I was wondering if the general guidelines for intellego imaginem allows you to see invisible things. If so, wondering how it does it. Most effects suggest they are destroying the species directly, getting around magic resistance. So what does a See Invisibility effect see?
Just destroying all the iconic species of an item makes it look like Vantablack.
Not exactly invisible, unless its surroundings are pitch black too.
To make an item invisible, one needs to magically make the iconic species of its surroundings pass through it - and this can be detected by spells like ArM5 p.144 Discern the Images of Truth and Falsehood.
One shot's position is supported by a discussion in the Jerbiton chapter of HoH: Societates where we learn that iconic (visual) species are carried by light rather than just generated by light. I am not certain why this distinction was made, perhaps to align with period thought on the subject, but it makes (IMO) the matter of vision and magic more complicated and less beileveable.
I prefer a simpler model where light stimulates images to produce iconic species which then travel on their own. (In which case discern the images of truth and falsehood would not detect invisible objects).
Erik Tyrrell, Tellus and me discussed this at some length here.
While there is always alot of discussion about species and perception, by RAW invisibility spells are simple PeIm, with shadows as the only drawback, not sensory black holes.
Which is one reason why I prefer to ignore the bit about light transmitting iconic species. If light is necessary to transmit iconic species and invisible things still leave shadows (ergo don't transmit light), then we're left with the conclusion that species need some other way to get from one side of an invisible thing to the other.