I 've always played it as you need to have a suitable connection to the creature you're researching.
So reading a book containing a true name - take 5xp from your study total and gain a True Name.
Spending time in the sacred ground of a genius loci - gain exposure (or possibly practice?) and over a couple of seasons you will have researched it.
To get one of Lasa Vegoia, you would either need a book on Magic Lore detailing a lot about her, or time spent in a place associated with her.
(technically, by Rules as Written you could spend 3 seasons getting a True Name to any spirit by exposure - I think the point is that this is too tedious for all but the most desperate magi. Most magi would prefer to read their Names of Power from a book, and senior members of Mystery cults will probably delegate researching new True Names to low-level initiates)
That's what bothers me : RaW, any mystery cult could use initiation scripts where the guy to be initiated has to find a new true name (to get a bonus for times spent) and give it to the cult. The cult would this way get dozens of them without anything else to do than waste the time of young members that seems too easy considering the description you get in the Titanoi section.
It makes sense the Daimon wants to be found because you give them power by spending vis for invocation but still... I much prefer what you suggest, It makes more sense for me to allow practice only it you're in a significant place or have access to some ressources (book on magic lore with a significant focus on her, multiple books or tractatus on magic lore somewhat related, ghost or people to interview for related knowledge...)
You have to know something about the Daimon or spirit before researching its True Name.
5xp is a lot, especially since that often just gives you the right to spend lots of vis to summon a daimon, to spend lots of time dealing with stories about spirits who may or may not be happy about your contacting them, and so on. Even if I can learn 2 True Names per season, who cares? The 120xp can give me the names of 24 spirits... or raise an Art from 0 to 15.
Rather than being a bug, it's awesome and totally appropriate that an established cult has built up a vast repertoire of True Names. Unfortunately, any member of the cult still needs to spend 5xp to know a True Name! I cannot learn this for you, the same way I cannot spend seasons of study to increase your Creo score.
There is what is the rules and there is what is the flavor. By the rules you can learn swimming while doing lab work in the Sahara. Obviously they were designed to rely on more judgement than that. So if you are doing lab work that is somehow related to the daimon whose name you want to learn you might gain exposure that way, or by reading books in which they are mentioned studying magic lore, or by examining objects that were theirs in life as self study... which isn't mentioned any more than it is mentioned that you need a single handed weapon such as a sword or mace to practice single weapon.
Which is completely reasonable if you are working on a ReAq effect, or an effect that involves sharks.
Which, by the rules, is satisfied by any book on Magic Lore, and this is reasonable. The book doesn't have to be about the daimon for me to gain insight into what its True Name must be.
And this isn't necessarily true either, sort of the way at the beginning of WW2 people got practice with tanks without there being any actual tanks available. (Different nations experienced different variations of this, from the Americans who painted TANK on some trucks so they could run exercises, to Germany in the 20s and early 30s with their 'agricultural tractors.')
Well, that's a fair comparaison, indeed the same thing could be said with the time "wasted" initiating a virtue from a mystery cult compared to the time spent studying. I can see different magus choosing different options and that's for the best.
A dedicated Theurgist would much rather have the true name of "Lasa Vegoia the Matron" than 5xp in any art but I'm not sure he would push It to 24 true names. It's all about what you get from each invocation I suspect he would try to achieve a specific goal with each true name It's not a linear progression like improving an art. Eg : If a player has been cursed it would be very beneficial to get the true name of Hipta the Nurse, much better than any 5xp in any arts, but I don't see him researching her if that's not the case It would then be a waste of time. Comparing It to initiating a virtue is probably more accurate IMHO.
It also depends a lot on vis availability, magus power level and Daimon powers...
My point isn't that "you need a tank to learn about tanks" it's that obviously you need something, you don't sit in a chair and meditate about tanks. I mean you can gain exposure experience from reading a fictional book which includes the ability (art and academe) being learned, but it is at least something. similarly to learn a daimon's true name you have to have some kind of appropriate reference- a poem to the daimon, a book on magic lore which is (or could be assumed to be) related in some way, someone to talk to who has heard a few stories, etc.
Even this is too generous. It's not enough to know something about the spirit. You have to actually have access to the True Name either through oral transmission or because it's in some text that you're reading. The 5xp represents the effort to internalize the True Name sufficiently to employ it, in the same way that a Lab Text for a spell requires a season of study to benefit from.
If you just know something about the spirit, then you can use the "Hermetic Synthemata" minor virtue from TMRE to learn something sort of like a True Name but not quite as good, albeit with more effort than 5xp represents and with the need for the aforementioned virtue.
This is all IMO, since I don't believe there's anything more in the rules than has already been mentioned (pretty much nothing). To make learning True Names easier would be overpowering, since the ability to target a spirit at AC range and with a +5 Penetration multiplier basically means a competent magus owns the spirit in question.
To my modest understanding, Synthemata gives you penetration bonus, It doesn't target the Daimon It target's the magus so. Unless I'm mistaken the ONLY way to get an AC to most Daimon is to get his True Name otherwise you simply don't have an arcane connexion to It.
It implies that you can get his true name somehow in the first place, sure It's easier If someone did the job before but there has to be a first one...
I think you're right about Synthemata. I like to believe ACs other than True Names exist to spirits and daimons (RoP:M notwithstanding), such as ancient temple idols, and that these ACs lack the overpowering +5 Penetration bonus of a True Name. There should be a way to contact and summon otherworldly beings without necessarily being able to easily overpower them.
Or you or some ancient magus could simply have run into the spirit in the past and used magic with range of less than AC to force it to reveal its True Name.
If you want to be still more accurate, it ought to be compared to learning/inventing spells. After all, if I have access to 24 spirits, I am really getting their powers. Instead, I could learn a bunch of spells and use some similar suite of powers myself.
So, 12 seasons of learning True Names (at 10xp/season)... or 12 seasons learning spells (plus 24xp from Exposure). Using True Names often involves spending lots of vis on stressful rituals, competitors for the spirits who also know their TNs, and stories about vengeful spirits who plan to do something about your getting good use out of your investment.
Indeed, most of the appeal (to me) comes from the fact that Daimons :
1-Have access to powers you can't replicate with Hermetic magic (grant virtues for example) )
2-Have access to powers that are very distant from the magus speciality : As a Theurgist you're probably more or less proficient at ReVi and MuVi and you might prefer spending seasons finding a suitable Daimon instead of learning 15 levels of aquam for which you don't have any interest except resolving the problem at hand.
The amount of vis, the risk of botching, specially while using wizard's communion is indeed a major drawback and calls for dedicated magus with appropriate virtues to mitigate part of It.
For the rest on the contrary, Daimons are exceptions among spirits, they can have multiple aspects summoned simultaneously so there isn't any problem with "competition" among theurgists, unless you want to summon It at the same place because there can only be one aspect of the daimon at a given place to avoid two aspects "meeting" each other.
Also Daimons are also generally happy to be summoned (unlike other spirits) because the get xp from the ritual, so unless you use Synthemata (which is more or less a threat, casting it is like saying to the Daimon : I can do whatever I want to You), the Daimon is normally willing to exchange his summoning (and the prospect of being summoned again with additional vis to gain experience) against one/some use of his powers. It doesn't really cost him anything and that's the only way he can become stronger.
What do you want to do with the spirit you have at your beck and call? That +5 penetration bonus, plus the ability to cast at your leisure that comes with an AC range means you can basically control any published entity short of the archangels in RoP:D. A Kosmocrator spirit with a Might of 50-75 is easily overpowered by a skilled Hermetic. A Might 75+ Protogonos is even with reach for the right magus. Ditto for Dukes of Hell (around Might 40) and even Hell's ruling Electors (75). Published Faerie Kings and Queens seem to be around Might 60, also within reach (I raise you a "Rumpelstiltskin" if you tell me Faeries don't have True Names). Let's not even think about Angels, whose supposed True Names are a staple of real-world occultism.
How about summoning the Jinni King of the East and raising an army of Ifreet? Or simply using lesser Daimons like Lasa Vegoia to grant you all the virtues you like, without the need for tiresome pacts. Just pronounce that Name while casting your favorite ReMe spell.
That's the question for any magic a spellcaster invests time into. So you've spent two seasons on that spell that makes your horse fly, now what?
Yes. I was talking about the general case. If we focus on daimons, then spending 5xp from any Magic Lore source is still not too cheap.
Investment (not counting needing good Art scores and a lab, since nearly magi want these):
You need to learn a unique summoning spell for that daimon. That costs time.
You need to spend 5xp for the TN. More time.
You need to spend a handful of vis per summoning/request/service. Ouch, especially considering the conversation about how much vis is available per year.
You need to cast a ritual that is probably risky. Cost unclear.
If you fail to penetrate, you need to recast. (IIRC.)
You aren't going to do this very often! So why worry about the 5xp?
At this point, you have a daimon that is well-disposed to fulfilling your request. But:
The daimon can always refuse if it (or the GM) does not like this particular request... or this particular magus. Vis wasted! The magus has no recourse either, because the daimon cannot be harmed and the Aspect can be dissolved should the magus attempt to coerce it.
The GM gets to decide what daimons exist in a saga and what powers they have and what their Might actually is. So the magus has access to nothing that the GM hasn't created or accepted. This isn't Amber, where a magus can walk the Pattern to find the Daimon of My Desire!
The daimon can always demand something from the magus beyond the vis spent to summon it.
As I look at it, I think that spending 5xps for a daimon's TN might be too expensive, rather than too generous!
Invulnerable daimons are, IMO, a misunderstanding based on the very vaguely written description of daimons in TMRE. The same book refers to "magics that force the spirit (such as True Names)" (pg. 117), which suggests that True Names work pretty much as they do across fiction and folklore (cf. Faust).
If your position is that True Names only exist for daimon spirits, only work with Theurgy (and not Goetia, vanilla summonings, or anything else), and that daimons are free to laugh at the spellcaster, True Name notwithstanding, then, yeah, even 1xp for the True Name is too much. Maybe we need to invent something called Truer Names that work the traditional way.
That thread - and others like it - were mostly about the generic "spell spirits" facet of Theurgy. I basically agree that this isn't of much use. The mastery of named daimons is a whole different animal.