"I understand," she murmurs back.

Aliens don't have castes! Some aliens, like her father or the leader of their city, she can sort into one caste or another by temperament fairly easily, but it doesn't seem to be strongly hereditary the way it is with Amentans and many, like her mother or ex-girlfriend, resist easy classification.

She has a college student's sleep schedule and should therefore maybe not comment there.

She finds pollution fairly concerning! Back home they can deal with all of that stuff with magic and the idea of an entire caste that's been rendered unclean by prolonged contact is horrifying. She suspects it could be solved with magic, most problems like that can, but she's not an expert on genetics and wouldn't have a good guess how.

They didn't really expect aliens to have castes just like theirs, and are very impressed that they've managed to handle pollution with magic! They would love to also handle pollution with magic, how is it done?

Incinerating stuff, mostly, mixed with some telekinesis.

Brilliant. Can Amentans learn it?

They haven't tried yet.

Why not?

Because while the reds' rioting over robots is of course unjustified the fact that they're universally convinced there'll be a genocide when people can do without 'em suggests that teaching people to dispose of these things safely without them before coming up with a solution to the problem of how to clean them would be a bad idea.

The theologians are confused.

What exactly is the point of confusion?

Why would it be a bad idea?

...Because then people might kill the reds.

...this is bad?

Okay, imagine Amenta had spaceships and encountered pre-spaceship aliens who had a section of the population with an extra biological function that was gross. Not excretory, not Unclean, just really gross. And they have this section of the population sequestered so they don't have to deal with it, which is reasonable, but they also emit pheremones which make the rest of the population more resistant to disease. If Amentans give them vaccines they'll slaughter this section of the population. Will they let this group of people die, on the grounds that aliens know best about aliens, or do they take measures to get them safe first, on the grounds that they can't be sure and would really rather not go down in history as enabling a genocide?

This sparks a lively debate, which winds up being mostly about the boundary between uncleanliness and mere grossness.

Amentans have dealt with having reds for a very long time. The aliens would like to be very very sure it will not result in genocide before upsetting the status quo.

Almost no one specifically desires that reds be dead. People do want to torch and develop the land they live on, though, some theologians discuss how deep you'd have to dig.

Presumably this is as easily done if they could be cleaned somehow as if they were dead.

Well, not if they got all demanding once they were clean or something.

Does that seem especially likely?

Who really knows?

Anyway. They'll cross that bridge if they come to it.

Cleaning reds is such an interesting idea and the theologians have lots of fun with it.

Productive fun?

Eeeenh. They do keep asking things like how she can be sure that molecules created by magic are really new.

Well, it seems to violate conservation of mass. Is that important? She got the idea that things stopped being unclean when they decomposed and turned into not the things that are unclean. If it's important they could just use clean mass brought in from elsewhere.