This American Life has a podcast called “No Coincidence, No Story,” in which they interview various people about amazing coincidences that happened to them.  This American Life is a popular program, so when they asked people to send in their stories, they got well over a thousand responses.  That means the ones that actually made it into the program were bound to be pretty amazing.  And they were.

The one I liked best was the man who was going to ask his girlfriend to move in with him.  On the way he stops at a store to buy something, and he notices that one of the dollar bills he was going to use to has the name of his girlfriend, Esther, printed on it.  He thinks this is a charming coincidence, so he holds onto the dollar, puts it in a frame, and gives it to his girlfriend.  It turns out that years before, the girlfriend, fed up with her bad relationships with men, impulsively decided to write her name on some dollar bills and put them into circulation. Her idea was that the man who would present her with one of those dollar bills would be her true love.  They are now happily married.  Sweet!

“No coincidence, no story” is apparently a Chinese proverb.  But it doesn’t really apply to modern fiction. I remember reading somewhere that a writer can get away with one coincidence per novel.  But even that seems like one too many for plot-driven novels of the sort I like to write.  This approaches being a law of fiction, like Chekhov’s Gun. Everything needs to be motivated; events that seem random and improbable need to have a “real” explanation.

But this is not to say that coincidences have no place in storytelling.  For example:

• Writer like Murakami, Pynchon, and Vonnegut create their own reality.  Don’t be surprised if weird things happen in that reality.
• Seems to me that there’s no problem with a coincidence starting a plot. That incident with the girl’s name on the dollar bill could motivate a romantic comedy, or even something darker.
• Comedies in general can employ coincidences.  I’m not a big fan of the movie Love, Actually, but I don’t mind the absurd coincidences that litter the screenplay.  For example, the prime minister goes looking for his girlfriend on Christmas Eve (he apparently doesn’t have people who can do this for him).  It turns out she lives next door to the secretary who is trying to have an affair with the prime minister’s sister’s husband.  Everyone ends up at the big Christmas Eve concert at a nearby school, where most of the rest of the characters in the movie are also in attendance for various random reasons.  OK with me.
• Thrillers can get away with some coincidences because the reader/viewer isn’t necessarily trying to follow every twist and turn of the plot.  Relying on coincidences isn’t exactly a virtue, but it doesn’t necessarily detract from your enjoyment.  I watched Rome: Open City for the first time the other night, and I was surprised to discover that it is basically a thriller (the screenplay, oddly, was co-written by Federico Fellini). The plotting is pretty crude, and a coincidence plays a totally unnecessary role in the proceedings.  But I realized this only after the movie was over.