I still don't it. I've read that souls were "washed away" from a person's body in the DreamSleave, wiping them clean. Kind of like take a drop from a bottle and putting it into a pond. Once the drop of water is in the pond, you can never get that same drop back because it is mixed in with an infinitely large pond, so to speak. That's just one interpretation I've read. It doesn't quite make sense with the ancestral spirits because obviously, if that were the case, what are all these free, or lost, spirits doing wandering around tombs and mountains instead of being washed away in the Dreamsleave?
So then what exactly are the qualities of a soul? That's actually an answer I'd like to know for Elder Scrolls as well as here on Earth. Souls aren't made of anything material, although neither is energy when you divide it down into the quarks, neutrinos, gravitons, strings, etc... (probably off-topic here)
If you have Nerevar's soul, what quality of Nerevar do you possess? I get that you have his soul within your body (or any of the 10 species, which is not to say that the Nerevarine could have been born a http://www.uesp.net/wiki/Lore:Sload or any of the other enigmatic species on Akavir) but what would the difference be between having Nerevar's soul within you and having some random simple beggar's soul from the 1st era within your body? Do you possess his courage? His fear? His personality? His quirks? His prowess? His sixual vitality? His temperment? I think the soul is the intelligence that drives and directs the outcome and behaviour of one's personality; the observer within the body, the consciousness that feels and that is filled with awareness. What are your thoughts?