Many of us look forward to retirement, that time in life when we stop working for a living. But what exactly is retirement and why do we retire? Does retirement always mean an end to work, or can it sometimes just mean a shift to a different kind of work? Ought we retire for purely selfish reasons, such as to give ourselves more leisure time? Or ought we retire for the public good, to give younger people greater opportunities for employment? In an age when people are living longer and technology is displacing more and more workers, how should our attitudes about retirement change? The Philosophers coax John Perry out of radio retirement to ask about all the work he's been getting done since stepping away from the mic.