Well, if you believe in the Gaeia theory (I got this from watching the Final Fantasy movie) Then we are all just little bits of a giant energy/ethereal field and there for we are all technically everyone. Kind of like the cells in your body, cell #1 is you and so is cell#2, so if they are both you then they must also be each other, I think.
I personally think it is about as likely to be true as any other theory.
But that does not mean that I believe in it. I wonder if it's even a real theory?