Would you sample a grape in the produce aisle without paying for it? Would you notify the cashier if she undercharged you? NPR's Susan Stamberg poses these and similar questions to shoppers at a supermarket. She then talks to Tom Morris, a self-described "public philosopher," about supermarket ethics, and ethics in the wider world. Morris, a former philosophy professor at Notre Dame, explains why he thinks taking even one grape in the supermarket "makes you a thief."