An engineer, a physicist, and a mathematician join a study on scientists' ability to survive in the wild

All three are left in different part of a desert island overnight, each with a can of beans but no openers.

The researchers come back in the morning to check on the scientists.

The engineer is sleeping soundly, next to an open can. Once woken up, he explains: "Well tin cans aren't that strong, so I kept bashing this can against a rock many times, until it gave in and opened up".

The physicist is also sleeping soundly (albeit in an awkward position like all physicists do), next to a neatly opened can. He goes to explain:" You see, the tension forces created by the joints between the different sheets of metal making the can means that if you apply precise forces on a few pressure points, the can just plops open. You can do this without effort, even with your bare hands"

The researchers then move on to the mathematician. As they approach him, they see that the can is still intact, while the mathematician is lying next to it in a fetal position, shivering, and continuously repeating: "Let's assume the can is open. Let's assume the can is open..."