carrier@brahms (Stephen Carrier) (11/08/86)
Regarding causality and reverse causality, isn't any kind of causality an illusion? I assume that causality is a manifestation of entropy increase. The arrow of time. What is it anyways? All nonstatistical laws of physics are symmetric under time reversal. The statistical laws, actually, are symmetrical, also, but they don't seem to apply in the reverse direction, because, in typical applications, some `scientist' (speaking loosely), creates an unusual situation of low entropy and watches it evolve into high entropy, where statistical mechanics suggests it should be. So the question is not why does entropy increase, but why isn't it already at the maximum? The universe apparently began as a system of very low entropy. If the state of the universe in the future is preordained (Remember, causality is bunk, so why not? It's only twice as outrageous as the fact that the universe exists at all.) to have low entropy, then eventual entropy increase is inevitable. In fact, the backwards evolution of this `preordained' state should obey the familiar laws, except in reverse. We are riding a wave of entropy away from the beginning of the universe. Maybe alien intelligence is/will be riding a wave in the reverse direction from the end of time, although to them, we would be in their future, although moving backwards. Between our realm and their realm, there would probably be a realm of very high entropy, where the universe would consist of a very thin gas, and there would be no phenomena that distinguish one direction of time from another. At least globally. Perhaps there will be local arrows of time, which disagree with each other. Is communication possible between intelligences with opposing arrows of time? John Brunner (in the novel "The Wrong End of Time") and Martin Gardner have considered these questions. The physisist and science-fiction writer Gregory Benford has considered the possibility and possible consequences of communication backwards in time in his novel "Timescape". If causality it bunk, then maybe time travel is possible, after all. Read Benford's novel for a resolution of the practical paradoxes via the many-possible worlds interpretation of quantum mechanics. It's something to think about. I think this is consistent with known physical theory. ucbvax!brahms!carrier Stephen Carrier/UCB Math Dept/Berkeley CA 94720 "Riding the entropy wave,...Wow! Tubular!" -surfer in the universe.