The Mole Agent is a charming documentary about a private investigator hired to find out whether elder abuse is happening at a nursing home in Chile. At the heart of the film is a deception, which raises questions about trust beyond the question whether lies can ever be justified by good intentions.

If you repeat something often enough, people are more likely to believe it. That's a phenomenon called the illusory truth effect. It can happen with smart people, and even when the statement is already known to be false. So why does repeating something make people more likely to believe it?

Do makers of films that fictionalize real events have obligations not to misrepresent in the interests of telling a good story, particularly when they aim to make a political point? Is it permissible to fill gaps in a story with fictionalized accounts of events?

This is a pretty terrible time to be a fan of truth. Politicians have always lied, of course, but few have dared to deny the verifiably obvious, such as the size of an inauguration crowd. Few have perpetuated conspiracy theories, such as the one about Obama’s place of birth.