How about if I read and study all your books and then generate a new one perfectly in your style (maybe using one of the common plot template you use often). Would the new book be mine or yours? No AI involved, but the black box looks similar from the outside.

How do they handle this now with writers and painters who imitate other artists?

Perhaps the best example of humans doing this sort of thing is in music. Artists take samples from one another’s works and use them to create new music.

I think the problem the GP highlights is roughly analogous to the case where an artist takes all of their samples from the album of one person and uses it to create a new song that sounds like the original artist made it. That’s a different thing entirely from taking a sample from one artist and a sample from another and then combining them with a new original beat and layering on some other original tracks.

What if someone used no samples at all but used all of the stylistic choices of the artist and made something that sounds like the original artist made it despite no part being directly copied?

"How do they handle this now with writers and painters who imitate other artists?" -> not a derivative work as long as no specific protected elements were copied.

Repainting or rewriting your work in different style would be a derivative work, but painting or writing a different work in your style would not be.

Oh, that's a good one. I suppose you're right in that it would be undetectable that you used an ML model to make the text unless you said so and in that case we'd probably treat it as a creative work.

We all do what? We don't all take your specific work, train a model on it, and then select an output to present as a new work. Those are the creative acts. And certainly, the output may be indistinguishable from something you yourself created, and given the structure and nature of neural nets it might even cause you substantial existential angst to see such work, but I don't see how any of those things would weigh in to a copyright claim. Your best bets for a claim would be either a claim of a 'derivative work' being created or perhaps that the use of your original work does not fall under the Fair Use case. Fair Use would be very weak here because generally you would need to show that the 'heart' of the work (your originals) was duplicated. Similarly a claim of 'derivative work' would have to be novel and would be very difficult when the actions of the AI author are considered to be part of the authoring process while your authorship process is very different. I could see it possible, but unlikely, than an ML system would produce something which, had it been produced otherwise by a human, could be recognized as a derivative work. That would be the criteria, likely the main if not sole criteria, used in a court case.

Suppose someone takes all the words from your comment above and reorder them. Whether this new prose has the same, another, or no meaning at all, combining your words to form something else is a creative act. Sometimes, creativity doesn't take much effort.