MAIN POINTS: Nature makes hallucinations and you test with nature to discover them. If there is a paranormal or supernatural it can make hallucinations too. For that there is no test. A hallucination can teach you truth and still be a hallucination. Science needs you to use the natural as the way to get to truth so science rejects the possibility of any hallucination but natural. Religion should be a matter of opinion and thus encourage you to think you have a god or genie in your fridge if you want to think there is. If you want to stay sane and honest then be scientific only.
“It is a commonplace of child psychology that both children and adolescents have considerable eidetic gifts and are able to visualise as outside themselves objects that present themselves to their conscious - or subconscious - imagination. These need not be regarded as hallucinations, for they will occur in perfectly normal children.” From Mary: A History of Doctrine and Devotion.
The book tells us that Karl Rahner outlined the test done by C M Staehlin on six boys to see how things would go if they were influenced to think they could see a battle in the sky above a specific tree. Two did not see a thing. Four did. Two boys reported the battle sounds. But all in all their accounts were so similar that you would think they had a real vision. Steps had been taken to ensure that they were not copying their stories off one another. They spontaneously agreed in the main and essential details.