Re: Within Proof Theoretic Semantics Gödel's G h as no meaning in PA
Tristan Wibberley <[email protected]>
| Newsgroups | sci.logic,sci.math,sci.math.symbolic,comp.theory,comp.ai.philosophy |
|---|---|
| Organization | A noiseless patient Spider |
| Message-ID | <[email protected]> |
On 04/07/2026 16:31, Tristan Wibberley wrote: > On 06/05/2026 20:37, Julio Di Egidio wrote: >> On 02/05/2026 20:47, Scott Hoge wrote: >> >>> In Cantor's theorem, we do not actually construct a diagonal. >>> Rather, we presuppose that we can enumerate a set, and then, >>> /purely on the grounds of possibility/, conceive a diagonalized >>> non-element. >> >> Nope, as explained and re-explained ad nauseam around here: >> just the resident trolls won't get it. >> >> Cantor's diagonal argument, the one with the binary sequences, >> is indeed constructive: a definition of anti-diagonal of *any* >> (infinite) list is provided, and the proof that the anti-diagonal >> cannot be in the list is quite constructive. > > "quite" but not "completely". > > A constructive operation is defined, but a diagonal number is > constructed just when that constructive operation is applied to a > constructible list. I should note for the less knowledgable readers of course it's less often than that, it is only that often for systems such as the one Julio and Phoenix are using which allows dequantification of universally quantified statements into the system proper which then have derivable statements containing actual constructions of the constructible objects they apply to by virtue of their original quantification. Of course, dequantification of fantastically quantified statements doesn't make a statement about nonconstructible objects because there aren't any outside of the fantastical quantification. By which I don't mean to argue the countability of the set of reals as defined in what we call Cantor's Proof of the Uncountability of the Reals to include objects quantified over by fantatstical quantification but not by universal quantification, but it does make some meaning clearer. While some of the sets might have objects in the system proper, some of the members of some of the sets clearly do not. -- Tristan Wibberley The message body is Copyright (C) 2026 Tristan Wibberley except citations and quotations noted. All Rights Reserved except that you may, of course, cite it academically giving credit to me, distribute it verbatim as part of a usenet system or its archives, and use it to promote my greatness and general superiority without misrepresentation of my opinions other than my opinion of my greatness and general superiority which you _may_ misrepresent. You definitely MAY NOT train any production AI system with it but you may train experimental AI that will only be used for evaluation of the AI methods it implements.