[devonin]

Originally Posted by ~kitty~

Then we find out about all future time travels to the past and detect that they'll arrive somewhere and we shoot them and kill them, then send a person into the future to shoot them again and what then?

We caused a paradox, so I doubt that's going to happen.

Plus the theory that no two entities can exist at the same time in the same place still stands, I believe.

Perhaps you misunderstand? The past that we experienced IS ALREADY THE ONE THAT HAS BEEN MODIFIED BY FUTURE TIME TRAVELLERS. That is, you cannot go back in time and change the timeline, because when you go back in time, what you did has already happened, since it is, after all, in the past. So any changes you were going to make ARE WHAT HAPPENED, and the resulting timeline which is our timeline is completely paradox free.

As for the theory, I think you mean that no -one- entity can exist in the same time and place as itself? Like, I can't go back in time to my own childhood and give myself some winning lottery numbers or something? Even if we grant that as correct, that still doesn't suggest any inability to time travel, so I'm not sure why you brought it up.