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Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: olcott <polcott333@gmail.com> Newsgroups: sci.logic Subject: Re: How a True(X) predicate can be defined for the set of analytic knowledge Date: Sat, 5 Apr 2025 16:03:28 -0500 Organization: A noiseless patient Spider Lines: 65 Message-ID: <vss5r0$375du$5@dont-email.me> References: <vrfvbd$256og$2@dont-email.me> <vrjn82$1ilbe$2@dont-email.me> <vrmpc1$bnp3$1@dont-email.me> <vrmteo$cvat$6@dont-email.me> <vru000$33rof$1@dont-email.me> <vrug71$3gia2$6@dont-email.me> <0306c3c2d4a6d05a8bb7441c0b23d325aeac3d7b@i2pn2.org> <vrvnvv$ke3p$1@dont-email.me> <vs0egm$1cl6q$1@dont-email.me> <vs1f7j$296sp$2@dont-email.me> <vs3ad6$2o1a$1@dont-email.me> <vs4sjd$1c1ja$8@dont-email.me> <vs63o2$2nal3$1@dont-email.me> <vs6v2l$39556$17@dont-email.me> <vs8hia$13iam$1@dont-email.me> <vs8uoq$1fccq$2@dont-email.me> <vsb4in$14lqk$1@dont-email.me> <vsb9d5$19ka5$1@dont-email.me> <04aa9edbe77f4e701297d873264511f820d85526@i2pn2.org> <vsbu9j$1vihj$1@dont-email.me> <vsdlso$3shbn$2@dont-email.me> <vsen5l$th5g$5@dont-email.me> <vsg1b2$2ed9k$1@dont-email.me> <vsh9c9$3mdkb$2@dont-email.me> <vsj073$1g8q1$1@dont-email.me> <vsjn4k$26s7s$3@dont-email.me> <vsqn07$1nmlv$1@dont-email.me> <vsrqrl$2rgr9$3@dont-email.me> <03ebb956fb92c0d27959296f63dd38f5bf8809ff@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sat, 05 Apr 2025 23:03:29 +0200 (CEST) Injection-Info: dont-email.me; posting-host="553bf603fba0ab686689915e3400961c"; logging-data="3380670"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/6blhDdrDkzR6MQm3Favhy" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:QsfNSQlRJiN+waxa1y+MDShG9x4= In-Reply-To: <03ebb956fb92c0d27959296f63dd38f5bf8809ff@i2pn2.org> X-Antivirus: Norton (VPS 250405-6, 4/5/2025), Outbound message Content-Language: en-US X-Antivirus-Status: Clean Bytes: 4592 On 4/5/2025 3:15 PM, Richard Damon wrote: > On 4/5/25 1:56 PM, olcott wrote: >> On 4/5/2025 2:44 AM, Mikko wrote: >>> On 2025-04-02 16:03:32 +0000, olcott said: >>> >>>> On 4/2/2025 4:32 AM, Mikko wrote: >>>>> On 2025-04-01 17:56:25 +0000, olcott said: >>>>> >>>>>> On 4/1/2025 1:33 AM, Mikko wrote: >>>>>>> On 2025-03-31 18:33:26 +0000, olcott said: >>>>>>> >>>>>>>> >>>>>>>> Anything the contradicts basic facts or expressions >>>>>>>> semantically entailed from these basic facts is proven >>>>>>>> false. >>>>>>> >>>>>>> Anything that follows from true sentences by a truth preserving >>>>>>> transformations is true. If you can prove that a true sentence >>>>>>> is false your system is unsound. >>>>>> >>>>>> Ah so we finally agree on something. >>>>>> What about the "proof" that detecting inconsistent >>>>>> axioms is impossible? (I thought that I remebered this). >>>>> >>>>> A method that can always determine whether a set of axioms is >>>>> inconsistent >>>>> does not exist. However, there are methods that can correctly >>>>> determine >>>>> about some axiom systems that they are inconsistent and fail on >>>>> others. >>>>> >>>>> The proof is just another proof that some function is not Turing >>>>> computable. >>>> >>>> A finite set of axioms would seem to always be verifiable >>>> as consistent or inconsistent. This may be the same for >>>> a finite list of axiom schemas. >>> >>> If ordinary logic is used it is sufficient to prove that there is >>> a sentence that cannot be proven in order to prove consistency or >>> to prove two sentences that contradict each other in order to prove >>> inconsistency. But if neither proof is known there is no method to >>> find one. >>> >> >> We are only talking about the inability to detect >> that basic facts contradict each other. I need a >> 100% concrete example proving this that this is >> sometimes impossible. >> > > Read Godel's proof. > > Note, this follows from the incompleteness proof, as a proof of > consistency yields a proof of completeness and thus any set powerful > enough to be incomplete also can not prove its own consistancy. We are not talking about a proof of consistency of the whole system, only a proof of consistency of a finite set of axioms. Simply test them against each other. -- Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer