Ideas, their meaning and their authors.
Congratulations! In case you didn’t notice, we are living in an absolutely new World where reading a text authored by a human or hearing his/her speech is not the only way to consume his or her ideas. We now have a ‘retelling machine’ that can explain the ideas that it ‘knows’ in its own words. Of course if the words are different… or absolutely different… or even intentionally absolutely different… this can be called a ‘derivative work’ of sorts but it would cost an arm and a leg to prove that it violates ‘copyright’. Moreover, in general, would you like to live in a world where armies of lawyers are profiting from court hearings like that? I don’t.
Later.