A doctor, an engineer, and a politician

A doctor, an engineer, and a politician were arguing as to which profession was older. "Well," argued the doctor, "without a physician mankind could not have survived, so I am sure that mine is the oldest profession." "No," said the engineer, "before life began there was complete chaos, and it took an engineer to create some semblance of order from this chaos. So engineering is older." "But," chirped the triumphant politician, "who created the chaos?"