h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

hi jank-

'doh! mean Hawkins thread not Genesis'

I fear you are confusing Stephen Hawking the well known cosmologist with the now deceased actor Jack Hawkins (most famous for his role in 'The Cruel Sea') or possibily the fictional cabin boy, Jim Hawkins, aboard the equally fictional schooner, the Hispaniola, Jim Hawkins

I am engaged on that thread and with Mr. Waling because of a circuitous connection wit Mr. T's intervention of the 'Compatibilsm is rubbish' thread where we are all trying to out do each other in being exceedingly boring (Note oblique but intentional reference to Mr. Kipling's Cakes here).

Having taken the necessary medication I am just about to 'do' the Festival for one last time without developing Glittering Eye Syndrome (which is unrelated to CLIBES except that both involve eyes)

On Sunday I shall assume a number of real roles that will include, but will not be restricted to, captain, (part-)owner and cabin boy and will sail the real 40ft Bermuda rigged ketch Das Boot ( named of course after the fictional U-boat, Das Boot) to parts other than the Spanish Main.....

(Memo to self I need to find a Nazi era Kriiegsmarine flag so I can sail under 'false colours' so emulating Long John Silver though lacking, of course, both pegleg and parrot.)

bsy

Hi Bx4,

The cut got me, I was just going to clarify:

let p = clearbury eats cornflakes at (x,y,z,t)

Then p is assigned a truth value in reference to a timeless fact, namely, clearbury eating cornflakes at (x,y,z,t) (or not).

Ig is an omniscient agent then we can say:

@(p <=> Kg(p))

What we can't do is reach clearbury's conclusion, namely that it wasn't possible for clearbury to do otherwise.

hi psi

busy at the moment but a quick summary.

The recent exchange between stephen and myself was not, except very tangentially about 'omniscience' It was more about three related issues and one, insofar as I can see, a wholly unrelated, one. Much of the discussion centred on the conditional:

If there will be a sea battle at (x,y,z,t) then there is a sea battle at (x,y,z,t)(P->Q)

1. Despite stephen's insistence that his argument was not about 'future contingents' it rested on the assertion of a tensed fact:

'My point is we agree (I think) that the reason it's true today that there will be a sea battle tomorrow is that there will be (assuming it's true)'(m495)

Which if it does not make P a future contigent certainly raises the issue of how a future tensed fact makes a future tensed sentence a true proposition. Stephen has not addressed this.

2. That incompletely indexed token relexive expressions like 'There will be a sea battle tomorrow' are not propositions unless they are fully indexed to the extent that they unambiguously reference a particular location ans time something like:

'There will be a sea battle in the northern edge of the Gulf of Patras, off Western Greece during 7 October 1571'

Note, that I am not requiring propositions to be tensless only the correlating fact. In fact this allows a future tensed proposition to be true without involving future contingents. stephen has not addressed this

4.Hintikka's argument that tensed propositions that are made true by being the correlate of a tenseless fact are necessary prpoposition and not contigent. Stephen has not addressed this.

5. A very odd argument indeed which seems to be based in part on the claim that in the conditional P->Q above in fact says P->P:

'Nothing to do with whether these are contingent events, it's just true because the second part of the statement is the same as the first' (M495)

Which is nonsense because P and Q are different prpositions by virtue of their tenses so the Priciple of Identity is irrelevant

Which is followed by an even odder claim that the Priciple of the Excluded Middle is of relevance to P->Q apparently because:

'So we start with assuming that certain possibilities are mutually exclusive like Clearbury eating cornflakes for breakfast or eating shreddies for breakfast and end up with an argument that does no more than show the possibilities are mutually exclusive.'

I have argued that neither PI nor PEM are of any relevance to the different propositions P and Q and that since both are made necessarily true by a correlating fact the ¬P and ¬Q do feature and so of little relevance.

'If g is an omniscient agent then we can say: @(p <=> Kg(p))

I'm not sure. I presume your treating @(p <=> Kg(P)) as a strict biconditional Such that

(p->Kg(p)).(Kg(p)->p)

I don't see a problem with the second term which is simply axiom T of epistemic system T. However, I think there are a couple of problems with the first term.

One being that without considerably more work it doesnt quite work as a strict conditional and also that some form of universal quantification is require to make the omniscience conditiion apply to all events in Ua rather than some arbitray event Ea.

This is bit fiddly though and I want to think about it further.

'What we can't do is reach clearbury's conclusion, namely that it wasn't possible for clearbury to do otherwise.'

You have lost me here. If there is a tensless fact that clearbury eats cornflakes (x,y,z,t) and as Hintikka argues this make P and Q necessary propositions how can they be contingent?

must dash
bsy

Hi Bx4,

I agree with most of that but feel that stephen's agreement could be achieved with a few tweaks. This unbridled optimism is of course folly. I just feel that if he took the tenseless fact aspect on board, all his arguments would pan out ok.

I'm a bit skeptical about this p -> @p business from Hintikka, so I'll read the paper and get back to you on that.

ttfn

hi psi

'I agree with most of that but feel that stephen's agreement could be achieved with a few tweaks. This unbridled optimism is of course folly. I just feel that if he took the tenseless fact aspect on board, all his arguments would pan out ok.'

I am not so sanguine. Stephen's claim that in P->Q, P and Q are identical suggests that he is tense 'blind'. Moreover since I think that our senses and cognitive structures are adapted to a 'ding fur uns' A-theoretic model of spacetime getting him to move from his tensed fact approach might be a bigger ask than you think.

I'm not clear why you think, if he accepted tenseless facts that his arguments would pan out. I find his argument that a principle of logic, the PEM is of any relevance to the ontological status of the fact.

It seems to me obvious that if P and Q are made true by a tenseless fact then to assert ¬P and ¬Q contravenes the PEM.

'I'm a bit skeptical about this p -> @p business from Hintikka, so I'll read the paper and get back to you on that.'

I'm not sure that the text of the paper is available on-line. I relied on my notes in my database on a print copy. I have now modified the database to accomodate scanned text but the Hintikka paper that is not on it

Hi Bx4,

You might well be right, but with smidge of amazing grace, and tenselessness accepted, he wouldn't need to frame things in terms of your P and Q. I thought he was moving in that direction.

The paper I have is:
"The Once and Future Sea Fight: Aristotle's Discussion of Future Contingents in DeInterpretatione"

and I've just noticed that I've also got:
"REASONING ABOUT KNOWLEDGE IN PHILOSOPHY;
THE PARADIGM OF EPISTEMIC LOGIC"

which looks like a barrel of laughs

ttfn

hi psi

'The Once and Future Sea Battle......'

That's the one. Do you have it as a printed text or an online document?

The fact that I have notes suggests that I had and may still have the papaper that I don't know where.

' he wouldn't need to frame things in terms of your P and Q. I thought he was moving in that direction.'

I don't think its my P and Q that present him with any difficulty it's his assumption that a principle of /logic/ is of any relevance to an ontology wherein there is the tenseless fact that precludes some /hypthetical/ alternative non-fac whatever that is.

'laughs'

But not 'banal'.

I have just turned up Kripke's 'identity and Necessity' which doesn't look a bundle of laughs either but has intersting things to say about epistemic and ontological necessity.

Hi Bx4,

"That's the one. Do you have it as a printed text or an online document?"
Pdf. I downloaded it yesterday. You'll have no difficulty in getting it if you don't have it already.

"I don't think its my P and Q that present him with any difficulty it's his assumption that a principle of /logic/ is of any relevance to an ontology wherein there is the tenseless fact that precludes some /hypthetical/ alternative non-fac whatever that is."
Isn't his view that, ontologically speaking, there can't be a sea battle at (x,y,z,t) and no sea battle at (x,y,z,t), and this means that a truth value can be assigned to p? Once we've done that, logical considerations involving p are subject to the principles of logic.

"I have just turned up Kripke's 'identity and Necessity' which doesn't look a bundle of laughs either but has intersting things to say about epistemic and ontological necessity."
Sounds fiddly...

hi psi

'Pdf. I downloaded it yesterday. You'll have no difficulty in getting it if you don't have it already'

It's available on Jstor and I have a Jstor account provided by our company but to use that is I think a form of theft and I'm not prepared to do that. I've googled but I haven't found a downloadable version. Push comes to shove I can always punt a for a paper reprint and get it faxed to me.

'Isn't his view that, ontologically speaking, there can't be a sea battle at (x,y,z,t) and no sea battle at (x,y,z,t), and this means that a truth value can be assigned to p? Once we've done that, logical considerations involving p are subject to the principles of logic.'

I don't have any problem with any of that where my problem lies i in this from stephen's M500

'What I mean is we are assuming mutually exclusive possibilities.

So we start with assuming that certain possibilities are mutually exclusive like Clearbury eating cornflakes for breakfast or eating shreddies for breakfast and end up with an argument that does no more than show the possibilities are mutually exclusive.'

(a claim with which you seem to agree -M502)

As I tried to explain to Stephen I don't think the PEM says anything about about alternate possibilities.

Also I think that that this also applies to some ontological equivalent MEP Since if there is a tenseless fact then it is impossible that there is not a tenseless fact and, contrariwise, if there is not a tenselees fact then it impossible that there is a tenseless fact.

I think my argument conforms to the Principle of Bivalence'

(I came across an interesting paper by Jean-Yves Béziau 'Bivalence, Excluded Middle and Non Contradiction'

which is available as pdf

Hi Bx4,

"It's available on Jstor and I have a Jstor account provided by our company but to use that is I think a form of theft and I'm not prepared to do that."
Fair enough.

"As I tried to explain to Stephen I don't think the PEM says anything about about alternate possibilities."
Well no, but that's why I offered my version above, with which you have no problem, as a sanitised version. So if this doesn't leave out of, or introduce anything important to stephen's point, then maybe he'd sign off on it?

"Also I think that that this also applies to some ontological equivalent MEP Since if there is a tenseless fact then it is impossible that there is not a tenseless fact and, contrariwise, if there is not a tenselees fact then it impossible that there is a tenseless fact."
I don't agree with this. I think this is a cryptoMSF.

"Jean-Yves Béziau 'Bivalence, Excluded Middle and Non Contradiction'"
Thanks, I'll have a read.

hi psi

'then maybe he'd sign off on it?'

I think he has still to sign of on a B-theoretic temporal ontology, tenseless facts and that furure tensed propositions are not thereby future contingents.

I don't have a problem with your sanitised version that excludes alternate possibilities. However, I think stephen might.

'I don't agree with this. I think this is a cryptoMSF'

I don't see that it does since I am not treating 'impossible' as a modal operator but using it, as I have pointed out to stephen, in the same vernacular usage that can be found in:

'C. I. Lewis introduced the notion of strict implication. One proposition implies another (If P then Q) in the strict sense of the word if and only if it is /impossible/ that P should be true and Q false, that is, if the statement “P is true and Q is false” is inconsistent.'[my emphasis]
('Strict Implication', Blackwell Dictionary of Western Philosophy)

However

Strictly if clearbury eats cornflakes at (x,y,z,t) then clearbury does not not eat cornflakes at (x,y,z,t)

symbolically

p->(¬(¬p)); from which

@(p=>(¬(¬p))); from which

@p=>@(¬(¬p)); from which (as I have already pointed out to stephen)

@p=>@p, which is simply the Principle Identity

but since in @p=>@p the modality is properly distributed over the antecedent and consequent of the strict conditonal no modal scope fallacy has been committed.

However from the Principle of Identity to say @p=>@p is simply to say @p which makes p a necessary prposition rather than a contingent one and a necessary prposition could not be otherwise which is rather my point.


@(

Hi Bx4,

"However, I think stephen might."
Maybe we should try to test that then.

"I don't see that it does since I am not treating 'impossible' as a modal operator but using it, as I have pointed out to stephen, in the same vernacular usage that can be found in:"
Sorry, I'm a bit twitchy after weeks in this rabbit hole.

"Strictly if clearbury eats cornflakes at (x,y,z,t) then clearbury does not not eat cornflakes at (x,y,z,t)

symbolically

p->(¬(¬p)); from which

@(p=>(¬(¬p))); from which

@p=>@(¬(¬p)); from which (as I have already pointed out to stephen)

@p=>@p, which is simply the Principle Identity"
I can't argue with that.

"However from the Principle of Identity to say @p=>@p is simply to say @p which makes p a necessary prposition rather than a contingent one and a necessary prposition could not be otherwise which is rather my point."
Aaargh, look at my twitchy eye! Where's my cryptoMSF gun?

hi psi

'Maybe we should try to test that then'

Do we need to given what he said at m500? However, I'll leave it to you my penchant for symbolism (also known as can't be arsked to write it out in longhand) seems to produce an adverse reaction

'Sorry, I'm a bit twitchy after weeks in this rabbit hole.'
I'm quite enjoying it but the I don't take the metaphysics of Free Will and Determinism all that seriously.

As i said to stephen, i think, it all about semantics (aka mucking about with words).....

'I can't argue with that'

I seem to be winning you round.......

'Aaargh, look at my twitchy eye! Where's my cryptoMSF gun?'

Can you have an MSF, crypto or otherwise, when you only have /one/ necessary proposition, @p?

Hi Bx4,

"I'll leave it to you..."
Ok, I'll try to test it. What B-theory stuff should I read first?

"I'm quite enjoying it but the I don't take the metaphysics of Free Will and Determinism all that seriously."
Well, who can?

"I seem to be winning you round......."
You could probably win me round to the idea that water is water while you're at it.

"Can you have an MSF, crypto or otherwise, when you only have /one/ necessary proposition, @p?"
The cryptoMSF is revealed by the fact that you think you have @p

hi psi
'Ok, I'll try to test it. What B-theory stuff should I read first?'
I thought I'd given you a link upthread. I'll try and dig it out.

There is also an excellent book by D H Mellor, Real Time II which is what I used as a reference. Don't know if it's still in print.

I think I may have mentioned it to stephen but he didn't pick it up. You may not need it if you an get him to see the the problems with the notion of tensed facts.

'Well, who can?'

Stephen and clearbury, perhaps?

'You could probably win me round to the idea that water is water while you're at it'

Be fair I have persuaded you that water is /necessarily/ water.

Seriously though, If you look at my recent exchanges with stephen he makes much of the PI.

His point escaped me since in:

If there will be a sea battle at (x,y,z,t) then there is a sea battle at (x,y,z,t); P->Q

the antecedent and the consequent are not identical.

However I recently came across an odd remark where he claimed they were so for him P->Q is P->P. This what I meant when he seemed to be tense 'blind' as far as the conditional P->Q is cncerned. Don't really get his point though.

'The cryptoMSF is revealed by the fact that you think you have @p'

Unless, you can show that to assert @p=>@p is not equivalent to asserting @p then I rather think I have .

Anyhow I'm going to indulge in an Ardbeg and so to bed.

Not sure how much I'll be on tomorrow . I have foolishly allowed myself to be sucked into a couple of threads starring celebrity village atheists of the Clintist persuasion that exhibit a lack of rigour that would make a parliament of decorticate rooks ashamed.

I have to extract myself without saying anything in the least critical of the guru of their quasi-religion. This is difficult because I despise Clint even more than I despise Ratzinger who probably at least believes in the snake oil he sells....

You Ttitch. I rant. So it goes
bsy

hi psi

'p->(¬(¬p)); from which

@(p=>(¬(¬p))); from which

@p=>@(¬(¬p)); from which (as I have already pointed out to stephen)

@p=>@p, which is simply the Principle Identity"
I can't argue with that.'

Just to say I had forgotten this from stephen:

'What it seems to me you are saying is that clearbury was explaning that what we all take to be mutually exclusive possibilities, one or other but not both, are mutually exclusive possibilities.

But of course we know the not both bit that's just a given.'

Where he is asserting the the PEM allows logically alternate possibilities.

bsy

Hi Bx4,

"Unless, you can show that to assert @p=>@p is not equivalent to asserting @p then I rather think I have ."
Aha! That's the source of our main disagreement I think.

To assert @p=>@p is /not/ equivalent to asserting @p

The easiest way to see this is to let p = psiomniac is the president of France at t1

then to assert @p=>@p is just to say that if necessarily psiomniac is the president of France at t1 then necessarily psiomniac is the president of France at t1

This is true (and is a tautology).

However, to assert @p would be to say that, necessarily psiomniac is the president of France at t1, which is false.

ttfn

hi psi

'Aha! That's the source of our main disagreement I think.

To assert @p=>@p is /not/ equivalent to asserting @p'

The Principle of Identity and modus ponens says otherwise.

@p=>@p,@p|-@p

'The easiest way to see this is to let p = psiomniac is the president of France at t1

'then to assert @p=>@p is just to say that if necessarily psiomniac is the president of France at t1 then necessarily psiomniac is the president of France at t1'
Indeed, So far so good:

'This is true (and is a tautology).'

And again so far so good. The Principle of Identity.'

'However, to assert @p would be to say that, necessarily psiomniac is the president of France at t1, which is false'

Well it would certainly be false if there was /no/ tenseless fact of the President of France a t1 but I don't see how it can be if there is such a fact.

Recall Leweis' definition of strict implication:

'One proposition implies another (If P then Q) in the strict sense of the word if and only if it is impossible that P should be true and Q false, that is, if the statement “P is true and Q is false” is inconsistent'

So lets look at whether the implication p implies p satisfies the criterion of a strict conditional.

1. It is impossible that if the antecedent is true then the consequent is false

2. Alternatively, we /cannot/ say 'p implies ¬p' without being inconsistent.

So 'p implies p' /is/ a strict conditional that we can say 'strictly p implies p' or symbolically 'p->p'.

Now for /no/ other purpose than distiguishing between the /occurrences/ of p in the antecedent andin the consequent let us label antecedent p, pa, and consequent p, be pc giving a->pc. From which by modus ponens gives:

pa->pc;pa|-pc (1)

Which means to say /if/ pa is true pc /must/ be true , that is

pa(T)(->pc(T);pa(T)|-pc(T) (2)

Now if there is a tenseless fact that at t1 psiomniac is the President of France, F(pPFt1), then the proposition pa, 'psiomniac is the President of France at t1' is made true by it being the correlate of F(F(pPFt1).

From which it follows that the inference (2) is not only valid but sound.

Now since we have pa->pc == @(pa=>pc)==@pa=>@pc***

From which starting with (2) we get:

p(T)a->p(T)c == @(pa(T)=>pc(T))==@pa(T)=>@Pc(T)

From which by modus ponens:

@pa(T)=>@Pc(T); @Pa(t)|-@pc(T)

So I seem to have shown contrary to your:

'to assert @p would be to say that, necessarily psiomniac is the president of France at t1, which is false.'

That to say 'necessarily psiomniac is the president of France at t1' is true, neccessarily

(there is prbably so glaring misstep in the above but I can't see it)


***This is none of my doing but rather of the modal logic loons insistence that the perfectly good Lewis strict implication shouldd be replaced by one tha faffs about with the primitive alethic modality and material implivation. As a committed Quinian I find this all a bit dodgy but so it goes.

Hi Bx4,

"The Principle of Identity and modus ponens says otherwise."
This is rather puzzling. Let's take it step by step, then perhaps we will be able to see whether one of us has made an error, or whether there has been a miscommunication.

let's call my claim above C.

C: Asserting @p=>@p is not equivalent to asserting @p

So first, without alethic modality, just in propositional calculus, and leaving aside strict implication for a moment, do you agree that:

C': Asserting p=>p is equivalent to asserting p

?

Where 'equivalent to' just means 'the same as'.

psi

p == p=>p

Yes