A few notes:
MJ's character has song spells which mostly come from Haston, but he has one inspired by the rules in Spellsong Sorceress. Stasheff wrote the basis for the first, and L.E. Modestit the second. Both have song magic, but they are very different universes.
In Spellsong Sorceress, magic is divided into two areas based on its effect: Clearsong and Darksong (with moons named for these as well.) Clearsong can be utterly brutal--MJ's spell is Clearsong and it rains fire arrows down on the enemy if I remember right.
The difference is Clearsong affects that which is not alive and never has been. Darksong directly affects the living and once living.
If you shoot an arrow at someone and focus on the metal arrowhead, Clearsong. If you talk about the wooden shaft, Darksong.
Darksong gets you massive headaches, backlash, explosions....
D&D's low level Charm spell is very clear Darksong by this schema. Of course, the D&D Wizard is thinking in terms of 'I have five spells of the third order that I can cast before I sleep...' and he is not affected one would say by arriving through a gate in to Modestit's world. Basic Multiverser understanding of magic here.
However, in Modestit's world, even if you don't realize the distinction of Clear/Dark you still can get zapped by it. If you learn to do song magic, but you don't get the whole distinction thing, it still can bite you.
Thus, the 'bite' is independent of the expectation. It is unexpected to refer back to my title.
Now, one way to deal with this is to have a deity modifying things. And at one point, Modestit's heroine muses that whoever runs the place really did not want people messing with the free will of others. You can burn a man to ash, but its almost impossible to enslave him by enchantment.
I have a different question related to this theme.
Dark Daddy Zaaz is performing a mighty ritual which he expects will push his power level to Over Nine Thousand(!). The moon is full, it is the tricentennial Night of a Hundred Screams, all the stars are in alignment, his sacrificial knife was hand carved from the jawbone of a still-living priest, and the altar in front of him sports an unconscious virgin of fourteen years. Everything is in readiness.
Except that the girl isn't really a virgin. He does not know this. No one knows this - not even the girl.
Can the ritual still succeed?
Um--I can understand the girl not knowing, but doesn't someone know? I mean, someone knows that there is a girl who doesn't know she's not a virgin, and that it is this girl, even if he doesn't know that this girl is on this altar being sacrificed as if a virgin.
Personally, I would say that if the spell requires "a virgin" it matters whether or not she is one, and the spell will fail for lack of a necessary component if she is not so in fact, no matter what anyone (including her) believes. Conversely, the spell might be designed to require a "sacrificial maiden" in which the virginity of the girl bonuses the skill, in which case the fact that she is not a virgin means that particular bonus does not attach, but the spell still has the requisite maiden and there might be a partial bonus for the fact that the girl is innocent in her spirit/mind, being unaware that her body was despoiled.
So it depends on the phrasing.
--M. J. Young
You have a point about the knowledge. I suppose my question has to do with the expectations-driven model of magic, and how it would account for this spell's failure in this circumstance. I want this spell to fail in this circumstance, but quite honestly, DD Zaaz is expecting it to succeed.
That sounds like a weak argument to me now, because people expect spells to succeed all the time that end up failing, but I feel like this case is different from those cases.
With Clearsong, you get some of the same effects as Darksong, if you go really massive in Clearsong.
So throwing a wooden spear a mile or boring a tunnel through a mountain might come out to much the same effect on the spellcaster (there is another complication I think which I'm going to ignore.) I think I'd say -50 Sitmod on spellcasting if Darksong, and you can earn that -50 by also doing Something Real Big with Clearsong.
Obviously, "expectations" is not the only factor in whether magic works. Bias is a big one, and the amount of power being called versus the ritual being used is certainly part of it.
Also, it should be obvious that the caster, as a character in the game, never really knows whether he will succeed or not. The player might do the math and come up with what he thinks is a certainty, but there are often factors the player does not know. A perfectly "certain" spell effect might be power blocked, for example.
What bothers me about your particular scenario is that it is stated specifically that the girl is not a virgin but does not know this. Someone knows it, though--that is, it being an established fact and not a possibility, the referee knows it. It has not been explained how it is that the referee knows this, but it apparently must be a fact of the scenario, or a problem determined on the basis of some game mechanic.
So what do we have?
We have that this is not a known fact until the spell is cast, and for some reason the numbers did not add up the way the player expected and he failed, or worse, botched. The detail of the girl not actually being a virgin is created after the fact as explanation for this. I can see that happening--but it's not the scenario you describe.
We could have that the caster acquires a girl whom he believes to be a virgin, but for some reason the referee decides to roll a general effects roll on this. On a bad GE roll, she's not a virgin. (We've got "good" GE rolls where she is "semi-soiled", a girl who is a virgin technically but could hardly be classed "innocent" in sexual matters.) On the worst possible GE roll, she is not a virgin but that fact is not discoverable by the caster, even by probing her memories, because she does not know it. In that case, the entire point of the GE roll is that it derails the spell, because a necessary component is not what it appears to be. It would be the same as if the spell required a diamond and the caster did not realize he was using a cubic zirconia; the fact outweighs the mistaken belief.
We could have that there is some plot or story reason why this girl is not a virgin but does not know it. In that case, the failure of the spell might be the way that the character discovers the secret; if the spell were to succeed, it would confirm that the girl was a virgin, which she is not (whereas spell failure will only tell the caster that something did not work right, and might point him to the truth). But it seems to me that if we know the girl is not a virgin and that she does not know it, there must be a good reason, and that would encompass that she cannot be used as a virgin sacrifice or other ritual factor based on her non-existent virginity.
Perhaps it's just that the gods know, and the magic knows, and the lie can't work no matter how much it is believed, unless believing a lie is part of the magic.
--M. J. Young
Knowledge exists in memory. Memory is fragile and mutable, and there are circumstances under which memories cannot be formed; also, people die. I retract my earlier concession, as I see no problem with constructing a scenario in which this is a fact of which no mortal has knowledge. (Not a scenario where no mortal could acquire this knowledge, just one where no one has, and any who had knowledge have lost it or ceased to be). You have a point about the gods, though, so in a way that's moot.
Perhaps it's just that the gods know, and the magic knows, and the lie can't work no matter how much it is believed, unless believing a lie is part of the magic.
I think this is explanation I was looking for. Magic responds to expectation, but it also interfaces with truth; if you expect that by sacrificing this maiden you will become immortal, but the magic knows she's no maiden, your expectation is irrelevant - you're not doing what you expect will bring your results.
The cubic zirconium example was actually the first thing I thought of (well, fool's gold was, but close enough), but when I got to making my post I went with the virgin sacrifice because it's such a popular trope.