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ost_uid0]I once figured out that the only way the past could be altered to your benefit is that it was done so by someone who was completely and wholly unconnected to you.
See, if you went back in time to, say, kill Stalin, history from the point of his "new" death would change.
Because of the change, the circumstances of your life and your parent's lives would change, and you, A.) may never be born, or B.) never experience the circumstance which would create the scenario of you even WANTING to kill Stalin.
In which case, you would never go back in time to kill him. Meaning, he would not be dead. Meaning, you would then return to the original line of events which propelled you on the course to kill Stalin. At which point, you would be stuck in a loop.
Anyway, you can't change time. There are too many unknown variables. The... whassitcalled... the Uncertainty Principle. Events have been set since the beginning of the universe ion the level of interacting energy and matter, we can never just SEE what's going to happen. The only reason why we can make choices is because we are not aware of those subatomic particles, even though they do have an effect.
It's kind of like the Matrix. But different.
The only conceivable way I could think of that a person could willy nilly change time is if they had somehow been pushed OUTSIDE the regular flow of time and space in some freaky parallel universe, where the various laws of the universe would not affect them. But then they'd probably be all out of step with time and never age, or age too quickly, etc.
So, all in all... time travel = too damn hard to figure out.
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