That abstract concepts like HP, AC, etc.. are used to communicate game world information that really exists as knowledge in game.
Most of the abstract concepts like Hit Points and AC are ways to quickly communicate ideas from DM to PC. Yes the player hears the term and translates it down to the character who then acts. The character though is acting on real knowledge. When he falls back, from the fight due to low hit points he is acting on in game knowledge.
No one denies that, or is unclear how, hp are used to communicate ideas from DM to PC.Hit points are a method of communicating in game state. The DM says you were hit for 14 points of damage. You deduct that from your total. You are that much closer to death. This is in game knowledge. However you define hit points. Whether they are wounds or stamina or whatever. I've tried to keep it simple by saying they are just a measure of your closeness to death.
And no one denies that, or is unclear how, hp totals communicate a character's closeness to death. But this isn't what causes people to assert that hp are metagame.
Here are some things that do cause that assertion (I am reporting from my own experience, both as a RPGer who was one of those who dropped AD&D for RM as soon as I learned a metagame-free RPG existed, and from membership of the anti-metagame RQ and RM play communitiies):
* "Closeness to death", in terms of hp loss, is not something that affects a characer's physical capabilities or performance;
* It is easier to heal a commoner who is very close to death (suffered 4 hp of a 5 hp total), than a super-resilient lord who has barely a scratch or two (suffered 14 hp of a 70 hp total);
* Hence hp aren't tracking something physically observable, like injury or physical wellbeing, but something intangible and unobservable (much as Gygax describes);
* Yet most actual play proceeds on the assumption that all the party members can observe both how close they, and how close their fellows, are to death.
* It is easier to heal a commoner who is very close to death (suffered 4 hp of a 5 hp total), than a super-resilient lord who has barely a scratch or two (suffered 14 hp of a 70 hp total);
* Hence hp aren't tracking something physically observable, like injury or physical wellbeing, but something intangible and unobservable (much as Gygax describes);
* Yet most actual play proceeds on the assumption that all the party members can observe both how close they, and how close their fellows, are to death.
So it's something unknowable and unobservable that nevertheless is used to make decisions all the time. Hence meta.
Suppose that someone says that in fact what is being observed is physical harm; and that we ignore the "death spiral" for reasons of "cinematic reality". Then why is it harder to heal a scratch on a lord than a severe bruise or break for a commoner? (Ironically, the only version of D&d to have proportionate healing, which actually addresses this issue, is 4e - which nevertheless, for reasons that escape me, has a reputation for increasing the meta!)
In any event, what causes people to assert that hp are meta is that "closeness to death" is not possibly something that the character, in the gameworld, can know, given the properties of hp that I articulated just above.
Classic Traveller has a simpler damage system than RM or RQ. It has only a very limited death spiral. But it doesn't have the properties that D&D hp do: healing is proportionate, and in any event (as in RQ) hp totals remain pretty constant across the course of play, so it's not harder to heal a scratch on someone who is good at dodging blows, than on an amateur who is hopeless at such stuff.
Here's a power I can conceive of that is not magical but is doable only once per day: mark 20 exams in 3 hours.a martial power that is daily and non-magical, is not something the character can ever conceive.
How do I know? Because I possess that power, but I can tell you that after doing it once in a day, you can't do it again.
(Of course, treating the recovery as on a strictly 1/day basis involves a bit of approximation and smoothing off of rough edges, but I don't see why that would be more objectionable in this case than any of the dozens of others where the game mechanics do that.)
The last serious run I did was on a 30-something degree day in fairly hilly terrain. After running, and then swimming, I had to get back to base by a certain time. So at various points I pushed myself. At a certain point I knew I couldn't push myself any further.Right after he pulls off the manuever can he really know for a fact that he can't do this purely physical thing he just did a minute ago. Can he know that by sleeping he can again have the option at any time during the day to perform a very specific manuever but only that one time.
Because I don't train seriously and don't have a coach, I don't know what my limits are in terms of pushing myself, but I know that I have them. If I was a serious athelete, I'm sure I would learn what those limits are.
(Whereas I do know what my limits for exam marking are, as that is something I do regularly and in respect of which I have coached myself hard.)