A Rule Is An Answer

As is eternal, there is discussion about RPG design theories, what is a rule, what is the purpose of a rule, etc.  I offer a definition that may be of some use, by looking at what might be the most fundamental way to define it (or, at least, the most fundamental way I can think of).

I don't think it's useful to try to say that all rules have the same purpose.  Obviously different rules, in different games, are designed for different things and for different reasons.  To actually get something universal, I think we need to go deeper, to a definition so obvious that it's almost useless on its own (but we can still use it in context to analyze things, and get use out of it when combining it that way).

So.  A game is made of rules.  Some of these rules are obviously game-rule types; a pawn can only move one space forward, while a rook can move any number of spaces in a straight line.  Other rules are less apparently part of the game, but are part of the game nonetheless; a Dungeon Master builds encounters following guidelines.  A player builds their player character and chooses their actions.  These are rules of a game as much as a rule about movement.

Combined, all the rules form the system or the game.  We're not debating whether or not the text on its own counts as a "game", we don't need that level of pedantry here right now.  Now that the game exists, the next question becomes; how does one play it?

Regardless of what the game is or what its rules are, you play the game by asking it questions, by interrogating it; what can I do, what can you do, what does this do, what's over there.  In TTRPGs, the process is the same whether you're trying to resolve a mechanical loop or if you're trying to explore the imagined world the game takes place in.  The way that those questions are resolved is by consulting the rules of the game.  A rule is an answer.

The most fundamental question to ask is "What happens next?"  and every game will be able to answer this.  Whether the answer is move to the next phase, roll some dice, ask someone at the table, end the game, or do something else, the game will provide an answer when you ask it what happens next.  As players (including GMs), your actions set up the context for the next question that the game is asked, and the rules provide the answer.

For example, a player says "I attack the guard".  This implies a question; what happens when you attack the guard?  The rules will answer that for you.  In another game, the player moves their pawn into a square containing an opposing piece; what happens next?  The rules answer.  Most TTRPGs have examples demonstrating that this is their core gameplay loop; the player declares an action, the GM consults the rules, and the GM says what happens next.  The rules are how the GM determines what happens next; they provide the answer to the player's implied (or explicit) question.

This is equally true for questions about the fictional world the game takes place in, such as "what's over that hill" or "what's in the chest".  The game will provide rules to determine that.  Depending on the game and what it cares about, these may be distinct rules, or they may be guidelines.  The way most RPGs are written, there's no real distinction between GM rules and GM guidelines, for the purpose of this discussion they're both rules.  The rule might be "the GM decides", "the GM rolls on a table", "the group determines by consensus", or anything else.  The point is that the rule is the answer.

Depending on what the rules care about, the answer might vary.  Some possible answers might be "You can't do that" (no, your bishop can't cast Meteor Swarm), "I don't care.  Three." (for things that the game doesn't really care about, it just gives you a quick answer and you move on), or "That's a great question!  Here's ten pages of charts to figure out the answer." (for things that the game wants to spend time understanding and resolving).  In some ways, this might cause the rules to abstract a complicated task.  Sometimes it might add complexity to something that seems like a simple task.  Sometimes the rules will restrict you with their answer, and sometimes they will empower you.  Most TTRPGs that lack a specific answer do have a general rule covering that situation, "Ask the GM/group", while most board games default to an answer of "You can't do that" if it's not covered by a rule.  (No, the Air Bud clause does not work in Monopoly.)  (The two types of games are more alike than most people think.  This general rule is the biggest difference between them.  The reason you can do anything in TTRPGs, and not in Monopoly, is because TTRPGs have a general rule that says if there's no rule that covers the situation, there's a person at the table empowered by the game rules to add a rule.  If Monopoly had Rule 0 for the banker, you could reinvent financial derivatives and sub-prime loans just like real banks!)

The only thing that every rule will always do is to answer you, when you ask the game a question.  To make this interpretation useful, we need to think about questions.  What we can do to use this is to think about what questions people will be asking our games, and what answer will we give?  How long will the answer take to understand and implement?  Do we really care about this question; is it really that important to have a good answer to it, or do we want to just pick something and move on?

(Generally, the less the game cares about a question, the more abstract and quick-to-resolve the answer will be.  If your game doesn't really care about traveling the wilderness, fine, make a single check for your journey.  If your game thinks this is an important and valuable question, provide a whole system for the experience.)

Appendix:  Semi-Related Rambling

Rulings over rules is a popular phrase these days (not quite as popular as it used to be, which is good).  It fits into this paradigm without any issues; it just means that it is not providing answers for many things, and answering those questions follows the default rule of ask the GM.  This is also totally consistent with the feedback that GMs of this game often give, which is that they feel like the game isn't helping them answer the questions that come up in play.  A rules-light game can avoid this problem by focusing the questions being asked.  If you only expect players to ask one or two questions in gameplay, then you only need one or two answers.  If you bill your game as an anything game that can do anything, you're going to need either some very broad answers or a whole lot of answers.  

This is where the importance of a game setting expectations comes in; these expectations can be set with prose, art, layout, and many more parts of a game.  If your game as a whole can get players to understand which questions to ask, and provide answers (in the form of rules) to those expected questions, it will generally be a smooth and understandable experience.  Conversely, if your game prompts players to ask questions that it doesn't provide answers for (again, in the form of rules), it will tend to be a frustrating experience that feels like it requires a lot of patching.