Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!mcnc!philabs!cmcl2!seismo!brl-tgr!gwyn From: gwyn@brl-tgr.ARPA (Doug Gwyn) Newsgroups: net.physics Subject: Re: Re: why FTL is illegal (wrt: free will). Message-ID: <7007@brl-tgr.ARPA> Date: Fri, 4-Jan-85 17:05:09 EST Article-I.D.: brl-tgr.7007 Posted: Fri Jan 4 17:05:09 1985 Date-Received: Mon, 7-Jan-85 02:27:16 EST References: <683@gloria.UUCP> <785@ariel.UUCP> <148@lems.UUCP> <152@talcott.UUCP> <277@rlgvax.UUCP> <20@spar.UUCP> Organization: Ballistic Research Lab Lines: 25 > ... I thought that even the simplest Newtonian models > of the universe result in intrinsically INSOLUBLE differential equations > (like the three-body problem). > > Doesn't this mean that prediction is impossible, even in a vanilla > Newtonian universe with more than two objects? The "three-body problem" is NOT insoluble; it just has no simple closed-form solution. Given enough computing resources, one can compute the motion of three gravitating bodies to any desired degree of accuracy. In practice, of course, one does NOT try to calculate even the classical motion of individual gas molecules; the amount of computation is just too burdensome. Instead, one sacrifices some degree of absolute detailed accuracy in exchange for statistical knowledge. That doesn't make things IN PRINCIPLE nondeterministic. The question becomes, how detailed do you want your predictions? Quantum considerations are of an ENTIRELY DIFFERENT type. According to conventional quantum theory, the evolution of a physical system proceeds according to INHERENTLY PROBABILISTIC laws; there are no underlying deterministic mechanisms at work. This notion is quite unsettling to one brought up in the Renaissance tradition.