[thedoc (OP)]

Gordon Cairns asked the Naked Scientists:
   
Concerning time travel and the grandfather paradox.

I know that travelling backwards in time is theoretically possible but paradoxes prevent change within a singular universe theory. My question is that if time travel was discovered by using a multidimensional universe theory could that be possible?

The only way I can begin to explain it is like this.

Person A invents a time machine and goes back to 1950. At this moment person A has not only went back in time but also shifted to an identical universe within another dimension. So now we have universe A with no person A and universe B with a current person A and a second person A in 1950. In this case the time travelling person A could kill their grandfather resulting in no birth of the second dimensions person A but still containing person A from the original universe.


What do you think?

[Colin2B]

Is this really the same paradox?
The people in the different universes are different individuals in the same way twins are individuals, they just look the same.
In one universe you now have a live grandfather whose grandson has mysteriously disappeared
In the other universe you have a man who has been killed in 1950 by someone unknown to him, who is not in fact his grandson. The real grandson in this universe has never been born, so there is no paradox.
What do you think?