Editing Unwritten: System Reference Document/Running the Game (section)

===Justification is Power===

Justification might seem like the least interesting of the roles that aspects play. However, using an aspect to justify an action or a situation gets the most mileage out of anything you can use it for.

Aspects are true. Because they are, they shape the game. Whether an action makes sense or not depends on the aspects that affect it. Dissecting a mysteriously dead animal makes perfect sense if you are a Former Medical Examiner or a Biology Major. Without that, it won’t fly.

Situation aspects offer the same guidance. For example, if a character is trying to sprint quickly across a room with Cluttered Floors, it makes sense to ask for a roll before they can move. If there is no such aspect, just let them make the move and get on to something more interesting.