There's no guideline for it, so its impossible within the scope of Hermetic magic. There is however a mystery known by the Merinita - Awakening (RoP:M, p. 104) - which allows spirits to be awakened in perfect natural places or animals.
As for memory spirits, they don't really seem to fit into the taxonomy of RoP:M ch 7. There will be a Theoi or Kosmokrator of memory, but that's probably not what you're after.
RoP:M page 103 notes that magi have to way to prove whether summoning an airy spirit "is tantamount to the creation of that spirit." A spirit representing a basic memory, or one representing the ability to store a few such memories, would definitely be an airy spirit. I would go with a straightforward ReMe spirit-summoning effect with this in mind. Sprinkle to taste with any memory-magic or spirit-mystery-magic that seems appropriate.
Interesting. If it's a spirit of memory that has been summoned (Ie a mentem spirit which is effectively of the purpose of remembering things) it's main desire, it's focus in life, as it were, should be to remember things, right?
If I recall correctly, to teach a spirit something and have it retain skills learned and memories gained, you must feed them vis, right?
The Mysteries Revised Edition, under Curious Common Magics: Spell Binding, gives a Re (Form) guideline for the summoning of a spirit (which is level 15). This is not actually part of any Mystery; any magus can cast such spells although the implication is that they are little-used. This guideline is repeated in several places, not least of which is Houses of Hermes: Societates, in the Tytalus chapter where an example of a Mentem spirit (in this case, the spirit of someone's anger) is described. Someone has already mentioned that summoning is equivalent to creation when it comes to airy spirits.
One (minor) problem is that the spell is R: Arc, and you are required to have an Arcane Connection to the spirit. A fire is an AC to its tutelary spirit, and the Tytalus spell summons a spirit of anger from an angry person; these things act as ACs to the spirits. How you'd do this for a memory is up to you.
So you are looking at a 40th level ReMe spell, minimum (Base 15, +4 Arc, +1 Diam). You must also Penetrate Magic Resistance of the spirit.
Could you not do a summoning spell with a random name?
You don't know if you are creating it, or if it existed already, but it is still there and answering to the name.
Saves time on tracking down and bargaining for a name...
Hmm, could abuse this by summoning a spirit, mining it for vis, then summoning using the same name, mining it for vis, repeat.
After all, it could be classed as a natural thing, like fish in a pond, or scorpions in sand...
A "CrMe version of the same spell" would create a spirit with Might out of nothing. Very few troupes would want that in their campaigns, I suppose - unless each casting would cost at least Might/5 vis. This is probably the reason why I have never seen such Creo spells in the books.
The CrAn guidelines level 5+ on ArM5 p.116 box can be used a blueprints - matching guidelines as needed to other Forms - to create 'spirits' without Might and Int, approved by the troupe.
So if one wants to create a golem, per se, the animating spirit would have either to be collected by capturing an existing spirit, or it would have to be an animal spirit (or at least, something controlled by An) ?
Or could you use the spell described by Mark Shirley to give it a simple mind ?
If you tried that in any saga I was running, you might find that you needed a new name for each version. Or that on re-summoning it, it had no vis. Or (if a memory spirit) that you'd forgotten the name...
I think that there is something in RoP:M (or maybe just in my mind) where any spell that 'creates' a magical being needs sufficient vis to give it its might. And a Vim requisite (or, in this case the spell would be CrVi with a Me req).
Creating a low might spirit might suit BlackLiger better than summoning an existing, higher might one.
Conjuring Memory's Servant CrVi(Me) Base 15, +1 Touch? = L20, Ritual to be permanent costing 4 pawns plus 1 pawn to make a Might 5 spirit of memory.
I would say that such a minor spirit could only memorise one particular type of memory, which it would need to learn according to the rules for magical beings - subtract its might (5) from any learning total/feed it one pawn of vis to counteract this.
This costs a lot more vis than a summoning spell (because it is a ritual), but is lower level.
Certainly RoP:M p.110 Spirits and Magic and the box on p.111 with new spell guidelines relating to spirits do not mention Creo. Creating elementals by ritual (RoP:M p.133 upper box, e. g. CrAq 30 Rarefy the Crude Water) is another matter.
The 1 pawn per magnitude of might is only a guideline. Some have more, (Pukis) and some have less (ghostly warder). Anyway the problem needs to be dealt with due to magical creature creation. The obvious solution is to limit the total vis produced to the ritual cost or less. If more magnitudes of might are created than vis used (Say a group creation spell) then some of those creatures have an abnormally low amount of vis.
Indeed. And my argument dealt only in rough quantities - not to become pedantic.
Since group creation spells (see ArM5 p.113) are limited by the overall size of the target they create, and the few examples of creation of things with Might (RoP:M p.133 upper box) I know of limit the Might with the size created (RoP:M p.135 box), this does not yet appear as a problem to me. If a campaign runs it loosely enough to allow rituals creating spirits with Might, though, they better provide rules for analogous Might limits without the need of an intermediate size.
Since, unlike Brutus, my goal is merely to make a spirit which can be present in my lab, preferably with the ability to talk, listen and watch, and if possible, in possession of the skill of the Art Of Memory, I would have no issue with having to spend vis to make the spirit, merely would appreciate knowing how much.
While I would rather avoid implying the concept further, as it has reached the point of being beyond a joke IMS, I am essentially looking for an equivalent to Jarvis from Iron Man. Something to which I can give instructions to remember a detail, then request that information back at a later point.
In addition, I would like to know what this forum's interpretation of it's presence would do with the casting flaw that I suffer a penalty of half my casting total if I am ALONE while attempting to cast a spell.
But their is no guarantee that the creature will even have roughly the same amount of vis. Ghostly Warders have none. This is important because if the amount of vis is within a few orders of magnitude of the expected amount ritual spells can create vis.
A group version of rarefy the crude water could target 10 size+0 bodies of water. 30 magnitudes of might combined. Or 100 size-3 bodies of water for 200 magnitudes. Or size-6 for 1000 magnitudes. Or size-18 for 10,000,000 magnitudes.
The ritual spell itself only costs 8 vis. When the targets are of any size of +0 or less, you need at least some of the elementals to contain no vis.
Also their are several other might creation spells. CeAn has one. Hermetic projects extrapolated it for CrCo, and Animae magic can do it as well. However none of this is a problem. As the ghostly warder show the vis amount guideline is merely a guideline. It can be more or less. Even nothing if the situation calls for it.
I would probably use the guideline in CrAn as a starting point. Talk with the storyguide, but the CrAn guideline, would put it around a 50ish spell.