Asked about a publisher’s claim that commercial operators must pay to use its material, a Perplexity spokesperson gave a four-word answer in substance: facts aren’t copyrightable. It’s a real defence, it’s been good law for a very long time, and it may be the wrong argument for what these systems actually do.

The copyright fight so far has been about training. Did the model ingest protected work to learn from it, and is that fair use. That question is enormous, unresolved and slow, and it’s being litigated in dozens of cases.