Okay, so how do we square that with--for example--the GM having complete preference control over the description of the outcome? Because some descriptions have significant impact, such that they condition future valid mechanics, while being, in D&D, completely and totally up to GM preference.
This one is on one hand similar to the input side, but has a subtlety on the output side that I will further address bellow. On the input side I have already pointed out how a corrupt referee can make an otherwise diegetic rule non-diegetic by letting their own preferences intefer. This in a similar way to how a soccer referee might compromise the intention of the rules of the game by letting a preference for one of the teams affect their judgement calls.
There is an argument to be had about the level of discoverability and accountability when it comes to such corruption. But I think this are concerns outside the scope of the mechanics itself, and hence seem strange to bring in when contemplating good language to describe properties of mechanics.
I'm really struggling to see how you could ensure that "all input into the mechanics is diegetic" with D&D--non-diegetic inputs crop up frequently. Battle Masters, for example. Or even the Champion, simplest of the simple subclasses on the simplest of the simple classes: what is the diegetic input for the Defy Death subclass feature? You have advantage on Death saves. How can that be diegetic?
I think the answer to this is relatively simple: Not all mechanics in D&D are "diegetical" (ref.
@clearstream 's improved terminology).
Okay....so....how do you pick which one? Because it seems to me that that now means the GM can invent anything they want, whenever, whatever, so long as it has the tiniest scrap of plausibility, boom, instantly diegetic, always forever.
This I agree is an important point. The
simplest way to address this is to seperate out the mechanics for determining success from the system for determining the resulting narration. I agree that the interesting unit of conversation is the synthesis of these, but I think this separation is useful for analysis.
For the first more "pure" mechanics part the input is the dominating part to see if the end syntesis is diegetic. I think the only requierement on the output side for this analysis to work would be that each outcome (usually easily enumerable) allow for
at least one narration satisfying the causality requirement. (As such a relatively weak condition)
But as you point out the system for how to actually determine narration based on the outcome of this mechanics is important for recognising if the causality criterion is satisfied. If the system for instance is that the referee rolls these dice for show, to then narrate what they prefer independent of the result, the synthesised mechanic clearly is not "diegetical".
I think however I think a system having just a few properties bring us a long way. First off - Assume this system is based on a human making a judgement call. This allow us in this stage be self - referential by instructing the human to make the narrative decission based purely on diegetic information
and the outcome of the analytical mechanical outcome
and their understanding of diegetic causality.
As you point out this instruction is not sufficient to produce an unambiguous outcome. And we are left with a philosophical question: A judge is asked to make an impartial decission between two options. There are nothing objective separating them. External randomisers are not allowed. Is this an impossible request?
I think ultimately the answer might be yes. However in terms of
practicality I think it is usefull to accept a honestly attempted to be impartial judgment call as not corrupting the process in terms of the "no preferences" requirement. If analytical categorization is required I think it in effect would count as another randomization step, even if explicit randomiser is not used due to practical concerns.
However, where would that leave D&D? A standard guideline for DMs are to in case several options are available, chose the most exiting one. I think if this guideline is in play, that compromises the entire ruleset in a way that makes hardly anything "diegetical". However following this guideline is optional. The same can be said about basically all DM guidelines.
So I think it is usefull to look at D&D (and most rpgs) as a toolkit for "building" a game. I have here argued that there is at least one common D&D "build" with barely a single "diagetical" mechanic in it's body. However I would argue that the toolkit do allow for building a game where quite a few (though not all) it's mechanics are indeed "diegetical" (allowing for judgment calls).
Again, I keep coming back to the notion of the failed Perception check as a critical breakdown point for this sort of assertion. The inputs seem diegetic; GM knows the party has just been exposed to something they might or might not notice, so she asks for Perception checks, essentially as a reactive defense; let us assume a DC of 15. The players roll. The high-Wisdom, Perception-proficient Druid rolls a natural 1: result 11. The 8 Wisdom, no-proficiency Sorcerer rolls a nat 20, result 19. The GM narrates this as the Druid being preoccupied with preparations for the day, while the air-headed Sorcerer was placidly looking out at the forest and spotted the enemy by chance.
Diegetic inputs, outcomes that are possible to understand in the way you described, being entirely well-grounded and naturalistic, something that anyone could have foreseen as a plausible result. Yet we as players know that this is the GM retroactively inventing the explanation, solely because of the dice, not because of skill (since skill would have said the exact antithesis of this event occurred). How can that qualify as diegetic? We're literally retconning the world in order to explain what happened!
This narration takes into consideration the skill levels. It go out of it's way to make sure the narration was made so that it honors the outcome of each individual check, while maintaining in fiction causality in light of the diegetic skill capabilities of the participants involved.
If the roles had been reversed, it would have hardly been neccessary to narrate sorcerer being distracted, nor that the druid happened to look into the forrest. The
purpose of the narration appear to be exactly what would be required for this instance of mechanic use to be "diegetical".
As such the GM ability to perform such "retroactive" justifications might be exactly what is
needed for the mechanics to be "diegetical". Without such powers we might quickly find ourself in a situation where the mechanic would indicate an outcome where it is
impossible to provide a narration that make causal sense in the fiction. In wich case the mechanic break the second criterion for being "diegetical".
I would like to add I am not sure why you would find a problem with such "retroactive" narration? The narration happens to have constraints on the
end situation of the narration, but among all the other constraints on narration I fail to see how this particular kind should be particularly problematic? There are no causality issues as seen from the fiction. I could possibly see how this could be a issue in terms of immersion, but I don't think it is widely reported as such?
That last one is gonna be a tough one to get through, because it makes such a porous boundary. What does it mean to be "dominated" by such? Does it have to be so nearly all mechanics that it's rare to ever see anything else? That would seem to "hardly count as a 'game'" by your own standard. Is it enough to be merely 50%+1? That would seem completely out of wack with how people talk about their expectations for such gaming. But leaving it open to individual interpretation just lands us right back in the same old problem of "so now any game is 'simulationistic' if the GM simply fiat declares enough of the mechanics to be so."
Agreed.
@clearstream 's approach is better in my opinion ref seperate reply chain with them.