Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site watdaisy.UUCP Path: utzoo!watmath!watdaisy!djsalomon From: djsalomon@watdaisy.UUCP (Daniel J. Salomon) Newsgroups: net.physics Subject: Re: predicting the universe with computers Message-ID: <6861@watdaisy.UUCP> Date: Fri, 18-Jan-85 12:33:12 EST Article-I.D.: watdaisy.6861 Posted: Fri Jan 18 12:33:12 1985 Date-Received: Fri, 18-Jan-85 15:06:51 EST References: <1027@sunybcs.UUCP> <215@looking.UUCP> Organization: U of Waterloo, Ontario Lines: 22 > No computer, now matter how powerful, can predict its OWN future, let > alone that of the universe. Or do I have to prove to you that no > computer can predict whether an arbitrary algorithm will halt in a > limitless universe? > > So the universe is definitely not predictable from within. Whether it > is FIXED or not is another matter, of course. > -- > Brad Templeton, Looking Glass Software Ltd. - Waterloo, Ontario 519/884-7473 The halting problem states that no Turing machine can be built that decides whether some other arbitrary Turing machine will halt. But there is no rule against predicting what a Turing machine will do for the next little while. The halting problem is more of a comment on the inadequacy of our logic systems along the lines of Russell's Paradox, than it is a statement about the universe. Turing machines also have the property that they have an infinite tape. This is the practical problem that one encounters when trying to build a halt detector. But it has not been shown that the universe is infinite. In fact I believe that Einstein proved that the universe is finite.