Being a mage doesn't actually do much to protect you from other mages, that's part of the problem. If it did I'd be a lot more okay with the idea of everyone learning.

Being able to teleport freely protects you from a lot. You can give people teleports to places but not free teleportation, right?

Right, but once you can teleport to three or four places anytime you want, the more likely problem if there's a hostile mage is that you won't notice them casting, not that you won't be able to get away, and being a mage doesn't help with that at all.

Magic sense can't be used to detect casting?

It can, but you'd have to be actively looking, and a hostile mage could just wait until you weren't.

Can anyone get good enough with it that they can use it all the time, in place of their regular senses -

Sort of, eventually; it's basically like learning each sense all over again, to figure out how to interpret it from the mage-sense. I can more or less hear - well enough that you could talk to me, not well enough to navigate by - but not really see with it. Touch would be easier but there's not much point; smell and taste would be very hard. My guess is that it'd take a couple hundred years to get as good at seeing and hearing with the sense as you'd be without it.

In Valinor that'd seem a good investment to a lot of people. Less so here.

Yeah. Hopefully this won't take anywhere near that long.

Can you osanwe people and borrow their senses while mage-sensing?

...I wasn't aware that that was possible. You probably can, but it'd be distracting, and it doesn't solve the problem of a hostile mage waiting until you're not using the mage-sense to do something to you.

No, I mean, someone could keep mage-sense up all the time and also function off other peoples' eyes once they got used to it, I know blind people who've done it....would they notice a hostile mage casting, if they were doing that...

They'd have to be paying enough attention to the mage-sense to notice things moving when they shouldn't, and that'd be tricky even without the distraction. It would be easier to notice hexes than environmental spells, though. On the other hand, even Eldar have to sleep...

Yes, but with groups of three or maybe four you might be able to get safety. Perhaps I'm worrying too much that this is a problem. The real solution is probably just to ask everyone to swear not to use magic in whatever ways we are very very sure we want to proscribe.

I'd like to find a solution that's sustainable in the long term, would that be?

Oaths? Oh, yes, definitely, they're absolutely binding and they by default last forever.

Yeah, I knew that, I meant more, like, are people going to resent having to choose like that, will it cause problems for people who choose one way or the other, that kind of thing.

Usually I'd say no but I've been away from my people for a very long time and shouldn't speak so confidently.

Sigh.

Well, it's not that urgent.

I'll ask my brothers about it the next time we talk.

She nods. Sounds like a good starting point, yeah.

I just don't want to phrase it in a way that doesn't let people react to a completely different situation a few centuries from now...

Yeah, I was thinking about that. What we want is for them to generally have to keep to whatever consensus there is about how mages should act, probably with some exceptions, and then as the consensus changes what they can do does too, but I don't know if there's a way to do that with oaths and even if there is it's a harder thing to ask of people, when it can get more restrictive as well as less.

And when the Enemy could have a way to force an evil consensus. 

That too, but we could probably say that the consensus thing starts when they're gone? And then we're back to needing something that might, in the worst case, need to last a while.