A post on Industrial Scripts examines the but-therefore process of ensuring that the events of your novel have forward motion and are connected by character choices.
Coined by South Park’s Trey Parker and Matt Stone, the but-therefore rule is a simple method for creating a cause and effect chain. In short, your character wants to take an action BUT something blocks his way. THEREFORE, your character makes a new choice. This approach helps you avoid stringing together story events at random. It also ensures that your protagonist is making active choices, rather than simply following your prefabricated plot route.
The article examines how but-therefore works in some classic stories, including Romeo and Juliet and Harry Potter. Interestingly, it also takes a look at two famous films told in non-chronological order to show how but-therefore can be applied even when your story approach is nontraditional.
If the screenwriters of Memento and Pulp Fiction can make the but-therefore rule work, so can you.
