Re: Within Proof Theoretic Semantics Gödel's G h as no meaning in PA
Mikko <[email protected]>
| Newsgroups | comp.theory,comp.ai.philosophy,sci.logic,sci.math |
|---|---|
| Organization | A noiseless patient Spider |
| Message-ID | <[email protected]> |
On 06/07/2026 20:11, olcott wrote: > On 7/6/2026 4:25 AM, Mikko wrote: >> On 05/07/2026 00:01, olcott wrote: >>> On 7/4/2026 12:11 PM, dbush wrote: >>>> On 7/4/2026 1:07 PM, olcott wrote: >>>>> On 7/4/2026 3:06 AM, Mikko wrote: >>>>>> On 03/07/2026 21:20, olcott wrote: >>>>>>> On 7/3/2026 12:35 PM, André G. Isaak wrote: >>>>>>>> On 2026-07-03 09:38, olcott wrote: >>>>>>>>> On 7/3/2026 4:28 AM, Mikko wrote: >>>>>>>>>> On 02/07/2026 17:49, olcott wrote: >>>>>>>>>>> On 7/2/2026 1:55 AM, Mikko wrote: >>>>>>>>>>>> On 01/07/2026 18:16, olcott wrote: >>>>>>>>>>>>> On 7/1/2026 2:24 AM, Mikko wrote: >>>>>>>>>>>>>> On 30/06/2026 16:58, olcott wrote: >>>>>>>>>>>>>>> On 6/30/2026 3:18 AM, Mikko wrote: >>>>>>>>>>>>>>>> On 29/06/2026 16:29, olcott wrote: >>>>>>>>>>>>>>>>> On 6/29/2026 1:14 AM, Mikko wrote: >>>>>>>>>>>>>>>>>> On 29/06/2026 05:52, olcott wrote: >>>>>>>>>>>>>>>>>>> On 6/28/2026 3:39 AM, Mikko wrote: >>>>>>>>>>>>>>>>>>>> On 27/06/2026 17:50, polcott wrote: >>>>>>>>>>>>>>>>>>>>> On 6/27/2026 1:53 AM, Tristan Wibberley wrote: >>>>>>>>>>>>>>>>>>>>>> On 20/06/2026 18:32, olcott wrote: >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>> A proof theoretic expression is known to be true >>>>>>>>>>>>>>>>>>>>>>> when >>>>>>>>>>>>>>>>>>>>>>> it is fully grounded in its atomic base. Only two >>>>>>>>>>>>>>>>>>>>>>> PTS semantics researchers deal with true Dag Prawitz >>>>>>>>>>>>>>>>>>>>>>> is the one that began this. PTS previously only >>>>>>>>>>>>>>>>>>>>>>> dealt >>>>>>>>>>>>>>>>>>>>>>> with semantic meaning and never got around to >>>>>>>>>>>>>>>>>>>>>>> true(L,x). >>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>> That's surprising, disregard for axioms? >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> If there is no sequence of inference steps in Q from >>>>>>>>>>>>>>>>>>>>> ~∃x x=S(x) to the axioms of Q then ~∃x x=S(x) is >>>>>>>>>>>>>>>>>>>>> ungrounded in the PTS atomic base of Q. >>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>> This does not mean undecidable or incomplete >>>>>>>>>>>>>>>>>>>>> it means that ~∃x x=S(x) is out-of-scope for Q. >>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>> It comes close. If ∃x x=S(x) is likewise >>>>>>>>>>>>>>>>>>>> "ungrounded" but in the >>>>>>>>>>>>>>>>>>>> language of Q then ~∃x x=S(x) and ∃x x=S(x) are both >>>>>>>>>>>>>>>>>>>> undecidable >>>>>>>>>>>>>>>>>>>> and Q is incomplete, bcause that is what the words >>>>>>>>>>>>>>>>>>>> mean. >>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>> Q also can't bake a birthday cake, this does not make >>>>>>>>>>>>>>>>>>> Q in any way "incomplete" relative to what it was >>>>>>>>>>>>>>>>>>> defined to do. Incomplete only counts relative to >>>>>>>>>>>>>>>>>>> its intended purpose. A car without an engine is >>>>>>>>>>>>>>>>>>> incomplete relative to a mode of transportation. >>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>> Irrelevant. The definition of completeness >>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>> It a misnomer and does not literally mean (as it implies) >>>>>>>>>>>>>>>>> that something is missing that could be added to make >>>>>>>>>>>>>>>>> it complete. >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> It does mean that something is missing that could be >>>>>>>>>>>>>>>> added to >>>>>>>>>>>>>>>> enabe a proof of an unprovable sentence. >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> Base-Extension Semantics (B-eS) allows that. >>>>>>>>>>>>>>> It never was incomplete. It always did what it was >>>>>>>>>>>>>>> defined to do. >>>>>>>>>>>>>>> When Q is extended to become PA it stops being Q and >>>>>>>>>>>>>>> becomes PA. >>>>>>>>>>>>>> >>>>>>>>>>>>>> However, there are theories that reamain incomplete even when >>>>>>>>>>>>>> more postolates are added, as long as there is a way to know >>>>>>>>>>>>>> which sentences are included in the added postulates. >>>>>>>>>>>>>> Important >>>>>>>>>>>>>> examples include Peano arithmetic and ZFC set theory. >>>>>>>>>>>>> >>>>>>>>>>>>> Base-Extension Semantics (B-eS) seems to be essentially a >>>>>>>>>>>>> cheat. >>>>>>>>>>>>> When we ask what is grounded in an atomic base of Q and we >>>>>>>>>>>>> add axioms to Q to become PA we cheated in that we changed >>>>>>>>>>>>> the original question rather than answered it. >>>>>>>>>>>> >>>>>>>>>>>> Yes, in a sense. But sometimes it is better to have a >>>>>>>>>>>> partial answer >>>>>>>>>>>> rather than no answer at all. Of course Q with any additional >>>>>>>>>>>> postulate is not Q but if the additional postulates are true >>>>>>>>>>>> about >>>>>>>>>>>> natural numbers then the strengthened theory is still a >>>>>>>>>>>> theory of >>>>>>>>>>>> natural numbers. PA is one such strengthened Q but still >>>>>>>>>>>> incomplete >>>>>>>>>>>> and can be strengthened further. >>>>>>>>>>> >>>>>>>>>>> Is (∀x, S(x) ≠ x) provable or refutable in Q? >>>>>>>>>>> Yes if you cheat, no if you don't cheat. >>>>>>>>>> >>>>>>>>>> As I already pointed out in another message, which you apparently >>>>>>>>>> missed, it is neither. >>>>>>>>> >>>>>>>>> Thus PTS would say that (∀x, S(x) ≠ x) is semantically >>>>>>>>> undefined in Q. >>>>>>>> >>>>>>>> And that differs from claiming that Q is incomplete exactly how...? >>>>>>> >>>>>>> The base definition of "incomplete" means that it is >>>>>>> not operating according to design spec. >>>>>> >>>>>> No, it is not. The term "incomplete" in its base meaning is >>>>>> appicable to various things that are not exprected to operate. >>>>>> >>>>> >>>>> The English word "incomplete" establishes the base >>>>> meaning (parent node) in the knowledge ontology. >>>>> >>>>> I will not tolerate deceptive terms-of-the-art. >>>> >>>> In other words, you intend to lie by misusing definitions. >>> >>> These definitions are the liars. >> >> Maybe your definitions, but not the usual ones, which tell truthfully >> how the defined words are used and understood by the experts. > > Within the natural preexisting order of the body > of knowledge There is no natural pre-existing order of the body of knowledge. > saying that incomplete(math) inherits > part of its meaning from incomplete(base) semantic > parent node is simply a lie. Then don't say so. > Using the code word of "cat" for a dalmatian dog > is equally dishonest. Then don't use that word, or if you need to, add "sensu ..." where ... is the author whose definition you refer to. > It violates the natural > preexisting order of the body of knowledge. The natural order of the body of knowledge is not pre-existing, it is non-existing. >>> Term-of-the-art >>> A cat is a dalmatian dog >> Perhaps some art but neither ailurology nor cynology. -- Mikko