Time Travel - Phil's Rambling Rants
Alternate universes make it possible to write some time travel stories without paradox or predestination, but the standard time plot -- something is wrong with the present, so we'll go back in time to change the cause, and come back to an altered present that we like better -- is inherently paradoxical. If going to the past splits off an alternate world line along the many worlds hypothesis, then you can go to the past, but you have to either come back to the present you came from, seeing no change, or you have to return to a present that doesn't have a slot for you, because you couldn't have left, because the reason you left wasn't in the past of that world line because you fixed it.
|Date:||April 26th, 2004 12:03 am (UTC)|| |
something is wrong with the present, so we'll go back in time to change the cause, and come back to an altered present that we like better
Agreed. I hate that premise; it's stupid.
If the characters view it as "I want to go live in a timeline where this didn't happen, abandoning everything and everyone in my own world," then it can work logically, as long as they can deal with living in a timeline where either they never existed in the first place, or else there are other copies of themselves already there (in either case, as you say, there is "not a slot" for them). However, that issue is virtually never addressed and it's very annoying. The notion of "fixing reality" in this way is completely absurd.
Yes, that kind of alternate-world 'time travel' is no harder to swallow than alternate-history stories, which I often enjoy. But I can't offhand think of a story that uses it -- which isn't to say I haven't read any :-)