• by Wendy Davis , August 5, 2025

A federal appeals court should decide whether Anthropic has a valid fair use defense to claims that it infringed authors' copyright by training its chatbot Claude on books downloaded from piracy sites, the artificial intelligence company says.

"Given the enormous stakes of this case -- and the many similar cases raising copyright challenges to generative AI (GenAI) technology -- the Ninth Circuit should clarify the governing legal rules before this court conducts a class trial where Anthropic could face hundreds of billions of dollars in potential liability," the company argues in papers filed Monday with U.S. District Court Judge William Alsup in the Northern District of California.

Anthropic's request comes in a copyright infringement lawsuit brought last year by the authors Andrea Bartz, Charles Graeber, and Kirk Wallace Johnson, who alleged in a class-action complaint that Anthropic infringed copyright by using published books to train its large language model Claude.

Anthropic defended itself by arguing that using books to train large language models is fair use -- regardless of whether the books were purchased legally or downloaded from piracy sites.

Alsup partially agreed with Anthropic. He ruled in June that the company's use of purchased books for training was "exceedingly transformative," and therefore protected by fair use principles.

But Alsup also sided against Anthropic regarding allegations that it also downloaded millions of pirated books, ruling that the company couldn't claim fair use regarding those downloads.

Last month, Anthropic asked Alsup to authorize an immediate appeal of that portion of the ruling to the 9th Circuit. The company noted in its request that a different judge in the Northern District of California -- Vince Chhabria -- largely sided with Meta in a similar lawsuit, ruling that the platform did not infringe copyright by downloading pirated books and using the content to train the large language model Llama.

The authors opposed Anthropic's request, contending in papers filed late last month that the company was attempting to bypass normal procedures.

"Faced with an emphatic rejection of its core position -- that it could steal books with impunity -- Anthropic urges this court to get out of the way so it can jump straight to the Ninth Circuit. That is not how litigation works," attorneys for the authors wrote.

They added that questions about fair use are "fact-bound" and not appropriate for immediate appellate review.

Anthropic counters in its new motion that the critical questions -- including whether a company's ability to assert a fair use defense turns on how it acquired the copyrighted material -- require appellate review, given that judges within the district have come to different conclusions.

The company adds that an immediate appeal is warranted in order to determine whether "acquisition from an unauthorized source" weighs against fair use.

"Nothing in the Copyright Act suggests that the fair-use defense applies with any less force when the defendant obtained the relevant works from an unauthorized third party," Anthropic writes.

"The entire premise of fair-use doctrine is that the defendant lacked permission to use the works -- whether a third party initially distributed the works without permission has no bearing on the analysis," the company adds.

Alsup is expected to address those arguments at an August 28 hearing.

Last month, Alsup said in a separate ruling that the case could proceed as a class-action on behalf of copyright owners of books in two libraries -- LibGen and PiLiMi -- containing pirated books.

Anthropic late last week asked the 9th Circuit Court of Appeals to hear an appeal of that ruling.