@Pedantic @Lanefan @EzekielRaiden @Manbearcat
Here's my attempt to elucidate the difference between (i) the concern about MUs/wizards violating @Campbell's principle, and (ii) garden variety action declaration that produces changes in the fiction, often advantageous to the position of the player who declared the action.
(ii) typically involves engaging meaningfully with the fiction, identifying a way in which the PC abilities, including the PC resource list/inventory, can interact with the fiction so as to produce the desired change. There is then, typically (not always) some sort of check/roll required to determine whether things work out as desired, which creates the possibility for things going wrong.
This is, in essence, playing the game.
(i) on the other hand is, in its actual working, basically indistinguishable from a fiat metagame ability. The player doesn't have to engage with the fiction beyond noting the initial description of the situation (eg a yawning cavern). There is no check/roll required to use the spell. The player just declares that the fiction becomes thus-and-so, and it becomes thus-and-so.
There is a type of play here, as the MU/wizard player has to be familiar with the various options on their spell load out - this is what creates the space for Manbearcat's possibility of "The Wizard player morbidly profligate + misplay-city". But while there is a fig-leaf of in-fiction rationale, the actual dynamic of play is the GM having to share control over the scene-framing with another participant - ie the wizard/MU player.
Here's my attempt to elucidate the difference between (i) the concern about MUs/wizards violating @Campbell's principle, and (ii) garden variety action declaration that produces changes in the fiction, often advantageous to the position of the player who declared the action.
(ii) typically involves engaging meaningfully with the fiction, identifying a way in which the PC abilities, including the PC resource list/inventory, can interact with the fiction so as to produce the desired change. There is then, typically (not always) some sort of check/roll required to determine whether things work out as desired, which creates the possibility for things going wrong.
This is, in essence, playing the game.
(i) on the other hand is, in its actual working, basically indistinguishable from a fiat metagame ability. The player doesn't have to engage with the fiction beyond noting the initial description of the situation (eg a yawning cavern). There is no check/roll required to use the spell. The player just declares that the fiction becomes thus-and-so, and it becomes thus-and-so.
There is a type of play here, as the MU/wizard player has to be familiar with the various options on their spell load out - this is what creates the space for Manbearcat's possibility of "The Wizard player morbidly profligate + misplay-city". But while there is a fig-leaf of in-fiction rationale, the actual dynamic of play is the GM having to share control over the scene-framing with another participant - ie the wizard/MU player.