When this faculty is developed a little further it makes one know also what is the reason behind every illness that a person has, whether mental or physical; and when this faculty is developed still further, one can also find out what would be the best way, the best remedy to cure this person. Avicerma, the great mystic of Persia, was a physician and a healer at the same time. The mystic is a healer by nature, but the attainment of the outer knowledge enables him to use his faculty best in the work of healing.