A few days ago in the other Magical Senses thread I wrote this:
We've had some more discussions about Magical Senses, which aren't really relevant to the other thread (hence this new one), but that quote serves to set the context.
So, Zeroth Question: Is my above conclusion correct? Is it the case that what a Magical Sense gives to the target is simply an augmentation of one of that character's normal senses with the effect of a specific Intellego spell?
Assuming that we're all agreed on that, there are a number of further questions that have come up.
So, First Question: given that what is being affected is the physical senses of the target, shouldn't there be a Corpus requirement? In fact, I wonder why magical senses aren't a MuCo effect, perhaps with an Intellego requirement.
The Second Question is that of whether Intellego effects can take any other form than enhanced senses. I think it's clear that they can (Librarian's Parma I have lent my 5th Ed. rulebook to one of the other players, so I'm relying 4th Ed. and memory) Frosty Breath of the Spoken Lie for example, produces an effect that is visible to all so it's clearly not an enhanced sense. What, then, is the advantage of enhancing a character's normal senses, rather than just casting a 'normal' Intellego spell?
The Third Question is that of whether magical senses are a spell -- that is, whether the process of bestowing magical senses on a character is a spell (that can be learned and mastered). It seems to work like a spell, but I don't see many examples of spells that create magical senses in the RAW, available to be taken as formulaic spells by new magi. Some varieties of magical senses are so of such obvious utility to all magi that it's surprising they're not on the reading list for the first day of apprenticeship (e.g. some way to sense raw Vis -- yes, it's only InVi1, but as a magical sight (so it has some range and directionality) new magi who are not Intellego or Vis specialists will have trouble sponting it with even momentary duration).
The Fourth Question is that of the form that magically sensed intelligence may take. If a character has his hearing (say) enhanced to detect the presence of water (an InAq1 effect) and he comes to a stream, what does he hear? Is that under the control of the spellcaster? Is it a fixed effect (perhaps related to the spellcaster, as is his sigil)? Is it just that he hears the running water in the stream more clearly (if so, what happens if he finds quiet water instead of a stream)? For that matter: What does Vis smell like? Sound like? Note that the answer to this one probably isn't important, and StoryGuide's fiat is as good an answer as any, but it'd be good to know if we've missed something.
Carrying on from that, the Fifth Question concerns the effect that the magical sense has on the target. Does the magical sense interfere with the character's non-magical senses. If our water-hearing character (supra) fell into the sea, would the spell deafen him? Can a mage cast a magical sense on enemies to confuse their senses (an offensive use of Intellego)?
The Sixth Question is that of whether all things can affect all senses. The sense of smell can normally detect only things that have an odour, so non-volatile substances don't have a smell and can't be sniffed out. Does the same apply to magical senses? Can you, for example, smell silver with an InTe magical sense (a la Probe for Pure Silver)? I'd say that as the magical sense comes from an Intellego spell it should be able to detect whatever that spell can detect, and that the sense affected is immaterial -- but it would be quite satisfying if the 'cheaper' magical senses of smell and hearing were actually more limited in this way than the 'expensive' sense of sight.
... and finally. If magical senses don't give the effect of a D&D clairvoyance spell, how do you achieve that in ArM? Perhaps that really is a MuCo effect, but that's not even hinted at in the RAW.