I had read a book ( The Rook by Daniel O'Malley) where the protagonist could stop people from sensing her. It worked so completely she could shout in their ear and they would not notice. I was wondering if I could do this in AM.
I have to look in Art & Academe to see what to do. Pg31 shows that Common Sense " receives all forms and images perceived by the external senses...". The new Perdo Mentem guidelines allow for the destroying aspects of Common sense ( pg33).
The base is either 3 or 4. Both could make sense but "remove important part" seems to cover it better.
Out of mind PeMe(15)
Blocks the sensation of the magi to the target. The target cannot sense the magi in any way. Even if the magi touches or speaks to them they will not notice. Only the target is effected. Others in the area can sense the magi as normal.
(Base 4, R: Voice +2: D: Concentrate +1)
There is a spell in the Guernicas section of HoH:TL that works generally, though its validity is questioned by many on the boards.
There is some discussion of senses in HoH:S and then an effect in MoH (a Merinita I think) that uses it. The name has "hide" or "hiding" or something in it.
As for A&A, be careful with destroying things that way unless you just want them to see or hear nothing at all. You're stopping them from understanding what their eyes see (or ears hear, etc.). You probably need Part or extra magnitudes for intricacy or similar to remove only a selected bit. But maybe I'm wrong. That just looks like what the guidelines indicate.
What I am looking at is destroying ( via Perdo) the ability to to associate senses with a person. IMHO, A +1 for intricate would suffice. I do not see how controlling a mind is needed. Otherwise it is nearly identical.
I wanted to be clear that no sight or sound or touch or smell of the magus is registered by the person.
I would think this would require a finesse roll, if nothing else to set a threshold of perception whereby the person might in some way bypass the work which was done. For example I may not see "the magus" but I a) catch a flash of movement where nobody is standing, b) notice a man whom I cannot identify but who looks familiar, c) notice everyone else reacting to someone I cannot see, etc.