Favourite SF paradoxes

[Mighty mouse]

All prescients seem to die young

If time travel were possible you could go back 20 minutes to put a bomb under your chair to go off 10 minutes later.

[Sharukem]

Originally Posted by Mighty mouse

All prescients seem to die young

If time travel were possible you could go back 20 minutes to put a bomb under your chair to go off 10 minutes later.

yes you could do that but what would the point of it? And if time travel was possible people would use it to their advantage by changing the past which would therefore change the future and completely mess up what we have today. Like I know people that still want the fur trade to be going on instead of money becasue they think that it would be better, yet there are people who want to bring back those who are already passed away like Alexander Graham Bell. And if they did that then we wouldn't have our phones and crapt like that. But yes I would find time traveling quite interesting in my mind. But to do it that is a whole other matter.

[Mighty mouse]

The way I see time travel working (outside of the relativistic type) is that whilst possible you would have to do it in a side dimension allowing observation but no causal contact.
Some law of quantum physics will doubtless prevent causal contact and stop you having any fun

[SpaceShip]

That sounds a bit like having your fortune told! How awful would it be to be watching something in the future that was absolutely, heartbreakingly awful and not be able to do anything about it except - if it weren't too far in the future - waiting for that event to actually happen! No - don't like that thought.

[BookStop]

You should try The Time Traveller's Wife. Excellent book that adresses that very issue.

[pyan]

Life-line by Heinlein covers it well, too. And try By His Bootstraps (same author) for an amazing paradox story.

[Mighty mouse]

That sounds a bit like having your fortune told! How awful would it be to be watching something in the future that was absolutely, heartbreakingly awful and not be able to do anything about it except - if it weren't too far in the future - waiting for that event to actually happen! No - don't like that thought.

No worries, I reckon time travel will only work backwards, otherwise it would conflict with free will.
In turn that would conflict with my proof that God exists which is:
If he didn't the universe would be a lot more fun

[SpaceShip]

Originally Posted by Mighty mouse

No worries, I reckon time travel will only work backwards, otherwise it would conflict with free will.
In turn that would conflict with my proof that God exists which is:
If he didn't the universe would be a lot more fun

I think the Doctor might have something to say about your first sentence.
I'm sure I don't agree with your second.

[Andrew Hook]

Of course, the paradox is: if time travel is possible then where are all the time travellers?

Liked "The Time Traveller's Wife" a lot, by the way. A very intricate and emotive book, but also a good story well told.

[steve12553]

Originally Posted by Mighty mouse

All prescients seem to die young

If time travel were possible you could go back 20 minutes to put a bomb under your chair to go off 10 minutes later.

Probably would add 20 minutes to the timer on the bomb which would be found by you in time to take it back in time to set it to go off too late to allow you to find it in time to take it back into time............................

Either that or when the bomb went off the you that set up the timer would cease to exist so the bomb would fail to go off. The explosion would sit on the verge of happening and maybe you would just sit there in that living hell almost blowing up for eternity.


Or.........

[SpaceShip]

Eh? .........

[j. d. worthington]

Similar to the "Grandfather Paradox": You go back in time and shoot your grandfather before he and your grandmother met. But in doing so, you make sure they had no children, so your father/mother didn't exist, so neither do you. Which means that you can't go back in time and shoot him, so they do meet, have children, and your father and mother get together and have you. Then you go back in time and shoot your grandfather before he and your grandmother meet, so they have no children, and so.....

I think mine is the one that serves as the frame and running thread throughout Van Vogt's The Weapon Shops of Isher. And, no, I won't explain that one here, as it would spoil the story for those who haven't read it... and I think it culminates in one of the nicest final lines in all fiction.

[Mighty mouse]

I wander what the time travel process is, say

1. You and bomb go back 20 minutes and co exist with previous self
2. You and bomb somehow replace the previous self
3. We have a mind so the physical person is unchanged but the mind goes back 20 minutes
4. It would only work by replacing atom for atom on a quantum level so you would have to slice a cube containing you and bomb from the present and interchange it with a cube in the past.

The question also arises what do you 'remember' in each case?

In relativistic time travel I think it occurs because of differences between different frames of reference. In non relativistic time travel are you are talking about moving between frames of reference?

In guess my personal take is that time travel proper is not possible as it negates the role of God.

[Harpo]

Originally Posted by Andrew Hook

Of course, the paradox is: if time travel is possible then where are all the time travellers?

Simple answer - when we get time travel it will be a matter of machines within which we travel through time. The machines themselves will not travel.
Suppose a time machine is built and it works for fifty years before breaking down. A person could travel anywhen during those fifty years. At the time when the machine breaks down, a new machine would be built alongside it, which work operate for the next fifty years (or however long). It'll be like elevators which each cover a section of skyscraper levels.

So - no time travellers until the first time machine gets invented and switched on. I predict december 21st 2012

[j. d. worthington]

Originally Posted by Harpo

Simple answer - when we get time travel it will be a matter of machines within which we travel through time. The machines themselves will not travel.
Suppose a time machine is built and it works for fifty years before breaking down. A person could travel anywhen during those fifty years. At the time when the machine breaks down, a new machine would be built alongside it, which work operate for the next fifty years (or however long). It'll be like elevators which each cover a section of skyscraper levels.

So - no time travellers until the first time machine gets invented and switched on. I predict december 21st 2012

I've seen you talk about this idea before, Harpo, and it's an interesting idea... but I have a question: How do you see it working, precisely? I mean, if the machine doesn't move, how do they travel in time? Is it physical travel? Mental travel (and if so, how does that work, since all the indications are that personality, soul, whatever you choose to call it, is an epiphenomena of the brain's functioning ... inseparable from the structure of the brain itself). And do they have any sort of interaction with the time they travel into? What happens to their atoms in the present, and where do the atoms that would comprise their being in that time come from? Etc.....