Reynard
aka Ian Eller
AI doesn't "understand" anything. Whatever else one might think about AI, none of the models we have today are anywhere near "thinking" machines. They are predictive machines at best, spitting our own knowledge back at us.
Time travel doesn't exist because time travel wiped out the timelines where it did
- Thread starter Whizbang Dustyboots
- Start date
MoonSong
Rules-lawyering drama queen but not a munchkin
A problem with the Many Worlds interpretation is that it would take infinite energy to create that many timelines.
The only way I see that time travel can be a thing is by properly set up wormholes and only in self-consistent travels. In other words, time travels that won't alter the past.
Reynard
aka Ian Eller
Which means only travel to the future, with no potential to interact with the past.
Imagine you opened a stargate to a planet 5 light years away, 100 years in the future. An astronomer could pass through the gate and use very sensitive telescopes to detect the composition of Earth's atmosphere (for example) 5 years in their past aka 95 years in Earth's future. If they showed the people on Earth's side of the stargate the data, Earth could respond by making different choices about pollution, thereby changing the past of the astronomer. So in order to avoid paradox, any stargate technology must not be able to act like a window.
Well, it already takes infinite enegy to create the universe we have, so that's not really a problem.
GMMichael
Guide of Modos
Or not be able to project things into the future. I think it would be a fine window if the astronomer could send her data 100 years further into the future, to a thoroughly-polluted Earth.
"Why didn't you tell us this 200 years ago?"
Reynard
aka Ian Eller
Right. The point is there has to be some pretty arbitrary constraints, which strongly ssuggests time travel just isn't possible. In the universe we have, the math is complex, but the rules seem to be pretty simple.
Whizbang Dustyboots
Gnometown Hero
I think the time traveling scientists realized there was no point in warning anyone.
Fritz Leiber worked this possibility to great effect in The Big Time and the related Changewar stories. Two basically incomprehensible powers are fighting for control of history everywhere and eveywhen. A very small fraction of people can remember changed history, and they get drafted into the war. Notably, the war is not converging on any kind of stable point.
Tom Sweterlisch takes up the “you can only travel to a future possible at the moment you go, and it collapses when you return” possibility in The Gone World, a really great story of sf horror. Explorers of the futures find a hostile presence far away and far from now, that gets closer in both time and space with every trip.
For sheer elegance, it’s hard to beat John Crowley’s novella “Great Work of Time”. Let’s see if I can explain the setup…
Envision a moment as a sheet of paper, or an infinite plane. It has its physical dimensions to the right and left. Down is all the history that led to now, and up is all the future implicit in the state of things st this moment. Time as we experience it passes perpendicularly to the moment. We don’t go up the plane; we go to a new plane, encompassing the next moment. And on and on, through however deep the stack of moments is.
A time traveler jumps off the train, so to speak. He does move up and down the plane. Changes he makes to history change the moment, which the real (for all the rest of us) present moves further and further away in a directional orthogonal to the time traveler’s moment. Over (his) time, the traveler finds the moment weakening, its laws of nature and history becoming more malleable. Consequences ensue.
