Forums before death by AOL, social media and spammers... "We can't have nice things"
|    sci.logic    |    Logic -- math, philosophy & computationa    |    262,936 messages    |
[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]
|    Message 262,752 of 262,936    |
|    olcott to Tristan Wibberley    |
|    =?UTF-8?Q?Re=3A_G=C3=B6del=27s_G_has_nev    |
|    28 Jan 26 12:08:43    |
      XPost: sci.math, comp.theory       From: polcott333@gmail.com              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.              > ...       >       >>> ∀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.              *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?       >                     --       Copyright 2026 Olcott |
[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]
(c) 1994, bbs@darkrealms.ca