The question of whether or not time travel should be allowed if it were possible is a good one.
Time travel would have moral implications if it was possible and so there would be lots of debate on the subject if anyone actually proved it possible.
But the first thing that would be needed if for some one to prove it to be possible.
There are many theories relating to time travel out there.
There are those that deal with the mechanics of such a task and those which deal with the implications time travel may have on the time line itself.
Stephen Hawking said:
"If you could have Time Travel, wouldn't they already be here telling us about it?"
This one sentence seemed to put a halt to the idea that time travel could be possible but another Physicist came up with a theory that would answer Stephen Hawking's question.
Frank Tipler stated that A device based on an artificially created black hole would only allow travel back to a period after it was created. This means it would not work straight away and that because we have not created one yet then no time traveler could get here.
What is known at the moment?
It is known that time travel is not possible in the current physics environment and that our understanding would have to change to make it a possibility.
By rewriting special relativity to create a timeless universe you could say that time travel is possible.
To decide whether or not it should be allowed if it were possible we need to look at two theories:
This paradox leads some scientists to believe time travel is impossible. Others say that the theory of parallel universes would make time travel possible even with this paradox.
Now lets take a look at Parallel Universe Theory:
This theory states that there are other realities that are different than ours in small ways. These could be things like:
Germany Winning WW2
It says that each event plays out in a different way in each parallel universe.
Using this theory we can say that if you went back in time and killed your grandfather then you would create an alternate reality where you don't exist but your reality would still be there.
So in conclusion we need to prove it is possible before we can really say whether or not it should be allowed as we don't really know what would happen if we could and did travel back in time.