Judge Finds AI Training on Complete Books ‘Reasonably Necessary’

The court found that Anthropic’s use of entire books to train its Claude AI models qualifies as fair use due to the transformative, non-competing nature of the output and the sheer volume required. However, it ruled against fair use for pirated copies added to its internal digital library, calling the scope of that copying unjustified.

3. THE AMOUNT AND SUBSTANTIALITY OF THE PORTION USED

The third fair use factor is “the amount and substantiality of the portion” of the copyrighted work used by the accused. 17 U.S.C. § 107(3). The crux of this factor is whether the amount was “reasonable in relation to the purpose of the copying.” Campbell, 510 U.S. at 586. Thus, the amount of copying is considered first against the work itself, then more importantly against the proposed transformative purpose. See Warhol, 598 U.S. at 543 & ...