Past lives, future lives, after lives, probably all just wishful thinking. I'll stick with my own theory of thought energy waves affecting impulse receptors in our brains as to why we feel/hear/see things that someone else did in the past. It goes like this: each thought generates a certain amount of energy, a wave, which you can measure with an eeg machine. The amount of energy exists at a certain frequency, and like radio waves, continue on past the receptors infinitely; however they are affected to some extent by oh, perhaps gravity and other engergy fields on the planet. So You have all these 'waves' flowing through us all the time; you just don't have receptors that can receive all of them, much the same way that a table top radio doesn't have the right tuners for every radio frequency signal reception. However, once in a great while, a person's receptors WILL momentarily match up exactly with the frequencies generated by a person who lived in the past, at which point they will experience whatever it was in that thought, in effect a momentary sight, sound or feeling exactly the same as someone who may have existed centuries (more, or less) ago. Much as we didn't have eeg machines two hundred years ago so that we didn't even know or could measure THOSE energy waves, at this point in time we are unable to measure the minute amount of energy going through the air around us which is generated with each thought. Doesn't mean that it isn't there; we just don't have the technology that can do it yet. This would also explain many of the sightings or hearing of what we believe to be ghosts.
Just one of my many wacky theories.