QUOTE (Yerameyahu @ May 8 2011, 06:15 PM)

Except the rules are explicit that you can, in multiple places. The clearest, classic example—but hardly the only one—is that blind magicians (e.g. ghouls) can cast spells using their astral sense. Don't you QED at us.

If you don't mind me asking; where are the multiple places? I won't argue that they can cast on the astral plane using astral senses, but I don't see anything about it either way in RC.
I thought this might be covered under blindness in RC, but no such luck. I do find it odd that they confirm that blindness does not inhibit astral perception (no one would expect it to), but neglect to mention anything about physical casting (which readers
would ask at this point).
"Note that since their astral perception is not a visual sense, Awakened characters with the Blind quality may
still perceive astrally, though gamemasters are advised to strictly
apply the Astral Visibility modifiers on p. 114 of Street Magic."
I can see this partially supporting your side, but the opening of this paragraph clearly states that it pertains to the astral realm.
"Determining cover works the same way on the astral
plane as it does in the physical world (see pp. 140–141, SR4).
Shadows of physical objects in the astral plane may be drab and
insubstantial, but they are still opaque and can prevent targeting.
Items that are transparent or mirrored in the real world
(like a car window) simply impair visibility as astral shadows.
Since there are no ranged weapons on the astral plane and spell
targeting depends on seeing your target, hiding behind physical
shadows works as well as hiding behind a vibrant aura."
QUOTE (Yerameyahu @ May 8 2011, 06:15 PM)

The difference is being on the same plane. If you're both on the physical, seeing their aura *is* seeing them (if anything, it's more real, metaphysically). The issue is casting across planes. It's like there's a big sheet of glass 'under' the astral: you can see auras on the physical, but you can't reach them.
A character using astral perception is active on both the physical and astral planes simultaneously. However, they cannot target both simultaneously. They need to spend a simple action to switch their
perception between planes.
If you can be attacked on both planes simultaneously, it would make sense that you could attack on both planes simultaneously, since there is something physically there to attack with. All you need to do is glue on some nasty astrally active daggers and sprint around wildly as you attack on the physical plane. The issue with magic is that you need to forma mystical link, which cannot be done without perceiving your target's
body (astral or physical).