Empty the Bath Tub

The health minister is visiting a psychiatric ward. He asks the head of psychology dept. "How do you determine if a patient is cured?"

The Psychologist explains: "We take them to the bath tub which is filled with water, hand them a spoon and a cup and ask them to empty the bath tub."

"I see", says the health minister, "the cured person would choose the cup because it's bigger and would empty the tub faster?"

"Actually, no." replies the Psychologist, "A normal person would simply pull the plug."