Lanefan
Victoria Rules
So what? None of the adventurers may have ever heard of the Caves of Chaos before the party stumbles onto them en route to somewhere else, but the Caves didn't just magically appear while the PCs were wandering by, and while the DM might have had them pre-placed the players would have made no decisions based on knowledge of the Caves, because they had none. Ditto the boxes.The point is that, unless someone actually engages in an act of authorship - actually writes the warhorse, or the boxes, into the gameworld - then they are not in any practical sense part of the gameworld. For instance, no player will form the belief "That warhorse (or those boxes) are part of the gameworld". No player will declare an action based on the premise of their existence. No GM will adjudicate an action, or frame a scene, having regard to them.
This is a different point than the idea of history, however. Once something of any relevance appears in the gameworld its history must also be considered, as per the vampire example. I don't care why those boxes are sitting in the alley (or, conversely, why someone took them away and burned them last night), but I probably will wonder why nobody knew about something as significant as a vampire before now (knowing full-well there may be a perfectly good in-game answer).
Side note: I think a similar discussion has come up before, something to do with whether the guards at a town gate exist before the PCs interact with them in-game. And then, as now, I posited that they did exist.
A good GM needs to be an imaginer first, a communicator second, an engineer third, a facilitator fourth, and an author maybe last if only to afterwards record the story written in the game play, such as it may be.To relate this back to its origins in this thread: I stated that a strength of The Forge is that they eschew appeals to the ingame perspective as a way of explaining play experience. If you want to teach someone how to be a good GM when it comes to random encounters, getting them to think really hard about the ingame situation is irrelevant. You need to teach him/her how to write good ingame situations. You need to teach him/her to be an author, not an imaginer.
Lan-"and a good measure of 'devious scoundrel' can also serve a DM well"-efan