In theory, Mobed Lore covers "knowledge of (Mobed) Initiation scripts", much of which is oral. And indeed, Mobeds can always self-initiate if they know the appropriate script. This raises a question: imagine a PC who is the last Mobed of an isolated Mazdean community - perhaps one travelling to set up a new home after losing their old one (incidentally, would a mobile fire tempe be a possible?).
By the RAW, which scripts would he have access to? None? All that his Mobed Lore + Pre qualify him perform? Something else? Please don't say "whatever your troupe thinks is fine" because if we had a clear idea we would not be asking Are there Virtues that would allow him to expand the number of scripts he knows? Would he be allowed to create "experimental scripts" as per TMRE?
RAW doesn't say much of anything about what scripts he will know - just as it doesn't say what scripts a member of some mystery cult will know.
So RAW literally is "whatever your troupe thinks is fine". Sorry, but that is the way it is.
If the mobed was well-trained by a knowledgable teacher he would likely know lots of scripts.
If the mobed was poorly trained by an old master in isolation from everyone else he might know the scripts for the initations he himself had gone through, and not much else.
There is no explicit answer about it, so let's leave it to each SG.
You could take the approach for Philosophae formula: one per level. It feels a bit generous that somebody barely knowledgeable in the cult would know any script, though. So maybe one per level, but only once the initiate is at least level 3, or if you want to be more restrictive: skill level -2 # scripts - so level 1 and 2 initiates know no script.
There are some scripts that are probably taught only to high level priest (with 5+ in the Lore) like Major Virtue.
That might be an oversight of the rule not to set limit on how many script a person can learn, but it might simply be a case of let SG rule that bit and let's not put too many rules.
Per rule, there is no limitation to self initiation, so you could theoretically try to research a Major virtue script with only a +1 level in Lore, but your roll need to be an exploding dice, so unlikely. And even if the experiment is successful - a potentially new script is created - the initiation might fail since it does not rely on a dice, so Pre + Mystery Cult Lore + Script modifier (+Risk modifier) must be higher than the initiation target. If this last part fail, he did not generate a usable script and the initiation fails.
So self-initiation is really hard unless you are already a strong initiate in the cult.
Such initiate should try to rediscover lost knowledge in ancient cult site, and a SG could assign either XP in the relevant Lore depending what are his discoveries (cult items, carving, buried temple), or maybe even unearth lost script. I could see engraving on wall describing initiation to follow: they could grant good bonus to re-constructed lost script (instead of re-inventing them from scratch) - you mentioned a mostly oral tradition, but pictural description might still be occurring.
Obviously, there is always the option of asking the dead, but it means discovering a dead priest that - for some reason - did not pass on (violent death without any burial rites ?)
Hmm, good idea.
Plagued by Supernatural Entity (ghost of old Mobed who won't rest - and won't let you rest until you've learnt and gone through all the Initiations).
Technically, witch covens (and Mobed Initiations specifically point you to HMRE for guidance) purchase Initiation scripts with Coven(ant) build points (script cost = script bonus). The problem is that this shifts the issue to Covenant rather than PC level, and it's not clear how to resolve it for a PC (witch or Mobed) loosely affiliated with an Hermetic Covenant.
I guess you could really say that if a PC who's not supported by a Covenant is technically part of a similar "entity" (a Mobed, with his FIre Temple; a witch, with her Coven; a Christian priest, with his Church - see TC) then the troupe should create that entity separately with the Covenant-derived rules. Hmm.
Personally I'd say they 1) know the initiations the have gone through, and 2) have a chance to know any others they could have used at the point when they lost access to the lore. Have them roll int+Mobed lore and give teh initiation a target number based on how rare you think it would be. Initiations outside of their range of capability to utelize they would not have learned. Also in calculating the difficulty to recall a script the number of elements should be a factor.
You might consider allowing a script they knew other mobed had used to be an inspiration towards reinventing the script as if it were being converted from another tradition.
I agree that any scripts personally undergone should be known for free.
Over and about that, there are many options,
They know the scripts they have found/been told explicitly.
Scripts are bought for xp, like philosophical formulæ for 5xp each.
One ( or n) known script(s) per level
A lore roll to know a specific script.
If the cult normally favours self-initiation, I think I would prefer 3 or 4. Scripts are really shared as part of teaching the cult lore. The randomisation of 4 may be nice, but it may lead to a character oddly knowing a lot of advanced scripts without knowing the one custom dictates that he ought to do next.
If the cult thinks badly of self-initiation, maybe only 1 makes sense.
I am not very fond of 2; it is an odd rule which does not fit the general system, but given that it is already used for philosophical alchemy, it is not that silly to extend its use, if you want to have more flexible and strictly balanced mechanism.
It is all a question of what kind of cult you want to promote? Do they share scripts freely, systematically, or only reluctantly?
One thing to keep in mind is that a script is not really something you need to learn.
Having it written on a piece of paper and working from that will work just fine.
In some cases scripts are primarily transmitted orally, so you won't find them written down anywhere.
In other cases, going down to the archives and digging through dusty piles of paper will yield old scripts that nobody has used for a century or two.
All depending on the cult/tradition.
Having scripts on paper certainly makes sense and makes it easier but the Op indicated that mobed's were an oral tradition which means that doesn't apply to this situation.
The OP setting was not only oral, but also a singleton. Memorising a dozen scripts that you have not seen executed is not a trivial learning task, especially when a tiny mistake might upset the powers that be.
Apart from the special case of OP, it is likely that some traditions live scattered and solitary lives, with little opportunity to seek out the script master upon need. This calls for such memorisation of scripts.
While the mobeds use many orally transmitted scripts, they also have plenty of initiation scripts that have been written down.
Nothing in the OP says there can't be written scripts available - but the question is the same for them as for orally transmitted scripts - how many?
Right. I assumed that his emphasising the oral tradition implied that he wanted to emphasise oral scripts.
If the scripts are written, it shifts the challenge from learning knowledge to hoarding material capital, and capital (starting equipment) is not a matter for rules in ArM.
And if scripts are normally written, why bother memorising them? OK, if there is nothing to the script but the RAW descriptions, then memorising is easy. I always assumed that there where essential rituals and prayers that had to be executed with no room for error, and that's not something I would memorise in a written culture.
Are there Virtues that would allow him to expand the number of scripts he knows? Would he be allowed to create "experimental scripts" as per TMRE?