Another good question is why AIs do not mindlessly regurgitate source material. The reason is that they have access to so much copyrighted material. If they were trained on only one book, they would constantly regurgitate material from that one book. Because it’s trained on many (millions) books, it’s able to get creative. So the argument of OpenAI really boils down to: “we are not breaking copyright law, because we have used sufficient copyrighted material to avoid directly infringing on copyright”.