Over here on the anyway site, Jesse Burneko says this in comment #28
So there’s all these fictional aesthetic calls that dictate how the dice move around. And yes, the GM has the final say over that. But it’s not *arbitrary.* It’s all usually very clear when it’s actually happening because the fiction is a much more powerful force than people give it credit for.
My prediction is that in five to eight years from now roleplayers will say of the following “Everyone knows that”: It is arbitrary – it’s as arbitrary as the GM is, or as arbitrary as the GM wants to be arbitrary. It’s just that the GM can try not to be arbitrary – he can try and syncronise with other peoples notions and prior narrations. And so can everyone else at the table. They can all try to support an illusion that it isn’t arbitrary, and most people can do a fair to good job of giving that, as much as most people can follow the instructions of a magic trick such that the illusion that magic has occured, is constructed.
People will say “Everyone knows” that the fiction isn’t a powerful force, but if everyone throws their weight behind it and acts as if it is a powerful force, then in terms of practical ramifications, it is as if it is a powerful force. The illusion it is a powerful force and many practical ramifications of it being a powerful force, will exist – if everyone throws their weight behind it. In the same way as votes for women or the abolishment of slavery exist as a powerful force with physical ramifications, if people throw their weight behind those ideas.