Aegis of the Hearth - is this a hermetic spell/ritual?
It can be re-invented but only at varying levels, not with varied parameters*. It is more powerful than it should be and has no Perdo requisites.
From this we know it's not fully understood or integrated. On the other hand, It is still cast using hermetic Arts (ReVi) and any maga may invent a version without acces to lab texts or indeed anything apart from a standard lab and her own mind - based on training appearantly any apprentice recieves. No oddities about this procedure or any element there of.
What does it matter?
As mentioned elsewhere, if the Aegis is not actually hermetic, it will not be subject to metamagical manipulations via Muto Vim. This may well be a desireable result in itself.
It would also mean that the Aegis could not be trivially undone via Unravelling the Fabric of Vim as it would not qualify as a hermetic spell, which again might well be a direable result - as per this discussion. This is also supported by the spell Removing the Hearth's Keystone in Hermetic Projects 8p. 94-95), which is otherwise just a father limited R: Touch version of Unravelling the Fabric of Vim.
[strike]Unfortunatly the same page has the Guttering of the Home-Fires - a MuVi spell specifically targetting the Aegis spell.[/strike]
I'm asking because I don't know what makes the most sense - nor which answer I'd prefer.
I can see arguments both for and against the Aegis being essentially a non-hermetic oddity.
[strike]Does this not already provide the canonical answer? If it is not Hermetic, MuVi does not work. This means if MuVi does work, it is Hermetic. Thus it is Hermetic.
We could argue about how Hermetic it is since it's not fully integrated, but any such argument should also take note that MuVi is the pickiest thing about spells being Hermetic. Then we'd also have to figure out specifically how varying degrees of being Hermetic matter.[/strike]
I completely agree. At one end of the spectrum we have magic that not every hermetic magus can use, but that can be learned with a single season of study. At the other end there's stuff that has nothing to do at all with hermetic magic at all and does not even require the Gift.
In abstract terms, we could certainly set the boundary for what's "non-hermetic" at different points in the spectrum. However, what spurred the argument was the fact that "non-hermetic" magics a) cannot be affected by MutoVim spells, b) cannot be affected by Unraveling the Fabric of (Form) and c) are harder to gauge by Hermetic magi when watching/hearing the caster. The term used in all cases is "non-hermetic", so it stands to reason that the threshold for all cases should be the same.
I think this is a somewhat different point than the one OneShot wanted to discuss, i.e. if the fact that the R/D/T parameters can't be varied when (re-)inventing Aegis of the Hearth means those parameters can't be varied with Muto Vim either. I think both points are interesting and worth discussing. Personally, I'd tend to keep as "hermetic" everything that uses Technique+Form (as well as the Parma Magica and Certamen), even when it requires specific Virtues that make it unavailable to "vanilla" hermetic magi. At the same time I'm tempted to agree with OneShot's position about the "rigidity" of Aegis to Muto Vim as an unstated but reasonable consequence of what Hermetic magi know about it, stipulating that any breakthrough that extends the applicable R/D/T categories of Aegis also makes the corresponding extensions available to Muto Vim. Note that these are not contradictory positions, as they make Aegis "rigid" as a consequence of its specific peculiarities rather than as a consequence of its "hermetic magic" status.
Yes, and I think all Original Research spells should have the same restriction as Aegis, but I'm not sure if they are equal or if MuVi is more restricted for some. There might be a good counter-example as to why one way is problematic, which is the only reason this lack of focus might be useful.
I feel they are equal - the only requirement for MuVi is that the spell (to be affected) is hermetic (and not spontaneous) as far as I can tell.
So I don't really see this mentioned lack of focus - to me it really boils down to:
Is this a Hermetic spell or not?
Or do we have to invent a 3rd category, ie. "insufficiently hermetic" - which is the option I'd prefer to avoid.
I would say that none of the defensive mechanisms that made the Order possible are hermetic. Hermetic is how you cast spells, but Parma and Aegis are not hermetic. Or not wholly hermetic. Parma can be taught to any Gifted individual regardless of them being unable to use Hermetic magic, and Aegis has some strong characteristics that correspond to non hermetic basic parameters (are not guidelines usable for other spells).