Maxperson
Morkus from Orkus
I'm not going to be discuss the definition of "uncertainty" with you.
To understand my viewpoint, to the extent you desire to do so, you have to view the uncertainty as existing at the level of the fiction. And the mechanic - an ability check or a passive check - resolves that uncertainty.
So, the player states a goal and approach. I don't know whether that succeeds or fails, so there is uncertainty as to the outcome. I set a DC and decide on an ability check or a passive check. Then I resolve the uncertainty into an outcome and narrate.
How is that different from the uncertainty existing at the level of fiction, which I assume means that the PC doesn't know if it will succeed or fail, and you deciding outright that the PC succeeds or fails? Or are you saying that the PC knows whether the action will auto succeed or fail, but the player doesn't and that's why the player stated he was going to try the action?
Edit: I'm also not sure how the bolded changes it, either. Presumably, you didn't know whether the PC would auto succeed or fail at something prior to the player stating that he tries the action, so you are resolving uncertainty that way as well.