Re: ... cosmology? KNIGHT & KNAVE

2004-07-30 Thread Bruno Marchal
At 12:47 30/07/04 +0200, I wrote: >Oh, any accurate machine (for which Bp->p is true) is obviously normal. This is false. But an accurate stable machine will be stable. Just substitute p with Bp in (Bp -> p) to get BBp -> Bp. That's stability, not normality. Bruno http://iridia.ulb.ac.be/~marchal/

Re: ... cosmology? KNIGHT & KNAVE

2004-07-30 Thread Bruno Marchal
At 09:53 29/07/04 -0700, Hal Finney wrote: Tell me again where I am going wrong. OK. Consider each of these examples: 117. q ... 191. Bp ... 207. p -> q Now, we will say that the machines "believes" something if it is one of its theorems, right? So we can say that the machine "believes q", it "

Re: ... cosmology? KNIGHT & KNAVE

2004-07-29 Thread "Hal Finney"
Tell me again where I am going wrong. Consider each of these examples: 117. q ... 191. Bp ... 207. p -> q Now, we will say that the machines "believes" something if it is one of its theorems, right? So we can say that the machine "believes q", it "believes Bp", and it "believes p->q", right? W

Re: ... cosmology? KNIGHT & KNAVE

2004-07-29 Thread Bruno Marchal
Hal, I didn't see the whole post. So here is a sequel. At 11:01 28/07/04 -0700, Hal Finney wrote: BM: > You are right. It is powerful, but rather fair also. > let us define a machine to be stable if that is the case. When the > machine believes Bx the machine believes x. HAL: So in my terms, I can

Re: ... cosmology? KNIGHT & KNAVE

2004-07-29 Thread Bruno Marchal
At 11:01 28/07/04 -0700, Hal Finney wrote: This is confusing because "I believe p" has two different meanings. One is that I have written down "p" with a number in front of it, as one of my theorems. OK. Let us call it the *intended meaning* of "I believe p" or of "Bp". The other meaning is the

Re: ... cosmology? KNIGHT & KNAVE

2004-07-28 Thread "Hal Finney"
This is confusing because "I believe p" has two different meanings. One is that I have written down "p" with a number in front of it, as one of my theorems. The other meaning is the string "Bp". But that string only has meaning from the perspective of an outside observer. To me, as the machine,

Re: ... cosmology? KNIGHT & KNAVE

2004-07-28 Thread Bruno Marchal
At 09:54 27/07/04 -0700, Hal Finney wrote: I am confused about how "belief" works in this logical reasoner of type 1. Suppose I am such a reasoner. I can be thought of as a theorem-proving machine who uses logic to draw conclusions from premises. We can imagine there is a numbered list of everyth

Re: ... cosmology? KNIGHT & KNAVE

2004-07-28 Thread Bruno Marchal
Hi John, At 17:19 26/07/04 -0400, John M wrote: Bruno, (and Class) We have an overwhelming ignorance about Ks and Ks. We don't know their logical built, their knowledege-base, their behavior. Indeed. Is the K vs K rule a physical, or rather human statement, when - in the latter case there may be

Re: ... cosmology? KNIGHT & KNAVE

2004-07-27 Thread "Hal Finney"
I am confused about how "belief" works in this logical reasoner of type 1. Suppose I am such a reasoner. I can be thought of as a theorem-proving machine who uses logic to draw conclusions from premises. We can imagine there is a numbered list of everything I believe and have concluded. It starts

Re: ... cosmology? KNIGHT & KNAVE

2004-07-26 Thread John M
'know' or 'believe' in the future. If I go to the Office of Records, I may learn what that 'K' is. John Mikes - Original Message - From: "Bruno Marchal" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, July 26, 2004 12:49 PM Subject

Re: ... cosmology? KNIGHT & KNAVE

2004-07-26 Thread Bruno Marchal
Hi, At 19:47 23/07/04 +0200, I wrote: Big Problem 5: Could a native tell you "You will never know that I am knight" ? Very Big Problem 6: Could a native tell you "You will never believe that I am knight" ? It was perhaps not pedagogical to say "big" and "very big". Here John Mikes would be accura

Re: ... cosmology? KNIGHT & KNAVE & beyond.

2004-07-24 Thread Bruno Marchal
At 16:58 23/07/04 -0400, Jesse Mazer wrote: Bruno Marchal wrote: All right. But modal logic are (traditionaly) extension of classical logic, so that causal implication, or >natural language entailment, when study mathematically are generally defined through modalities + >"material implication".

Re: ... cosmology? KNIGHT & KNAVE

2004-07-24 Thread Bruno Marchal
At 14:46 23/07/04 -0400, Stephen Paul King wrote: Dear Bruno and Friends, After having read Smullyan's wonderful little book and reading these posts I would like to point out a problem that I see. The notion of Knights and Knaves, as Truth and Falsehood-tellers (or "reporters") respectively

Re: ... cosmology? KNIGHT & KNAVE

2004-07-23 Thread Jesse Mazer
Bruno Marchal wrote: All right. But modal logic are (traditionaly) extension of classical logic, so that causal implication, or >natural language entailment, when study mathematically are generally defined through modalities + >"material implication". So in a sense, you confuse yourself by prem

Re: ... cosmology? KNIGHT & KNAVE

2004-07-23 Thread Bruno Marchal
All right. But modal logic are (traditionaly) extension of classical logic, so that causal implication, or natural language entailment, when study mathematically are generally defined through modalities + "material implication". So in a sense, you confuse yourself by premature anticipation. I know

Re: ... cosmology? KNIGHT & KNAVE

2004-07-23 Thread John M
PROTECTED]> Sent: Friday, July 23, 2004 9:09 AM Subject: Re: ... cosmology? KNIGHT & KNAVE > Hi George, > > At 22:17 22/07/04 -0700, George Levy wrote: > > > >>(problem 4) > >>You get a native, and asks her if Santa Claus exists. > >>The na

Re: ... cosmology? KNIGHT & KNAVE

2004-07-23 Thread Bruno Marchal
Hi George, At 22:17 22/07/04 -0700, George Levy wrote: Hi Bruno Bruno Marchal wrote: You get a native, and asks her if Santa Claus exists. The native answers this: "If I am a knight then Santa Claus exists" What can you deduce about the native, and about Santa Claus? First let's assume tha

Re: ... cosmology? KNIGHT & KNAVE

2004-07-23 Thread Jesse Mazer
Bruno Marchal wrote: Let us suppose the native is knave. Then what he said was false. But he said "if I am a knight then >Santa Claus exists". That proposition can only be false in the case he is a knight and Santa Claus >does not exists. This only works if you assume his "if-then" statement was

Re: ... cosmology? KNIGHT & KNAVE

2004-07-23 Thread Stephen Paul King
Dear Bruno and Friends, After having read Smullyan's wonderful little book and reading these posts I would like to point out a problem that I see. The notion of Knights and Knaves, as Truth and Falsehood-tellers (or "reporters") respectively, tacitly assumes that these entities are Omnisci

Re: ... cosmology? KNIGHT & KNAVE

2004-07-23 Thread Bruno Marchal
At 16:15 23/07/04 +0200, Jan Harms wrote: > (problem 4) > You get a native, and asks her if Santa Claus exists. > The native answers this: "If I am a knight then Santa Claus exists" > What can you deduce about the native, and about Santa Claus? Lets give a name to the sentence: S="If I am

Re: ... cosmology? KNIGHT & KNAVE

2004-07-23 Thread Jan Harms
> (problem 4)> You get a native, and asks her if Santa Claus exists.> The native answers this:  "If I am a knight then Santa Claus exists"> What can you deduce about the native, and about Santa Claus?Lets give a name to the sentence:S="If I am a knight then Santa Claus exists"1. If t

Re: ... cosmology? KNIGHT & KNAVE

2004-07-23 Thread Bruno Marchal
Hi George, At 22:17 22/07/04 -0700, George Levy wrote: (problem 4) You get a native, and asks her if Santa Claus exists. The native answers this: "If I am a knight then Santa Claus exists" What can you deduce about the native, and about Santa Claus? First let's assume that the native is a

Re: ... cosmology? KNIGHT & KNAVE

2004-07-22 Thread George Levy
Hi Bruno Bruno Marchal wrote: You get a native, and asks her if Santa Claus exists. The native answers this:  "If I am a knight then Santa Claus exists" What can you deduce about the native, and about Santa Claus? First let's assume that the native is a knight. Since he tells

Re: ... cosmology? KNIGHT & KNAVE

2004-07-22 Thread Bruno Marchal
James, You may be saying something, but the problems are not that sophisticate. There where "default hypothesis", sure, like the hypothesis that the Knights and Knaves understand English ..., knows how to use a phone, and are able to survive more than a nanosecond ... There might be sense in your r

Re: ... cosmology? KNIGHT & KNAVE

2004-07-22 Thread James N Rose
ge- > From: James N Rose <[EMAIL PROTECTED]> > Sent: Jul 22, 2004 8:26 AM > To: [EMAIL PROTECTED] > Subject: Re: ... cosmology? KNIGHT & KNAVE > > Bruno, > > Nice story and game depiction; it does help - somewhat - to explain > a more expansive generalization of

Re: ... cosmology? KNIGHT & KNAVE

2004-07-22 Thread James N Rose
Bruno, Nice story and game depiction; it does help - somewhat - to explain a more expansive generalization of 'decidability' ..the bedrock on which 'logic' (at least for the traditional understanding of that term) relies. Global consistency 'permits' decidability 'which permits' logic. But t

Re: ... cosmology? KNIGHT & KNAVE

2004-07-22 Thread Bruno Marchal
Hi All Perhaps George Levy is right and I should explain better the strategy before proceeding. The role of the logical puzzle is to encourage you to some introspection. The puzzle are easy but at some point we will give the puzzle to the machine just for studying its "psychology". You will see Joh

Re: ... cosmology? KNIGHT & KNAVE

2004-07-21 Thread John M
- Original Message - From: "Russell Standish" <[EMAIL PROTECTED]> To: "John M" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]>; "Bruno Marchal" <[EMAIL PROTECTED]> Sent: Tuesday, July 20, 2004 7:29 PM Subject: Re: ... cosmology? KNIGHT &

Re: ... cosmology? KNIGHT & KNAVE

2004-07-21 Thread Bruno Marchal
George, At 21:17 20/07/04 -0700, George Levy wrote: Bruno, John, Russell I am half-way through Smullyan's book. Nice! You will see how easy it will be to state precisely the main result and the open problems in my thesis once you grasp the whole FU. Of course, to really appreciate, there will be a

Re: ... cosmology? KNIGHT & KNAVE

2004-07-20 Thread George Levy
Bruno, John, Russell I am half-way through Smullyan's book. It is an entertaining book for someone motivated enough to do all these puzzles, but I think that what is missing is a metalevel discussion of what all this means. Mathematical fireworks occur because we are dealing with self-referenti

Re: ... cosmology? KNIGHT & KNAVE

2004-07-20 Thread Russell Standish
"What would your other brother say is the road to Baghdad?" Then take the other direction! Cheers On Tue, Jul 20, 2004 at 06:18:43PM -0400, John M wrote: > Dear Bruno, > > perhaps the list will forgive me a bit of distraction upon your knight > and knave k

Re: ... cosmology? KNIGHT & KNAVE

2004-07-20 Thread John M
Dear Bruno, perhaps the list will forgive me a bit of distraction upon your knight and knave koan. I call it a koan, because within your conditions there is no right solution to either of the questions. IMO Problem #1 is open, #2 is subject to unlisted circumstances. (Common sense). To make the qu