it could be said that 'the world' in any rpg is only present while it is being jointly imagined - ie while play is happening. And that it comes into existence by people proposing things and having them affirmed or denied by the group. In that sense 'the world' is made up of the focus of group imagination at a particular time and the collective memory of past proposals being accepted or rejected. Is 'the world' ever in moving or in stasis? Or does it remain undefined up until the moment someone focuses attention on some part of it during play?
Ok, I think I understand where you are going now and how you understand the advice.
I'm not sure 'undefined' is the only quality to consider. Something can be defined, but still be flexible, in that as long as you haven't introduced it you can still change it. Something can be defined, but also be unrefined, in that you may have a notion in a broad outline but not have imagined out all the particular details.
Also keep in mind that even by your terms, things exist outside of the knowledge of anyone at the table. People at the table, especially but not exclusively the storyteller, can know things about the scene that aren't revealed to anyone else - and therefore exist in the world but NOT within the groups shared imaginative space. Therefore we can never say the whole world is in the group's collective imaginative space alone. What exists in a collective space might be only the tip of a very large unrevealed iceberg.
By your understanding of what it means, I think i can take a stab at the question.
What you gain by being flexible is that if you see that your original conception is definately going to not work out, you can always switch to something that might. I might point out though that this doesn't necessarily have to be approached as changing the setting. Often it is enough to change your plans about the mechanical resolution of the player's interaction with the setting.
What you put at risk is a player's sense of accomplishment, the player's trust, your own ability to remain unbiased and neutral, and to a certain extent the ability to surprise the player. I also find that often during a session as a DM it's easy to lose confidence in your self and panic, and that often you don't make the best of decisions when paniced, stressed, hurried, or harried. Many of the times when I've waved my story teller wand behind the screen to change my original conception, it's been something I've regretted, making the scene worse rather than better.
Ultimately, should you come armed with firm ideas, should you invent on the fly, should you change your ideas, or stick to your plans are decisions with no easy right or wrong answer. If the goal is to make the best possible game, I think it would be a mistake to say, "You should always act this way." There are too many circumstances where that would be wrong. The trouble is, since we can't see the future, we are always going to make some mistakes. I think what can happen though is a player or storyteller can be the victim of one of those mistakes, ruining the game, and thereafter they assume that the problem is with the tool, and not the application of the tool. There are some tools that I would strongly caution players against using, in the same way I might caution a writer against using sentence fragments. But I would never tell an artist, "Never do this." I would strongly discourage for example using railroading techniques. There are times however when a railroading technique can be used as a form of player empowerment or to escape potential pitfalls along the way, that no one, not even the players would want. The trick is knowing when to use what, how to use it skillfully, and not getting too locked into the idea that there is one right way to achieve a particular goal.
Yes, I think it can mean that. But again, I think it can mean something else. Because we could ask the question 'Who decides if a player character is involved?'
I would suggest it is the player. So I think you're correct that if the GM can offer 'hooks' with a 100 per cent success rate you end up with play in which the Burning Wheel statement is adhered to.
Again, the GM isn't a prophet. Besides which, this is strictly speaking wrong. A GM that gets 100% bite rates on his hooks almost certianly doesn't have players that feel empowed to make important choices. He has players that think they don't have any choice but go along with the DM's ideas. No matter how much you are playing to player interests, you'll never get things 100% right.
I'd suggest Beliefs allow the player to launch directly into action without the GM saying anything or offering anything beyond what was established by the group during set-up.
You don't need mechanics for proactive play.
I read the BW statement as a call for players to be pro-active from the very start of Act 1 Scene 1, and for GMs to react, to make them fight for what they believe.
I believe that that is the BW author's intention. Whether or not that statement says anything of the sort no its own, I'm very skeptical of. Whether any given player can simply be proactive is a wholly different matter. In my experience, a proactive player is proactive regardless of the system. The trick to allowing proactivity in my experience is to provide a detailed sandbox, with the expectation of refining the detail depending on player action. It would require an extraordinary GM to improv a sandbox for a proactive player and not end up with either a rowboat world or an unsatisfying thin gruel of validated expectations fed back to the player. If you don't put enough toys in the sandbox, it's very hard for even an creative player to be inspired enough to be successful. I have definately played under improv DMs where both I and the DM could never quite get a finger on where to go with each other's direction, and in retrospect I've seen things I could have done that just didn't occur to me at the time. And I've gone home as a DM having improv'd a scene to an unhappy conclusion, sit down to record the results write about what to do next and just smacked myself on the forehead because I overlooked something I probably wouldn't have overlooked had I made better contingencies. On the other hand, some players simply aren't proactive by inclination. You have to prompt them into action, and they have varying degrees of inertia once moving. You can't dump a bunch of sand (or even legos) in to their lap and say 'build something', whereas if you present them with a problem and a pile of junk to solve the problem with they will come up with a creative solution.
