gordon@stats.ucl.ac.UK ("Gordon Joly, Statistics, UCL") (09/15/88)
To: AILIST@ai.ai.mit.edu, bph@buengc.bu.edu cc: gordon@cs.ucl.ac.uk Subject: The Uncertainty Principle. Date: Mon, 5 Sep 88 09:38 EDT From: "Gordon Joly, Statistics, UCL" <gordon%stats.ucl.ac.uk@NSS.Cs.Ucl.AC.UK> In Vol 8 # 78 Blair Houghton cries out:- > I do wish people would keep *recursion* and *perturbation* straight > and different from the Uncertainty Principle. Perhaps... But what is the *perturbation* in question? "Observation"? Blair also observes > Electrons "know" where they are and where they are going. And I know where I'm coming from too, Man! On page 55 (of the American edition) of "A Brief History of Time", Professor Stephen Hawking says ``The uncertainty principle had profound implications for way in which we view the world... The uncertainty principle signaled an end to Laplace's dream of a theory of science, a model of the universe that could be completely deterministic: one certainly cannot predict future events exactly if one cannot even measure the present state of the universe precisely!'' And what of "chaos"? Gordon Joly.
bph@BUENGC.BU.EDU (Blair P. Houghton) (09/19/88)
Date: Thu, 15 Sep 88 14:59 EDT From: Blair P. Houghton <bph%buengc.bu.edu@bu-it.BU.EDU> To: AILIST@ai.ai.mit.edu Subject: Re: The Uncertainty Principle. Newsgroups: comp.ai.digest In-Reply-To: <19880915011015.4.NICK@HOWARD-JOHNSONS.LCS.MIT.EDU> References: <19880915011015.4.NICK@HOWARD-JOHNSONS.LCS.MIT.EDU> cc: Organization: Boston Univ. Col. of Eng. >In Vol 8 # 78 Blair Houghton cries out:- >> I do wish people would keep *recursion* and *perturbation* straight >> and different from the Uncertainty Principle. And Gordon Joly Whines Back: >Perhaps... But what is the *perturbation* in question? "Observation"? By "recursion," I actually meant feedback, which was the process to which Heisenberg-o-morphic uncertainty was being applied in order to invoke chaos in artificially intelligent systems. Lessee if I can verbosify the intuitions: Uncertainty exists because one can not determine the state of a particle system unless one has: a. infinite time to make the measurement with zero energy; or, b. infinite energy to make the measurement in zero time. (it's usually equivalently described as: "determining the momentum requires a long distance over which to observe, hence the particle's position, which can be anywhere along that distance, is not known; and, determining the position requires a very short distance for observation, which causes the error of the momentum measurement to increase.) This is manifest in the fact that adding energy to the system in order to make an understandable observation will necessarily change the state of the system. This DOES NOT mean that observing the system creates uncertainty. Such a thing is equivalent to saying that observing the perfectly flat surface of the ocean causes waves to form, when in fact it is the observer's boat's bobbing in the water that causes those waves. THIS is the "perturbation in question." >Blair also observes >> Electrons "know" where they are and where they are going. > >And I know where I'm coming from too, Man! > >On page 55 (of the American edition) of "A Brief History of Time", >Professor Stephen Hawking says And I'm s'posed to argue? No Way. >``The uncertainty principle had profound implications for way in >which we view the world... The uncertainty principle signaled an >end to Laplace's dream of a theory of science, a model of the >universe that could be completely deterministic: one certainly >cannot predict future events exactly if one cannot even measure >the present state of the universe precisely!'' > >And what of "chaos"? Actually, it means we have to keep our error-bars polished and ready. I wasn't ready for infinite-precision laboratory equipment, anyway. Theoretically, it means our theory has to be treated the same way we treat experimental data; we could even begin to consider current theory to be the data of logical deduction experiments, which is I believe a view consistent with Einstein's of mathematics as an imprecise method for describing nature at the incept. --Blair "It's always a nice feeling to be consistent with Einstein."