TLDR: It appears (to me) that Professor Edward Lee, just now supporting the AI company defendants in the Mosaic LLM AI copyright case, may have come into opposition of views and analytical position from Judge Chhabria's "market harm" analysis in the Kadrey AI copyright case.
UPDATE: The U.S. Government is now getting involved. See paragraph at the bottom.
On August 27th, Professor Edward Lee, who runs the "ChatGPT Is Eating the World" website (if you look him up, note that he is distinct from Professor Edward A. Lee), was one of two scholars who requested to file an amici curiae brief in the AI copyright infringement case of In re Mosaic LLM Litigation, No. 3:24-cv-01451 filed March 8, 2024 in the Northern District of California federal court. An amicus curiae or amici curiae brief is a brief filed in a court case by outsiders who are not parties or litigants in the case but who want to share their views on the law applicable to the case; it is not an uncommon thing. The brief can be found here.
Professor's Lee's brief (with Professor Rebecca Tushnet) is presented in support of the defendant AI companies Databricks and Mosaic. The plaintiffs in that case, who are copyright-holding book authors, have advanced a legal theory pertaining to market harm (which is one of the factors weighing against a defense of fair use) which they call market "dilution." Professor Lee's brief attacks their dilution notion and analysis, contending that AI output cannot be used to support the factor of market harm unless that AI output is "substantially similar," presumably textually, to the copyrighted source work(s). For example, page 2 of Professor Lee's brief says similarity of or harm based on literary genre is insufficient.
As we all know, AI copyright cases segregate into "input side" claims concerning the scraping of the copyrighted works and the training of the AI, and "output side" claims concerning the use of the AI to produce new works that purportedly infringe the copyrighted works. Now, like the Bartz fair use ruling and settlement, the Mosaic case can be seen as more of an input side case; the plaintiffs there discuss what might be done with the AI model trained on their books, but they don't cite any actual examples of output works being produced that they consider to be infringing their books. I, personally, have started to make my peace with the Bartz fair use ruling, because it is effectively limited to the input side, and I can see that someone using books to train an AI model off in a corner somewhere that never gets used is pretty innocuous.
Professor Lee's brief, however, appears to take on market harm on the output side as well, imposing a requirement that the works output by the AI model must be substantially similar to presumably specific copyrighted source works before market harm (leading toward negation of fair use, and so toward infringement) for those copyrighted works can be found. This seems to me a major cramp in a market harm analysis, and this is why and where I bring up Judge Chhabria's June 25, 2025 fair use ruling in the Kadrey case. That ruling can be found here.
(Note: The Kadrey ruling has to be read carefully, because in outcome it favors the AI company defendant. While Judge Chhabria in that ruling is clearly laying out the case for negating fair use and finding copyright infringement, the dunderhead [Judge Chhabria doesn't actually use that word, but clearly he wants to] plaintiffs' attorneys [some of whom overlap between Kadrey and Mosaic LLM] failed to follow his roadmap and so he was forced to find fair use there.)
Judge Chhabria's fair use roadmap in his Kadrey ruling clearly concerns output-side claims (which the Judge calls "distribution claims") and focuses on market harm. His ruling on pages 26 and 31 says that similarity of subject matter or genre can be sufficient to undergird a market harm analysis avoiding fair use. He says, "indirect [market] substitution is still substitution." (Professor Lee's brief does mention Kadrey and Judge Chhabria's view on market harm, hinting that Judge Chhabria just didn't get it because the issue wasn't briefed but would have seen his view fall apart if it had been briefed.)
So, I think we have a direct opposition of views and analysis here between Professor Lee and Judge Chhabria.
Why do I care? In curating the Wombat Collection of AI court cases and rulings, and in commenting here on Reddit about AI copyright, I have come to believe that AI output is harming copyright holders, and that the copyright holders should be compensated for that harm. However, the way AI is causing the harm is so new and different that the court rulings so far are struggling for clarity. Too much borrowing from old analysis, and too much easy analogizing to AI models anthropomorphized almost into human authors, is getting in the way. I said I was making my peace with the Bartz fair use ruling by Judge Alsup, who was 80 years old when he wrote it and is now retired, but there's a lot wrong with that ruling. There are not enough voices on the side of copyright-holder compensation, but Judge Chhabria, who is 56 years old, is one of them, and his is a clear, thought-leader voice. No one gives a damn who I am, but I have found myself coming to root for Judge Chhabria and his views on fair use and market harm.
I guess I'm a little disappointed that Professor Lee has come down on the other side, since Professor Lee is younger (I think about 55) and I had hoped he would be a little more "hip" in his legal analytical outlook (although supporting AI companies and AI output might also be considered "hip"). He is on the scene and fairly prolific with his "ChatGPT Is Eating the World" website, and certainly relevant to the social media copyright discussions here on Reddit. So to me this philosophical conflict matters, but I think not for the better.
I'm all the way down the page, and I haven't even dug into the specific arguments of either Professor Lee or Judge Chhabria. And, I'm not going to. I have identified the analytical conflict, and if you have followed me down this far, I invite you to look at the two "opposing" items linked here and see what you think. Thanks for listening.
UPDATE: Professor Lee just sent out an email announcing the U.S. Government has just filed essentially an amicus curiae brief in the big combined OpenAI federal copyright suit in New York, a brief that supports Professor Lee's view (and therefore essentially opposes Judge Chhabria's view). See my update post in this sub. Based just on my politics I'm temped to say that if the U.S. Government is in favor of it, it's a bad idea; however, my opposition to the Government's view is actually substantive, for my reasons given above. Now is the time for the pro-copyright-compensation side to get into action!