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

Posted:

**Tue Jan 22, 2019 3:34 pm**For the discussion of all things philosophical, especially articles in the magazine Philosophy Now.

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Posted: **Tue Jan 22, 2019 3:34 pm**

Posted: **Tue Jan 22, 2019 3:35 pm**

Of course. I am happy to oblige.Speakpigeon wrote: ↑Tue Jan 22, 2019 3:34 pmNo need for gimmicks. All you have to do is prove the argument not valid.

For all you know, I may be waiting for you.

EB

Please provide the truth-table for "MAY"

For all I know you may be waiting for me.

For all I know you may not be waiting for me.

There is a 50% chance that you may be waiting for me.

There is a 50% chance that you may not be waiting for me.

If there are no probabilities in "MAY" then I may be wrong.

If there are probabilities in "MAY" then I may be right.

There is a 50% chance that there are probabilities in "MAY".

There is a 50% chance that there are no probabilities in "MAY".

So with all your sophistry I still can't get a damn answer to a simple question: Are you waiting for me? Yes or no!

"Maybe!", proudly declares the sophist.

https://en.wikipedia.org/wiki/Decidabil ... cal_system

P.S I do insist on the $100 - for my sake, more than yours.Each logical system comes with both a syntactic component, which among other things determines the notion of provability, and a semantic component, which determines the notion of logical validity.

Posted: **Tue Jan 22, 2019 4:29 pm**

Since there are no probabilities in "may" then I guess there is no semantic distinction between:Speakpigeon wrote: ↑Tue Jan 22, 2019 3:32 pmThere'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.

* Speakpigeon may put his money where his mouth is.

* Speakpigeon will put his money where his mouth is.

Wait and see, I guess.

Posted: **Tue Jan 22, 2019 5:49 pm**

No need for gimmicks.

All you have to do is prove the argument not valid.

EB

All you have to do is prove the argument not valid.

EB

Posted: **Tue Jan 22, 2019 6:18 pm**

Seems we having a hard time deciding whether the argument is valid or invalid. I wonder why?Speakpigeon wrote: ↑Tue Jan 22, 2019 5:49 pmNo need for gimmicks.

All you have to do is prove the argument not valid.

EB

Oh yea... because decidability.

https://en.wikipedia.org/wiki/Decidability_(logic)

I notice you haven’t furnished a truth-table for the semantics of "MAY" yet. This makes it difficult to determine the validity of your argument. One may just accuse you of obscuring the truth.Each logical system comes with both a syntactic component, which among other things determines the notion of provability, and a semantic component, which determines the notion of logical validity.

Posted: **Tue Jan 22, 2019 7:40 pm**

Because those aren't arguments, they're just a pair of statements that C might or might not have something to do with A.Logik wrote: ↑Tue Jan 22, 2019 6:18 pmSeems we having a hard time deciding whether the argument is valid or invalid. I wonder why?Speakpigeon wrote: ↑Tue Jan 22, 2019 5:49 pmNo need for gimmicks.

All you have to do is prove the argument not valid.

EB

The setup includes some of the language of an argument, but that's just a disguise. The bit that goes therefore doesn't depend for its truth on the premises at all, so it isn't a conclusion, it's just a sentence with "therefore" inserted up front to confuse you.

I've given up on waiting for philosopher to get done over

Posted: **Tue Jan 22, 2019 8:20 pm**

The argument is probably valid. Chance is involved in such an argument therefore one should know what are the chances.

Posted: **Tue Jan 22, 2019 8:40 pm**

Well, either the argument is valid or it isn't. It's definitely not a question of probability. May be you're unsure, but "probably" isn't the proper word in this case.

I don't see where "chance" could come.So, if you could try to pinpoint for me what in the argument would introduce a factor chance.

Reminder (2nd argument)

EBP1 - For all we know, A may be the state of some part of B;

P2 - What C does is determined by the state of some part of B;

C - Therefore, for all we know, what C does may be determined by A.

Posted: **Tue Jan 22, 2019 9:02 pm**

To be honest I simply see the argument as a tautology. A and B are subsets of X. Is A = B possible? Yes, end of story.Speakpigeon wrote: ↑Tue Jan 22, 2019 10:08 amOK, 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

Posted: **Tue Jan 22, 2019 9:03 pm**

This is not a classic argument.Speakpigeon wrote: ↑Tue Jan 22, 2019 8:40 pmWell, either the argument is valid or it isn't. It's definitely not a question of probability. May be you're unsure, but "probably" isn't the proper word in this case.

You used "may" in P1. The chance comes from there. If you replace may be with certainly is then the argument is valid. If you replace may be with impossibly is then your argument is invalid. May sites somewhere between certainly and impossibly.Speakpigeon wrote: ↑Tue Jan 22, 2019 8:40 pmI don't see where "chance" could come.So, if you could try to pinpoint for me what in the argument would introduce a factor chance.

Reminder (2nd argument)EBP1 - For all we know, A may be the state of some part of B;

P2 - What C does is determined by the state of some part of B;

C - Therefore, for all we know, what C does may be determined by A.

Posted: **Tue Jan 22, 2019 9:06 pm**

Lets assume B is made up of 100 parts.

Let A be the state of any one of those parts: Ba

Let C be determined by the state of part: Bc

Without any further information the probability of Ba coinciding with Bc is 1/100.

There is a 99% chance the conclusion is false (and therefore the argument is invalid)

And 1% chance the conclusion is true (and therefore the argument is valid).

The fewer parts B has - the higher the probability of this being a valid argument.

The more parts B has - the lower the probability of this being a valid argument.

Let A be the state of any one of those parts: Ba

Let C be determined by the state of part: Bc

Without any further information the probability of Ba coinciding with Bc is 1/100.

There is a 99% chance the conclusion is false (and therefore the argument is invalid)

And 1% chance the conclusion is true (and therefore the argument is valid).

The fewer parts B has - the higher the probability of this being a valid argument.

The more parts B has - the lower the probability of this being a valid argument.

Posted: **Tue Jan 22, 2019 9:18 pm**

Well, yes. OK.Atla wrote: ↑Tue Jan 22, 2019 9:02 pmTo be honest I simply see the argument as a tautology. A and B are subsets of X. Is A = B possible? Yes, end of story.Speakpigeon wrote: ↑Tue Jan 22, 2019 10:08 amHow 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

Still, it seems curious to me that our science computer loud spoke-person here should have no ready method for dealing with such a simple argument you and me find just so obviously valid. Isn't that curious?

EB

Posted: **Tue Jan 22, 2019 9:23 pm**

Speakpigeon wrote: ↑Tue Jan 22, 2019 9:18 pmWell, yes. OK.

Still, it seems curious to me that our science computer loud spoke-person here should have no ready method for dealing with such a simple argument you and me find just so obviously valid. Isn't that curious?

EB

For all we know If you play the lotto you MAY win.

For all we kow if you play the lotto you MAY not win.

I guess both arguments are valid then...

Time to bow out of the intellectual paralympics.

Posted: **Tue Jan 22, 2019 9:44 pm**

No, it isn't but it's not a complicated argument. You only need to take once difficulty at a time.

"May" isn't about "chance", it's about knowledge and uncertainty, as signalled by the phrase "For all we know".bahman wrote: ↑Tue Jan 22, 2019 9:03 pmYou used "may" in P1. The chance comes from there. If you replace may be with certainly is then the argument is valid. If you replace may be with impossibly is then your argument is invalid. May sites somewhere between certainly and impossibly.Speakpigeon wrote: ↑Tue Jan 22, 2019 8:40 pmI don't see where "chance" could come.So, if you could try to pinpoint for me what in the argument would introduce a factor chance.

So, given what we know, it is possible that A is the state of some part of B. No probability. Either it is true or it is false that given what we know, it is possible that A is the state of some part of B. No probability, no chance, no uncertainty.

For example, it is true that, given what we know, it is possible that a wave is the state of some part of the sea. It's not only possible, it's true. So, there's no uncertainty or chance or probability inherent in the form of the argument.

Second, we find "may" in the conclusion too, which is necessary to make the argument valid. But since the argument is valid, the conclusion will be true whenever the premises are true. There's no uncertainty in validity. It is valid or it isn't. The level of uncertainty will come when you substitute A, B and C with concrete terms, such as 'wave" and "sea". For example, if you substitute in premise 2, it is very definitely uncertain that what people do is determined by the state of some part of God, so any argument including this proposition as premise 2 would indeed be very uncertain, but not because of "may". If I put "may" in front of premise 2, then it becomes inevitably true in many cases: for example, it is obviously true that, for all we know, what people do may be determined by the state of some part of God. And here it's not "might", but "may", since we have no idea as to probabilities.

EB

Posted: **Tue Jan 22, 2019 9:51 pm**

Since you appear to be exercising Cunningham's law...Speakpigeon wrote: ↑Tue Jan 22, 2019 9:44 pm"May" isn't about "chance", it's about knowledge and uncertainty, as signalled by the phrase "For all we know".

Uncertainty is all about probability.

https://en.wikipedia.org/wiki/Uncertainty#Concepts

Measurement of uncertainty

A set of possible states or outcomes where probabilities are assigned to each possible state or outcome – this also includes the application of a probability density function to continuous variables.[2]