Concept· 3 min
Why do LLMs hallucinate?
Hallucinations are confident-sounding but false outputs — a natural consequence of models predicting likely text, not truth.
Key idea
LLMs optimize for plausible next tokens. When they lack real knowledge, they invent plausible-sounding facts, citations or code.
Example
Asking a model for research papers by author X may return real-looking titles, journals and years that don't exist.
What to remember
- Ground answers with RAG or tool use to reduce hallucination
- Ask for citations and verify them programmatically
- Lower temperature and structured outputs help, but don't eliminate it