In reading Art and Academe, I was a bit confused to find that there wasn't much spoken about how spirits relate into this process.

Are spirits intelligent Forms, and when they manifest, are they Informing matter? (This idea is absurd in retrospect.) Except spirits can be targeted with Mentem magic...

Are they perhaps InFormed Matter that simply lacks categories for mass and the like? Specifically, the Category of Substance.

It wasn't mentioned in A&A because spirits aren't part of the academic world. However, RoP:M has something to say about it. Spirits are pure form, with no material component. They can be affected by Mentem magic because they are intelligent.

Substance is a necessary category; a thing is not a thing without it. Purely by possessing substance are the other categories inherited, you can't have substance without the rest. However, there were some C13 authors who believed that spirits, angels, and demons were made of a substance so fine and subtle that it is inperceptible. In ArsM, this is true for demons who cannot wholly let go of the material world, however it is not true of angels or spirits.


I find it vastly amusing that the option I disregarded as 'absurd' was, in fact, correct.

So even when a spirit (however intangibly) occupies an intangible space or acts in a manner, it is not described by the categories of Relation and Action, but is something else entirely? Mystery, or does this have a name?

This was answered by Thomas Aquinas - a bit later than official ArM5, but still...

Aquinas was referring specifically to angels, but the ArM5 version of the saint would probably extend this definition to all intelligences.

See : newadvent.org/summa/1052.htm

Quick summary: while spirits have no location by virtue of having no substance, they are finite. Only God is infinite, and thereby omnipresent. So an angel must have a location. In other words, they can be said to be in a place because they cannot be everywhere; which is not quite the same thing as a substance being in a place because it inherits it by virtue of being material. (Hey, don't look at me! I didn't invent it!)



Ow, that was physically painful yet somehow it made some sense to some degree.

In short: Yes, spirits have location but it's weird.
I find that 'containing' a place/person bit to be perfect for describing the relation a spirit entity has to its given concept or location. I wonder if I might go so far as to say that the spirits of all things reaching out to one another nearby is the basis of the Group target... it always seemed that magic was the action of semi-sapient spirits and so would recognize such distinctions, and semi-sapient spirits responding to word and gesture fits with the Roman opinion of how magic operated...

Might be getting a bit too far afield there.