Grandfather Paradox - Do we have free choice?

First, I'll state the grandfather paradox for those of you who don't already know it.

This paradox can give us two different options -

• Time travel is impossible
  
• Our lives are written, and we have no choice in them.

However, time travel is indeed possible. Of course, not in the form of stepping into a machine and appearing a few days later/earlier, but in the form of relativity. If a pair of twins splits paths - one stays on earth, and the other goes on to travel in space, then when the twin who traveled in space comes back, the other twin will have aged more than the one who traveled in space has. Hence, it is possible to warp time, and to travel through time.

So my question is:
Are our lives really written? Can we change them?

 

Another few options that could arise from your paradox are

1. Time travel "creates" a separate reality
2. There are separate realities in time ( which would nullify free will )
3. Novikov self-consistency principle -According to this hypothesis, the only possible time lines are those entirely self-consistent—so anything a time traveler does in the past must have been part of history all along
4. Nonexistence theory - say you committed the grandfather paradox, according to this theory you would return to a reality in which you never existed ( but you still exist. )
5.Quantum many worlds interpretation - every seemingly random quantum event with a non-zero probability actually occurs in all possible ways in different "worlds", so that history is constantly branching into different alternatives. The physicist David Deutsch has argued that if backwards time travel is possible, it should result in the traveler ending up in a different branch of history than the one he departed from.

For your question:

We have free will because we have no choice otherwise. Dwelling on the concept is not productive imo.

 

The Grandfather Paradox is negated by something called the Novikov Self-consistency Principle. The principle states that, in basic terms, if you can achieve time travel and go back in time then if you try to do something to alter the original time line the action will fail. It says a timeline is completely consistent and cannot be changed.

But Time Travel would only be possible if we could travel sufficiently fast enough, but considering the speed that you would have to travel to make an actual impact on the 'time stream' it will be near impossible. Even then time travel is only relative to the viewer and one doesn't actually time travel but instead is effected by Relativity by experiencing the stretch of spacetime.

Time travel is a traditional physics impossibility, but there may be a way in quantum physics because we are still learning about quantum physics. I mean if electrons can be in two places at once then what implications does that have to quantum travel if we learn to harness that.

http://en.wikipedia.org/wiki/Novikov_self-consistency_principle

 

There is not proof that you can travel back in time however. With the twin scenario the twin moving at the immensely fast speeds almost stand still in time, while time on earth keeps on going.
The past already happened, and can not be gone back too. Unless I guess you figure out a way for instant transportion and travel faster than the speed of light, although I think Einstein proved the speed of light is never achievable to the person who is traveling fast, because light will just travel that much faster from the person.

 

interesting thread OP

i've been told and read a few times and currently believe; time is an illusion? man made rather.. or is this relative to "time & space"? (idk if there is even a difference, i'm here to learn!) so if the said "time" could be manipulated, what could stop us from doing an action that would redefine us?

As for OP's twin example, i've heard stories of people falling in cold rivers or through ice, freezing, but doctors have had accounts where the person actuallys starts living again once defrosted, and it's unexplainable how. **Not talking Cryogenics here.
All they know was the body was in a stasus; which makes it pretty safe to assume the cells were moving and developing so slowly that in a sense during the hours of "frozen death", the body wasn't aging...

I think I'm writing my life right now though tbh. I highly doubt there was a plan that today i would read this thread and think about this question and answer it accordingly... seems pretty off the wall. but hey, anything is possible.

I've always thought, if my life is planned already, what if i ... stabbed myself in my arm! ... then i think... well i was probably supposed to question if my life was on a set path, so in thinking about veering off the path, you wonder if that in itself is part of YOUR path... ugh.. my head hurts..
TL;DR: Some of my idiotic ideas that i would like to know more about ^_^

 

Time Travel is impossible, if we go back we create errors/paradoxes and we can't go forward because its purely potential.

 

With all of the above posts taken into account,

The Novikov principle is not proven. It could, very well be wrong. It's just one of many theories out there.

As for time travel, we can already observe time travel with particles. When I talk about current time travel, as I said in the OP, I don't mean stepping into a "back to the future" car. I mean small fluctuations and warps in space-time which lead to a possible change in the "time" dimension.

Anyways, this thread isn't so much about the "time travel" paradox, but more about us having free choice.

 

This is a very wise man. I especially like his views on time travel creating "seperate realitys" and out of everything else I've read on this thread, this makes the most sense. Ive never studdied time travel so I have no clue. But if Someone asked me I would refer to this to explain it. Very well done.

Or maybe your just watching to much Donni Darko?

 

Doesn't the impossibility of going backwards (not forwards at a slower rate) through time make the question irrelevant to free choice?

 

Like i mentioned the future is pure potential. It can't be pre-written, hence we do have free choice. If going back into time would cause paradoxes as such then all it does is change the potential of the future ahead of that time we have traveled back to. This potential matter or energy that is time can't be measured or have set values/characteristics.

 

Assuming time is linear.