Or alternatively it empowers the players to make impactful decisions with real meaning as the fictional reality their characters inhabit is not an amorphous mutable mess.
I’m a famous no-myth hater and so I endorse this message but it’s a bit more complicated than all that. It depends what no-myth means in the context it’s used.
There isn’t actually a reality behind the scenes and so what we’re talking about is the process of (1) deciding what things are in a scene (2) deciding what things can enter a scene (3) deciding what previously established ‘stuff’ changes that doesn’t appear in a scene.
So let’s look at fixed stuff first. The most common fixed elements are locations and NPC attitudes. If you have a dungeon map and the process of deciding what’s in a scene involves looking at the map, and in fact you ‘have’ to look at the map. We can consider that fixed.
Fixed = must be this way, you’re not allowed to suddenly change it.
Then, time and distance is commonly added but at different levels of granularity.
So in Sorcerer I might write that Maximilian is going to blow up the telecommunications tower on Tuesday. It’s a bit fuzzy though and so I ‘can’ choose the most dramatic time to blow it up, as long as it’s on Tuesday.
At greater granularity I might have to decide the actual time it blows up.
Same with space (and everyone can see how this connects with time). The entrance to the ruins are in the wetlands v the entrance to the ruins are 3 miles south by south east into the wetlands.
Anyway this matters a bit because when you decide what’s in a scene you may have to track where various npc’s are and the different levels of granularity matter.
So my general process of scene framing, in Sorcerer and Apocalypse World, is to figure out where the NPC’s are (roughly) what they’re up to (called Bangs), then see what the various P.C’s are doing and seeing if they intersect with each other in some way, that’s where I’ll cut to. I do that with somewhat fuzzy granularity unless it matters but it’s never on the granularity of something like GURPS.
Anyway I might have gone off on a massive tangent. My main point is that there’s a process by which stuff is introduced and thinking about stuff in terms of the imaginary world can obfuscate that process.
Now no-myth at it’s best is a reminder that we can use the fuzzy granularity and the non-fixed points to make things cool. Also to be wary of what points we fix and how we fix them and how we communicate that information to make sure choices can retain thematic charge.
For instance: Imagine you decide that the Players lover has been kidnapped and is being held in a basement under the tech building. The player doesn’t know this and blows up the tech building for unrelated reasons. Well then you’ve committed yourself to saying their lover is dead.
Which, I think you should do and I think it’s perfectly legitimate. Yet you can see how this starts collapsing all theme into what basically amounts to, naughty word happens. Which isn’t particularity satisfying.
So one very good use of no-myth is to contrive ways to communicate consequences and to do this constantly. In fact I do this all the time.
At it’s worst (and in fact in it’s original form), no-myth basically gives unilateral control to the GM with the instructions ‘make it interesting and thematic.’ Which means the GM is now part entertainer, part psycho-therapist.
Anyway, in my ideal world people wouldn’t use the term because I tend to use it in it’s original context and if people are using differently (which happens a lot) then I have to figure out what they mean. That’s maybe a me problem though.