D&D’s relatively dense combat rules have a simple explanation: A good TTRPG rule prevents and/or resolves arguments.
A bunch of stuff falls out of that supposition. It starts with the idea that people playing a TTRPG are going to argue about things. In board games, arguments usually arise because of poor implementation in design.
A boardgame might fail to account for a specific case in the game. An interaction between two cards isn’t clear. The rulebook is difficulty to follow, causing everyone who reads it to come away with a different take on how things work.
TTRPGs, because of their broad scope, tend to generate arguments that start inside the fictional reality of the world and then leak over into the rules. Even a game with perfect design is going to have disagreements. Why is that?
When you play a TTRPG, you attempt the messy process of merging the imaginations of multiple people into a single, shared narrative. If you have ever collaborated on anything creative, you have learned this lesson: The hardest part of group work is getting everyone’s individual pieces to talk to each other.
Each of us is our own, internal universe. Our thoughts, ideas, and experiences burble together to create a unique view on reality. When we create anything - code, game rules, story ideas - they are inevitably colored by our unique traits.
Bringing those pieces into a cohesive whole is difficult. In every product I’ve worked on, the toughest work involves cleaning up the seam lines between one person’s work and another’s. It’s messy, time consuming, and always rife with errors.
A TTRPG is a tool that melds our shared imaginations into one, cohesive story in real time. That’s a difficult task!
Consider the following question that might come up in play: “Can the orc with a light crossbow hit the paladin from the opposite side of the gorge?”
At a table with four players and a DM, one player might think the distance is too great for the crossbow to reach. Another might consider that the light rain makes the shot almost impossible. A third might think of the muddy trail the paladin walks on and conclude that dodging is so difficult that the orc has a better than average chance of hitting.
As a general thing, there are three ways we could answer that question:
The DM decides. The DM answers the question based on their understanding of how crossbows work, the distance involved, and their knowledge of archaic weapons. This approach puts a lot of pressure on the DM to accumulate a wide range of knowledge and apply it in an even-handed manner. It assumes that the DM has a better understanding of how crossbows work than the players.
The player decides. As above, but with the added layer that they probably have a clear interest in the final answer being no. Maybe we ask the players to vote, but that leads to frequent breaks in the game as we pause to organize voting.
The rules and dice decide. The rules give a crossbow a maximum range. They confer an advantage or disadvantage based on the environment. The paladin’s armor and skill determine if they are an easy target. The orc’s training gives a base accuracy. The dice step in and provide the final answer.
Most players and DMs prefer option 3. I think they’d see it as the fairest approach. Presumably, the designers of the game account for how crossbows work, how skilled the orc is with ranged attacks, and so on.
The rules, having been printed in a book, are there for everyone to reference. The players can make informed decisions if they take the time to read them (let’s pause to let every DM out there chuckle at that thought…), while they give DMs a starting point to make rulings when a weird, unexpected case inevitably shows up.
Combat is filled with this potential pitfall. Given that it can determine life or death for a character, or have a profound effect on how a game proceeds, a battle is likely to generate many, many arguments as the group mashes their individual, creative faculties together into a shared experience.
The rulebook and dice step in as neutral arbiters, allowing the DM to play an adversarial role to make fights more fun and challenging. The rules apply to players and NPCs, and everyone at the table uses them as a shared, cognitive space to resolve actions that otherwise might boil down to arguments and hurt feelings.
So that brings us to social interaction.
As a basic premise of the trad TTRPG form, players are given tremendous latitude to manage their character’s internal experience and decide how that translates into play. You might argue over what a player decides (“Are you sure that picking her pocket is a good idea? We need her help!”) but that’s an argument made to sway the player, or is made between characters within the game’s fiction. The rules don’t step in to tell you how to play your character. Arguing mechanics would be nonsensical in that situation. There are no rules for determining how your character feels or deciding what you want to do, because the rules leave that up to you.
The DM, being another player, enjoys that same latitude when it comes to running NPCs. However, the game has to account for characters with a high Charisma, or training in skills like Persuasion. The rules typically give DMs advice on how to alter an NPC’s attitude based on the result of a skill check. Those rules apply only to NPCs, and the DM is free to modulate the outcome based on the NPC’s personality, relationships, and other factors.
The argument space is much more limited. Look back at the three options above for resolving an attack: DM decides, player decides, rules decide.
In a social interaction, the DM is the source of truth for what an NPC thinks, how they feel, and how they decide to act. Part of the fun of being the DM is getting the chance to play multiple characters. Among those three options, letting the DM decide makes sense. The DM is exercising the same power as a player who decides how their character acts.
In D&D-like games, we tend to see rules that allow characters to influence but not dictate NPC actions. Even highly mechanized games need to allow this latitude. We know what happens to every NPC or monsters when their hit points reach 0. But if you succeed on a Charisma check the outcome is entirely dependent on what the DM thinks an NPC will do given that a player has impressed or swayed them.
Thus, D&D-likes have complex rules for combat because that is an area of the game where the shared understanding of the world benefits from neutral, random resolution. Social interaction, being driven by each participant’s creativity, can and should lean on DM adjudication.
I have never understood why D&D, and games like it, are described as a "three-legged stool" of combat, exploration, and social interaction, yet just about every game will give you 20 pages of combat rules, 2 pages of exploration rules, and a one-size-fits-all 2d6 reaction table.
The problem I have with all of this comes down to this quote by you: "The DM, being another player..." I don't want to be another player. I want to be a neutral arbiter of how the world responds to player actions.
I feel like saying social interaction should lean on DM adjudication overly burdens the person at the table who is already the most burdened by the mechanics of the game.
This article gave me a new angle in which to see game mechanics. Up to now, I have never thought of mechanics in game design in this very common sense practical way i.e. that of a system that prevents arguments among players. I just saw game mechanics as simple, automatic ways to resolve uncertainty in acts or events in a fantasy world. However, from game design perspective, especially with a emphasis on people having fun with a system...it makes sense that game mechanics would evolve in this way. People want people to play their games, so they want them to have fun, and therefore build systems to prevent conflicts among players, not just to account for "what happens".