So what the heck do I need a GM for?

Over on this post: I want to play with all the rules, Meera asked some fantastic questions. These questions were too good to leave in the comments section, so here they are.

Does it change if, in one of those, say, laissez-faire systems, the GM makes an effort to explain their interpretations ahead of time? (I’ve tried to push that effort with ADRPG, for example – I make clear what my suppositions will be ahead of the game, including how I run attributes, etc.)

First off, I really like “laissez-faire” as a phrase for that kind of play: “Hands off our roleplay, mechanical system!” That’s good.
To your question, does it help if you clearly explain how you’re coming to your conclusions? Yes, absolutely, for that game, by which I mean “for your game.”
If you look at all the Amber stuff we wrote up for Things in Heaven and Earth back in the day, you’ll see a pretty heavily defined system for conflict resolution — we took those four basic stats of Psyche, Strength, Endurance, and Warfare and came up with umpteen derived values from them. Further, there were ways to get those numbers to ‘act’ higher than they actually were, depending on what you were doing in a conflict — going all-out, playing defensive, whatever.
And I think I was clear about how that worked, and how I read it, and the fact that Ranks didn’t matter that much to me, but the actual point scores did. Randy’s run a lot more Amber than me, and he’s gone even further with developing these system plugins.
Did that help keep everyone on the same page, with regards to understanding their chances in specific conflicts, sure. Yes, absolutely. I’d hazard a guess and say the game was fun for everyone most of the time, and that any frustrations that arose came from other areas, not from a misunderstanding about how the rules would work in my game. The same would be true, I am sure, in yours.
My point is this: all of that work in my game wouldn’t have helped the player one tiny little bit the next time they played in YOUR game, or if they went to ACNW and played in a game Epoch was running. I may have documented “my system” to the point where it was essentially a concrete, written down set of rules (which I probably did because that’s what I as a player want), but it’s still essentially written down documentation on how *I* will interpret things.
Such a game’s system is still, put another way, entirely Subjective. The subjectivity is just really really well documented. 🙂 Subjective things like that are always going to shift with a new GM in the chair.
I would say that clearly communicating in that way would definitely help a player jump from one game to another person’s game with the minimum amount of fuss and confusion, but at the same time, I’ll assert that Game One and Game Two are, at the heart of it, actually different game systems, because the system’s game engines (the GM) are fundamentally different.
A person can say “I love playing Amber” and go play with a new group of people who are, objectively, great players, and hate it. Afterwards, they might say “I just didn’t like how they did things.” What I think they’re saying is “They were not playing the same game as I do — the one I said I love.”
I want to be able to say “I like playing Game X.” And have someone else say “I like playing Game X also!” and have us actually be talking about the same system. That’s what I mean when I say “I want to play with all the rules.”
Now, is one GM, even playing with all the rules, going to present a different game than another GM? Certainly! That’s great!
Which brings me to the next question…

My other question is, do you prefer a GM not being necessary then?

Prefer it? No, that’s not what I’m aiming at at all.
I’ve played in a few GMless or near —
Hmm. Let me back up.
In general, a game needs focus. Direction. A strong sense of theme that helps everyone get on the same page. One way or the other, that goal needs to be achieved when you sit down at the table with the other players.
There are several ways to do that.
1. The EASIEST and FAIRLY EFFECTIVE way to do this is with a GM.
What does that look like? They can tell a player “no, a samurai isn’t going to fit in this game at all — we’re playing in Musketeer France — try again.” They can tell people where things are going to be set, what’s going to be happening in the background, and maybe even dial it down really tight and say “You all have some kind of strong relationship, good or bad, with three people from this list of NPCs.” or “You’re all marines in the same unit.” Or whatever.
Easiest: One mouthpiece, making decrees, clearly. (Note: it’s most easy for everyone BUT the GM, for whom it is often fucking HARD WORK. This can get easier when the game you’re running has a very clear theme built into the game, like The Mountain Witch or My Life with Master.)
Fairly Effective: No one else needs to ‘know’ or ‘decide’ anything — they can just listen to the GM and act accordingly. (Again, easy for everyone but the GM.) The downside is, only one person has the ‘vision’, and everyone else has to try to understand it.
2. A VERY EFFECTIVE, but HARDER (for everyone but the GM) way is to have a GM, but let the theme and sense of purpose to the game come out of clear and sometimes structured discussion before the game starts, so that when folks contribute to the fiction of the game during play, they contribute things that FIT. It often still falls to the GM to enforce the group-determined “feel” of the game.
Primetime Adventures and Mortal Coil do that very explicitly. They both have GMs. The Pool and Universalis and Breaking the Ice do this as well, but with either no GM, or a GM-role that switches around. There are other games that do that as well. Games like Donjon, which has a LOT of player-authorship but very little (read: no) discussion in the rules of how to agree on a theme in the group tends toward pretty silly play, unless the players back up and say “okay, we’re all going to agree to do THIS kind of game, okay? Anyone who adds stupid shit gets kicked in the nuts.” or something.
(Inspectres often gets silly as well, but it’s SUPPOSED to, so that’s okay.)
3. An Effective, but MUCH HARDER (much more effort from everyone) way to do it is with a game that strongly dictates a theme for the game, but leaves no one in the GM role to enforce it. That means that it falls to everyone to hold to the standard set by the game and not fuck around. It also means that everyone has to put a lot of personal, GM-level effort into understanding what that setting is… either that, or you need a sort of psuedo-gm to help people understand it.
The Shab al-Hiri Roach does this. Polaris does this. There are others. These can be super-awesome games, but while they’re a lot easier on the person who usually GMs (and they get to play! Yay!), it’s more work for everyone else.
So, in summation, I think even without being that laissez faire system adjudication, a GM can serve very well for reinforcing the integrity of the game world. That’s the FIRST thing.
What else do they do? Or, to go back to Meera:

What is the role of the GM in that case? (I don’t mind – I think I agree more and more each second that I consider what you say, but I’m curious. I have always argued that if a computer can do that interpreting, I might as well be playing a computer game.)

I actually said this in the original post, but I’m going to make it very explicit here.
When you are playing a game in which a mechanical, objective system is being used to determine the results of all conflicts, this is what the GM does, to a greater or lesser degree, depending on the system, presented in reverse order of importance:
1. Enforce the setting (as mentioned above).
2. Interpret system results (which is a very different thing from *determining* results). “You beat him by a ton… yeah, he totally gives in.” This ties into…
3. Playing the NPCs truly, according to their motivations and what they want.
4. Developing, presenting and pushing conflict-laden Decision Points at the players. (“Do you go after the bad guys who stole your temple’s holy relics, or the other group who have your little sister and are heading for the slave markets of The Black City of Ys?”)
3. and 4. are huge. Setting that stuff up is 99% of all the prep I do for games.
More importantly, they are two things that a computer just can’t do. 🙂