I mentioned before the House Rule I was intending to use for D&D to cut down on trips out of the dungeon to spend a week resting up after each room, namely that after a combat you can spend 1 GP worth of bandages and salve to “bind your wounds” back up to the the maximum on your character’s hit die (or your actual roll, whichever was less). That is, if you’re a Magic User with 2 HP at level 1, you can bind back up to two. If by level 3 you have 6 HP, you could restore yourself to a maximum of 4 (the most you could have rolled at 1st level).
This is mostly motivated by meta-game considerations, since it’s really boring to have a fight, retreat, rest a week, rinse and repeat all the way through the first couple of levels of a dungeon, but it prompted me once again to think about Hit Points in D&D (and similar games) and what they really represent, and I think I had a minor epiphany. It’s well known that you can’t really interpret Hit Points as being your ability to withstand physical damage, for all kinds of reasons, but most of the proposed alternatives, no matter how hand-wavey (luck, favor of the gods, etc) aren’t very satisfactory since they don’t really match the game mechanics. If it’s favor of the gods, for instance, why do fighters get more of it than clerics? And why would sleeping or being tied up completely negate your destiny and allow you to be taken out with a single hit? If it’s reflexes, why do Thieves get so little, and why is it that high Constitution helps but high Dexterity doesn’t?
Then it occurred to me: you can’t explain it as a single ability or quality, because it’s an abstraction of how hard you are to kill for all kinds of reasons based on your long combat experience. This isn’t as silly as it may sound at first. It happens to be true that for as far back as we have records of warfare, experienced soldiers survive longer, and one of the best predictors of success in combat is how seasoned the troops are. It’s also not a winnowing process, where all the clumsy, slow and unlucky soldiers die, leaving only the hardy and tough ones. Troops definitely can go through a process where they go from being green, to seasoned, then veteran. On the other hand, you can’t keep troops in the field indefinitely or they’ll lose their edge.
So, at least in my game, in general Hit Points represent that state of combat readiness that makes the veteran soldier able to react almost instinctively to avoid all the hazards that kill the green soldiers so easily, including not just reflexes, but awareness of surrounding, mental toughness so as not to hesitate in the slightest, physical conditioning, economy of motion, and so forth. Damage, in this view, is primarily not actual wounds but the kind of accumulated fatigue and minor injuries and strains that require not just a night’s sleep to restore but days or weeks of R&R. Only that very first hit die represents real, sustained damage to your body, which is why almost anyone at first level can be taken out by a solid blow from almost any weapon, and anyone, no matter how experienced, can be slain instantly if they’re rendered helpless. This also, to my mind, satisfactorily resolves why it’s Fighters and Dwarves that can improve their Hit Points the most, with Clerics, Elves, and Halflings somewhat less able, and Thieves and Magic Users, even if they’ve gone through all the same combats, lag behind. It also fits with Constitution being the attribute that modifies Hit Points.
This fits reasonably well with my house rule on binding wounds. On the one hand, I am letting people just patch up actual tears and holes in their flesh with a few bandages and maybe some stitches, which is a bit generous. On the other hand, it fairly clearly establishes why it’s only that first hit die that can be restored (bandages are just no substitute for R&R). I think it also makes for a sense that, at least for the first couple levels, all the characters are improving their physical conditioning (unless they were lucky enough to roll max HP at the start).