I'm looking for a quote that I can't seem to find but could swear I've read a long time ago about Vim being the Form that covers the Soul. If anyone can point me towards the (or any?) such citation I'd be appreciative.
Doubtful vim covers the soul, since there is the limit of the soul, and so an art couldn't cover something that is outside the scope of hermetic magic.
The limit of the soul says that Hermetic magic cannot create an immortal soul. It says nothing about affecting an existing soul.
The description on the limit of the soul (ArM5 p80) goes on to say that angels and demons are nothing but immortal souls - and hermetic magic certainly can affect angels and demons.
You are correct if you go only by the text of that paragraph discussing the limit, but I believe it's slightly more complex than that when correlated with other texts, and possibly linked to the fact that what happens to a soul is a decision of the Divine, which is infaillible. You would think if the actual limit was Creo Soul, then Rego Soul, Intellego Soul and Perdo Soul would work. And yet...
- There doesn't seem to be hermetic guidelines to assess whether a soul is in a state of sin, which you would think might be important to an order which is mostly christian... Mind you, this could be merely an absent guideline that could be invented, but I'm not sure this is so simple.
- Magi rely on a flawed shadow of life renewed or complex contraptions like the living corpse, rather than fully healing a body to the point where life is possible with Creo Corpus and then doing Rego on the soul to summon it back in it's own body... and yet having a non-christian soul available via a ghost to summon doesn't seem to allow magi to escape the limit of the soul which prevents Creo Corpus from creating life on the grounds that you can't create a soul which they wouldn't need to actually create at that point... It could be, for the sake of argument, that being dead is now the soul's essential nature, but relying on two different hermetic limits to justify the same kind of restriction on bringing back the dead may not be an optimal explanation.
- Lay to rest the haunting spirit does say that philosophers don't believe destroying the Might of a ghost destroys the actual soul of the dead, which is immortal. If destroying the might of a ghost which is neither in heaven nor in hell doesn't destroy the soul, why would perdo vim destroy the soul of a demon or an angel rather than merely destroy their might and ability to manifest on earth - is their soul somehow more mortal than a mortal's soul? Unless of course, destroying the might of a ghost actually destroys the soul, and hermetic magi are merely in denial over that because of its implications.
The Limit of the soul seems to be more complex than it is described. I don't have a perfect answer, but I think making such assertions as "Vim covers the soul" or "Mentem covers the soul for humans" to be extreme simplifications.
I seem to recall reading somewhere that ghosts are spirits, not souls - so a living human requires all three of a body, spirit and soul.
I don't remember is this is canon in the 5th edition, but it certainly has been earlier.
I remember reading infernal ghosts really have their souls in hell even if their spirit is on earth, and that pagan ghosts often believe themselves to be in whatever afterlife world they believed in, but that it isn't clear whether the ghosts are merely hallucinating.