The rest are examples of abstracted mechanics, in which a range of various factors and circumstances are rolled up into a simplified numerical value for the sake of convenience. HP and Saving Throws each represent a character's ability to avoid serious harm or death through a combination of skill, experience, natural ability, luck, fate, divine favor, magical assistance, etc. XP for gold made the assumption that adventurers who amassed large amount of wealth had faced and overcome many difficult challenges to do so. Armor and weapon restrictions assumed some combination of cultural and practical factors.
All of the above mechanics still have a direct association with specific behaviors and outcomes in the game world. Take HP for example. It is directly affected by a character's experience level, class, and ability scores, all of which are things an avatar would have some awareness of. It also degrades as a character absorbs blows, gets tired, or presses their luck repeatedly - again all things the character could feel and understand. So when a player uses HP to make informed decisions about when to flee or continue fighting, or whether or not to jump off a 20' cliff, we can easily envision the character making the same decision based on the same set of information.
You're quite right that saving throws and hit points are abstracted. The same mechanic can refer to a number of quite different properties of the game world. But isn't this very rules feature what TA is complaining about when he talks about the war devil's
besieged foe ability? He bemoans the multiple possible explanations, saying that to provide a specific explanation is to make a house rule. Isn't there the exact same need, if there is such a need, to 'pin down' the abstract mechanics of saving throws and hit points as there is to explain
besieged foe? I don't agree with what TA says here, but it applies equally, imo, to saves and hit points -
So now we've established that any attempt to provide an explanation for this mechanic constitutes a house rule: Whatever explanation you come up with will have a meaningful impact on how the ability is used in the game. Why is this a problem?
First, there's a matter of principle. Once we've accepted that you need to immediately house rule the war devil in order to use the war devil, we've accepted that the game designers gave us busted rules that need to be fixed before they can be used. The Rule 0 Fallacy ("this rule isn't broken because I can fix it") is a poor defense for any game.
...
These massive house rules also create a disjunction in the game. One of the things that was identified as problematic in the waning days of AD&D was that the vast majority of people playing the game had heavily house ruled the game in various ways. That meant that when you switched from one AD&D group to a different AD&D group, you could often end up playing what was essentially a completely different game.
In the case of AD&D, this widespread house ruling was the result of disaffection with a fundamentally weak and inconsistent game system. House ruling, of course, didn't disappear with the release of 3rd Edition -- but the amount of house ruling, in general, was significantly decreased and the consistency of experience from one game table to the next was improved.
Ofc, TA is wrong about
besieged foe, the rules do in fact provide a game world explanation. I would assume that when he wrote the article, the author only had access to the power description and not the accompanying text on pg 67 of the MM -
They use besieged foe... to direct their subordinates against dangerous foes
TA imagines conducting an interrogation of a character, asking him to explain why he can only use Trick Strike once a day. Surely a similar interrogation could be conducted regarding hit points. We could ask how a character on one hit point who fled, or sought rest or healing, knew he was badly wounded or severely fatigued, given that none of his capabilities were impaired in any way. His movement, his skill use, his ability to strike, to deal damage, to avoid blows, all of these were functioning at full capacity. And yet such a technique of interrogation, uncovering inconsistencies, insufficient explanations, is deemed capable of uncovering dissociated mechanics.
We might equally ask why a character jumped off a great height with such abandon. He seemed certain he could survive. How so?
Regarding xp for gold, Gary Gygax is perfectly honest about it having no game world justification, ie being a dissociated mechanic -
Players who balk at equating gold pieces to experience points should be gently but firmly reminded that in a game certain compromises must be made. While it is more "realistic" for clerics to study holy writings, pray, chant, practice self-discipline, etc. to gain experience, it would not make a playable game roll along. Similarly, fighters should be exercising, riding, smiting pelts, tilting at the lists, and engaging in weapons practice of various sorts to gain real expertise (experience); magic-users should be deciphering old scrolls, searching ancient tomes, experimenting alchemically, and so forth; while thieves should spend their off-hours honing their skills, "casing" various buildings, watching potential victims, and carefully planning their next "iob". All very realistic but conducive to non-game boredom!
- DMG pg 85
Your explanation, that in gaining gold, PCs will be very likely to use all their character abilities, is a perfectly good one. It's just that it's not the justification given in the text. So we have a situation where the users of the game text are having to create their own explanations, which is precisely what TA dislikes about
besieged foe.
Pre-3e editions of D&D are, imo, full of what TA would call dissociated mechanics. OD&D, as far as I'm aware, doesn't provide many justifications for its rules. 1e does provide some, even then they are often honest about the real reason being gamism or playability, for example the explanation for the lack of a critical hit system on page 61 of the DMG. Vancian magic itself was chosen with game balance in mind, as described in the article 'The D&D Magic System' in the Strategic Review #7. Likewise the use of weapons and armour -
Why can’t magic-users employ swords? And for that matter, why not allow fighters to use wands and similar magical devices? On the surface this seems a small concession, but in actuality it would spoil the game! Each character role has been designed with care in order to provide varied and unique approaches to solving the problems which confront the players. If characters are not kept distinct, they will soon merge into one super-character. Not only would this destroy the variety of the game, but it would also kill the game, for the super-character would soon have nothing left to challenge him or her, and the players would grow bored and move on to something which was fun.
- Gary Gygax, “Role-Playing: Realism vs. Game Logic”, Dragon #16
Even Gary's simulationist justifications in 1e were added after the fact. It was mechanic first, explanation second -
When questioned about the whys and wherefores of D&D I sometimes rationalize the matter and give “realistic” and “logical” reasons. The truth of the matter is that D&D was written principally as a game — perhaps I used game realism and game logic consciously or unconsciously when I did so, but that is begging the question. Enjoyment is the real reason for D&D being created, written, and published.
- Gary Gygax, “Role-Playing: Realism vs. Game Logic”, Dragon #16
Contrast this with 4e daily powers, which dissociate the mechanic (i.e. how often you can use the power) from any meaningful factors or circumstances a character would conceivably be aware of or able to influence in the game world (such as skill level, experience, fatigue, luck, or prior preparation). The mechanic allows the player to make informed decisions about when to use it, but provides no explanation of how the character would arrive at the same conclusion.
As has been said upthread, there is a game world explanation for martial daily powers on page 54 of the PHB, which talks about using up “physical and mental resources”. The character could certainly be aware of such.
