I'm of the opposite view point. Imaginem can only affect "generators".
A magus generates imago that overwrite the image behind. If you PeIm, nothing will overwrite and the image behind passes through freely.
With that approach, you must use a different sense to detect the thing.
I agree. Perdo is all about destruction. The image is destroyed. There's nothing to see.
If a SG hates invisibility, one suggest the species needs to exist for a small amount of time. The justification being one cannot destroy something which doesn't exist. Then a sufficiently strong enough spell can spot the species before it is destroyed.
I personally think species destroyed, the end, is better, but RPGs and Ars are all about what the person who's running the game wants.
Yes, there is nothing to see, however my understanding of the spell is that it compares the images projected (in this case none) vs the images that should be projected by the target - which is why is it subject to spell resistance - the species sent by the eyes of the caster connect with things and analyze whether the species the target emits is right or illusory. The spell isn't analyzing incoming images (there would be none to analyze here to detect the invisibility) - it's analyzing whether things are projecting the right species. If it was merely analyzing the species to see if it has been changed, I'm not sure why spell resistance is discussed at all. It would be a bit of an odd spell that detects invisibility when it fails to penetrate Parma Magica but fails to detect invisibility when it succeeds in penetrating it. So it's irrelevant here, I think, whether the species are destroyed because at the end of the day what is projected makes the analysis and the comparison.
Invisibilty spells alter the image of an invisible being, because they replace it with images around that being. They don't just cancel species emitted from an invisible being, which for HoH:S p.61 iconic species would just leave a lightless hole where the being was and thus make the spell useless.
With ArM5 p.144 Discern the Images of Truth and Falsehood a mage
can tell whether an image has been created or altered through a spell,
provided that the Illusion spell's level is equal to or less than the level -5 of DtIoTaF.
Perdo means Perdo, not Muto. You aren't changing species but destroying them. And you can't detect altered species where there aren't any.
Also, when somebody uses a ReIm to move your image to a distance, in the original spot the real caster remains invisible, not a lightless hole.
In that case, any anti-illusion spell should detect that the image of the caster is being manipulated (without MR, since the species are outside the parma), but not the original place where it should be.
So, to me, to counter invisibility there are 4 options:
The critical misunderstanding happening often is, that moving or destroying an image of a thing just involves affecting the species it emits. This is not the case.
Note that (HoH:S p.61)
Iconic species are carried in light
and Imaginem does not affect light: this is the domain of Ignem.
EDIT: See also here.
As Imaginem affects images, the resulting handling of species is sometimes tricky - and shadows are beyond its power.
Such an Invisibility spell is easy to invent but would fail its purpose: no need to publish it. Just destroying the species it emits leaves a featureless shadow standing around: anything but invisible. Destroying a visual image involves moving iconic species around the object made invisible.
Quite. So again ReIm - moving images - does not just move your iconic species away: it moves others in.
Also says that:
Species are particles that are continuously emitted from objects, and that, when they strike the sense organs of the body, evoke a response.
So, saying that you cannot destroy the species on the source using PeIm because they transmit through light, sounds like your interpretation.
Also, your interpretation means that all the invisibility effects should be Muto or Rego, yet they are Perdo.
I didn't even say that.
You can destroy iconic species emitted by an object. But you cannot destroy the shadow it casts. That shadow as such is then visible and featureless. This lack of features needs to be mitigated by moving iconic species from other sources onto the light there is around the object.
You could have written Invisibility that way. But once you stomach that you destroy an image with Perdo Imaginem (ArM5 p.146), not just iconic species, and for this need to move species from elsewhere, you can also design Invisiblity as written in ArM5.
Note, that the concept of species in Ars Magica was not published 2004 and could not be referenced in ArM5.
The concept of species is described in the core rule book for ArM5 on p79, in the Imaginem section.
You are correct.
For the invisibility spells to work as written, it is the the new visual species generated by a wall, a person, whatever, which ocludes seeing behind the object, not the object itself.
Otherwise destroying the visual species of a person would result in a person shaped black hole, which would be useless. If species needed to be manipulated around the invisible person, there'd be a rego requisite, and there is not.
Yep.
Let's look at an example: a grog in front of a red wall is turned invisible with VoI (ArM5 p.146).
That grog still casts a shadow and blocks light. Iconic species from the wall (HoH:S p.61) need light to be carried. There is hence no way to have light naturally pass through the grog to carry iconic species from the red wall behind to his front and turn him red. This still needs to be done by the VoI magic.
Just think of a chameleon turned red to hide before the red wall.
I'm confused by a lot of what has just been posted here. The guideline the invisibility spell uses doesn't say it destroys any species at all. It doesn't say anything about altering the image of the person. So I feel like a lot of these statements don't mesh with the guideline.
The guideline actually says it destroy's the thing's ability to affect sight (visual species). So the object can neither give off nor block visual species.
We also have to tread carefully with visual species and darkness, as we know in ArM5 that some people can see in total darkness. We don't know exactly what those people see, but they do see.
If there's a concept that wasn't decided in 2004 (and 2009), it would be that something stops the other optics species from going through the dagger. I haven't heard of such an effect on this forum until that one thread in 2020 or so.
Will it? Wouldn't the auditory species upon which Eyes of the Bat depends be destroyed if there is a PeIm spell destroying sound on the target?
For the sake of game balance, I would say no. Discerning is different for detecting, and it implies that there is something to discern rather than a void to fill. The discussion makes it clear that it is not the only interpretation, but then again, we are not very likely to build a consistent system of physics based on species, so I would rather rely on game balance, which has to be a troupe judgement.
If you want to allow a blanket sollution, I think it has to be The Discerning Eye. Intellego can detect what's there. InIm detects images, and if the images are destroyed, there is nothing to detect. However, spells can be made to detect any, but not every, kind of invisible things; you can detect invisible people with Corpus, invisible animals with Animàl, and the cleverest idea was already proposed, you can detect the invisibility effect with Vim.
First, we're talking about invisibility, so lack of visual species. Second, these species are coming from the air, not the being. So even if this were silence rather than invisibility, the being emitting no auditory species would be irrelevant. The reason I said "if they're solid" (liquid would work, too, but I was thinking non-spiritual mostly) is that this spell detects the boundaries of the air, so if they're spiritual then there won't be a boundary with the air.
Even though The Discerning Eye specifically works through extromission? That is stated in the spell's description -- a magical sense that works using species projected by the caster and which is reflected by surrounding objects. It is then compared to what is seen from natural species. So if the magical species is either blocked by magic resistance, or because it is destroyed by the invisibility effect (which is not necessarily the case), then the caster would detect a void at that location. The shape should be discernable, though not the details.
It could also be that the extramission species go through the invisible object and naturally reach the wall behind. The spell description is pretty clear when there is a false image, but completely silent when there are no illusion "generator" to detect.
Second sight explicitely mentions invisibility, and I don't believe a simple spell should completely shunt a Virtue. Even abusing MR to disable invisibility for all low-Might creature is excessive. So there are reasons to limit the scope of The Discerning Eye.
For invisibility to work, the effect has to allow the species of other images to either pass through, or flow around, the target of the spell. This may be a side effect of PeIm effects, as an Image may be required to interrupt the path of species in the first place. It might help explain transparent things like water/air/glass which have little to no image of their own, so random species flow right through them.
It's possible that solid opaque objects don't actually block species either, but instead overwhelm the image behind them with their own species. So when an image is destroyed, the image behind them is no longer overwhelmed, and can be seen.