Alfred Hitchcock (and if you don't know who HE is, look him up. I'm not a library) used to refer to this term in his mysteries (turns out Hitchcock probably didn't invent the term: a man named Angus MacPhail did) to explain something in a story that sets the plot in motion but has little or no significance in and of itself. A great example of this would be from a non-Hitchcock film, Casablanca. (and if you don't know THAT movie, go away and watch it. I'll wait.) In Casablanca, there are these "letters of transit" that everyone is looking for. The letters supposedly would allow someone fleeing Nazi Germany and its holdings to get past any border check. A freedom fighter, Laszlo, needs the letters to escape the ever-tightening Nazi dragnet surrounding him and his wife. In reality, the letters wouldn't work at all. Since Laszlo is a VERY wanted man, he would of course not be able to flash some documents to a Nazi officer and force the latter to let him go. Still, the letters provide the "motive force" of the story--it gives the characters in the story something to do initially, a reason to enter Rick's, a reason for the Nazi's to start crushing things, and so on and so forth. The story of Casablanca isn't, though, about the letters at all. It's a love story, it's about courage, it's about..just go watch it.
In my latest piece of writing, I was having trouble (see the previous post). Once I settled on the ending that helped. I now knew where I was going. Still, I was having trouble getting the story's engine running so I could get to that ending. I had written about 8,000 or so words, but I felt like the opening act was winding down and I had not real idea what the plot was about (not what the story was about, but the plot).
I needed, in other words, a MacGuffin.
Strangely enough, I had already written it, but I had placed too much importance on it. See, Hitchcock very famously said, "The main thing I’ve learned over the years is that the MacGuffin is nothing." That sounds odd, but in light of Casablanca's letters of transit, it all makes sense. See, that great Faulkner quote, which I never tire of: "The human heart in conflict with itself is the only thing worth writing about." The story is about your protagonist and his or her struggle with his or her own demons. It's Rick deciding that he loves Ilse, and the world, enough to suffer quietly for them.
I actually had the MacGuffin written, but I didn't realize it (I won't say what it is here). My problem was that I was treating it as the STORY, when it wasn't. It was just what kept the story going, what kept people in the story active.
I remember when the realization came to me. It was that epiphany people talk about so much but so rarely experience. I suddenly saw the story in a whole new light. This doesn't mean it will be easy to write, and it doesn't mean I don't need to think of plot elements, but it does mean I am a step closer to finding out what this story is about.
Be seeing you!