On "I believe them": multiple posters in this thread have talked about how they find playing (say) Dungeon World or Burning Wheel or some other game that is generally described as non-simulationist more immersive than RPGs which rely heavily on GM narration to tell the players what their PCs know and believe. So now, do those games turn out to be simulationist after all?
Or to put it another way: the boundaries of "simulationism" in this thread seem to be drawn based on the casual universalisation of particular experiences and preferences - eg because
this particular poster imagines (though they have no play experience) that playing Marvel Heroic RP or a fantasy variant thereof would be un-immersive, they posit that it is un-immersive in general and hence not simulatioinst.
On "noetic satisfaction", "exploration" and "investigation", coupled with "my role as GM": this seems to me to be obviously pointing towards RPGing where a principal activity in play, perhaps the principal activity, is the players declaring actions that prompt the GM to tell them things about the setting: either things the GM has already prepared/authored, or things that the GM works out by extrapolation from what they have already prepared/authored. If this is what is intended by "simulationism", then I think it would be help to be clearer about it.
If that is not what is intended, then lets talk about player contributions to the subject which is investigated, explored, intuited and cognised. In my 4e game, the player of the wizard routinely articulated - speaking for his PC - theories of how magic worked, what its potentials and limits were, etc. These would inform his use of his Arcana skill, his approach to rituals etc. To me those seem to be
simulationist moments of play, based on the ideas
@clearstream has set out. But they have nothing to do with
GM authority over the fiction.