Time travel doesn't exist because time travel wiped out the timelines where it did

[Stalker0]

Anyone else look at the paper? This about sums up the level of argument:

Which is also a somewhat faulty logic. The paper assumes that because a machine can have its lifetime extended from 10 to 20 years, its inevitable to extend it to 1000 years or infinite timespans.

But with every incremental step your faced with newer more complex problems, and you hit limits you didn’t previously know existed.

It might be possible…or it might be impossible and we just don’t know yet.

 

[The Firebird]

Which is also a somewhat faulty logic. The paper assumes that because a machine can have its lifetime extended from 10 to 20 years, its inevitable to extend it to 1000 years or infinite timespans.

But with every incremental step your faced with newer more complex problems, and you hit limits you didn’t previously know existed.

It might be possible…or it might be impossible and we just don’t know yet.

Yep, that was my point. The assumptions it uses are not well grounded.

 

[GMMichael]

I would prefer that by the time someone figures out how to do time travel they have also figured out that time travel is so dangerous and vile that its purveyors and all blueprints for it must be annihilated.

This is something AI would do. Humans like to hold on to their vile ideas.

Which reminds me - this whole analysis discards the Many Worlds interpretation, in which no timeline ever needs to be (or can be) eliminated at all...

I'm onboard. The (many) world in which a time traveler pops up out of nowhere (or in place of the air particles that were previously there) isn't non-existent. It's just way, way down on the probability scale, so no one's likely to ever detect such a thing, much less actually travel in time.

 

[Reynard]

I think we wake up.in a parallel reality everyday. It's just that the vast majority of them are so close to the one you fell asleep in you can't tell the difference.

But every once in a while you can sense it. Berenstein and all.

And very, very rarely, someone lands in one that doesn't track and they end up in the asylum.

 

[Richards]

I travel through time constantly. One minute into the future every 60 seconds, like clockwork.

Johnathan

 

[Reynard]

I travel through time constantly. One minute into the future every 60 seconds, like clockwork.

Johnathan

Interestingly, that isn't actually true. The differences are miniscule but not nonexistent. You travel through time differently on a plane versus sitting on a couch, or taking a walk versus taking the train.

 

[Umbran]

This is something AI would do.

Hardly. At the moment, AI doesn't even understand consequences, much less have moral compunction against them.

 

[briggart]

Which is also a somewhat faulty logic. The paper assumes that because a machine can have its lifetime extended from 10 to 20 years, its inevitable to extend it to 1000 years or infinite timespans.

But with every incremental step your faced with newer more complex problems, and you hit limits you didn’t previously know existed.

It might be possible…or it might be impossible and we just don’t know yet.

I just scanned quickly through the paper, but I think that's a simplification that doesn't really alter the main conclusion.

The underlying assumption is that a time traveler can use a time machine to enact an infinite number of changes to a timeline. Even with an unbreakable machine, a time traveler won't be able to do so, because sooner or later they would die.

But as long as we assume that the typical amount of changes introduced by a traveler is the same across all travelers and timelines, this would just amount to an overall rescaling of all transition probabilities, which is already accounted for in the paper.

My gut feeling is that also if you allow variation in the number of changes an individual TM can introduce in a timeline, as long as that variations are not correlated with the number of TM present in that timeline, you should get the same asymptotic behavior.

IMO, this is just somebody having a bit of fun with a toy model that is being given more relevance than it deserves by a popular science magazine. It may even be polished enough to get published in an actual journal (you don't publish on arxiv, you just upload to it. As the name implies, it's not a journal but an archive.), but in the end it's just a bit of math dressing around the idea that if alterations to a timeline introduced by time travel are equally likely to create a timeline with a lower or greater number of TM, sooner or later you are bound to end in a timeline with 0 TM, at which point the process stops.

Interestingly, that isn't actually true. The differences are miniscule but not nonexistent. You travel through time differently on a plane versus sitting on a couch, or taking a walk versus taking the train.

It's still 60s every minute. There is just not an absolute time that flows equally for everyone, so my 60s are different from your 60s.

 

[Eyes of Nine]

A technology that no one really needs that also destroys massive amounts of valuable resources? Oh, not only will it get done, Wall Street will demand it gets done.

Deserves a

 

[jolt]

Physics doesn't separate the concepts of space and time the way a lot of games and fiction do.