..." Or something similar.

I don’t mind when assumptions are clearly labeled as such. It’s presenting them as if they were fact that I have an issue with.

“If A then B” vs “A, therefore B”

[MSC]

9 minutes ago, swansont said:

I don’t mind when assumptions are clearly labeled as such. It’s presenting them as if they were fact that I have an issue with.

“If A then B” vs “A, therefore B”

I get that; there are times though where even though "if" was used, the assumption itself still sounds like it was pulled from ass or ether. This might just be due in part to the lack of an explanation as to why it was necessary to make the initial assumption. There is also just a difference in principle and method, as I personally don't like to base my premises on assumptions but factual observations and if I ever do have to make an assumption, it is ordered more toward the conclusion being the assumption, based on the facts of the premise.

So it's more like "premise A and B are true, therefore we can assume C" an example; we observe stars to be hot and spherical, therefore we can assume all stars are hot and spherical until proven otherwise. 

Another example; We observe humans to be engaged in value based behaviors, therefore we can assume humans have and care about values. I could maybe go a step further and say it may be safe to assume this makes it impossible for a nihilist to exist without engaging in behavior that betrays nihilism.