Spell Prerequisite question

[David Johnston2]

Originally Posted by Prince Charon

I called it a houserule because some people get up in arms about it if someone says to apply that to spellcasting.

<shrug> Doesn't matter much one or t'other. Even with the highest TDMs and skill, you'll still roll 18s. And if you're casting dozens of times a day you'll be summoning a demon on a monthly basis.

[Plane]

Originally Posted by maximara

Normally this is (No Spell Prerequisites +30%)
but it doesn't seem to be applied in this cae.
Anyone know why?

I overlooked this question. Didn't actually know about that group of enhancements on T67 ("Power Investiture as Modified Magery") until today.

I would say it DOES apply, but that the +30% from the right column is conveniently cancelled out by the -30% of "Limited Spell List" from the left column. The only difference is that instead of it being limited to what the deity provides, it's limited to what the racial template provides.

This is pretty much a designed cancel-out I would think, much like the pairs of Inspired Learning + No Magic Item Sensitivity (both 20) and Pact + No Zero-Level Requirements (both 10) and Functions as a Different Talent and Sanctity Replaces Mana (both 0)

I would say the +30/-30 combination applies to Magery 1+ but am not sure as to whether the feature (balances out to 0%) applies to Magery 0 or not.

Another approach might be to design a limited enhancement for Magery 0 or 1+ ("No Spell Prerequisites for Limited Spell List only +21%) but we'd have to think about how that would function differently...

If you are benefitting from built-in NSP for Fixed Magic / Racially Innate Magic then I'm guessing it would apply to your Magery 0, but that creates the problem of suddenly you don't need prereqs for spells except perhaps for those requiring Magery 1+ since you didn't take the NSP enhancement on higher levels of magery.

Another conceptual challenge here is you don't actually need Magery 0 to learn spells at all: you could live in a High Mana society where non-mages learn and cast spells, for example. In that case, a "Limited Spell List" limitation (as with Power Investiture) isn't going to affect you for learning purposes: you should still be able to learn baseline spells like someone lacking Magery 0.

Originally Posted by RyanW

in either event, there is no way to make a mage that can only cast Fire spells without also giving him Magery 1+.

Per basic set yes, which Thaumatology fixed on T20 (Partially Limited Magery) and T21 (Limited Magery 0)

Originally Posted by Stormcrow

Spell prerequisites are simply the background needed to access a particular spell. They're no different than any other skill prerequisite, whether imposed explicitly in the rules (you need Mathematics [Applied] to learn Astronomy) or by the GM (you can't learn Artist [Body Art] if you're an elf because they believe that marring the body is sacrilege).
..
If you know a spell innately, you don't need to know its prerequisites.

I think while usually you need a prereq to LEARN a spell you didn't already know (which racially innate casters don't need to do, they were born knowing it) you don't need prereqs to RETAIN a spell or to USE a spell.

B99 Wild Talent for example seems like it could let you cast ANY spell without needing to worry about prereqs for it:

Wild Talent does apply to skills that normally have no default,
provided you meet any advantage requirements.
For instance, you could cast unknown magic spells provided you had Magery

Wild Talent normally lets you roll at your raw IQ (no penalty, no bonus) but there is a note with the "retention" enhancement if you want to spend character points to expand the use of these skills beyond your "per game session" limits. This normally works like you spend 1 point and there's a 1 month period where you're -2 to use it and can't spend additional CP to boost it. That period is ignored on a critical success of the original IQ roll, while a failure means you'd need to use your per-session roll again to try and spend your CP, and a crit fail loses the CP

Lacking prereqs prevents improvement beyond the 1-point level and inflicts an additional -4 to skill, which I assume stacks with the initial -2 to skill for a total of -6 during the 1st month.

One other big factor in Mage battles (for those wizards with Magery 1 and IQ 12+) is taking Foolishness then Forgetfulness. Temporary loss of a prereq spell gives -2 to the spell for which it's a prereq.

Outside these 2 situations, I don't know if there are other rules for how being sapped of a prereq would affect use of a skill, like for example if buying skills using Modular Abilities as B71 does not address prereqs. Another case is failing your IQ roll for Maintaining Skills.

These don't apply to spells (or languages) but M71's Lend Skill / Borrow Skill spells (communication and empathy) also might be able to give you (temporarily) a skill you lack a prereq for, and there's no mention of any penalties for lacking a prereq, like in your example, borrowing Astronomy without knowing Math.

Does anyone know how that works BTW? Like do you need the prereq of math to use it at Default (IQ-6) or is the prereq only for being able to put your 1st point into it?

If you needed the prereq to use the default then you shouldn't need the prereq to use the specialty (Observational, B179) but while specialties default to one another, the no-double-defaulting rule would prevent you from using the baseline Astronomy skill based on a default no-point-invested version of Astronomy (Observational) ?

[RyanW]

Originally Posted by Plane

Per basic set yes, which Thaumatology fixed on T20 (Partially Limited Magery) and T21 (Limited Magery 0)

True, but that's a complete reversal of the Basic rule (and, incidentally, Thaumatology's rule is the way I've been doing it since I initially saw the idea of Magery 0, sometime before 4e was released). Basically, you have to pick one or the other, and you may have to reinterpret other rules (like Racially Innate Spells on B453, and many in Fantasy) accordingly.

[Prince Charon]

Originally Posted by David Johnston2

<shrug> Doesn't matter much one or t'other. Even with the highest TDMs and skill, you'll still roll 18s. And if you're casting dozens of times a day you'll be summoning a demon on a monthly basis.

OK, then we are definitely talking about different things. I'd say that your reply was more to maximara than to me (though part of the problem is that I was, as usual, posting while tired), as the houserule that I was talking about originally was that you don't get extreme results (like summoned demons) from a critical failure if you're not casting under stress.

[Plane]

Originally Posted by RyanW

True, but that's a complete reversal of the Basic rule (and, incidentally, Thaumatology's rule is the way I've been doing it since I initially saw the idea of Magery 0, sometime before 4e was released). Basically, you have to pick one or the other, and you may have to reinterpret other rules (like Racially Innate Spells on B453, and many in Fantasy) accordingly.

Not sure how RIS might be different in Fantasy but it seems like Thamautology's ability to mod Mag0 just adds additional options.

Magery 0 having no limits on it I think means you count as having non-Racial Magery 0 for all purposes, including the ability to cast any non-racial spells you learn later, sensing non-racial spells, sensing magic objects, etc.

If we assume the +30/-30 tradeoff from Power Investiture is at work here, then RIM could benefit like:

1) I didn't need a prereq to learn that spell
2) I am not penalized in casting that spell when lacking that prereq

but have balanced drawbacks similar to power investiture like:

1) I am limited in the number of spells my magery functions for (similar to one college) so I can't cast non-racial spells (like power investiture can't cast non-deity spells) when in normal or less mana (since anyone can cast spells they know in high mana)

Where the comparison to Power Investiture gets blurry is because:
1) power investiture swaps sanctity for mana
2) power investiture has a built-in enhancement to ignore level 0

I'm thinking that since Magery 0 isn't limited in basic set that somoene with racially innate spells doesn't actually need to purchase Magery 1+ with a limitation at all, and this would only limit getting the talent-based bonuses and higher-spell prereqs?

[RyanW]

Originally Posted by Plane

Not sure how RIS might be different in Fantasy but it seems like Thamautology's ability to mod Mag0 just adds additional options.

All of the Basic limitations are pretty explicit that limiting Magery 1+ completely removes spellcasting when the requirements of the limitation are not met. The options in Thaumatology represent a new and incompatible (and quite frankly, better) interpretation.

[Plane]

Originally Posted by RyanW

All of the Basic limitations are pretty explicit that limiting Magery 1+ completely removes spellcasting when the requirements of the limitation are not met.

Do they? Reviewing B67/B68 if you look a Dark-Aspected for example, what makes you think "can only use your powers in darkness" and "your abilities" refer to Magery 0 (which this does not modify) rather than just the additional power Magery 1 gives atop that?

It clearly doesn't refer to ANY spellcasting because I think we could probably agree that someone with Magery 0 [5] + Magery 1 (Dark Aspected -50%) [5] could still cast spells in bright daylight as long as there was High Mana, just like someone who lacked Magery altogether.

Once we realize this doesn't extend to all spellcasting we can realize it may not apply to Magery-0-casting either, but rather Magery-1 casting. As in you don't get the +1 except in the dark, don't learn spells faster except in the dark, can't cast spells with Magery 1 prereq except in the dark...

I think you're right about how One College Only was originally worded though, I can't wiggle my way out of this:

You learn other spells as though you were a nonmage, and can only cast them in high-mana areas.

It's the part about casting that seems critical (because AFAIK magery 0 learns spells like non-mages already, there's no 10% study time reduction or spells that require JUST magery 0 and not magery 1) because it does seem like it's limiting magery 0 even though there's no discount for it.

Same with detection:

You cannot detect magic items unless they contain at least one spell of your college,

It creates the problem where Magery 0 [5] is actually better than Magery 0 [5] + Magery (Limitation -??%) [?] despite being worth fewer points, since you get always-on detection and casting capabilities.

So based on that I can see your point, if One College Only didn't give a discount for 0 yet affected it, then maybe RLM affected M0 too despite not discounting it.

On the same basis though, the change to One College Only should probably be assumed to apply to RLM too.

Stuff like Solitary (potentially a worse spellcaster in High Mana than a non-mage) or Dance (removes need to speak) probably need to be reworked using Thaumatology's new approach?

[RyanW]

Originally Posted by Plane

Do they? Reviewing B67/B68 if you look a Dark-Aspected for example, what makes you think "can only use your powers in darkness" and "your abilities" refer to Magery 0 (which this does not modify) rather than just the additional power Magery 1 gives atop that?

Day aspected begins exactly the same, but then says "When the sun is down, you have none of your magical abilities, although a look at your aura reveals that you are a mage." (Emphasis added) That suggests to me that "your abilities/powers" was intended to mean your ability to cast spells.

Originally Posted by Plane

I think you're right about how One College Only was originally worded though, I can't wiggle my way out of this:

You learn other spells as though you were a nonmage, and can only cast them in high-mana areas.

Dance, Musical, and Song all say "You must ... to cast spells."

[maximara]

Originally Posted by roguebfl

Dispute Kromm pointing that spell do follow the rules for skills

As pointed out before something is keeping Marlin-1's United States isn't filled to the brim with Demons. Similarly Merlin-3 is in much the same boat and there is nothing to show Europe under the Third Reich is a demon infested nightmare...of course with the Third Reich running things for certain peoples a demon infested nightmare might be an improvement. ;-)

I should point out that summoning a demon is itself a 18 on the Critical Spell Failure Table. So one has to critically fail on the spell and then get a really bad result (0.5%) on the table.

Being generous to the demons and assuming skill 12 for the average joe that is 1.4% and the chance of getting a demon out of that is 0.5% or 0.00007 or 0.007% per casting.

But, assuming Merlin-1 has the same population of our Earth in 2004, there are 292.8 million in the US alone. Going by the 1:1000 have magery 1 that gives us 292800 mages. Assuming each one of these casts a single spell per day statistics suggests that 1 demon per day is summoned. If we back extrapolate that Magery 0 is 10 times as common as magery 1 than that number becomes 10 demons per day

Moreover, thanks to GURPS Thaumatology there are the Stable Casting enhancement (+40%) and Stabilizing Skill perk options.

[maximara]

Originally Posted by RyanW

Day aspected begins exactly the same, but then says "When the sun is down, you have none of your magical abilities, although a look at your aura reveals that you are a mage." (Emphasis added) That suggests to me that "your abilities/powers" was intended to mean your ability to cast spells.

GURPS Thaumatology (pg 21) gives conflicting information on this: "The standard rules for Magery (pp. B66-67) imply that one cannot apply limitations to Magery 0."(sic) Now it tries to handwave this but it contradicts the previous Partially Limited Magery (pg 20) section where you "apply limitations to some but not all of a wizard’s Magery levels"

"Magery 0 costs 5 points for all mages" (Basic set pg 66)

So per "Partially Limited Magery" all mages with Special Limitations have Magery 0 (normal) + Magery (limitation) and are able to cast any spell not require Magery1+ regardless of the limitation while "Limited Magery 0?" says the opposite. Kindly explain why Partially Limited Magery is not applied in this case.