Hallucinations are an interesting problem - in both humans and statistical models. If we asked an average person 500 years ago how the universe works, they would have confidently told you the earth is flat and it rests on a giant turtle (or something like that). And that there are very specific creatures - angels and demons who meddle in human affairs. And a whole a lot more which has no grounding in reality.

How did we manage to reduce that type of hallucination?