What a hallucination is
This is the name for a confident but false answer: an invented source, a book that does not exist, a wrong date or a quote nobody said.
It is not lying in the human sense. The model simply wrote plausible text.
Why it happens
The model picks words that sound natural after the ones before. If an invented name sounds convincing, it will use it, because it does not check anything against a database of facts.
Mistakes are most common with rare things, exact numbers, very recent news and little-known people.
How to check
1. Ask for sources and open them yourself. If the link does not lead where it claims, do not trust the answer.
2. Look for numbers and names in official or reliable sources: government sites, major newsrooms, original documents.
3. For important decisions (health, money, documents, law) use AI only as a hint and check the decision with a professional.
Glossary
- Hallucination
- A confident but false AI answer: invented facts, sources or quotes.
- Fact-checking
- Comparing a claim with a reliable source before you rely on it.