A mathematician, a physicist, and an engineer were staying in a hotel during a convention.
In the middle of the night, for no apparent reason, a fire broke out in the engineer’s wastebasket. The engineer rushed into the bathroom, emptied the ice bucket, filled it with water, and dumped it on the fire, quickly putting it out. Satisfied that the problem was solved, he went back to sleep.
A short time later, a fire broke out in the physicist’s wastebasket. The physicist rushed into the bathroom, grabbed his calculator, frantically performed a few calculations, then filled a cup with a precisely measured amount of water. He carefully poured it onto the fire. As the last drop hit the flames, the fire went out. Satisfied that the problem was solved, he went back to sleep.
Finally, a fire broke out in the mathematician’s room. The mathematician rushed into the bathroom, saw the ice bucket, saw the cup, and saw the faucet.
Satisfied that the problem could be solved, he went back to sleep.
Explanation: The engineer solves the problem practically, the physicist solves it scientifically with precision, and the mathematician only proves a solution exists. Since mathematicians often focus on existence rather than execution, he considers the problem solved without actually putting out the fire.
