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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 |
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