During the French revolution, hundreds of people were guillotined. One day, three men were led up to die. One was a lawyer, one was a doctor, and the third was an engineer.
The lawyer was to die first. He was led to the guillotine, the attending priest blessed him, and he knelt with his head on the guillotine. The blade was released, but stopped halfway down its path.
The priest, seeing an opportunity, quickly said, "Gentlemen, God has spoken and said this man is to be spared; we cannot kill him." The executioner agreed, and the lawyer was set free.
The doctor was next. He was blessed by the priest, then knelt and placed his head down. The blade was released, and again stopped halfway down.
Again the priest intervened: "Gentlemen, God has again spoken; we cannot kill this man." The executioner agreed and the doctor was set free.
At last it was the engineer's turn. He was blessed by the priest, and knelt, but before he placed his head on the guillotine he looked up. Suddenly, he leapt to his feet and cried, "Oh, I see the problem!"