Behavior: Ground Rules for Telling Lies

The average American prevaricates some 200 times daily

When is it permissible to tell a lie? Never, according to Augustine and Kant. Machiavelli approved lying for princes, Nietzsche for the exceptional hero—the Superman. Most other philosophers, and ordinary folk, are less certain, allowing some lies, but not others. After some 2,500 years of moral speculation, says Philosopher Sissela Bok, mankind is still trying to work out ground rules for acceptable lying.

In her new book, Lying, Bok—the wife of Harvard President Derek Bok and daughter of Swedish Sociologist Gunnar Myrdal—traces the history of convoluted arguments on the subject. For instance, Grotius said...