In the long human effort to understand the deep structure of reality through mathematics, a new kind of claimant has arrived at the gates. OpenAI announced that its artificial intelligence had solved the Navier-Stokes problem — one of seven Millennium Prize challenges that have stood unanswered for a quarter century — only to find the mathematical community pushing back with a question older than any algorithm: what does it mean to truly prove something? The dispute, unfolding across institutions and headlines in 2026, is less about one equation and more about who holds the authority to declar