Story analyst Billy Mernit joins Michael Phillips to test one of Hollywood’s most enduring (and slippery) unofficial rules: Howard Hawks’ idea that a good movie is three good scenes and no bad ones.

Mernit, an instructor and writer known as the “guru of rom-com,” brings nearly three decades of reading studio scripts and a working knowledge of how films get evaluated before they ever reach the screen. Together, they dig into what makes a “good scene” in the first place.

Is Hawks’ dictum still useful? Or, like so many Hollywood rules, is it less a law of motion pictures than a reflection of how we choose to remember them?