As an experiment, an engineer, a physicist, and a mathematician are placed in separate rooms and left with a can of food, but no can opener. In the first room, the engineer is snoring, with a battered, opened and emptied can. When asked, he explains that when he got hungry, he beat the can to its failure point. In the second room, the physicist is seen mouthing equations, with a can popped open beside him. Engineers think that equations approximate the real world.
Scientists think that the real world approximates equations.
A Mathematician, a Biologist and a Physicist are sitting in a street cafe watching people going in and coming out of the house on the other side of the street. First they see two people going into the house. After a while they notice three persons coming out of the house. An engineer, a physicist, and a mathematician are shown a pasture with a herd of sheep, and told to put them inside the smallest possible amount of fence. The engineer is first.