"Very good. Let me clarify. Compulsion is defined as any of the set a weaves that compel a human subject to action. Weaves that compel non-humans are defined differently, woven differently, used differently, and are not illegal. This is a very complicated subject. Too much to cover in one afternoon."
She sipped at her tea.
"And yes, if someone was willing, then it is not illegal. The trouble is, no one in their right mind would consent to this... which then brings in more complexity. If you were brought before the Hall of Sitters, could you prove that your subject was not insane or coerced? Did he/she have complete information on what the weave would do? This, too, is a very complicated subject.
"Finally, the laws of affirmative defense encompass self-protection, protection of property... etcetera. Much like the second Oath, this allows for the use of Compulsion if there was no other way to save your life."
Mirin took a deep breath. "If you wish to study Compulsion, Elia, you must first learn the laws that bind us. This would be for you own safety, so that you do not inadvertently incriminate yourself. Even better is to keep your ability a secret and use it rarely. It is my opinion that students should be able to pursue any study they find interesting. Any knowledge, even forbidden knowledge, may prove useful. But others are not so liberal.
"So, this meeting needs to stay between us," she said, forcefully. She eyed the girl, and then sighed and massaged her temple. Mirin had only managed to keep her own ability hidden for a few months, and had made no real progress until Aria Sedai - and later, Lydarian Sedai - had stepped in. It felt strange, now, to be the one sitting at the other side of the table. To be the one wearing the shawl, the one opening the doorway to darkness and guiding the student through.
And yet I still know so little, she thought. Even after joining the Black Ajah, which had opened wide the floodgates to forbidden knowledge, she knew that the art of Compulsion had wide swathes of uncharted territory. It frightened her, sometimes, how little she knew, and how much had been lost in the years since the Age of Legends...
Suddenly, motherly instinct reared its head. Was this the best for Elia? Just as quickly, she dismissed the thought. Ha! Had Lydarian cared about her safety or innocence? Had Aria cared for reputation or morality? Mirin nearly bit her cheek in amusement.
"Well, Elia," she said. The corner of her lip quirked upwards. "Is this something that you want to learn? And why? Don't give me any nonsense about wanting to learn for the sake of learning. Learning Compulsion is learning how to use it. And that is very tricky, indeed. So."
Mirin looked deep into the girl's green eyes.
"Why would you ever use Compulsion? Why do you want to?"
She waited eagerly for the Accepted's answer. The unemotional mask that she usually wore slipped away to reveal a strange expression of greedy expectation. Elia's answer would determine everything. If she did not speak the right reasons, Mirin prepared to embrace saidar and wipe the memory of this meeting from the girl's mind.