A cruise ship is hosting a conference of experts. The ship breaks up and sinks. Several people make it to a nearby island. They search for food in the crates washed up on shore, but all they find are cans.
A chemist says, "If we put a can in a fire, the contents will expand and burst the can."
The architect says, "That's fine, but we need some kind of structure to catch the contents."
The engineer starts planning the structure.
Then the economist steps forward and says, "You're going about this all wrong." Everyone asks about his big idea. He says, "Assume a can opener...."