John and Mary were both patients in a mental hospital. One day, when they were walking around near the hospital’s pool, John suddenly jumped into the water, swam to the bottom and stayed there. Mary quickly jumped to his rescue. Hearing about this heroic act, the chief nurse ordered that Mary was let go from the hospital, considering her now mentally stable. The nurse went to Mary to tell her the news and said:

- Mary, I have some good news and some bad news. The good news is that you are free to go; seeing as you were capable to act rationally and save another patient’s life, we came to the conclusion that this proves your full mental sanity. The bad news is that John, the patient you saved, hang himself with the belt from his robe in the bathroom. I am sorry to tell you this, but he is dead.

Hearing this, Mary replayed:

- He didn’t hang himself. I’ve hanged him there to dry. So, when can I go home?