The world is not magic. At least, that is, the actual real world around us. That's the great insight we've achieved over the course of centuries of scientific investigation into the universe. It all follows rules; everything has an explanation (which is not the same as everything having a reason). So I was struck by this blog post by screenwriter John August. He talks about the movie Groundhog Day, in which Bill Murray's weatherman character is stuck in a time loop of unspecified duration. For a film that seemed fairly inconsequential at the time, it's really a great starting point for all sorts of conversations -- I use it in my book to talk a bit about time-travel paradoxes. (Did I mention I'm writing a book?) But August uses it to illustrate the cinematic usefulness of unexplained magic. Even in a fictional universe, you don't want it to be completely magical -- there need to be rules, otherwise it's impossible to have a coherent drama in which the characters struggle to achieve some goal. In Groundhog Day, the goal is to win the love of Andie MacDowell, although different stories make different choices. But the central conceit of the movie -- Bill Murray is stuck in an endless loop, trying to get out -- remains completely unexplained. In an early version of the script, apparently, there was some talk of a voodoo spell that set the time loop in motion. Removing that bit of explanation was an incredibly smart decision. If it had been included, the focus on the story of the protagonist's journey would necessarily have been diluted by the attention paid to the voodoo spell. The movie worked much better with that little bit of magic remaining unexplained. You can just imagine if Murray's character had been a physicist instead of a TV personality. Forget about winning someone's love; the guy would have spent millions of years trying to figure out the mechanism behind his travel in a time loop. It's great when scientists talk to Hollywood, but thank goodness they haven't taken over.