DescentBB

Interestingly, the latest thinking agrees with the hypothesis I'm using in my time travel novel: you can go into the past but you can't change the present no matter what you do.

It's quantum theory which enforces the "once probability states collapse to a single option, nothing can change it."

http://news.bbc.co.uk/2/hi/science/nature/4097258.stm

There is another way to interpret it though: if changes in the past affect the future (the present), then the changes are all internally consistent: if you killed your Dad, it'd turn out he WASN'T your dad. Or if he was your dad, then your attempts would fail.

i.e. if I make changes in the past, the present reconfigures itself for the inconsistency, and if people vanish - that's OK, because no-one has any memory of them, or what they did.

its flimsy.

it doesn't prevent something like becoming your own father - and presumes the existance of a senitence that would discourage attempting to kill your parents.

now? no

Later? no. We won't last that long.

end of story.

Hrmm, basically it's summed up like this:

If you were to go back in time, whatever you do in the "past" affected the "present" that you came from. Sounds like a pretty deterministic model to me.

Unless everything is really only a probability field..

Bizarre. So what happened to Fry in Futurama isn't possible?

...wouldn't a change in the past create a new timeline/universe so that the original present would "not really exist anymore?" You could go back in time and kill your dad in another timeline or parallel universe, but your dad would still exist in the original timeline so nothing would really happen in regards to your own existance.

Come to think of it.. I'm a time traveller. .. So far, I've traveled 40+ years into the future .. However.. i stay in the present simitaniously.

Am I cool or what?

Zoop: according to this theory, no, because in order for that to happen (you killing your own father) it must have already happened. Such an occurrance is impossible (0% probability) so therefore it will never occur.

My take is, and has been for some time, "who knows, who cares".

Mobi, that's just a brainfart you're having.

What about going to the not-so-distant past and killing yourself? The future will re-arrange itself to omit you, but then you could never have killed yourself in the past. But then the future wouldn't have re-arranged itself, so you would have been able to kill yourself. But then, etc... etc..

Although it is only a mathematical concept, you could abuse imaginary time to explain something like this, though. According to that, the universe has all possible histories, so it never had to make a choice. However, to us, there is only one real timeline, all others are imaginary. If you were able to get back in time, you'd shift to an imaginary timeline, thereby becoming real to you, and you'd be able to do whatever you wanted because it's supposed to happen in that timeline. The only flaky assumption you have to make in this model, is that whenever you change from timeline, you end up in the correct one (i.e. the one where you actually went back to the past). But this can be explained by the antropic principle.

This also messes with determinism and free will. You have no free will, because your timeline is already laid out for you. If you would take other descisions, you'd be in another timeline.

Then again, if you force interpretations on a mathematical model such as this one, you're bound to come up with things like this. It's very interesting to think about it, but it's a mental experiment and nothing more. Let's leave it at that.

kinda like cold fusion.

so it's quantum fate?

i like it

i generally think of it as a fate based probability field: "the closer you come to causing a paradox, the more likely the possability of you failing", and this is (unperceivable to us, mere humans) all under the control of the greater universe itself. murphy's law gets entered into the science books eh.

Only the present exists. To travel to the past would assume that all of the past exists now or in the future. It doesn't. The future doesn't exist either. The only One who can exist in past present and future is the One who created time in the first place. Not even Angels can achieve this feat, and you think its within the grasp of humans?

My theory on it: If time travel where ever discovered in the future, someone would have traveled back in time and goofed up eventually, thus alerting us to the existance of someone from the future in our universe... I.E. if people came back here from the future, eventually we would figure out that it had happened, and would know that some day we where going to discover time travel.

if nobody travels back and disturbs the inventing of beer then i,am happy.

Time is made of the fabric of the universe. Any attempt at traveling back thru it would unmake it and all within it.

How do you think the donosaurs went extinct ? Hunting parties from the future of course.

Grendel wrote:How do you think the donosaurs went extinct ? Hunting parties from the future of course.

Isn't that what that upcoming movie based on a Ray Bradbury short story is about?

In a more related theme, let me paraphrase something from Douglas Adams: "There are those who theorize that, if someone ever figures out exactly how the universe works, it will be replaced with something even more fantastic and ridiculous. There are others who speculate that this has already happened."

Heh, yes.

I think the word 'incomprehensible' came in there, as well...

Easy. If you want to go back in time, just cease and reverse the expansion of the universe.

Argh! My plan is ruined. So if I go back in time with a list of winners at the track, apparently I am guaranteed to lose. Guess I'll take the time machine apart and just keep on workin'. *sigh*

Still seems like there's a paradox in there to me.

Time travel isnâ??t possible no matter how you look at it.

dissent, you'll never have a list of winners at the track. It will always be a list of losers.

dissent wrote:Argh! My plan is ruined. So if I go back in time with a list of winners at the track, apparently I am guaranteed to lose. Guess I'll take the time machine apart and just keep on workin'. *sigh*

Still seems like there's a paradox in there to me.

you could get the accurate list perhaps, but you will be hit by a car before you get to the track.

yea.. just like Groundhog's Day.

Time travel has ALWAYS been possible... Sadly, only in one direction...Forward. One day at a time.