Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!mcsun!ukc!edcastle!aipna!cstr!tim From: tim@cstr.ed.ac.uk (Tim Bradshaw) Newsgroups: comp.ai Subject: Re: Artificial vs. ''real'' intelligence Message-ID: Date: 7 Jul 90 14:05:49 GMT References: <1990Jul2.182411.4441@king.mcs.drexel.edu> <5734@jhunix.HCF.JHU.EDU> <598@dlogics.COM> Sender: news@aipna.ed.ac.uk Organization: CSTR, University of Edinburgh Lines: 35 In-reply-to: dsa@dlogics.COM's message of 6 Jul 90 21:17:48 GMT >>>>> On 6 Jul 90 21:17:48 GMT, dsa@dlogics.COM (David Angulo) said: > In article <5734@jhunix.HCF.JHU.EDU>, ins_atge@jhunix.HCF.JHU.EDU (Thomas G Edwards) writes: >> >> One thing for sure is that QM functions, being physical functions, >> can be determined by physical devices. > No they cannot. Please stop saying this. It is incorrect as has been pointed > out here many times. Is this true? I have a paper by Deutch where he proves something he calls the `physical Church-Turing principle': Every finitely realizable physical system can be perfectly simulated by a universal model computing machine operating by finite means. For QM & something he calls a `universal quantum computer'. He also demonstrates that such a machine is in theory possible to construct & that it has many interesting properties. Note that this principle is *not* true for classical mechanics and the conventional universal Turing machine. I think that it is (one of) Penrose's ideas that the brain may be a quantum computer. I also think that this is unlikely, actually, since it is too big & too hot. All it seems likely to be able to rely on is some sort of random oracle & one can easily add this to a normal Turing machine. Apologies if this goes over old ground. --tim Tim Bradshaw. Internet: tim%ed.cstr@nsfnet-relay.ac.uk UUCP: ...!uunet!mcvax!ukc!cstr!tim JANET: tim@uk.ac.ed.cstr "Quis custodiet ipsos custodes?"