Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1exp 10/6/83; site hlexa.UUCP Path: utzoo!linus!security!genrad!decvax!harpo!eagle!mhuxi!houxm!ihnp4!hlexa!hsf From: hsf@hlexa.UUCP Newsgroups: net.books,net.philosophy,net.sf-lovers Subject: Time and Immortality (part 2) Message-ID: <290@hlexa.UUCP> Date: Wed, 12-Oct-83 17:46:17 EDT Article-I.D.: hlexa.290 Posted: Wed Oct 12 17:46:17 1983 Date-Received: Thu, 13-Oct-83 22:35:08 EDT Organization: AT&T Bell Laboratories, Short Hills, NJ Lines: 82 (c) Copyright 1983 by Henry Friedman (Copying for personal use by users of net is authorized.) Is Yesterday Really Gone? (continued) There is an analogy that is often used to describe our ina- bility, as three-dimensional creatures, to fully comprehend a four-dimensional universe. We are asked to imagine the plight of hypothetical two-dimensional creatures living in, as they see it, a flat, two-dimensional world. Physicists and mathematicians belonging to this flat world might some- day discover that there was a wider, three-dimensional real- ity. They might even describe such a universe of three- dimensional cubes and spheres, etc., mathematically, but they would be unable to fully visualize such strange objects. The closest the two-dimensional creatures could come to visualizing a cube would be as a series of separate squares; they might see a sphere as a series of circles. Analo- gously, we, as three-dimensional creatures, can only visual- ize four-dimensional spacetime as a series of separate events. One element of a four-dimensional universe that might dis- turb many is its apparent determinism. If future events already exist, what would be the meaning of saying that we have free will? There are several different ways to address such questions. Some philosophers say that the question of determinism versus free will is not decided one way or the other by the idea of a four-dimensional universe. For "determinism" means not only that a future event is fixed, or definite, but also that it could be definitely predicted *in the present* if enough of the causal details were known. In other words, determinism is the traditional idea in Newtonian physics of a "clockwork universe," whose every condition is inexorably dictated by its "initial condi- tions." In such a clockwork universe causality would reign supreme. However, the concept of a deterministic, clockwork world has been largely discredited by quantum mechanics, which has shown that the behavior of subatomic particles is essen- tially random. The further implication is that such random- ness may also apply to much of the larger world of everyday reality. So one could argue that the proper term for the state of future events in a world of four-dimensional space- time is "determinateness" (definiteness), not "determinism" (clockwork causality). Others would add that questions about free will are essen- tially meaningless, anyway. For whether or not we actually have free will, we have no choice but to act as if we do. All of the above arguments notwithstanding, some of us might be deeply disturbed by the idea that our futures are com- pletely decided. And there is still another possible interpretation of the future in a four-dimensional universe that is neither determinate nor deterministic. Physicist Paul Davies ("Other Worlds") and science writer Gary Zukav ("The Dancing Wu Li Masters") describe a new concept that has arisen as one possible explanation for some of the para- doxes inherent in quantum theory: the concept of "many worlds," also called "parallel universes" or "alternative possibilities." In quantum mechanics, the random paths and behavior of suba- tomic particles are described by mathematical equations that give the probabilities for the possible ways a particle can act (Schroedinger wave equations). In the conventional interpretation of these equations, the actual observation of a particular path for a particle causes the alternative pos- sible paths to "collapse" into non-existence. In contrast, the concept of parallel universes states that every possible path continues to exist -- in a separate branch of the universe! (This chapter to be concluded in Part 3.)