Copyright does not cover ideas, period. If you write your own novel and use your own word choices, even if you copy the plot structure exactly and the same character names while writing a new book, it’s not even considered a derivative work under the law, it’s a new work. Copyright covers copying the fixed work itself. You aren’t in violation of copyright unless you copy the words themselves.

The flip side is that this is why the article’s discussion about randomness and monkeys on typewriters is irrelevant to copyright law. It’s a copyright violation to produce the same “fixation” no matter how you do it. If you generated a random sequence of characters, and it happened to match a NYT best selling book, you violate the book author’s copyrights, and claiming it was random isn’t a viable defense. Intent to copy can make it worse, but lack of intent does not absolve. There is precedent for people coming up independently with the same songs and one being successfully sued.

Do note that there are other laws that might cover plagiarism of ideas, trademarks, code, etc., copyright isn’t the only consideration, but copyright seems to be often misunderstood. We definitely have some novel questions because of the scale of AI’s copying, the nature of training and the provenance of the training data, and because of AI’s growing ability to skirt copyright law while actually copying.