Well, there is the reincarnation interpretation, which implies that souls are not born complete, but are 'seeds' that grow thru the incarnation in many, many cycles of existence as many life forms. It's still very anthrocentric in the way it assumes we humans are the last vessel a soul inhabits before it can free itself of corporeality.

If 'souls' are the energy patterns created by our nervous system, and energy cannot be destroyed (as classical physics attests), then souls are eternal, but they do not remain in the same state as we think of them when we die, but become matter which is exploited by other life for the purpose of keeping it's energy pattern stable.

Self-aware entities that can exist outside of the body? Perhaps... it's hard to just discard the experiences of people who've 'died'. If it was just 'the tunnel of light' they experienced, I'd chalk that up to a physiological phenomenon. But then you have people 'coming back' with accounts of conversations with dead relatives and such. Just a variation of the dream state?

Time is not a fixed constant, so it's possible that 'eternal soul' is a metaphor for a sort of supercondensed point of subjective awareness at death that encompasses our entire lives.

I really don't know. The world is full of things we cannot always explain with empirical science. I find using mythology as a substitute for real knowledge a lazy way of filling in the gaps, tho.