Because you are obsessed with the idea of past, present, and future, you are forced to think of reincarnations as strung out one before the other. Indeed we speak of past lives because you are used to the time sequence concept... You have dominant egos, all part of an inner identity, dominant in various existences. But the separate existences exist simultaneously. Only the egos involved make the time distinction... a thousand years in your past or in your future - all exist now.