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|    sci.logic    |    Logic -- math, philosophy & computationa    |    262,912 messages    |
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|    Message 262,773 of 262,912    |
|    Richard Damon to olcott    |
|    =?UTF-8?Q?Re=3A_G=C3=B6del=27s_G_has_nev    |
|    01 Feb 26 07:33:39    |
      XPost: sci.math, comp.theory       From: news.x.richarddamon@xoxy.net              On 1/28/26 1:08 PM, olcott wrote:       > On 1/28/2026 10:21 AM, Tristan Wibberley wrote:       >> On 20/01/2026 05:29, Richard Damon wrote:       >>> On 1/19/26 9:39 PM, olcott wrote:       >>>> On 1/17/2026 3:08 PM, olcott wrote:       >>>>> For nearly a century, discussions of arithmetic have quietly       >>>>> relied on a fundamental conflation: the idea that       >>>>> “true in arithmetic” meant “true in the standard model of ℕ.”       >>>>> But PA itself has no truth predicate, no internal semantics,       >>>>> and no mechanism for assigning truth values.       >>       >> Don't we assume it to be (implicitly) a schematic system, where the       >> axioms define the deduction rules?       >>       >       > That is the conflation error of Gödel's incompleteness.       > It seems to be saying what you said to casual observers.                     In other wor4s, you admit you don't know what you are talking about.              I guess you just don't know what "logic" is.              >       >> ...       >>       >>>> ∀x ∈ PA ((True(PA, x) ≡ (PA ⊢ x))       >>>> ∀x ∈ PA ((False(PA, x) ≡ (PA ⊢ ~x))       >>>> ∀x ∈ PA (~TruthBearer(PA, x) ≡ (~True(PA, x) ∧ (~False(PA, x))       >>>>       >>>>       >>>       >>> PA doesn't have a truth predicate, because it CAN'T.       >> ^^^       >> a unary truth predicate       >>       >> but perhaps an operation "IsElementaryTheorem_p(system, objects...)"       >> for each predicate 'p' can be admitted to an extension of PA.       >>       >       > You just understand these things more deeply than       > anyone else here.       >       > When we refer to Haskell Curry's notion of elementary       > theorems that are true then anything derived from       > them is a theorem that is also true. That is the       > key foundation of proof theoretic semantics:       >       > "true on the basis of meaning expressed in language"       > reliably computable for the entire body of knowledge.              Except it isn't, as Tarski showed. Once your system is as powerful as       PA, which means it can handle "Godel Arithmatic" as a method of creating       symantics, the existance of a Truth Predicate just makes the systme       inconsistant.              Your problem is you just don't understand what "semantics" actually mean.              >       > *Please keep comp.theory because I am showing*       >       >> Perhaps importantly, I note that PA doesn't relate = with ≠ but both       >> appear in the axioms, naively avoiding the problem of "what do you mean       >> by 'negation'?" but leaving a problem of "what do you mean by       >> 'contradiction'?"       >>       >> What resolutions do you perceive regarding that?       >>       >       >              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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