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

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   Message 262,763 of 262,912   
   olcott to Mikko   
   Re: The Halting Problem asks for too muc   
   31 Jan 26 09:26:43   
   
   XPost: comp.theory, sci.math   
   From: polcott333@gmail.com   
      
   On 1/31/2026 2:56 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.   
   >>>   
   >>   
   >> If there was then there never would be a Tarski proof.   
   >> https://liarparadox.org/Tarski_247_248.pdf   
   >   
   > Irrelevant. Tarski's proof is what it is and there is no "occurs_check"   
   > there.   
   >   
      
   Sure and a car that has a missing engine will always   
   be a car that will not run.   
      
   --   
   Copyright 2026 Olcott

              My 28 year goal has been to make
       "true on the basis of meaning expressed in language"
       reliably computable for the entire body of knowledge.

              This required establishing a new foundation
              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)   

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