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[McLesterolBeast]

Does the definition of validity require that all circular arguments be valid, even if the premises are contradictory? For example, X, not X, therefor X. I realize a circular argument is always valid and, due to the nature of the definition, so is a contradictory argument - but when the two go together, it seems that it can't be. It was a multiple choice question on a midterm, for anyone who cares.

The textbook i had explained the requirements for validity in different ways. One was that it being an argument where if all the premises are true, then the conclusion would also be true. In the case above though, the premises cannot all be true, so it cannot even meet the requirements for consideration of a valid argument (or it seems like that). From the above definition of validity (though i dont even think it's a definition, but more of a test), a circular argument with contradictory premises wouldn't have the potential to be sound, and therefor making it invalid (correct me if im wrong).

Other sections say that it is valid if the conclusion merely preserves truth, which still raises questions of whether it can be valid since it both preserves truth and denies it. When they say that it must "preserve truth", it isnt clear whether it's intended to mean "the whole truth", or simply _a_ truth.

I fully expect this to drop off the front page in a matter of minutes. If you think you know though, take a shot.

 

[Hitokage]

No claim can serve as its own support. That's why circular arguments are logically broken.

So there you go.

 

[McLesterolBeast]

Like i said, according to my formal logic textbook, it's defined as valid in regards to formal logic (and as far as i know, that's the general consensus in the academic world). It just isn't a useful argument. That isn't the question though.

 

[fart]

what kind of formal logic is this? in mathematical logic what you're saying is completely meaningless. you'll have to give your definitions and logical rules if you want more discussion, because none of your logic works in any of the formalized systems i know of.

 

[McLesterolBeast]

Ok, here's the issue more clearly.

It gives three conditions that ought to be met in order to ensure validity.

d1: the premises support the conclusion. (there's a few pages on why a circular argument can get away with satisfying this)
d2: if all the premises were true, then the conclusion would also be true.
d3: it is impossible for the premises to be true with the conclusion false.

D2 is what i've got an issue with in this situation. If all the premises were true, the truth of the conclusion would be ambiguous... at best.

 

[fart]

it seems to me that you need to think about this in a more bottom-up manner. start with the rules then present your proposition. that definition requires more definitions that we don't have, and i can't be sure are consistent with what i'm familiar with.

 

[McLesterolBeast]

D1,2 and 3 are the three conditions for validity according to my textbook. Every search ive done has come up with similar conditions (worded slightly differently), and all confirm that a circular argument is valid.

 

[McLesterolBeast]

I can sort of see the reasoning behind it, but its semantical.

d2 and 3 rely on the fact that the premises CANT be true, so no condition can exist where those conditions are unmet.

d1 is somewhat of an issue since its unclear whether all premises must support the conclusion, or whether there must only be sufficient support and all extra ones are dismissed.

Regardless, i think youre right about it being an issue of an issue of definitions. They probably have a way of justifying it satisfying d1.

Im just hoping there was someone who could try and articulate why d2 and d3 are not satisfied, or not satisfiable, and why it ought not to be valid (the text alludes to many logicians objecting to its validity, but doesnt give specifics because it says the consensus is that it IS valid)

 

[NotMSRP]

In math, you start with axioms and postulates that you take for granted to be true. You don't question them because they just make sense to you; your brain doesn't complain.

They serve as a starting point. Circular logic doesn't work in mathematics because there's no starting point. Contradiction is that the conclusion ended up false which implies that the starting premise or proposition is false.

In other words, I don't know what kind of logic you are using. Doesn't seem like a type of logic that I would easily accept.

Is this suppose to be logic in a social context?

 

[McLesterolBeast]

...

formal logic. If you aren't familiar with it, i dont know how more specific i can be. I think aristotle was responsible for it's groundwork, though im not sure of the history.

This isn't really a mathematical question though, and if you aren't familiar with the field then it will look pointless.

 

[ballhog]

Actually, if you spend any time with it it will look pointless. Still interesting as an idea though.