Bosch’s symbolic genius is hard at work in this painting. It used to be thought that a stone was the cause of madness, and if removed, it would cure the individual of insanity or folly. The stone was removed through trepidation, or drilling a whole into an individual’s skull and literally removing the “stone.” Bosch’s play on the imagery in the painting is beyond literal. The person performing the procedure is wearing a funnel hat, which at the time meant he was a charlatan, and the woman wears a book on her head, which also suggests folly. Combined, the images are a satire on madness and folly, as they depict a ridiculous scene, filled with symbolism of the nonsensical.