The Parable Of A Lunatic And His Friend

There was a man whose friend, it seemed, had lost his mind and had become a lunatic. The lunatic behaved sensibly in most every way, except for one. You see, the lunatic had become convinced he was dying of a horrible disease and the only way he could be cured would be if he committed his entire diet to only one specific and special organic grain, everyday. The lunatic was so sure of his disease, and the cure, he preached about it to his friends all the time.  

His best friend, seeing how outwardly healthy the lunatic was, argued with him that if he thought he was dying to go to the doctor and have a complete physical. So the lunatic went. Upon completion of the physical the doctor pronounced the lunatic healthy; without disease. The doctor's report only served to encourage the lunatic's friend to further ridicule him for his belief that he had a deadly disease.  

Still the lunatic depended fully upon the special organic grain, everyday, to cure him of his undiagnosed disease.