"When in doubt, have a man come through a door with a gun in his hand."
Okay, it probably shouldn't be called a 'law'. But I didn't make it up. This quote by pulp novelist Raymond Chandler, famed for his gritty detective novels, has become a perennial piece of advice for those with writer's block.
Of course, a man with a gun may not be entirely appropriate if you are not writing a detective novel. Chandler was hardly intending to propose a general rule; he was specifically writing about his works, as the full quote demonstrates:
"Undoubtedly the stories about [hard-boiled detectives] had a fantastic element. Such things happened, but not so rapidly, nor to so close-knit a group of people, nor within so narrow a frame of logic. This was inevitable because the demand was for constant action; if you stopped to think you were lost. When in doubt, have a man come through a door with a gun in his hand."
From the introduction to The Simple Art of Murder, 1950
A general formalization of Chandler's Law would be something like: "If you are stuck, have something exciting happen". There have been a number of variants on the theme: NaNoWriMo writers may prefer "If all else fails, have Ninjas burst through the wall and attack someone" (a variant intended to maximize the need for elaboration and backstory); and Monty Python coined a derivative guideline for comedy writing, "if a scene is starting to go on too long, drop a cow on somebody".
"Suddenly there was a tremendous crash as the front door burst open. I looked up to find myself staring down the barrels of a couple of police .38 specials."
-- Farewell My Lovely, Raymond Chandler