## Poll on the validity of two arguments

What is the basis for reason? And mathematics?

Moderators: AMod, iMod

## Are these two arguments valid?

1st argument - Valid
4
25%
1st argument - Not valid
3
19%
1st argument - I don't know
1
6%
1st argument - The argument doesn't make sense
1
6%
2nd argument - Valid
4
25%
2nd argument - Not valid
3
19%
2nd argument - I don't know
0
No votes
2nd argument - The argument doesn't make sense
0
No votes

Total votes: 16

Speakpigeon
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### Re: Poll on the validity of two arguments

Atla wrote: Mon Jan 21, 2019 10:05 pm Part of B in premise 1 and part of B in premise 2 are not necessarily the same, but it's possible that they are the same, and that's enough. If there's supposed to be more to the argument then I don't see it.
OK, thanks, that's it, and I think that's the best way to articulate the idea.
There is one remaining issue, though. Given what you just explained here, with which I fully agree, how do you prove validity in this case? How do you prove that the conclusion cannot be false if we assume both premises as true? Are we supposed to recognise you as the Oracle of Validity, or is there a method to prove that kind of arguments?
EB
Speakpigeon
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### Re: Poll on the validity of two arguments

Logik wrote: Mon Jan 21, 2019 10:14 pm
Speakpigeon wrote: Mon Jan 21, 2019 10:02 pm Since there isn't much else to understand, so, suddenly you can understand the argument?!
So you accept the argument is valid, or is it still somehow nonsense?
I am entirely ignoring your use of 'state' to parse your argument.
Ah, good, that's the way.
I think we could replace, in the two premises, "state" by "S", and "state of B" by S(B). Can your parsing agree with that?
There's nothing more to the word "state" here, at least as far as validity is concerned.
Soundness can only be impacted by what we mean by "state". However, you have to reason about validity independently of the issue of soundness.
Logik wrote: Mon Jan 21, 2019 10:14 pm The state of B can be coincidental not incidental to C. Correlation is not causation etc.
The argument doesn't mention causation. You would need to tighten a bit your parsing here. P2: What C does is determined by the state of B. So, the word used is "determined", not "caused".
Further, this point is also irrelevant to the question of validity. The same term is used in premise 2 and in the conclusion. So, we can also replace "determined".
For example, we can replace "What C does is determined by X" by D(C, X). Can your parsing agree with that?
Logik wrote: Mon Jan 21, 2019 10:14 pmIf the state of B is red (as in the colour) I would hesitate to conclude that what C does is caused by red.
And that's again only relevant to soundness, not validity, but given that A, B and C are unspecified terms, soundness cannot be assessed anyway.
So, I'm not asking you whether the premises are true, but whether if we assume that the premises are true, it is possible for the conclusion to be false.
So, valid or not valid?
EB
Last edited by Speakpigeon on Tue Jan 22, 2019 10:34 am, edited 4 times in total.
Logik
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### Re: Poll on the validity of two arguments

Speakpigeon wrote: Tue Jan 22, 2019 10:08 am There is one remaining issue, though. Given what you just explained here, with which I fully agree, how do you prove validity in this case?
Your argument is valid on the basis of you avoiding commitment.

"what C does may be determined by A"

"MAY be" can never be false. Therefore your argument can never be false when the premises are true. Therefore it can never be invalid.

What C does may be determined by A. Is a truism.

What the economy does MAY be determined by God. Anything is possible... (I had to fulfill FlashDangerpants's wish).
Speakpigeon
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### Re: Poll on the validity of two arguments

Logik wrote: Tue Jan 22, 2019 10:30 am
Speakpigeon wrote: Tue Jan 22, 2019 10:08 am There is one remaining issue, though. Given what you just explained here, with which I fully agree, how do you prove validity in this case?
Your argument is valid on the basis of you avoiding commitment.
Come on, if you're a computer scientist, we're talking about logic, not about whether I'm avoiding committing myself. That's definitely not a logical issue.
Once you accept meaningfulness, the argument is valid or it is not. So, we agree it's valid?
Logik wrote: Tue Jan 22, 2019 10:30 am "what C does may be determined by A". "MAY be" can never be false.
That's not true.
If I know that A is not B, then it's not true that may be A is B (epistemological modality).
If necessarily A is not B, then it's not true that may be A is B. (metaphysical modality).
If we know that what C does is not determined by A, then it not true that what C does may be determined by A.
Logik wrote: Tue Jan 22, 2019 10:30 amTherefore your argument can never be false when the premises are true.
So the argument is valid.
Yes, and you're correct it's because of the "may" in the conclusion, but the conclusion on it's own could well be false.
Logik wrote: Tue Jan 22, 2019 10:30 amAnd equivocal.
Oh, gosh, no. Equivocation is something else entirely. The language of the argument is very precise and definite. Zero equivocation.
Equivocal
1. Open to two or more interpretations and often intended to conceal the truth. See Synonyms at ambiguous.
2. Characterized by a mixture of opposing elements and therefore questionable or uncertain: Evidence of the drug's effectiveness has been equivocal.
See?
Still, given what you've learn in the last 24 hours, you should be able to formalise fully the argument since you accept it's valid. You're the science computer specialist here, and the parsing now should be crisp, so, what's holding you?!
EB
Logik
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### Re: Poll on the validity of two arguments

Speakpigeon wrote: Tue Jan 22, 2019 10:50 am The language of the argument is very precise and definite.

To make such claims of language requires some extraordinary evidence
Speakpigeon wrote: Tue Jan 22, 2019 10:50 am 1. Open to two or more interpretations and often intended to conceal the truth. See Synonyms at ambiguous.
All language and logic is open to infinite interpretations. Unless the rules for interpretation can be enforced.

As a computer scientist - I know this. Do you?
Speakpigeon wrote: Tue Jan 22, 2019 10:50 am See?
Still, given what you've learn in the last 24 hours, you should be able to formalise fully the argument since you accept it's valid. You're the science computer specialist here, and the parsing now should be crisp, so, what's holding you?!
EB
All I've learned in the last 24 hours is that you are an Aristotelian. A classical logician. Long way ahead for you.
Speakpigeon wrote: Tue Jan 22, 2019 10:50 am intended to conceal the truth
Oh yes! I Love this part!

By your own rules (which I don't really adhere to).
Either this statement is true:

What C does may be determined by A

or this statement is true.

What C does may NOT be determined by A.

Since your argument brings us no closer to actually deciding which one of the two above is true, would you say that you have revealed the truth?
By LEM again either:
A: You have revealed the truth.
B. You have not revealed the truth is true.

Would you say that "not revealing the truth" is the same as "concealing the truth", or is that a false dichotomy?

If it is not a false dichotomy then it's equivocation.
If it is a false dichotomy. Then lets just say that while you have not concealed the truth, you have not revealed it either.

Because either the state of C is or is not determined by A is a truism.

Which is why I referred you to probability theory right in the beginning. What probability do you have in mind when you use the word "MAY"?

If there is 1 in 1000 chance that C is determined by A, would you evaluate your conclusion as "true"?
What about 1 in 1000000?
What about 1 in 10000000000000000000000000000000000000000000?

What about 1 in X?

Is there any value for X (other than 0 and ∞) which would make you assert the "MAY" as false?
Speakpigeon
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### Re: Poll on the validity of two arguments

OK, so, I guess I was too presumptive here.
Contrary to what I had hoped it has appeared in the last few hours that all the extraordinary might and wisdom of the representative of the computer sciences industry lobby here can't prove the validity of a very, very simple modal argument that many people though untrained in computer sciences can nonetheless understand intuitively to be valid.
Ah, well, that's just life.
I guess I can only now hope philosophy can help.
EB
Logik
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### Re: Poll on the validity of two arguments

Speakpigeon wrote: Tue Jan 22, 2019 2:22 pm OK, so, I guess I was too presumptive here.
Contrary to what I had hoped it has appeared in the last few hours that all the extraordinary might and wisdom of the representative of the computer sciences industry lobby here can't prove the validity of a very, very simple modal argument that many people though untrained in computer sciences can nonetheless understand intuitively to be valid.
You can prove the validity of any argument as long as you define your semantics.
Can you define the semantic meaning of "MAY" ? A truth-table will do.

It boils down to decidability. https://en.wikipedia.org/wiki/Decidability_(logic)
Speakpigeon wrote: Tue Jan 22, 2019 2:22 pm Ah, well, that's just life.
I guess I can only now hope philosophy can help.
EB
No. It can't.

Q.E.D
Speakpigeon
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### Re: Poll on the validity of two arguments

Logik wrote: Tue Jan 22, 2019 3:14 pm Can you define the semantic meaning of "MAY" ? A truth-table will do. No. It can't. It's just an illusion.
But that's all you had to tell us. Why go into a tantrum about it. Our in-house computer sciences expert here can't define the logic of "may". That's all we need to know. Thanks you for articulating this perhaps difficult piece of trivia about you.
Me, I'm satisfied normal people understand the argument and understand it is valid.
Still, you should look into it. Maybe a Nobel Prize is waiting for you.
EB
Logik
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### Re: Poll on the validity of two arguments

Speakpigeon wrote: Tue Jan 22, 2019 3:21 pm
Logik wrote: Tue Jan 22, 2019 3:14 pm Can you define the semantic meaning of "MAY" ? A truth-table will do. No. It can't. It's just an illusion.
But that's all you had to tell us. Why go into a tantrum about it. Our in-house computer sciences expert here can't define the logic of "may". That's all we need to know. Thanks you for articulating this perhaps difficult piece of trivia about you.
Me, I'm satisfied normal people understand the argument and understand it is valid.
Still, you should look into it. Maybe a Nobel Prize is waiting for you.
EB
That's a lot of sophistry there.

All you need to define "MAY" is to provide a value for P(A) ∈ [0,1].

Any number other than 0.5...
Last edited by Logik on Tue Jan 22, 2019 3:26 pm, edited 1 time in total.
Speakpigeon
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### Re: Poll on the validity of two arguments

Logik wrote: Tue Jan 22, 2019 3:14 pm It boils down to decidability. https://en.wikipedia.org/wiki/Decidability_(logic)
Yes, it does.
The argument is intuitively valid because our brain can work out the decidability of the conclusion on the basis of the premises assumed true.
Your brain can't. Too bad.
EB
Logik
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### Re: Poll on the validity of two arguments

Speakpigeon wrote: Tue Jan 22, 2019 3:25 pm The argument is intuitively valid because our brain can work out the decidability of the conclusion on the basis of the premises assumed true.
Your brain can't. Too bad.
Not beyond .5 probability. Which is the same as flipping a coin.

Too bad your brain thinks it can.
Speakpigeon
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### Re: Poll on the validity of two arguments

Logik wrote: Tue Jan 22, 2019 3:25 pm All you need to define "MAY" is to provide a value for P(A) ∈ [0,1].
No probabilities in "may". Yet our brain can work out modal arguments. Except yours.
Where are probabilities in the logical truth that A and A implies B therefore B?
EB
Logik
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### Re: Poll on the validity of two arguments

Speakpigeon wrote: Tue Jan 22, 2019 3:28 pm No probabilities in "may".
Very good then. So you can provide us with a truth table?
Speakpigeon wrote: Tue Jan 22, 2019 3:28 pm Yet our brain can work out modal arguments. Except yours.
I am happy to demonstrate your idiocy as soon as you put forward the truth-table for "MAY".

But I do want to make things more interesting, because empty words are no fun.
I like to make bets. For money and stuff.

So that being stupid hurts.

\$100 to a charity of the winner's choosing?
Speakpigeon
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### Re: Poll on the validity of two arguments

Logik wrote: Tue Jan 22, 2019 3:26 pm Not beyond .5 probability. Which is the same as flipping a coin. Too bad your brain thinks it can.
There's no probability in "may". And yet we do it.
There are no probabilities in the logical truth that A and A implies B therefore B and yet we do it.
EB
Logik
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### Re: Poll on the validity of two arguments

Speakpigeon wrote: Tue Jan 22, 2019 3:32 pm There's no probability in "may". And yet we do it.
There are no probabilities in the logical truth that A and A implies B therefore B and yet we do it.
Yes. This is a 2nd time you state your misunderstanding.

Truth-table please.