An economist, a chemist and a physicist..........

An economist, a chemist and a physicist are marooned on a desert island. Their only food is a can of beans, but they have no can opener. What are they to do? The physicist says: "Let's try and focus the tropical sun onto the lid—it might melt a hole." "No," says the chemist. "We should first pour saltwater on the lid—maybe that will rust it." The economist interrupts: "You're wasting time with all these complicated ideas. Let's just assume a can opener."