Hallucination
A hallucination is content the model generates because it is statistically plausible, not because it is true. It is a structural consequence of next-token prediction rather than a bug to be patched: the model optimises for plausible, and plausible and true usually coincide, right up until they do not. Grounding, retrieval, and verification reduce it; nothing eliminates it. In practice: Invented case citations, invented DOIs, invented API endpoints — all classic, all confidently formatted. ...