If you toil in the mines of TTRPG design for long enough, you are likely to come across terms like gamist, narrativist and simulationist. This GNS theory has been mostly abandoned these days, but it (or similar thoughts) pop up often enough. For instance, Shannon Appelcline, author of the four-volume TTRPG history, Designers & Dragons, recently wrote an article in which they claim that the GNS theory is reflected by the dominant play cultures:

“It's also interesting to look at this all from the lens of Ron Edwards' GNS Theory in ‘System Does Matter’ (1999), which suggested that gamers were either gamists (who enjoy challenges), simulationists (who enjoy the creation of secondary worlds), or narrativists (who enjoy stories).

Today, as it happens, we also have three major categories of RPGs: OSR, mainstream, and indie. It's perhaps not a coincidence that there's a rough correspondence between the three gaming categories and Edwards' three categories of games. OSR games are largely gamist and indie games are largely narrativist. The mainstream games are the rougher correlation, but they do tend toward simulationist on average.” - Shannon Appelcline

For the record, I don’t agree with this analysis. A more nuanced evaluation of these dominant gaming cultures is presented by John of the The Retired Adventurer blog in his oft-cited Six Cultures of Play post. In this more historical approach to evaluating play cultures, the three cultures Appelcline identifies are really each a reaction to the “Trad” style of play (OSR and Story Games were each reactions against Trad’s then-dominance, while Neo-Trad/OC was an evolution of Trad). But I digress. My point is that OSR and Post-OSR players can be and often are just as interested (or disinterested) or simulationsism, or as it is more commonly known, realism, as gamers of any other play culture.

But what do we mean when a game is realistic? It means the game accurately reflects reality (a loaded term that you shouldn’t expect to get unpacked in a blog that’s mostly about science fantasy elf-games). A more technically correct term would be verisimilitude, because the fiction of games can only ever seem real, not be real. But can depicting an elf throwing a magic fireball at a dragon seem meaningfully realistic or unrealistic when elves, magic balls of fire and dragons do not exist in reality (not yet)? Why does reality seem realistic? Does reality even seem realistic? I would argue that in both reality but especially in games, “realism” can be seen as logical consequences applied consistently.

Realism in games is reinforced when the fictional consequences flow logically from the fictional actions. By “logically,” I mean simply that there is a reason for the consequence. These reasons may come by referencing how similar actions function in our reality, in the genre and stories the fiction is inspired by, or by analogy to prior events in the fiction. For instance, if the fireball hurts most creatures but doesn’t affect the dragon, this could be a logical consequence by reason that the dragon is immune to fire. None of this reflects anything in reality, but it can be considered realistic in the game because the fictional (non-real) consequence of the fireball follows logically from the fictional (non-real) reason of the dragon’s fire immunity. It’s similar to our actions in real life obeying the predictable laws of physics. When I jump, the earth’s gravity will eventually pull me back down. Knowing the rules, be they a system or physics, provide some information of likely consequences of certain actions that helps people make decisions about their actions. To some, when they demand realism in their games, what they want is complexity—more detail, more fiddly rules, more calculations, more math. But this misses the point and tends to produce games that are less realistic, not more. For instance, when gravity acts to pull me down, I am sure there are a number of calculations involved in calculating the force it exerts, how quickly I fall, the impact of my fall, et cetera ad infinitum. But when I jump and land back on the ground, I am not making those calculations nor am I thinking about them. So a game that inserts that level of crunch (in the derogatory sense) doesn’t produce an experience any more “realistic” than a game that doesn’t mention gravity at all, except to say that falling creatures take X amount of damage upon landing.

Realism in games promotes player agency. In the aforementioned Six Culture of Play post, John describes the emphasis OSR play cultures place on player agency, saying “The OSR draws on the challenge-based gameplay from the proto-culture of D&D and combines it with an interest in PC agency, particularly in the form of decision-making. The goal is a game where PC decision-making, especially diegetic decision-making, is the driver of play.” In an exchange between two luminaries of the OSR, Chris McDowall of the Electric Basionland and Ben Milton of Questing Beast, on McDowall’s aptly named podcast, the Bastionland Podcast, points out how providing logical consequences promotes both verisimilitude and player agency. In this exchange, which I have edited for clarity, McDowall and Milton, who were both trained as school teachers, discuss the similarities between pedagogical practices and running OSR-style games (italics added to emphasis my own points):

Ben Milton: As I got better at teaching over time and I was reading all these OSR principles, they just kept seeming exactly the same. Like one thing we kept being taught at school, from all these coaches, is teaching logical consequences. If the consequences for poor behavior by a student are arbitrary, not consistently enforced or don’t match what they did wrong, then it’s much harder to enforce discipline. And it’s just the same thing in games. If a player does something bizarre and off the wall, just apply logical consequences. What reasonably happens from that? And you just keep moving, and hopefully they learn and maybe they don’t, but the world is responding realistically to their actions, and it’s much easier to learn in an environment like that.

Chris McDowall: Yeah, one of the principles in Electric Bastionland is the idea of information, choice and impact. And as you were saying, it’s weird how much that lines up with teaching. We can’t talk about teaching for the full length of this thing, but this will be the last one I promise—if you have people who are misbehaving, you have to tell them what will happen. You say, “If you carry on setting that fire in the corner of the classroom, then you’re going to have to be taken out of school,” so you give them the information, give them the choice and make sure the impact is relevant to that choice. And it’s exactly the same in roleplaying games. If they don’t have the information, and if the impact of their choice is random, it’s really hard to feel like it’s a fair system.

Systems and rules play a role in promoting realism, but it largely falls upon the rulings at the table. Systems often try to cover common situations and suggest consequences for certain actions. For instance, a system might prescribe how much damage a character takes when falling from a certain height. However, systems cannot cover what consequences should logically follow every conceivable action the player characters might take. Every system is necessarily, as Arnold Kemp defines in that famous Goblin Punch post, "Rulings Not Rules" is Insufficient, an incomplete system. As such, systems rely on rulings to fill the gaps between the rules. But not all rulings promote realism. Rulings that are arbitrary, inconsistent with prior rulings, or do not logically flow from the fiction violate the sense of “realism” within the game. As Arnold describes it, the worst type of rulings are those that go against common sense, which can be understood as a failure of logical consequences within the fiction of the world (emphasis added):

“Bad rulings are ones that are slow or confusing. But the worse rulings are the ones that are ultimately unsatisfying, in the sense that they don't give results (or chances of results) that mesh with the player's expectations of how the world works. If you make some rulings, and the consequence is that halflings are more intimidating than orcs, that's (probably) a bad ruling. If you make some rulings, and the consequence is that even the most untrained peasant has a 90% chance to track anything, that's a bad ruling. Just as players use common sense to come up with stuff that requires a ruling, use common sense to make rulings (as opposed to precedent or some other analogous rule you saw somewhere else).” - Arnold Kemp, Goblin Punch

A game’s realism is greatly improved by developing a “common law” of rulings. Common law is a type of law that arises not out of royal edicts or legislative drafting but from prior rulings on particular cases. These are rulings, not rules. The idea is that judges (but we might call them referees instead) make rulings based on each situation as it presents itself but will consider past rulings in coming to their decision. A referee can also draw principles from prior rulings and apply them to new situations. For instance, if the referee rules that magic fire doesn’t burn or even singe the clothes worn by a target, there is an embedded principle that elements summoned by magic behave differently that elements in nature. So the next time the wizard casts a lightning bolt spell into a lake, the referee might apply that same principle and say that the lightning does not electrocute everything in the water because magic lightning doesn’t behave like non-magical lightning. Even more important than the consistent application of principles is the expectation that the referee will rule the same way each time the same situation presents itself. For example, if the referee says a fireball spell cannot burn books during one session, they should not allow the fireball spell to burn books a few sessions later. (In the common law, this expectation is known as stare decisis, which is certainly a verbal component to some spell.)

A referee who develops a common law of rulings and guiding principles makes it easier for their players to predict how the world is likely to react to their actions. Players who are armed with an understanding of how the world is likely to react to their actions are equipped with better information to make meaningful choices between potential courses of action. Whether you call this logical consequences, the ICI principle, common sense or “realism,” the bottom line is that a referee that applies logical consequences in their games will produce a game with more player agency and present a world with greater verisimilitude in the minds of the players.