Yeah it is. The only protection in copyright is called derivative works, and an AI is not a derivative of a book, No more than your brain is after you’ve read one.

The only exception would be if you manage to overtrain and encode the contents of the book inside of the model file. That’s not what happened here because I’ll chat GPT output was a summary.

The only valid claim here is the fact that the books were not supposed to be on the public internet and it’s likely that the way open AI the books in the first place was through some piracy website through scraping the web.

At that point you just have to hold them liable for that act of piracy, not the fact that the model release was an act of copyright violation.