This is my first post here.  I'm probably posting this in the wrong place, in the wrong way, and at the wrong time.  I apologize in advance for any and all mistakes I make, now and going forward...

That said, I have been role playing for many years (either 25 years, or 'since Christ was a Corporal').  I have played so many games I can't even begin to list them, but let's stipulate to all the big titles, and quite a few of the smaller indie type titles as well.  In that time, I have developed a lot of ideas, theories, and feelings about this hobby.  The idea that I'd like to post about here and now is: There are two, and only two, meathods of preparing and refereeing any role playing game; namely the 'common law' method and the 'civil law' method.  As background for those who may not be aware, 'civil law' referes to the systems of written, legislativly enacted ordences based on Roman law.  The primary example is the Napolionic Code.  'Common law' refers to the system of non- or semi-legislatively enacted laws based on precendent and inference.

The 'civil law' method is the first method that many novice referees try to use.  In summary, this method is the referee equivalent of player 'rules lawyering'.  The 'civil law' referee uses the game text as the ultimate authority on referee judgement, and does not create new solutions to problems that arise during play.  A typical 'civil law' referee will make rulings and judgements based on the core text of the game rules according to the strict construction of those rules.  The 'civil law' referee is prone to ending arguments with a statement of 'because that's what the rules say', and not be flexible in response to player concerns or requests.
The ‘common law’ method is the method that some referees mature to in the fullness of their careers.  In summary, this method allows the referee to adjudicate novel problems that develop during play using resources outside of the approved game text, including his own judgement.  The referee using the ‘common law’ method is also more flexible when dealing with player concerns or requests.  The ‘common law’ referee is prone to providing rationales for his decisions (particularly when ruling from sources outside of the game text) rather than brute force rule arguments.  While the ‘civil law’ referee remains firmly within the rules of the chosen product, the ‘common law’ referee often uses rules and ideas presented in other game products to inform his rulings. 
This is obviously not a fully formed theory, more like the genisis or germ of a theory.  I’d like to hear other thoughts on this idea, before I commet to writing something more formally structured.

I have two comments.

First, how does this matter to RPGs? Is the punch line that inflexible, authoritarian GMs are worse than flexible, consensus-loving and reasonable GMs? Seems fair enough, although it doesn't apply to games like Paranoia, does it. But you supply much more theory than you need to support your argument. Formalistic rulings unrelated to the particular circumstances of the case are bad both in Common Law and Civil Law. And the Common Law (which you seem to consider superior) would frown upon supplying more theory than needed to arrive at a judgment. "The life of the [common] law has not been logic; it has been experience." (O.W. Holmes)

Second point: I don't think your characterization of either the common law or the civil law is sound. (Frankly, it sounds like a half-digested summary from an introductory course in a U.S. law school, complete with the "common law is superior" implication.) There is a strong argument to be made that civil law systems are less formalistic and more flexible. The common law derives from Roman law, too, but from the forms (rather than the substance) of Roman law, and it has a strong tradition of rigidity. So much so that rulings in the common law tend to resort to fictions to achieve reasonable results rather than to abandon rules whose application is hard to reconcile with reasonable results. "Strict construction" is common law idea and not a civil law idea---civil lawyers tend to regard such a thing as both unattainable and undesirable. Long story short: differences between common and civil law are much more subtle than one would think and broad statements about either are difficult. Another example: the Napoleonic you cite as representative of civil law is based as much on "Germanic" law (in the form of the côtumes practiced in northern France up through the 18th century) as on Roman law. Modern German law, the other main strain of civil law, is clearly based on Roman law, but is much more flexible and prone to go out side the "game text" than most common law jurisdiction.

I probably shouldn't have gone on like that. Sorry.  And I don't propose to continue discussing comparative law.

I do agree that flexibility and a broader, unorthodox approach in game-mastering is usually preferable. Many great ideas floating around and if they fit, use them.

Actually, what I'm trying to get at is the ability of the 'Common Law' referee to use sources outside of the actual product game text they have adopted for thier game.

Example:  The group is playing Game X, a fantasy role playing game.  A question comes up because Alice wants her character to make a blood sacrifice to release the mouldering hordes of Foo.  The referee, Bob, doesn't know of any rule in Game X covering blood sacrifices or the hordes of Foo.

Now, were Bob a 'civil law' referee, he might make the ruling that Alice's character can't perform the sacrifice, or release the hordes, because no rule exists in the game rules that they are playing by.  This is not an unreasonable or wrong ruling, it is one based on the idea that the group consented to play by a certain set of rules, and that's it.

Were Bob a 'common law' referee, he might make the ruling that Alice's character can perform the sacrifice and release the hordes, because there is a rule in Game Z that allows for such, and even though they aren't playing Game Z right now, he would agree to using the mechanic to cover this situation.  This ruling, in effect, expands the current Game X text that the group is using to include the new rule, at least for this one event, and possibly as a house rule for the future.  This isn't really a right or wrong ruling either, it's just one that allows more flexibility by allowing rules that exist in other systems to be brought into effect in the group after play has already begun. 

Hi Jim,

Welcome to the Forge! Is there an instance of real-life play you can describe that relates to this issue? I think that might help me understand the relevance of what you're describing. At the moment, it sounds like "Sometimes, some people only use the rules in one text, and sometimes, some people use rules from multiple texts"

Can you describe a situation where you've used rules from another text to inform play? What was the effect? When would you do this again? When would it be a bad idea?

The lauding of the 'common law' approach leads to 'Herbie-ism' from the system does matter essay, and people giddily declaring how they didn't roll a single die all session.

I think your support of 'common law' comes from an entirely flawed assumption that it's better - it's 'better' only in as much as if your legs have been blown off, dragging yourself across the ground with your arms is 'better' than just lying there, I'd agree.

By legs blown off, I mean that if the written procedure for gameplay is incomplete, then it's had it's legs blown off. Incomplete as in if I took the rules to chess, tore them in half then handed half of it too you, incomplete. RPG's have been, by habit seemingly, for some time sold as incomplete, for various sums of money. Even more procedure complete indie games these days like capes or 3:16 have no ending rules - they are like a book with the last chapter torn out.

Your dislike for 'civil law' (and thinking that it's more mature to do 'common law') stems from the fact that as a roleplayer you've never been given a complete procedure. NO ONE can apply a complete procedure following 'civil law' when they do not have a complete procedure to apply! Of course anyone who tries to apply a complete procedure seems bad somehow - they aren't actually being given a chance to actually apply a complete procedure, so all you get is wreckage.

You've never actually experienced a complete procedure RPG. I'm not sure anyone has actually (as in written procedure rather than 'lets call anything that happens at the game table 'system''), though boardgamers and card players experience full procedure games all the time. But regardless your judging 'common law' as being better than 'civil law' when you've never actually experienced  'civil law' except in a bastardised sense. Your 'more mature' approach is to drag yourself along with your hands, rather than just lie there a legless lump. It's not a greater approach - try dragging yourself with your hands when you have perfectly intact legs, so to speak, and you'd agree.

Finally, I think it's fairly pointless to discuss theory as in 'fixed concepts/facts that we work from' when what you talk about is all flexibility. Someone will just come along wanting to be so flexibile they discard the civil/common notion, and so roleplay design theory keeps gaining and losing the same inch of ground, over and over with new words and nothing new to show for it, for perpetuity.

But that's gunna happen anyway, so on with the show.

I had a a similar thought, but it was from my non-lawyer layman understanding of what 'common law' was - I thought 'common law' was all about precedent, and applied to the gaming table it wouldn't be about adapting rules from other systems...which to me sounds like one country adopting the laws of another country in order to adjudicate its cases...but rather applying a certain consistency at the table, e.g.:
- as we migrated from Pathfinder Beta to Pathfinder Actual, it became murky how many attacks a tiger animal companion gets on a charge, so we keep using what we'd always used
- one of the players realizes we've been playing the 'flying' rules wrong the entire campaign;  rather than adopt the correct rules, we just keep playing it the way we have been;  we'll switch next campaign
This is more 'fair' than saying "Ok, now we're going to start playing by our new understanding of the real rules instead of the way we've always played" because nobody gets nerfed. 
But, whether you're going to be about the text of the rules or precedent, it matters much more for gamist groups where the players are more concerned about min/maxing, etc...