The Law of Comparitive Advantage

“Two plus two equals five is not without its attractions.”

A bit off topic, but this reminded me of an Economics joke I heard. The Law of Comparative Advantage in Economics explains how, through use of specialization and international trade, two plus two can equal five. The joke took this principle and made a funny pun:

A mathematician, an accountant and an economist apply for the same job. The interviewer calls in the mathematician and asks "What does two plus two equal?" The mathematician replies "Four." The interviewer asks "Four, exactly?" The mathematician looks at the interviewer incredulously and says, yes, four exactly. Then the interviewer calls in the accountant and asks the same question "What does two plus two equal?" The accountant says "On average, four - give or take ten percent, but on average, four." Then the interviewer calls in the economist and poses the same question "What does two plus two equal?" The economist gets up, locks the door, closes the shade, sits down next to the interviewer and says "What do you want it to equal?"