Xref: utzoo comp.ai:5264 talk.philosophy.misc:3351 sci.philosophy.tech:1811 Path: utzoo!attcan!uunet!aplcen!samsung!shadooby!sharkey!itivax!dhw From: dhw@itivax.iti.org (David H. West) Newsgroups: comp.ai,talk.philosophy.misc,sci.philosophy.tech Subject: Re: Can Machines Think? Message-ID: <4689@itivax.iti.org> Date: 21 Dec 89 21:57:16 GMT References: <31821@iuvax.cs.indiana.edu> Reply-To: dhw@itivax.UUCP (David H. West) Followup-To: comp.ai Organization: Industrial Technology Institute Lines: 28 In article kp@amdahl.uts.amdahl.com (Ken Presting) writes: |What makes the multi-body problem a counter-example is not just the fact |that the problem has no closed-form solution, but the chaotic nature of |the mechanical system. | |In a chaotic system, an arbitrarily small change in initial conditions |will over time produce an arbitrarily *large* difference in subsequent |states. [...] |That was a rough sketch of a proof that not all causal systems can be |modeled by programs. Let me add a plausibility argument, so |that the claim will not seem counter-intuitive. | |What makes the analog causal system different from the algorithm is that |each state of the analog system encodes an infinite amount of information. Real intelligent systems (e.g. humans) function quite successfully at a finite temperature despite the influence of thermal fluctuations (Brownian motion), which cause finite random perturbations of everything. A finite system embedded in a thermal environment cannot encode an infinite amount of information. This would seem to indicate that your argument has no bearing on what may be necessary for intelligence, at least over a time-scale short enough that the physical embodiment of the intelligence is not disrupted by thermal fluctuations, whether or not these are chaotically amplified. -David West dhw@iti.org