Relatively Uncertain: Taking Control of Game Physics
Every campaign needs a game physics, whether the GM knows it or not. And, in fact, they all have one, whether it’s specified or not, and whether the GM knows that or not, as well.
Boy, that was a short article! Now that we’ve established both need and solution, can we move on to another topic, because this one sounds both geeky and boring? Well no – not so fast, fly-boy.
Why? What’s a “Game Physics” for, anyway?
The Game Physics is what the GM uses to decide anything that’s not explicitly stated in the rule books. It’s also what the GM uses to comprehend and interpret those things that are explicitly stated in the rule books, and the standard of comparison for cases where one of the rules doesn’t work – either producing nonsensical results or being in aparrant contradiction with another rule. It’s the GM’s understanding of how the game world actually works.
The Usual Game Physics
Most GMs don’t explicitly spell out a Game Physics, don’t analyse things to that level of detail, either for themselves or for their players. They make rulings based on one all the time, mind you, but never put together a comprehensive picture of the inner workings of the universe, relying on “the usual game physics” – which is to say, they rely on their understanding of how the real world works, and rule that the book’s description of the various unusual phenomena possible within the game system constitutes the equivalent of the laws of physics for those particular subjects. And, most times, that’s all the players want or need.
From time to time, the GM will make a game ruling (which should get added to the House Rules of the campaign to maintain consistancy). Each such ruling should either be explained by the existing Game Physics or should expand apon it.
For example, it’s very easy to take player knowledge of physics and apply it to the game world. Lever action, harmonic oscillations, centrifigal force, gunpowder and plastic explosives, plastics, rifled gun barrels, electronics, microchips, pocket calculators, etc. The GM is perfectly entitled to rule that any or all of these don’t work in a fantasy campaign in order to preserve the level of technology within the game at an appropriate level. Every time he does so, he is changing the physics of the world in ways he probably doesn’t understand.
So why go beyond that?
An excellent question. There are multiple benefits to a more explicit approach to defining a game physics.
First, it puts players and GM on common ground. They will know right off the bat that certain things won’t work, so don’t bother trying them – which in turn helps them stay in character by only doing things the character expects to work.
Second, if the GM extends his understanding of the game physics beyond that of the characters, he can maintain consistancy of rulings and technology even if the game develops into untapped areas of high-technology. This is obviously valuable in certain genres – SciFi and Superhero being the obvious ones. It means that the players and NPCs are playing by the same ground rules, whether they know it or not – if a PC attempts an experiment which reveals a physical principle that they didn’t know, they will get an unexpected result and an explanation for certain things that may have happened in the campaign’s past. They can even extend the game physics beyond it’s starting point if they are so inclined. Instead of technobabble, we have technology – with limits and failure modes and creative applications.
I would contend that the same is true in any campaign – only the specific subjects change. In a horror campaign, the better the GM understands the “mechanics” of summonings and metaphysical manifestations, the better he can run such games. In a fantasy campaign, the more he knows about how magic actually “works” in the game world, the more he can push beyond the rules as and when necessary – something I touched on in a previous post (A Quality Of Spirit: Big Questions In RPGs).
Third, it makes the job of being a GM easier, and quicker. Instead of having to mull deeply over questions and their implications when they arise, an understanding of the game physics often lets the GM make an immediate ruling without batting an eyelid and get on with the game.
And finally, it adds extraordinary depth and verisimilitude to the campaign. Instead of a shared fictional world, it starts to feel like a real world that the characters happen to live in. This last has been known for as long as there has been science fiction – you have to establish the ground rules before readers can really get into the story. Read any SF novel, and you’ll find that a key element of the first quarter or so of the book is an establishment of the scientific principles that matter to the story. Read a short story, and you’ll generally find it in the first couple of paragraphs, certainly within the first two pages. A side benefit of doing so is that even when contradicted by later scientific discoveries, a story can remain timeless if the story is good enough – examples include the Lensman series (E. E. ‘Doc’ Smith), the Skylark Of Space series (‘Doc’ Smith again), the Incompleat Enchanter series (L. Sprague DeCamp and Fletcher Pratt), the Black Cloud (Fred Hoyle), The Known Space series (Larry Niven), and the list just goes on and on and on from there. Contrast this with any of the… poorer SF of the past century, and you’ll find that either this material is absent, or it’s so abstruse that most readers can’t follow it (or get bored trying).
In a nutshell, it takes the flash-bang-wizardry out of the picture and lets a story be judged on its merits as a story. Applying the principles to an RPG brings the same benefits to the game.
The Downsides
It can be a lot of work doing a comprehensive game physics (it can also be a lot of fun). But the real downside is that it can be harder to impart a sense of wonder.
I would contend that modern audiances/players already find that harder to tap into, another subject that I’ve written about in the past (Are Special Effects Killing Hollywood?).
So it can be argued that adding additional impediments is the last thing that you should be doing. It can also be argued that part of the GM’s job is fitting the game to the expectations of the players, and that modern players mandate a modern approach – and GMs should be grateful that there are ANY side benefits in doing so. I’d love to hear other people’s thoughts on this subject!
The Conservation Of Counterintuition
Another common approach is to rule that if a phsyical law seems counterintuitive, or just too difficult for the GM to understand, or requires higher mathematics, it just doesn’t work. That means that most GMs draw the line at Relativity – anything more complicated (including relativity itself) is out, anything less complicated is in. This is true even in modern and sci-fi campaigns. Any technology appropriate to the game era that relies on those physical priciples still works, but the physics are different because the complicated stuff just isn’t there.
Of course, different people will have different levels of understanding of physics; what seems obvious to me may not be obvious to them, and vice-versa. But as a rule of thumb, this one principle is enough definition of a simple game physics to make it useful.
The Metaphilosophical Properties of Genius
When I first started GMing, this was the game physics that I came up with, and it’s still perfectly servicable. It derives from the fact that physics and chemistry and science in general used to be known as “Natural Philosophy”. The concept is that the state of knowledge contemporary to any time period is a complete and accurate description of the way the physics of the time period actually works, but that occasionally individuals come along of sufficient intellect to (literally!) reshape the world with a deeper understanding. Thus, heavy objects fell faster than light ones until Gallileo performed his famous experiment to prove that they fell at the same speed.
I even evolved a house rule: 5 points of intelligence above whatever constituted “genius” permitted one breakthrough with sufficient effort. On that basis, Sir Isaac Newton gets an INT on the D&D scale of about 60, Nicola Tesla gets a score of about 45, and Gallileo rates a 40. If you had a little less than this, and spent twice as long on it, your theory might also be correct – but would take decades or even centuries to become accepted.
Evolving a unique game physics for your campaign
Okay, so (assuming that I’ve convinced you that having one is worthwhile), just how do you go about constructing a game physics for your campaign?
Well, you start with one of the three foundations described above.
You then go through the rulebooks of the game you are running and add explanations (in terms of physics) for anything they permit that the foundation physics doesn’t cover. It might be “magic works”. It might be “the gods are real.” It might be that “morality has measurable physical effects” (lawfully-aligned weapons doing extra damage to chaotically-aligned targets and so on). It might be “FTL is possible”, or “superpowers exist”, or “time travel is possible”.
Each time you add such an item to your game physics, re-examine the central concepts of rules and genre and cross off anything that is now explained. For example, one theory as to the nature of divinity might also cover the “morality” question above, while another did not.
These explanations can be as extensive or simple as you like – a single sentence, or multiple pages.
At every stage, you have the option of deciding that this part of the game rules simply doesn’t work in this particular game – decisions that can have significant repercussions; see, for example, Garry Stahl’s article on removing alignment from his campaign. D&D without magic, or without gods, would be no less significantly altered.
You can also explicitly remove selected parts of a subject, or give them additional explanation that radically reinterprets them. D&D without Necromancy is an example of the first; the treatment of Illusions in my Shards Of Divinity campaign is an example of the latter, one which I’ll blog about some other time.
Once the rules and genre conventions are fully dealt with by the game physics, the next step is to think about anything else that makes this particular game, and game world, unique, and make sure that they are also covered by the game physics. An example of this is the Cyphergate in Johnn’s Riddleport campaign-in-development.
The final step is to go over the compiled Game Physics and create any house rules that are needed to put a game mechanics interpretation on the principles you’ve devised.
How Much Should You Tell Your Players?
Your first house rule should usually be that there is a Game Physics and that it will be used as the basis of any rulings that you are called apon to make as GM. The Game physics determines what is possible and what is not.
My players have come to expect a fleshed-out game physics lurking in the background of my campaigns, so I don’t need to include this, but WOULD need to warn them if it was not the case.
After that come any house rules that result.
I DON’T necessarily tell the players what the game physics actually are – how many characters would actually know that? Instead, I let the players seek to deduce the physics from their interaction with the world. I might let the occasional principle dribble out in response to particular skill rolls if they are relevant, but that’s as far as it goes.
How Much Should your NPCs know?
Another trick that I’ve found useful is to rate each line in the game physics in terms of how abstruse the knowledge is on a scale of 1-4. This permits me to edit copies of the game physics into formats describing the knowledge level of commoners, educated laymen, well-educated nobility, experts/sages, and GM only. Anything beyond their level of understanding is replaced with a dumbed-down version or the simple statement “it works”.
Commoners in an uneducated society get nothing more than the foundation rule and “it works” for everything else. And – for authenticity – I’ll sometimes insert deliberate fallacies and misunderstandings and superstitions. Experts will get only one or at most two of the advanced principles, in all other respects they are at the level of educated laymen; Sages also only get one or two advanced principles, and are considered to be at the level of well-educated nobles otherwise.
I find it easiest to go from most educated to least educated – the GM knows it all, so he gets the actual game physics, everyone else will have less than that. When inserting falsehoods and fallacies, I will work back up the heirarchy, adding comments such as “The common supersitition is (blah blah blah)…”
The result is a “bible” for the roleplaying of different levels of education within society that ensures consistancy. After you’ve used them for a while, the consistancy of format that results from editing a copy of an existing document makes finding what you’re looking for second nature, and you will often not even need to refer to these “bibles”.
Going Further
Another key point that’s worth remembering is that the game physics can always be revised or extended. It represents the combined level of understanding of a collection of contemporary experts, and is not necessarily gospel – and is certainly not the last word. Thus, if any problems arise within the game physics, those physics should evolve to encompass a solution and an explanation. This may move the game physics a little closer to the real world, or it may make it stranger.
It can be very useful to have some knowledge of how certain physical laws were proven, as these will inform you of how things will be different in your world. For example, you might decide that sound and light travel at the same speed – in that case, you would hear the thunder at the exact same time as you saw a flash of lightning, and would hear the axe chopping the tree in perfect time with the motion of the axe-head striking the wood. (I don’t know why you’ld bother with that one, personally, but it’s just an example).
Ramifications
The obvious ramifications have already been mentioned, in the earlier section detailing why a Game Physics is worth having. But there are also some more subtle consequences that are worth mentioning.
The first of these is that each game physics lends a subtly-different flavour to each different campaign. Even though they use the same core rules, my Shards Of Divinity campaign is distinct from my Fumanor Campaigns, which was different from my Rings Of Time campaign. While some of that derives from the characters and some from the differences in adventures, some of it is a spice from the game physics.
Secondly, there is a continuity of such flavours from one campaign in the same game world to another; it’s not just as shared history that connects the two Fumanor Campaigns that I currently run with the predecessor campaign, they feel like they’re taking place in the same world.
Thirdly, the game physics can form a common foundation amongst several GMs, permitting a shared world experience that I can’t believe would be possible any other way.
And finally, it makes it easier to keep one campaign distinct from another – an absolute necessity when you run as many of them as I do!
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February 4th, 2010 at 12:02 pm
Another good article. Did you invent the term “Game Physics?” I feel like I’ve heard it somewhere before. Either way it is the perfect term for this concept.
“But the real downside is that it can be harder to impart a sense of wonder.”
In my experience, AD&D is the worst offender. I’ve heard many geeks debate “how magic works” in the context of AD&D (and later, 3e and 4e). To me, this sucks some of the fun out of a fantasy setting; if you know how magic works, it’s no longer magic! Of course, the fun of exploding people with fireballs remains, and may even be more fun, because a deeper understanding of Game Physics allows better explosions (the classic example: trap your enemies in the web spell, and then ignite the web with the fireball).
For a traditional science fiction genre, this is particularly appropriate, since the fun comes from exploring the ramifications of the premise, and that means the premise needs to be reasonably well defined. But for a more magical, fantastic setting, where I want that sense of wonder, I prefer NOT to have well-defined physics. A great science-fiction example is the X-Files. That series had a “freaky weird thing of the week” episode structure, and what made each episode so freaky and weird is there was no consistent, underlying Physics to it (at least, from the audience’s perspective). Things made just enough sense for the audience to understand what was going on, but not why. The feeling of mystery this creates would be really good for a fantastic, mythological, or fairy-tale RPG setting.
February 4th, 2010 at 12:03 pm
I am going to have to start doing this.
So far, I have just gone by what the book says and if anyone wants to bring in any science that requires more advanced technology and materials than existed during the middle ages then it just can’t be done (at least in the real world physics way).
The biggest and most successful “Game Physics” I have consistantly used (in the 2 campaigns and MANY 1-off dungeon crawls I have done) is the banning of anything related to chemistry and atomics. The following are things I have actually had to say/rule before based on the above ban:
“Oh, so you want to mix some carbon into that iron? Well what is carbon exactly? Oh yeah, it is an element, on the table and everything… Hmm, you seem to be forgetting that this world has only 4 elements, those being Earth, Fire, Water, and Wind. If you want to take some points in Knowledge(Alchemy), maybe I will let you try to discover a way to strengthen your sword. Or you can just go buy an Adamantine one and call it good.”
“So you want to use that pile of items to make a battery? Sorry, what makes you think that a world using the 4 mystical elements also has electrons? Yes, electricity does exist, but it is magical. If you want to take some points in Knowledge(Arcana) you can attempt to research a magical energy storage device.”
So yeah, steam power is about as high-tech as I let my fantasy games get, not counting magical tech of course. Players trying to bring real world physics into D&D usually just breaks the game, and at least with my system I can give them “logical” reasons for not being able to do that, other than just saying “In the real world it took decades for that theory to be worked out, by some of the most intelligent people to ever live at that. What makes you think your Int 8 fighter can invent it in 6 seconds?”
February 4th, 2010 at 12:42 pm
@Will: Thanks for the positive comments. No, I didn’t invent the term “Game Physics”, it was in use when I started playing back in the early 80s. I’ve continued to use it since it is, as you point out, the perfect term for the concept.
The advantage to developing your own game physics for D&D is of course that the PCs don’t KNOW the physics, just the practical “engineering”, ie casting of spells. By making the game physics more advanced knowledge than the cutting edge of understanding within the game world, not even a high Knowledge skill can get them the answers. To uncover the true principles, players first have to ask the right questions, devise experiments to test their theoretical answers, and then interpret the evidence correctly.
For example, what if all magic worked only because the power of spellcraft used the dreams of someone who was sleeping, somewhere in the world, to simulate the effects of the spell – then simply translated those effects back from the dream-world into the real world? If you knew that then you could use scrying techniques to track a given mage’s spells to the dreamer responsible, and then use mind-altering spells of your own to alter the way their spells behaved without their knowing why it was happening! Or a large-scale effect that prevented people from dreaming could mean that magic stopped working, or became completely unreliable. Or perhaps “other things” (nightmares) could find a way to “ride” the connection from the dreamer back into the real world – so that every spell you cast had a chance of summoning some horrific (and hostile) creature.
So long as the PCs don’t know why it’s happening, D&D becomes no worse an offender than any other game.
@Robert: The real problem with carbon steel is the high temperatures required. A lot of people forget that for every pound of “steel” that was cast in the middle ages, it took an acre of wood converted into charcoal to perform that casting. (An acre is 0.40469 hectares or 4047 square meters, for anyone who needs to know – that’s about 63.5 meters square). How many men does it take to fell an acre of timber? Steel manufacture changed the english landscape!
You might find Ars Magica to be an interesting resource. The Game Physics that they include is based on the four elements and is more or less accurate to the ancient beliefs that predate modern chemistry. I’m told that this can really be difficult for modern players to get their heads around.
As for steam power, that really requires carbon steel for the boilers – cast iron is too brittle… but perhaps magic can come to the rescue.
“Give me full power on the engines, Scotty!”
“Ah’m Sorrrry, Captain, but the pentagrams they will’na take any more!”
February 4th, 2010 at 1:11 pm
@Mike: I didn’t know that it took so much wood to make steel, but now that I do it will add yet another hurdle for the PC’s. Another one I usually use is that in such a fantasy realm, with mystical elements and magic, why would chemical reactions be the same as the real world anyway? Even if they somehow found carbon and harvested enough wood, why would mixing carbon with iron produce steel as opposed to a huge explosion :P? I will also have to pick up Ars Magica now, at least I will have a consistent source as opposed to just me ruling on the spot.
The steam power problem I look at the same as with trying to make steel swords: Why bother when there are so many vastly superior fantasy materials to work with? Yeah you can’t make a steel sword, but you can pick up a mithral or adamantine or cold iron one and call it good. If you want something even better, then you either search for a legendary and rare superior material (Starmetal maybe?) or do some VERY high DC alchemy and/or arcana checks to create something superior via magic or alchemy.
Basically the point I try to make to my players is that the stuff in these various fantasy realms exists seperately from, not in addition to, real life materials.
February 4th, 2010 at 6:59 pm
Robert, that’s not the amount of timber needed for making steel, that’s the amount for cast iron – that’s an acre of timber for every set of horseshoes, or for about a square foot of ring mail. Steel requires even higher temperatures and about 10 times as much fuel, by weight!
England was once mostly forest, with isolated farmsteads. The countryside is now mostly fields. Ironworking caused the change.
I have to admit that I was surprised by the quantities as well, the first time I heard them.
February 4th, 2010 at 10:06 pm
I recently played a game set in Carolingian Europe as the Carolingians understood. Physics based of greek books most of the world had never read… what with being written in a language only a couple scholars in the Frankish court actually spoke. Demons were real, magic was powered through prayer.
Anyway, it was a lot of fun.
But most memorable was working through the physics… if Galileo was wrong, then the speed of a falling object increases with its mass. Thus, you can dive off a building to catch anything smaller than you are, and you will reliably fall faster than it.
My DM said it was the most sensible way to understand D&D Magic… just use Aristotelian Physics.
Richard.
February 5th, 2010 at 4:43 am
@ Richard – that’s pretty much the recipe of Ars Magica, I think.
February 4th, 2010 at 11:49 pm
Great article. As the sort of person who has a limited understanding of real physics beyond what I’ve actually experienced, that’s how I think players should understand it. I understand dynamic force and weight loads because I hoist things on rope. A person who works with fires knows how it behaves and so on. It’s so hard to keep player knowledge out of this, but they should discover how the physics work as it applies to their character’s knowledge.
I’m going to have to incorporate this into my games!
February 5th, 2010 at 4:59 am
@Spaceman: Thanks. Anytime someone admits to a ‘limited understanding of physics’, I immediatly recommend that they hunt up a copy of Isaac Asimov’s “Intelligent Man’s Guide To Science” or the revised version, “The New…” . It explains the scientific principles without the math, making it easily digestable by those who aren’t naturally inclined towards hard science. I use mine all the time to explain things to my less-science oriented players.
February 7th, 2010 at 4:01 am
I liked reading this. I will post this on digg. I am sure you will get some thumbs up :)
April 2nd, 2010 at 4:10 pm
[…] Dickenson: The Old English Peep Show. W. Somerset Maughm: Cakes and Ale or the Skeleton in the …Relatively Uncertain: Taking Control of Game Physics …Every campaign needs a game physics, whether the GM knows it or not. And, in fact, they all have […]
April 9th, 2010 at 8:26 am
Great Article! This is a pretty thorough look into the concept of game physics with some cool ideas. I’ve been keeping a tag on the “How” and “why” in my campaigns for quite a while, but I’ve not really thought it through in quite this level of detail.
I find that knowing how things work enables a kind of consistency that provides a good foundation for building a campaign world on. Of course, you don’t tell the players about it, but they learn the action and reaction of things and slowly gain enough knowledge to make educated guesses about how to take advantage of the physics.
There’s nothing more satisfying that having players devise ingenious proactive plans based on their fragmented understanding of the rules of the universe which enables them to overcome some dangerous opponent. Like you say, What if spells harness the power of sleeping people… once you work that out there are so many interesting applications you can use you confound and confuse your foe!
Really enjoyed this!
Cheers,
-Kaine-
.-= -Kaine-´s last blog ..Volatile Memory =-.
April 9th, 2010 at 8:49 am
Thanks -Kaine-. Your last paragraph descibes perfectly the reasons why I enjoy talking and thinking about game physics and metaphysics – because in order for the players to reach the point you describe, they have to have confidence in the consistancy of the game physics and certitude in their understanding of it. It’s a huge compliment to a GM when that happens – hence the satisfaction.
November 13th, 2013 at 11:04 am
[…] Relatively Uncertain: Taking Control of Game Physics – I take a close look at game physics – why you need one, the assumptions that underpin them, downsides, and how to create a manageable one. […]
June 17th, 2014 at 12:36 am
[…] Relatively Uncertain: Taking Control of Game Physics […]