Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!ukma!nrl-cmf!ames!ucbcad!zen!ucbvax!bloom-beacon!athena.mit.edu!sethg From: sethg@athena.mit.edu (Seth A. Gordon) Newsgroups: sci.misc Subject: Re: Engines of Creation: Nanotechnology Message-ID: <1919@bloom-beacon.MIT.EDU> Date: Tue, 1-Dec-87 00:10:43 EST Article-I.D.: bloom-be.1919 Posted: Tue Dec 1 00:10:43 1987 Date-Received: Fri, 4-Dec-87 03:15:05 EST References: <1445@m-net.UUCP> <4560@well.UUCP> Sender: daemon@bloom-beacon.MIT.EDU Reply-To: sethg@athena.mit.edu (Seth A. Gordon) Organization: Massachusetts Institute of Technology Lines: 30 In article <4560@well.UUCP> pokey@well.UUCP (Jef Poskanzer) writes: >In the referenced message, russ@m-net.UUCP (Russ Cage) wrote: >}You have to find it first. The difficulty is that, in order to decide >}if a particular bit of nanomachinery is Gray Goo (or a part thereof), >}you have to analyze its program to see if it ever quits reproducing. >}This is exactly equivalent to the halting problem, which is insoluble. > >Congratulations, you've just proved that the human immune system is >equivalent to solving the halting problem, and therefore impossible. >--- From what I know of both subjects (i.e., about what Hofstadter wrote in _Godel,_Escher,_Bach_ and _Metamagical_Themas_), a *PERFECT* immune system is equivalent to solving the halting problem, and therefore impossible. Our immune system can IMPERFECTLY control infections, just as there are ways to IMPERFECTLY recognize infinite loops. We could always try using a blowtorch. OK, so we wouldn't always succeed... >Jef > > Jef Poskanzer jef@lbl-rtsg.arpa ...well!pokey > "Greetings from the World's Biggest." Seth Gordon, 52 Massachusetts Avenue #102, Cambridge, MA 02139-4324, US of A. a.k.a. sethg@athena.mit.edu [Internet] |---------------------------------- a.k.a. sethg%athena.mit.edu@mit-eddie.uucp | By the time you read this message a.k.a. sethg%athena.mit.edu@mitvma.bitnet | it may not even be *my* opinion.