That causal process has very little in common with the causal processes that bring it about that, if I go to a teahouse looking for members of a particular sect, I find any of them there. The most obvious difference is that whether or not, in real life, I meet any sect members doesn't depend upon whether anyone takes up a suggestion I make about an interesting idea.
Whether or not the GM making decisions about the gameworld, and then conveying that to the players, makes for good RPGing seems a matter of taste. But whether or not such a process is like real life seems a straightforward matter of fact. It's not.
I realize this has been going on for more than 100 pages, and I hope I can be forgiven for weighing in with an oblique viewpoint more or less cold, but I'm in the middle of reading
The Science of Discworld II, having recently finished
The Science of Discworld, and these two books have a lot to say on this topic.
I'll try to keep my summary brief: the gist of the discussion is that things happen on Discworld because they are what people expect. Causality is driven by the universe's high 'narrativium' content, which (in short) converts assumptions into reality. It's why there's always a good story; everything is subjective. For example: the sun is a comparatively small fireball that goes around the disc, because it appears to be a comparatively small fireball that goes around the disc, or, put another way, "because of course it does."
Our universe is presented as a counterpoint to this reality, where there is no narrativium. Things happen here because they have been following an arc guided by ultimate physical laws. Causality is therefore objective, even though we may often attribute subjectivity to it, that being human nature.
But the books are quick to point out that humans are a sort of fly in this ointment -- that we are very good at generating our own narrativium. When stories are demonstrably not true, we can and do change that. An obvious example of this is that man clearly can't stand on the moon, according to the established physical laws of this universe. It is hundreds of thousands of kilometers up the gravity well, and we can't breathe there, among other obstacles. And yet, men have stood on the moon. We made the story real.
This is true in a lot of smaller ways, too, but I'm not going to try to rewrite the books here. They are great reads; you should pick them up. My point is that sometimes, even in the real world, whether or not you meet sect members at the teahouse (metaphorically speaking) absolutely does depend on someone taking up a suggestion of an interesting idea.
The books also make some fascinating observations about how causality always appears linear in our universe at first, but uncomfortable questions start to arise when you really start looking hard at its relationship to thought. That's only tangentially relevant here, but still an interesting side point.
