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   sci.logic      Logic -- math, philosophy & computationa      262,912 messages   

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   Message 262,774 of 262,912   
   olcott to Mikko   
   Re: The Halting Problem asks for too muc   
   01 Feb 26 09:18:03   
   
   From: polcott333@gmail.com   
      
   On 2/1/2026 4:28 AM, Mikko wrote:   
   > On 31/01/2026 17:23, olcott wrote:   
   >> On 1/31/2026 2:41 AM, Mikko wrote:   
   >>> On 30/01/2026 16:35, olcott wrote:   
   >>>> On 1/30/2026 3:34 AM, Mikko wrote:   
   >>>>> On 29/01/2026 15:57, olcott wrote:   
   >>>>>> On 1/29/2026 3:12 AM, Mikko wrote:   
   >>>>>>> On 28/01/2026 15:49, olcott wrote:   
   >>>>>>>> On 1/28/2026 3:54 AM, Mikko wrote:   
   >>>>>>>>> On 27/01/2026 17:32, olcott wrote:   
   >>>>>>>>>> On 1/27/2026 2:17 AM, Mikko wrote:   
   >>>>>>>>>>> On 26/01/2026 18:58, olcott wrote:   
   >>>>>>>>>>>> On 1/26/2026 10:45 AM, Richard Damon wrote:   
   >>>>>>>>>>>>> On 1/26/26 10:22 AM, olcott wrote:   
   >>>>>>>>>>>>>> On 1/26/2026 6:55 AM, Mikko wrote:   
   >>>>>>>>>>>>>>> On 25/01/2026 15:30, olcott wrote:   
   >>>>>>>>>>>>>>>> On 1/25/2026 5:24 AM, Mikko wrote:   
   >>>>>>>>>>>>>>>>> On 24/01/2026 16:18, olcott wrote:   
   >>>>>>>>>>>>>>>>>> On 1/24/2026 2:23 AM, Mikko wrote:   
   >>>>>>>>>>>>>>>>>>> On 22/01/2026 18:47, olcott wrote:   
   >>>>>>>>>>>>>>>>>>>> On 1/22/2026 2:21 AM, Mikko wrote:   
   >>>>>>>>>>>>>>>>>>>   
   >>>>>>>>>>>>>>>>>>>>> Anyway, what can be provven that way is true aboout   
   >>>>>>>>>>>>>>>>>>>>> PA. You can deny   
   >>>>>>>>>>>>>>>>>>>>> the proof but you cannot perform what is meta-   
   >>>>>>>>>>>>>>>>>>>>> provably impossible.   
   >>>>>>>>>>>>>>>>>>>   
   >>>>>>>>>>>>>>>>>>>> The meta-proof does not exist in the axioms of PA   
   >>>>>>>>>>>>>>>>>>>> and that is the reason why an external truth in   
   >>>>>>>>>>>>>>>>>>>> an external model cannot be proved internally in PA.   
   >>>>>>>>>>>>>>>>>>>> All of these years it was only a mere conflation   
   >>>>>>>>>>>>>>>>>>>> error.   
   >>>>>>>>>>>>>>>>>>>   
   >>>>>>>>>>>>>>>>>>> It is perfectly clear which is which. But every proof   
   >>>>>>>>>>>>>>>>>>> in PA is also   
   >>>>>>>>>>>>>>>>>>> a proof in Gödel's metatheory.   
   >>>>>>>>>>>>>>>>>>   
   >>>>>>>>>>>>>>>>>> ∀x ∈ PA (  True(PA, x) ≡ PA ⊢  x )   
   >>>>>>>>>>>>>>>>>> ∀x ∈ PA ( False(PA, x) ≡ PA ⊢ ¬x )   
   >>>>>>>>>>>>>>>>>> ∀x ∈ PA ( ¬WellFounded(PA, x) ≡   
   >>>>>>>>>>>>>>>>>>           (¬True(PA, x) ∧ (¬False(PA, x)))   
   >>>>>>>>>>>>>>>>>   
   >>>>>>>>>>>>>>>>> Those sentences don't mean anything without   
   >>>>>>>>>>>>>>>>> specificantions of a   
   >>>>>>>>>>>>>>>>> language and a theory that gives them some meaning.   
   >>>>>>>>>>>>>>>>   
   >>>>>>>>>>>>>>>> In other word you do not understand standard notational   
   >>>>>>>>>>>>>>>> conventions that define True for PA as provable from the   
   >>>>>>>>>>>>>>>> axioms of PA and False for PA as refutable from the axioms   
   >>>>>>>>>>>>>>>> of PA.   
   >>>>>>>>>>>>>>>   
   >>>>>>>>>>>>>>> There are no notational convention that defines True,   
   >>>>>>>>>>>>>>> False, and   
   >>>>>>>>>>>>>>> WellFounded with two arguments. And you did not specify   
   >>>>>>>>>>>>>>> in which   
   >>>>>>>>>>>>>>> context your sentences are true or otherwise relevant.   
   >>>>>>>>>>>>>>>   
   >>>>>>>>>>>>>>   
   >>>>>>>>>>>>>> “x is a single finite string representing   
   >>>>>>>>>>>>>> a PA‑formula, such as ‘2 + 3 = 5’.   
   >>>>>>>>>>>>>> True(PA, x), False(PA, x), and WellFounded(PA, x)   
   >>>>>>>>>>>>>> are meta‑level unary predicates classifying   
   >>>>>>>>>>>>>> that formula by its provability in PA.”   
   >>>>>>>>>>>>>>   
   >>>>>>>>>>>>>   
   >>>>>>>>>>>>> In outher words, you ACCEPT that the meta level can define   
   >>>>>>>>>>>>> what is true in PA?   
   >>>>>>>>>>>>>   
   >>>>>>>>>>>>> I thought you said that PA had to be able to determine the   
   >>>>>>>>>>>>> truth itself?   
   >>>>>>>>>>>>   
   >>>>>>>>>>>> We need a meta-level truth predicate anchored   
   >>>>>>>>>>>> only in the axioms of PA itself and thus not   
   >>>>>>>>>>>> anchored in the standard model of arithmetic.   
   >>>>>>>>>>>   
   >>>>>>>>>>> That predicate is not computable.   
   >>>>>>>>>>   
   >>>>>>>>>> That was Tarski's mistake.   
   >>>>>>>>>   
   >>>>>>>>> No, Tarski's proof is about a different problem, though the   
   >>>>>>>>> results   
   >>>>>>>>> are related and there are much similarity in the proofs. Tarski   
   >>>>>>>>> did   
   >>>>>>>>> not use Turing machines in the proof but a computability proof   
   >>>>>>>>> must   
   >>>>>>>>> use that.   
   >>>>>>>>   
   >>>>>>>> Because you refuse to understand the underlying   
   >>>>>>>> details of what occurs_check means I cannot   
   >>>>>>>> explain to you how Tarski erred.   
   >>>>>>>   
   >>>>>>> Irrelevant. There is no "occurs_check" in Tarski's proof.   
   >>>>>   
   >>>>> That would have no effet. Even if the metalanguage had an   
   >>>>> occcurs_check   
   >>>>> it would not be necessary to use it in a proof.   
   >>>>   
   >>>> It would only seem to have no effect because you   
   >>>> never bothered to understand what an occurs_check is.   
   >>>   
   >>> That assumption is false.   
   >   
   >> So far you have conclusively proven that you   
   >> do not understand what an occurs_check is.   
   >   
   > That's false. Your "proof" is not sound.   
   >> If you want to provide that you do know then   
   >> you must provide all of the correct details.   
   >   
   > That's false. Irrelevant details should not be included. Obvious details   
   > shold not be included, either, except those that someone asks about.   
   >   
   >> Merely claiming that my statement is false   
   >> is an assertion entirely bereft of supporting   
   >> reasoning thus inherently baseless.   
   >   
   > If you don't understand some point in the justification you may ask.   
   >   
      
   baseless claims are rejected out-of-hand   
      
   >>>> Truth is computable because “meaningful sentence”   
   >>>> is defined as “sentence with a well-founded   
   >>>> justification tree,” and evaluating any well-founded   
   >>>> tree always terminates. Anything else isn’t truth-apt.   
   >>>   
   >>> That "bcause" is wrong. Whether a sentence has a well-founded   
   >>> justifiation tree is not computable, especially for arithmetic   
   >>> sentences.   
   >>   
   >> My one half page of text explaining all of the key details   
   >> of my 28 years of work was completely validated by five   
   >> different LLM systems. proof theoretic semantics is correct   
   >> model theoretic semantics is profoundly wrong-headed.   
   >   
   > That "proof theoretic semantics is correct model theoretic semantics"   
   > may indeed be profoundly wrong-headed but there is another possibility   
   > that you just don't understand it.   
   >   
   >> Your ignorance of the details of well-founded proof theoretic   
   >> semantics makes your rebuttal baseless.   
   >   
   > No, that does not follow.   
   >   
   >>> But that does not alter the fact that an existence or non-existence   
   >>> of a metalanguage feature that is not present in the justification   
   >>> tree is irrelevant.   
   >   
   >> An existence or non-existence of a metalanguage feature   
   >> is entirely anchored in a totally wrong-headed notion.   
   >   
   > It does not matter where sometihing irrelevant is anchored.   
   >   
   >> The only way that this can be seen is to become an expert   
   >> in well-founded proof theoretic semantics.   
   >   
   > No reason to belive that.   
   >   
      
      
      
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