Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Keith Thompson Newsgroups: comp.theory Subject: Re: Refutation of =?utf-8?Q?Turing=E2=80=99s?= 1936 Halting Problem Proof Based on Self-Referential Conflation as a Category (Type) Error Date: Mon, 21 Apr 2025 15:08:34 -0700 Organization: None to speak of Lines: 31 Message-ID: <87cyd5182l.fsf@nosuchdomain.example.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Date: Tue, 22 Apr 2025 00:08:35 +0200 (CEST) Injection-Info: dont-email.me; posting-host="e72db596057d83171632e4a496618536"; logging-data="3230107"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX18IVbgaH+Sw2fXKflD+ns76" User-Agent: Gnus/5.13 (Gnus v5.13) Cancel-Lock: sha1:kX3rpJRts4mp0QmDtxPTzgelImc= sha1:sCcAOxpN7TYQwsUGahDnxhZ7WZ4= Bytes: 2542 Mr Flibble writes: > This document refutes Alan Turing’s 1936 proof of the undecidability of > the halting problem, as presented in “On Computable Numbers, with an > Application to the Entscheidungsproblem” (Proceedings of the London > Mathematical Society, 1936), by leveraging the assumption that self- > referential conflation of a halt decider and its input constitutes a > category (type) error. The refutation argues that Turing’s proof, which > relies on a self-referential construction, is invalid in a typed system > where such conflation is prohibited. You're acknowledging that it's an "assumption". Sure, *if* you **assume** that "self-referential conflation of a halt decider and its input constitutes a category (type) error", then Turing's proof is invalid in a system where that assumption is true (if your terms can be rigorously defined). Of course Turing's proof wasn't intended to be interpreted in such a system, and there is no actual self-reference. If Turing's proof actually relied on self-reference, you might have a valid claim. The proposed halt decider does not operate on itself, or on a reference to itself; it operates on a modified copy of itself. Are you ever going to answer my questions about Goldbach's Conjecture? [SNIP] -- Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com void Void(void) { Void(); } /* The recursive call of the void */