Souls, what are they?

A lot of fan discourse about the souls treats them as indivisible, individual, atomic entities. The whole 'which Daedric prince calls dibs' question is based on that assumption. One recent thread on r/Skyrim (sadly deleted for some reason) even equaled sacrifice to Boetiah and Mephala as gifting the soul to them, and built the whole idea of ambiguous sacrifices to provoke the Daedric war.

What I want to do is to cast doubt on it. There are several very significant lore events and pieces that reinforce the idea that the soul is fragmentable, that the soul energy is separate from the 'self', and even the 'self' can be in several places at once.

The whole narrative of the Underking and the Arcturian heresy shows us that you can mix two souls and separate them back into two distinct entities along the new lines.

The variations of the vestige lore actually introduce a third element - the vestige as the core of identity and memories that is separate from both the soul itself and the body. And that is essentially a Daedric blueprint of personhood that can regenerate new bodies for itself.

And in Skyrim, Olaf One-eye seemingly can be in two places at once, being a spirit in Sovngarde and a draugr in his tomb. Also, I remember something about the Hist being able to reincarnate the Argonian souls with or without memories.

One of the ways to parse it would be to treat the 1) soul energy (as used to power the enchantments and the sacrifices), 2) memory and identity (what forms the vestige), 3) the core of self-hood (what we as mostly post-christians call a soul) as three separate entities. That would describe most of what we see in the games in non-contradictory way.

Yet another more out-there reading would be to stop treating the soul as an entity, clearly divisible and a part of a zero-sum game. What if the possible solition of the 'multiple Daedric princes allegiance' issue is just them carving up a soul along the arbitrary lines? Hircine takes what makes a predator, Boetiah takes a part that betrays. That would line up with the way we see the mortals in the Daedric realms as very damaged.

Also, in some cases we need to remember that the soul may not even be the source of the energy, a symbolic act of doing something with it can count for both the sacrifice and enchantment.