@Bill Zebub
- There are no psychological facts in the game-world.
- There are psychological facts in the real-world, relating to players and DM.
- Game rules cannot alter psychological facts.
Therefore.
- Given the only facts bearing on if a character I control takes action X are psychological facts.
- In that case, it is not possible for game rules to play any part in deciding if that character takes action X.
As you might see, I take the most parsimonious path to preserving the truth of this theory. I say that game rules can't overwrite psychological facts, while allowing the game rules to otherwise continue to work in their normal way. I simply say that - when all's said and done - they can do no harm to psychological facts.
I also allow for a subtlety that I believe can enhance our roleplay. I don't say that psychological facts are informationally isolated from the outcome of game rules. Only that the rules cannot alter them. Psychological facts can alter themselves, if they feel moved to by the outcome of the game rules. There may be other facts that are altered by the game rules with that same outcome, and I preserve that possibility instead of destroying it.
[EDIT I hope you will notice an assumption that is at issue in connection with the above, which is that ability checks within the scope of Persuasion and Intimidation are attempting to alter psychological facts. That is a very odd assumption, because if it is true that game rules cannot alter psychological facts, it is unreasonable that these game rules should be attempting to do so. Thus we might suppose another set of facts, about the character's volition. Those obviously could be altered by the game rules. You can see how unstated positions on whether the abilities are attempting to alter psychological facts or character-volition facts, and whether those are even separable, must lead to disagreement.
In this regard however, we should apply Occams Razor. Seeing as psychological facts alone are sufficient to motivate character actions, it is not necessary that there be any character-volition facts. As we should prefer not to multiple entities unnecessarily, and given it is up to us what is included in our game theory, we should not commit to the existence of character-volition facts. Or to put it another way, we should understand the necessity of character-volition facts before we commit to them. One way they could be necessary is if they were the only facts other than psychological facts that could possibly bear on if a character takes action X. However, we have what we think of as physical facts to do that job in the game-world.
The problem is, that leaves Persuasion and Intimidation stranded as game mechanics. Setting aside that they are simply a mistake, one way to salvage them is to suppose that there are volition facts for all creatures in the game-world other than player-characters. We might suppose that such creatures need volition facts as they lack psychological facts to motivate them. It would be strange to think so, however, because it is obvious that DM can and must supply motivating psychological facts in their relation.
Thus we need a hypothesis that makes it required that creatures other than player characters have a mixture of psychological and volition facts to motivate them. One is to observe that they are regulated by a set of rules that do not apply to player-characters, which are the social interaction rules in the DMG. Those rules create cases where no physical facts bear on if a creature takes action X, but volition and psychological facts still do. I think we suppose that the volition facts trump psychological facts in such cases, but as it is up to DM whether and how they apply, that produces no particular dystopia. (Another of the very many reasons for robustly preserving DM mastery of rules.)]