So watching Godzilla vs. King Ghidorah (1991) today, I once again encountered one of the odder “rules” for time travel, that someone can’t exist twice in the same time.
I first encountered this back in comics. There’s an old story where Superman travels back in time and meets Superboy and can’t leave that era because existing twice screws up the time stream.
Doctor Who has the Blinovitch Limitation Effect which says the same thing. It explains why if the Doctor fails, he can’t simply go back and repeat the effort: he’d be doubling himself and causing a time disruption.
In Timecop, we learn temporal counterparts can exist in the same time, but they can’t touch or Bad Things Happen.
This is one that presumably makes sense to the writers but I just don’t get it. Fourth-dimensionally speaking, me today is at a different point in four-dimensional space than me six years ago, or even yesterday. It’s like a curved PVC pipe stretching through three-dimensional space—no part of the pipe gets in the way of the rest of the pipe. Not even if they’re lying on the floor in the same bit of two-dimensional space.
A more logical variant is that if you meet yourself, you might wind up causing a time paradox or letting slip something about the future. But that’s not what the writers above are going with.
I guess it’s just a convention that’s common enough (though far from universal) that writers keep reusing it. But I could live without it.
