gjphw (08/06/82)
There seems to be continual debate about the nature of time, the possibility of time travel, and the issue of personal determinism. I would like to advance some observations about our concept of time. The present, common conception of time derives from the success of classical mechanics (e.g. dynamics, falling rocks, projectile motion, celestial mechanics, and special relativity). For all of these, time appears as a simple parameter which can be reversed at will. This is not the absolute time concept of Newton, but still a simple concept. Quantum mechanics treats time in the same way as classical mechanics. Since classical mechanics (or dynamics) is so successful at describing and predicting phenomena, its philosophical assumptions are also accepted. Metaphysics is implied by the physics. Time can then be viewed as merely another dimension (or more exactly a coordinate "ict"), similar to any of the spatial dimensions, in which we will one day realize the freedom of motion. Travel through time is, in principle, possible and, since all future is calculable, we are predestined to follow this predictable path. This view of time as reversible conflicts with other experiences. People, and rocks, only age. What if time, as it appears in thermodynamics, is treated as the paradigm? (Statistical mechanics attempts to bridge the gap between dynamics and thermodynamics, with more emphasis on the dynamics side of the subject.) I. Prigogine, in "From Being to Becoming", argues essentially for this. Experience with very complicated systems requires that time be a one-way parameter (irreversible). In addition, the predictability of a phenomenon is limited (entropy). A particular phenomenon cannot be predicted with arbitrary precision as time proceeds from some initial conditions (this situation is called weak time correlation). So, not only is time travel into the past not possible, the future is not very calculable (or predictable). Having thought about this issue of time and determinism, the concept of time derived from thermodynamics appears to be more reasonable. While time irreversibility makes me uncomfortable with science fiction stories about time travel into the past, I am consoled by the idea that I am not predestined to follow a predictable path through the future. How any of this relates to free will is open to discussion. Pat Wyant ihuxn!gjphw
G:wing (08/10/82)
One other thought on time (This might also be a response to Paradox, but I haven't read that article yet). Our past could already be formed by the future. Case in point: The Star Trek episode with Gary Seven shows the Enterprise traveling back in time to Earth. Because of what Gary Seven and the Enterprise do, the American nuclear warhead satillite blows up a bit over a hundred miles above Earth. Although Gary Seven at first thinks that they have changed history, William Shatner remarks that they have records of the specific event they caused to occur in their history database (no flames, please!) of that satillite blowing up just as they saw it. Paradoxes cannot occur. The One And Only, Philip L. Wing U.C. at Berkeley decvax!ucbvax!g:wing