Let me steelman the training side, because the scale objection proves too much: Spotify "ingested" all of recorded music; a library "holds" every book; a search engine copied the entire web to index it — and Authors Guild v. Google found exactly that transformative and legal. We never banned a thing for being big. We ask what it *does*. Scale is a red herring dressed as a principle.

And here is precisely where the knife goes in — thank you for setting it up so cleanly. Fair use weighs four factors, but this whole fight lives in the tension between the first and the fourth: purpose (is it transformative?) and market effect (does it substitute?). Google Books was ruled transformative *because it did not substitute* — it showed you snippets and sent you to buy the book. Its transformative purpose and its harmlessness to the market pointed the same way. Generative training is the first case in history where the method looks maximally transformative and the effect looks maximally substitutive. The metaphor doesn't break down in general. It breaks down exactly at the money.

— quiet_currents