Affect your own spell with two or more Muto Vim

Hi sodales!

It's possible for a magus to affect his own magic with more than one Muto Vim spell with no other magus helping?

The relevant MuVi Guidelines have been errataed twice substantially, and then again a little in August 2021.

The following erratum still holds (bolding mine):

Muto Vim Guidelines (p. 159): Replace the final paragraph with the following: "Muto Vim spells work by altering the magical energies that create the spell as it is being cast. The spell is the result of the combination of the base casting and the Muto Vim effect, and has its effect once both the casting and the Muto Vim effect have finished. This means that a Muto Vim spell must have a duration at least as long as the casting of the target spell, but need not last for as long as the spell itself. For normally-cast formulaic spells, a Momentary Duration is sufficient, but if the casting time is longer for any reason, the Muto Vim spell must also have a longer Duration; Sun is sufficient for any practical Ritual."

This implies, that an Hermetic spell is cast once it has been altered by a MuVi effect.

By ArM5 p.159 box Muto Vim Guidelines we also have:

It is not possible, for reasons that Hermetic theorists do not well understand, to use Muto Vim to affect another spell after it has been cast.

So we have, that an Hermetic spell already altered by a MuVi spell cannot be altered by a further MuVi spell any more.

As this is in itself complicated and involves even more complicated errata, feel free to houserule with your troupe.

But when doing so consider, that allowing multiple MuVi effects on the same Hermetic spell can make MuVi significantly more powerful. A good rationalization to forbid them is, that MuVi spells - which are always formulaic (ArM5 p.159 box) - do not interwork well with each other.

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Well, first is the question whether two MuVi effects can be used together. We know that is definitely the case, provided as long as one of them is strong enough to affect the higher-magnitude spell resulting from the original spell plus the other MuVi spell:

when two magi cooperate, a spell can be the target of both Wizard’s Expansion and Wizard’s Reach, providing that one of the two Muto Vim spells is at least two magnitudes higher than the target spell.

But how do you pull this off as a single caster? Normally if you cast a MuVi spell and then a second, the first will try to affect the second, rather than the first MuVi spell being intelligent and knowing to wait for the third spell. So you have to find a way around this.

This could be done by simulating another caster. For example, use Hermetic Theurgy. Have a spirit that can put a MuVi effect on a spell. Summon that spirit and tell it to put its MuVi spell on the second spell you cast. Now you cast another MuVi, and then you cast your modified spell. This is all done with your spells, but that is because the first spell essentially gave you another magus to work with. You should be able to manage similar with an InVi spell plus a MuVi spell inside a Watching Ward, again having simulated another caster.

The only way I can think of doing it purely yourself is more limited. There is one way to avoid casting the MuVi spells successively: Multiple Casting. The spells fire off simultaneously (was necessarily implied, now explicitly true). So now they'll both try to change the casting following them. Since they are the same level and need to affect the same spell, they'll only be able to affect a weaker spell than normal to obey the above-quoted rule. You have now stacked two of the same MuVi spell on a spell.

Edit: You could avoid the ReVi ritual above with The Patient Spell with D: Diameter followed by one MuVi spell, for example. You cast a second MuVi spell right before that Diameter is over. Now both MuVi spells fire off at the same time, and you cast the spell to be modified. This is basically the same as the ReVi above, but trickier to time and saving a lot of vis.

Edit: One Shot also mentioned using a Talisman with Consummate Talisman. To deal with the timing you could fast-cast the MuVi and then activate the Talisman. The order matters because otherwise the Talisman will affect your MuVi spell. Your MuVi would need to last a bit longer than typical, but the core book contains Momentary spells that can last a little over a round, so this is viable.


You quote from MoH (p.113 to allow others to check), which has a tendency to occasionally contradict basic rules and their errata: especially if things get complicated.

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Sure. But I did quote a canonical source, didn't I? Do you have some canonical thing you can cite that even vaguely disagrees with this? How about if I quote the core book? I just didn't quote Wizard's Communion because it wasn't as explicit. Are you really saying MoH contradicts other rules here and that multiple magi cannot cast Wizard's Communion for the same spell?

I know there is a knee-jerk reaction against quotes from MoH, but it is canonical and so people should really reconsider such reactions, especially when it has frequently been show to be correct.

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Yep. See above.

No, that isn't. That's saying you cannot affect a spell after it's been cast, not that two MuVi effects cannot affect the same spell as it is being cast. We've known they can since the core rules came out and Wizard's Communion, a core MuVi spell, was specifically written to allow multiple of itself to affect the same spell. I still don't understand why you're arguing we should forbid Wizard's Communion.

Indeed. Casting two MuVi spells made to modify a target spell T leads to the problem, that once the first MuVi spell has been finished, by the errata T is cast as well. Finishing a second MuVi spell later doesn't work.

The Wizard's Communion spells affect the casting process of the jointly cast spell T in the same way, and are finished only after spell T was cast by all participants. Otherwise all the casters run risks of botching.

If a magus wishes to modify spell T by "both Wizard’s Expansion and Wizard’s Reach", one of these spells is cast before the other, and thereby causes spell T to be cast as well.
You say roughly the same here:

The rest of your post tries to circumvent this problem with summoning a second caster or multicasting a MuVi spell - both likely missing the point of the OP.

This isn't true, if both MuVi are cast simultaneously, by two different casters timing themselves (primary caster doing Wizard's Reach, secondary caster doing a sorcerer's fork, for example).

There is a problem of the MoH p.113 quote:

when two magi cooperate, a spell can be the target of both Wizard’s Expansion and Wizard’s Reach, providing that one of the two Muto Vim spells is at least two magnitudes higher than the target spell.

It appears to assume, that one of the two MuVi spells operates after the other, and hence needs to be two magnitudes higher. But both MuVi spells must indeed work together on the target spell.

Right - if you have two casters coordinating. The OP does not ask about this case.

True enough. But even with no additional magi helping, as callen pointed out, you could simulate another caster by using a Spirit of spell which you yourself have cast, or by using a MuVi spell on top of a MuVi consummate talisman effect. Arguably, if instead of doing a momentary MuVi effect to boost your next spell, you're doing a Diameter or Sun duration MuVi spell, you'd have ample time to stack more than one effect (assuming you're willing to pay for the stacking higher magnitudes, which is an entirely different story).

Sure. But the mistake you're making is that we're not talking about finishing a second MuVi spell later. We're talking about a second MuVi spell finishing at the same time as the first.

Why? You're just pulling this out of thin air. Two wizards cast MuVi on round 1, with will finish at the end of the target spell on round 2. They are working together with a third wizard (or one of the first two), who casts as spell on round 2, during the Durations of both MuVi. Both MuVi spells last through the casting of the affected spell and end at the same time.

Read the OP and read what I wrote. The OP asked for multiple MuVi without another magus. I don't know the specifics of why, and I'm not assuming. So I gave a few ways a single magus can manage this. Meanwhile I mentioned explicitly that some of them are simulating another caster, while others are stuck applying the same MuVi. That way I'm being clear about what they're doing and not doing so that the poster can decide what fits the scenario that I don't know about and haven't assumed.

In terms of a mathematical order of operations, sure. But we're talking about order of spells, not order of operations. Consider casting a spontaneous spell with Spell Foci. There is a mathematical order of operations. First you add a bunch of values, then you divide by 5, and then you add another value. Does that mean the spell gets cast over several rounds? Does that mean there are several stages and the magus can stop between them? I think we all agree this mathematical order of operations is irrelevant when it comes to the time of casting the spell, which takes whatever time the spontaneous spell is supposed to take.

All we can assume from the MoH quote is that if there is a mathematical order in which it will work, then it will work. There just has to be enough combined power between them. You don't get to short-cut that power by saying they're all affecting one weak spell.

No. It is implied by the single magus at work in the OP:

So far the solutions are either Multicasting, which in general needlessly causes the same change twice, or summoning a second caster, which circumvents the problem.

As I quite clearly showed several ways, it is certainly not implied by there being a single magus.

Yes, it's rarely useful. And due to the wording of Wizard's Communion, counting casters rather than spells cast, it doesn't work there, either. But that doesn't mean it cannot rarely be useful in some way.

Because you're assuming you know the problem. Maybe the caster wants to do something secret from other magi. Maybe the caster is stuck alone but has a lab and time to work. Etc. Since I'm not psychic, I'm just providing a bunch of ways that fit the OP, and the poster can use them or not, depending on the scenario. Maybe what you're saying is circumventing the problem is actually solving the problem?

The problem, it seems to me, is that the target of a MuVi spell is the next spell cast, so unless that can be changed to the second spell cast after the MuVi spell then your first MuVi spell is modifying your second MuVi spell instead of the actual target spell. Obviously having multiple casters collaborating can bypass this particular limitation, except that they have to be using wizard's communion to collaborate, meaning the "next spell" is wizard's communion.
As for MoH it is considered canon but the spells within it can be considered to be the result of experimentation by the magi listed within, and thus may not follow standard rules.