Time Travel discussion

Ken Claybourne has slipped back to 1968... to save Dennis Wilson from Charles Manson and the Family!

Maybe this sounds petty because I wouldn’t be saving anyone’s life, but I would go back and prevent the Fox vault fire which destroyed Theda Bara’s films among many others.

That's interesting. When I've asked my students that questions, I normally get two answers. 'Kill Hitler' or 'Stop Shakespeare.'

Kim wrote: "That's interesting. When I've asked my students that questions, I normally get two answers. 'Kill Hitler' or 'Stop Shakespeare.'"

Many say the worst thing we could do is kill Hitler. Someone more competent may take his place. :(

How does one judge whether a change is good or bad? Suppose you had some way to accurately measure world-wide "well being" and:

* 5 years after the change shows a huge improvement
* 25 years after the change shows less of an improvement, but still big
* 100 years after the change shows only a little improvement
* 500 years after the change shows humans have become extinct
* 1000 years after the change, the aliens living on Earth are doing wonderfully

How many time frames would one need to check? What weight should be applied to each time frame?

I love what ST:TNG did with the concept. Picard is dying of a heart problem, but the god-like Q gives him a chance to change what is causing the heart problem -- a fracas he and his fellow academy cadets had with some off-worlders in a bar, which damaged Picard's heart. Picard "undoes" the incident by convincing his friends to back down and not get into the fight. As a result, Picard learns to "back down" from every challenge in his life, taking "the safe road". As a result, he becomes a lackluster officer in a mundane position. He hates what his life has become. That incident had been a pivotal point in his life, even though it causes his death decades later.

https://en.wikipedia.org/wiki/Tapestr...

So would saving Kennedy be good? Not according to Stephen King. Hitler affected world history but he was a madman. Someone with the smarts may have succeeded. Plus countless people would never have been born as people coupled off differently..
Star Trek also did it with City on the Edge of Forever

Interesting question and I don't have an answer to it. What inflection point and change would make the world better? That is impossible to know, but so fun to think about.

Could we stop Columbus from "discovering" America and save the Native Americans from having their way of life wiped out?

Or the ever popular "kill baby Hitler" - I have always wondered why no one ever says, "I'd kidnap baby Hitler and have him raised differently so maybe he would have a different view of the world."

I don't have an answer for this question, but now I have a question to play with insisde my head for the rest of the day. Thank you for that!

of course change too much and you might not have been born which creates a paradox cause if you're not born you could not have gone back in time...see BTTF1, Marty and siblings start to vanish as he has changed a fixed point in time. Of course, that's why Doctor Who references these, fixed points, things that can not be changed.

The paradox is easily solved with the multiverse concept...

Randy wrote: "The paradox is easily solved with the multiverse concept..."

Multiverses and time travel are two different things in my view

Jeff wrote: "Multiverses and time travel are two different things in my view"

I can imagine two scenarios for time travel (going backward):

1. The time traveler can't change anything, although he can repeat something that was already done. Creating a loop. For example, killing their own grandfather, but then ending up being their own grandfather. Basically, this is just showing ignorance of what actually happened in the past.

2. When the time traveler changes something, they create a new multiverse. Any future they return to reflects the change they made, and is not the multiverse they traveled back from. They can never return from whence they came because just the act of traveling changes something.

Is there something else that rules out logical paradoxes?

Randy wrote: "Jeff wrote: "Multiverses and time travel are two different things in my view"

I can imagine two scenarios for time travel (going backward):

1. The time traveler can't change anything, although he..."

If they do change something they can't return to a different multiverse cause maybe they stopped their parents from getting together...BTTF the kids start to vanish and Marty would have been next...in City on the Edge of Forever, as soon as Bones jumps through the portal, the crew on the planet lose touch with the ship cause events in the past have altered their reality so Enterprise vanished, they were saved as they were within the Guardian's protective shields (I guess)
The future is so much safer to travel to but then you can't take back technology or you change what you witnessed...but who wants to see when their own life would end?

Jeff wrote: "If they do change something they can't return to a different multiverse cause maybe they stopped their parents from getting together."

Yes, they can't return. But they can go forward in time in the new multiverse they've created. They don't need to be born in that multiverse. They were born in one and the act of time travel moved them to another -- one that they may never have existed in. But that doesn't mean a different version of them can't also be created in that multiverse. But they would be two physically separate beings.

When moving forward in time, they aren't "returning". They are physically traveling forward. Just as they physically traveled travelled backward.

Jeff wrote: "BTTF the kids start to vanish and Marty would have been next"

...which creates a paradox, so that model of time travel doesn't work.

Jeff wrote: "The future is so much safer to travel to but then you can't take back technology or you change what you witnessed"

When you travel backwards with the new technology, you once again break off into another multiverse.

Any time you move backward or forward. Just the fact that your physical body must change the time you've arrived into.

You cease to exist in the multiverse you travelled from. You now exist in the multiverse you travelled to. No paradoxes.

Something I posted several years ago on another thread:

==============================================

The three theories of time travel:

https://i.redd.it/113sh5f2bikz.jpg

I don't agree with the way it's worded, especially on the third, but still it was an interesting summary of types of time travel.

I kinda like the idea of multiverses being something different than TT.

Also, I just started reading what I'm calling 'Miffly at the End of the World' in my subconscious, the new book that is actually titled One Day All This Will Be Yours and it humorously discusses how to go back in time to fix things and then return to the 'future' you consider home.

Randy wrote: "Jeff wrote: "If they do change something they can't return to a different multiverse cause maybe they stopped their parents from getting together."

Yes, they can't return. But they can go forward ..."

ya, but no time travel story goes into multiverses, you stop your parents from meeting you cease to exist, a grandparent is killed as a child and you cease to exist

...which is why they don't make sense.

Randy wrote: "...which is why they don't make sense."

what doesn't

Time travel stories without the multiverse model create paradoxes like the one described, so they don't make sense.

I can't go back to kill my own grandfather and cause myself to cease to exist, because then I wouldn't have been able to go back and kill my own grandfather.

that's why it's called a paradox...(it gave Captain Janeway headaches)....