But what I’m saying is that you can do (b) without mechanics that affect character behaviour or thinking; you merely frame situations that challenge their values. But it’s up to the player, not the dice, to decide how they react.
Yeah, I don’t disagree with that, but that isn’t the point I was making (more on that at the bottom) and there are also differences when you couple (a) and (b) and when (b) is on its own.
The differences lie in two things:
1) “Conception of character (internal relationship to self and external relationships with others) arising/evolving through play contingent upon situational decision-space > action and resolution > consequences > systemitized, binding fallout” vs “inviolable preconception of character overwhelmingly (if not wholly) dictating through line of relationship to self and external relationship.”
The first is about conception emerging through play with a hell of a lot of that out of your hands. The second is about preconception being mapped onto the gamestate/fiction (either by the player directly, by the GM curating content to facilitate that, or by everyone at the table being meta-aware of the resolution mechanics having a giant MY STUFF - OFF LIMITS signature).
The player in the first is continuously staking and risking and testing character conception (internal orientation to self and relationships) during play. The 2nd is not. They always have the first and last and only say because their preconception is inviolate.
2) The other difference is in the perception of adversarial GMing. The first one looks like always-on adversarial GMing to someone unacquainted to the play. The 2nd looks like content curation (by both GMing and by that MY STUFF - OFF LIMITS resolution mechanics) that facilitates preconception of character. If you just dropped that first sort of GMing into the 2nd, there would be a whole lot of crying foul going on.
As to the point I was making, it was the formulation of:
If (a) then (b)
You can’t have (a) without (b). It’s fundamental (and, in large part, the point).