Rational vs. Irrational Hit Point Systems

[CCarter]

So for awhile I've been pondering a theory on how hit point systems in various games can be classified, and thought I'd see what people thought. I'm thinking they could roughly be put into four types, which are:
Irrational Hit Points & Damage - the least useful setup, as seen in D&D. HP and damage relate to each other and nothing else.
Rational Hit Points - you can run varied game mechanics off your 'hit points', but not your damage e.g. Tunnels & Trolls.
Rational Damage - you can run various game functions off your damage, but not your total HPs. Marvel Super Heroes, True20/ Mutants & Masterminds
Rational HP And Damage - Shadowrun and White Wolf maybe? You can run game mechanics off either damage or total hit points.

I'm using rational here to mean 'this value has meaning within the context of other game mechanics' rather than the mathematical sense. I'm open to a better term. I considered 'arbitrary' as well.

D&D (all versions) would be an example of what I'm calling a wholly 'irrational' system. You have some number of hit points, which is a very wide spread of possible numbers. If you're hit you take some number of points of damage, which is an even wider spread of possible numbers. Damage subtracts from Hit Points, and that is the only thing you can do with either number: neither variable has a value which relates to any other variable in the D&D system. There are a couple of mechanics which try to work off your total hit points: Power Word Blind for example blinds you if you have less than 200 HP, or Death Touch kills you if you have less than [d6 per caster level] current HP, but in general these mechanics don't work at all, or don't relate to the usual game mechanic where you roll a d20.

Likewise, there are a couple of mechanics which try to work off the results of a single damage roll, rather than your total HP. For example, a Concentration check has a DC based off the total damage dealt, or Defensive Roll has a Reflex Save DC based off the damage you just took. Coup de grace is another example. None of these mechanics work particularly well either - damage inflates with level much faster than either skill bonus or save figures.

Other game systems of course have HP figures that do work for either of these cases i.e.
*you can have a system that lets you do something with your total HP i.e. gives some penalty based on your character's overall condition - what I'm calling Rational Hit Points.

*you can have a system where you can do something with a single damage roll, like making some sort of resistance roll, or using the damage figure to adjudicate a rider effect. A character might have a power that will be more likely to stun or knock back an opponent if it does (say) 10 damage than if it does 3, or fire damage of 7 points might be more likely to set something on fire than fire damage of 3 points.
That's what I mean by Rational Damage.

An example Rational Hit Point system for example would be Tunnels and Trolls. Damage subtracts directly from your Constitution value; your new reduced CON affects CON-based rolls so that you couldn't hold your breath under water as long, resist fatigue or save against poison. (Whether you want to do this and have a death spiral is another debate entirely, but the functionality is there; in the T&T example its not too bad for PCs since it only affects CON-based rolls).
There are not many examples of this sort of system that I can think of. (GURPS might be able to do this since it has hit points = character Strength, except that with its 3d6 roll under mechanic damage would drop a character's chance of making a roll very quickly).

One Rational Damage Roll system example would be be Marvel Super Heroes. Damage you deal is equal to your STR (or your Power rating in Energy Blast or whatever, which is on the same scale). Damage values use the same ranking as everything else in the system. Aunty May can hit you for 2 damage which rolls on the Feeble column, or the Hulk can hit you for 100 which uses the Unearthly column. The damage value can directly be compared to someone's Strength to see if they're likely to be knocked back, or to the Material Strength of an object to see if it may break (though the system does have problems doing opposed rolls).
True20/Mutants & Masterminds might be another example - though it doesn't really have HP at all. 'Damage' just gives the DC of a Toughness check to see if you move down a wound category, and it'd theoretically be possible you could use the DC for something else instead.

Having both Rational Damage and Rational Hit Points at once is difficult. A character's Hit Points value has to be larger than the damage off a single attack, or characters die in one hit, so both can't be used to get a number in the same way. Dice pool systems like Shadowrun or Storyteller that use Soaking may do both at once, though I'm not very familiar with the current version of either.; "Con" and damage rolls function on the same scale, and then a wound track can provide penalties on some rolls if desired.

Thoughts?

[hogarth]

An example Rational Hit Point system for example would be Tunnels and Trolls. Damage subtracts directly from your Constitution value; your new reduced CON affects CON-based rolls so that you couldn't hold your breath under water as long, resist fatigue or save against poison. (Whether you want to do this and have a death spiral is another debate entirely, but the functionality is there; in the T&T example its not too bad for PCs since it only affects CON-based rolls).
There are not many examples of this sort of system that I can think of.

Traveller worked this way as well (damage was deducted from one or more of your physical stats).

One Rational Damage Roll system example would be be Marvel Super Heroes. Damage you deal is equal to your STR (or your Power rating in Energy Blast or whatever, which is on the same scale). Damage values use the same ranking as everything else in the system. Aunty May can hit you for 2 damage which rolls on the Feeble column, or the Hulk can hit you for 100 which uses the Unearthly column. The damage value can directly be compared to someone's Strength to see if they're likely to be knocked back, or to the Material Strength of an object to see if it may break (though the system does have problems doing opposed rolls).

I'm honestly not seeing much of a difference vs. D&D aside from the static damage (which was a terrible system, IMO).

My two cents: Personally I'm fine with hit points or health points that are only good for determining a Critical Existence Failure threshold. I don't think it's a coincidence that most tabletop RPGs and video games work that way.

[fectin]

I'm not sure why one is rational and the other is irrational. Just as counterpint, Aunt May gunning you down should be basically the same as anyone else gunning you down, and it's a little hokey that papercuts send you into a death spiral.
The "best" damage answer is probably something like Exalted or FantasyCraft, where you either have lots of health at each penalty level, or make saves based on damage taken to avoid falling to the next penalty level. I've played both though, and neither is really better than the DnD model.
On damage, I'm less clear what you mean. Is it that you object to weapons dominating damage (in which case, look at shotguns) or that you want character stats to at least influence it (in which case, DnD STR bonuses seem to fit fine)?

[Avoraciopoctules]

When I saw this thread's title, I thought it would involve multiplying HP by π. Or possibly i. I am thankful that this forum seems to be steering clear of such ideas.

[Josh_Kablack]

I'm using rational here to mean 'this value has meaning within the context of other game mechanics' rather than the mathematical sense.

Well that's saner than I had expected from the thread title. Also somewhat less entertaining.

I'm not entirely sure what you are trying to get at here, other than asking for open responses to different ways of handling HP and Damage?

On that subject, there is also Feng Shui, which basically uses D&D HP, but has impairment thresholds and uses the amount your HP are negative as the DC of a save to avoid dying from wounds after the fight. I guess you would tag that as irrational.

[CCarter]

Yeah, sucked you all in with an entertaining thread title that doesn’t live up to the hype..Thanks for the replies anyway.

Hogarth: OK thanks for the info on Traveller.

On MSH: the difference between Marvel and D&D is that in Marvel you could take an amount of damage and translate this into a ‘chance of success’. If I take 50 points of damage in D&D, there’s no reasonable (= rational) way to get a DC for a check off that.
If an attack deals 50 damage in Marvel, I know that any additional effects for it are “Amazing” rank –which for Marvel needs a table but which translates to an 75% of a success. If my fire bolt hits a guy and deals 50 damage, I could roll my 75% chance of success to see if he’s on fire. If he’s fire redardant for 10 points and only took 40 damage, I could use the rank for 40 (Incredible) and have [checking the table] a 70% chance of setting him on fire.
As far as why most games use ‘irrational’ systems – I think these are just the easiest to design.

I don’t mind the static damage so much, but MSH is just the only example I could think of. I don’t think a rational damage system need to be static damage.


Fectin: I’ve probably explained this badly but on damage, I just think its a plus if a system can use damage for other effects (you are clubbed in the head for 15 damage; what’s the chance you’re knocked down?).
I guess ‘lots of health at each penalty level’ is perhaps what I’d call Rational Hit Points (if it does it well - it could be just a kludge on an irrational system), while ‘roll based on damage to avoid moving to next level’ I’d call Rational Damage (you’re getting a DC directly off a damage roll). If these weren’t better than D&D, my theory may have sprung a leak somewhere...so what was crappy about the Exalted/Fantasy Craft damage systems, anyway?

Stats influencing damage isn’t what I was getting at so much. In D&D the Str modifier adding to damage is fine but all the other potential modifiers makes the final damage value too erratic to be used to determine a check DC or do anything else useful. Which means if there's a special effect as well as damage the feat or spell or whatever has to have a DC generated arbitrarily, that is only vaguely related to the damage.


Josh: I’d probably class Feng Shui as ‘Rational Hit Points’ from what you said, since both the save based off your negative HP, and the impairment thresholds, are effects/penalties that are connected to a character’s total hit points, instead of the damage they’ve taken from a single specific injury. I suppose I might still call it an irrational system if it does these things badly, though. I’ve only played Feng Shui once and was suckered into playing a Big Bruiser, so I didn’t get to see the damage side of things much

As far as what I’m looking for –its pretty general. Maybe more examples of different systems (particularly the systems that do both things, since this seems difficult), any actual benefits of ‘irrational’ systems, or just gaps in the thinking here.

[tzor]

I'm using rational here to mean 'this value has meaning within the context of other game mechanics' rather than the mathematical sense. I'm open to a better term. I considered 'arbitrary' as well.

Darn, I was hoping for a discussion of "You take PI damage."

I suppose I should start a discussion on complex damage "You take 4 + 5i damage."

[RadiantPhoenix]

Well, in Arkham horror they have sanity and stamina, which kind of work like a complex number system for hit points, with each quadrant being a different state (healthy, unconscious, devoured, insane).

EDIT: Except you don't actually go into those quadrants, because the game doesn't actually have you go below zero in either of those stats, you just enter those states when you touch the border.

[tzor]

One of the biggest problems (or benefits if you are on the other side of the question) of the totally irrational system is that they promote the "A Hero is a Hero until oh crap ... he's as good as dead." The fact that someone can be 100% effective at full health and at one point short of falling over and bleeding to death is something I've hear complains about since forever.

It also broke the 4th wall of gameplaying, especially in the early editions. Seriously, how do you know your current hit points? How do you feel them? How do you really know it's time to run away. (Don't ask and we won't tell folks.)

The other systems are good in their own respetive ways and I have certainly played enough of them. But it's hard to apply to D&D with their heroic attitude towards damage. Perhaps a "heroic damage soak" system that moves attribute damate to your soak pool (hit points) based on some random parameter?

[hogarth]

One of the biggest problems (or benefits if you are on the other side of the question) of the totally irrational system is that they promote the "A Hero is a Hero until oh crap ... he's as good as dead." The fact that someone can be 100% effective at full health and at one point short of falling over and bleeding to death is something I've hear complains about since forever.

As Frank noted before (and I'm paraphrasing), if you ask a player what sort of rules he'd like to see, you can easily end up with two diametrically opposed answers. For instance, "if you're about to die, you should be barely able to do anything" and "if you're about to die, you should be able to make a great heroic effort to save yourself".

[tzor]

I agree, I just wonder whether the solution to "the posibility to make a heroic effort to save yourself" is best done through the 100% power level until zero hit points. It doesn't appear in most classical literature.

The classical hit model typically has the hero with reduced abilities until the "heroic" moment. Popeye eats the spinnach, Undergod opens his ring and eats another energy pill, and so forth.

Although it's a bit more complex than this idea, it really does cover the whole of a lot of the old Dragonball combat sequences. (Get the shit beat out of you until you realize "you can't do this to me, I'm important" and BAM, your twice as a bad ass as you were at the start of the fight.)

I also think that if you used a rational system, then the notion of healing surges makes even more thematic sense. It think the combination of the two is far more interesting than suffering no consequences from damage whatsoever. Moreover it gives the healing surge a greater dimension than just filling up the HP tank to continue to drive down the combat road.

[CCarter]

Apparently I suck at explaining, so I'll try it again. Maybe scaled vs. un-scaled would be better words that irrational/rational. I've given two completely different things quite similar names as well. Damn.

Damage can be set up so that either of these are options:
*a characters' total hit points can be used to determine a DC/check modifier.
*a damage roll from one attack can be used to determine a DC/check modifier.

Because [total HPs] >> [one damage roll], you can't easily have both options at the same time.
You can also have a hit point system so badly set up that you can't do either (D&D).

'Death Spiral' is a feature of the second option only (modifier based on total hit points aka 'Rational Hit Points'). Wanting characters to always be on 100% power until they die isn't unreasonable, but even if you do want that, there may be uses for scaling your total hit points beyond just having a death spiral. For example, Death Touch in D&D is an attempt to make a roll with a difficulty based off a target's total HP. The question is - would these cases still be common enough to make it worth bothering with ?

Note Death Spiral is only a feature of a 'Rational HP' system (where your total HPs can generate DCs), not of the 'Rational Damage' system which is completely different (where individual damage rolls can generate a DC).

If you *don't* want current total HP to ever make a difference, then it would still be preferable to have a system where you can base DCs off of damage from single attacks so you can instead have working rules for cases like coup de grace/ Defensive Roll/ Concentration checks after taking damage).

[sabs]

Didn't there used to be a something about Total Damage from 1 attack vs Con, could result in a save or die situation?

[hogarth]

Didn't there used to be a something about Total Damage from 1 attack vs Con, could result in a save or die situation?

That's from d20 Modern, I think.

[shadzar]

D&D (all versions) would be an example of what I'm calling a wholly 'irrational' system. You have some number of hit points, which is a very wide spread of possible numbers. If you're hit you take some number of points of damage, which is an even wider spread of possible numbers. Damage subtracts from Hit Points, and that is the only thing you can do with either number: neither variable has a value which relates to any other variable in the D&D system. There are a couple of mechanics which try to work off your total hit points: Power Word Blind for example blinds you if you have less than 200 HP, or Death Touch kills you if you have less than [d6 per caster level] current HP, but in general these mechanics don't work at all, or don't relate to the usual game mechanic where you roll a d20.

Thoughts?

As usual when things like this come up, why do the things have to be connected?

I am guessing you are talking of 3rd edition with PW: Blind, as 2nd states it at 100 HP, because it is an area affect with a range of 100 HP worth of creatures in effect. A cute attempt by strange method to take into account the spell gets used up upon those it effects, especially since HP isn't connected to sight.


Otherwise why does HP have to be in any way shape or form connected to ANY mechanic, other than death?

It does one thing, and does it very well.

If you start connecting it to many things, then connect it to all. You start getting sleepy at certain HP, you have fewer HP if you haven't slept etc...

Netbooks did this sort of stuff as the niche within the niche that is RPG.

If HP only represents how much damage you can take before being felled, then it doesnt need to connect to anything else.

[CCarter]

Didn't there used to be a something about Total Damage from 1 attack vs Con, could result in a save or die situation?

I've seen this in Unearthed Arcana as well (pg 119). Its a pretty grotesque add-on that doesn't work at all. The DC is always 15 rather than being damage-dependent.

As usual when things like this come up, why do the things have to be connected?

I am guessing you are talking of 3rd edition with PW: Blind, as 2nd states it at 100 HP, because it is an area affect with a range of 100 HP worth of creatures in effect. A cute attempt by strange method to take into account the spell gets used up upon those it effects, especially since HP isn't connected to sight.


Otherwise why does HP have to be in any way shape or form connected to ANY mechanic, other than death?

It does one thing, and does it very well.

If you start connecting it to many things, then connect it to all. You start getting sleepy at certain HP, you have fewer HP if you haven't slept etc..

3rd ed. already has a few mechanics that use damage or HP to give a DC, they just work badly. (For power word blind I meant 3E, though 2E power power words mainly differ in the number of HPs). 2nd ed. has its 'numbed' and 'useless' values, death from massive damage, the power words... maybe other things I've forgotten.

I think its more elegant to connect things where possible. I suppose its a point that yes, interconnecting things & adding extra uses to them does risk making them work less good at the one thing they currently do.

On the sleep thing: I don't really see how this connects? I've seen sleep with a 'fatigue point' system though e.g. LegendQuest has a Sleep spell that gives a target fatigue points, with penalties based on what % of fatigue points they have left if they're not wholly unconscious.

[shadzar]

I think its more elegant to connect things where possible. I suppose its a point that yes, interconnecting things & adding extra uses to them does risk making them work less good at the one thing they currently do.

On the sleep thing: I don't really see how this connects? I've seen sleep with a 'fatigue point' system though e.g. LegendQuest has a Sleep spell that gives a target fatigue points, with penalties based on what % of fatigue points they have left if they're not wholly unconscious.

I see more to connect things where a connection is required, rather than to just have a connection to say it is connected.

Take Ability Scores today and how useless they really are because they do little to nothing. Take what all they did in the past. They were a target number, and actually performed a function more than a modifier to other things. Now they have been connected to too many specific things that ability scores could be rolled on a d6 and just record the number as the bonus given for that "stat".

Ability scores were connected to EVERYTHING where possible, and it reduced them to nothingness.

The "fatigue system" is an excellent example...it can check HPs to find out the state of the character, but doesn't ened to be connected so much that it affects them.

X% of HP or under and you suffer -1 penalty to some THING, due to fatigue.

But the system shouldn't reverse that wherein sleep causes a loss of Y% HP because you didn't get much sleep, as the sleeping is part of the fatigue system, not the damage system.

That allows them to be very loosely connected, but not interfering with ones main purpose, such that it gets destroyed such as ability scores, and the confusion caused by HP over the years to where they are becoming less viable a thing to use at all.

the "power word" series, as well other spells that check HP is a bit silly considering it is checking for things the HP don't represent well, and should be checking on a more stable system that doesn't fluctuate based on poor dice rolls at character creation or level gain. Level for example would have been a better metric to use with the "power word" series for example as you could affect X levels worth of something, such as turning undead does. Since the HD of a monster is in direct proportion to its "level".

I mention sleep solely because the abstract many view HP as contains all such things as ability to continue on, rather than just strict damage required to die, aka life meter. But I much prefer the life meter and can explain it quite well when using 0 or -10 as the death number under HP for the editions of (A)D&D i play without removing SoD.

So when you use HP to represent fatigue and all the other too numerous components of the abstract it represents, sleep can and should affect the amount of damage you can take as you are already fatigued from lack of sleep, or sleeping in armor, lack of food, etc; such that it should show in your HPs for that day. Like you are weakened for the situational basis of day-to-day life, but i prefer to represent that not with how much damage you can take through HP, but rather with the things you can do elsewhere. Disease and such that actually cripples or debilitates the body, would be things that would impede the HP and change it, while sleep or other things that affect the mind or aim, and effectiveness, will affect their respective functions within the game, but penalty to hit, not able to always use all attacks, etc that muscle memory doesnt handle since the mind may be trying to take over for it.

Some TV show recently tested texting vs drinking and driving and found texting and driving to be slightly more dangerous, because under intoxication your mind wasnt taking over muscle memory, but allowing it, while texting you were trying to actively override your muscle memory of doing things and the reaction time was reduced because the conscious mind is slower than the subconscious mind, or those reflexes used when allowing muscle memory to perform itself on auto-pilot.

[Psychic Robot]

As far as hit points in theory goes, I hate D&D's system with its lack of realism or making sense. As far as hit points in execution goes, I like D&D's simplicity and ease of use.

[fectin]

As far as hit points in theory goes, I hate D&D's system with its lack of realism or making sense. As far as hit points in execution goes, I like D&D's simplicity and ease of use.

It has been said that democracy is the worst form of government except all the others that have been tried.

True in both cases.

[CCarter]

I see more to connect things where a connection is required, rather than to just have a connection to say it is connected.

Take Ability Scores today and how useless they really are because they do little to nothing. Take what all they did in the past. They were a target number, and actually performed a function more than a modifier to other things. Now they have been connected to too many specific things that ability scores could be rolled on a d6 and just record the number as the bonus given for that "stat".

Ability scores were connected to EVERYTHING where possible, and it reduced them to nothingness.

I think I see what you mean about the widening meaning of ability scores. The core mechanic of d20+stat modifier+skill/stat etc. both made odd numbers meaningless and also, in order to apply a modifier to virtually every roll, broadened the definitions of the attributes so that CHA also included your magic power (Use Magic Device), Wisdom helped you listen or spot things (gotta love how Venerable characters get better eyesight ) and Con helped you concentrate, for example?

I'm not necessarily trying to connect stuff just arbitrarily, though. I can see a number of mechanics in 3.5E that *could* potentially be damage-based rolls, but aren't usually done that way because that works so badly as a mechanic. 3.0 seems to have more of these - like Harpoon damage in the Arms and Equipment guide, where a harpoon is more likely to stick in if it does more damage - which 3.5 moved to DCs that are pretty much level-based for the same sort of thing, for feats like 'Head Shot' (confuse a guy with a DC based off your dex /sneak attack dice) or Anvil of Thunder (stun a guy when you hit them, with a DC based off your Strength/level).
Potentially, many or most secondary effects of many warrior and some rogue type feats or abilities could quite reasonably (IMHO) have a target number related to the damage - if the damage system supported that.

On the power words, I suppose Power Word could be Hit Dice based, to be consistent with other effects like Turning, Sleep, Cloudkill, Circle of Death...though it also means the fighter is as vulnerable as the wizard to being stunned or blinded.

As far as hit points in theory goes, I hate D&D's system with its lack of realism or making sense. As far as hit points in execution goes, I like D&D's simplicity and ease of use.

Maybe the alternatives to just straight-up subtracting HP are too complex to work?

OK...I think it would help if I had more examples of systems where damage is used to generate a DC/check modifier, since currently I only have a couple of examples of systems that do this (Marvel Super Heroes, maybe Mutants & Masterminds?)

I could imagine a dice pool system like Shadowrun or White Wolf working with the principle - soaking for example relies on damage and CON being expressed as similarly-scaled dice pools ? - but I don't know either in enough depth to know if they have used damage rolls for anything weird.

[shadzar]

I'm not necessarily trying to connect stuff just arbitrarily, though.

So other than trying to affect a now defunct system such as stats like CON, what would a change in HP affects outside of things it currently is supposed to represent?

Also HP altering CON in earlier editions would be a bit far fetched with how little CON actually gives to HP, you would not really be able to alter CON, and the stats really are the physical starting point of the character. not things that should naturally change, and most character sheets that just had you change the scores without saying what natural was then the altered was a pain in the butt, unless something was changing it like draining. Tracking magic items for instance. With a system that altered the stats based on HP a lot of the game could turn into recalculation rather than playing.

It is one of the reasons D&D left it alone, since the system has enough calculations to be made and other accounting, that taking a little damage would halt gameplay if you had to constantly change everything else based on the recalculations.

For video games this would go fast and easy as the computer could do it without having to stop play, but at a table, the game would stop, and maybe so would the momentum to return where you were when you lost the HP to begin with.

I don't recall Shadowrun or White Wolf that much cause i didn't really like their themes, but what I recall of WW, there was a LOT less things to calculate than in D&D.

Rifts and many others were pretty much the same thing as D&D, and that HP and the way it interacts, or doesnt, with other things may have been what kept me with it.

So what could D&D use HP for that wouldnt grind the game to a halt during play to do these recalculations?

[CCarter]

The theory here is very general - a framework to let me compare various RPGs or build better ones myself - 'how do I try to apply this to D&D' if I were rebuilding it is a big question, as it would involve major changes.

'HP altering CON' - I think the equivalence which would make the most sense is when [1 point of bonus lost] = loss of your level in hit points. So a 7th level character would lose 2 Con each time they lost 7 hit points.
That number is in line with natural healing in 3E (where you heal your level back in HP per day) and would be in line with the way HP are assumed to work in 3E. Basically as characters level up they're learning to 'roll with the punches' so that each of their natural hit points (from CON or class) is 'stretched out' by their level.
That would apply a wound penalty from damage to CON-based rolls only rather than all checks - Fortitude saves, general Con checks, Concentration rolls.

This falls apart abit in earlier editions since HP bonuses from CON are irregular (i.e. 10-14 = no bonus HP at all, then +1 each extra point e.g. +4 at 18), and stop coming beyond level 9 or level 10. If you were doing it in 2E, I suppose capping it at 10th level makes sense (-1 Con per 10 HP lost if you're over 10th level?).

Using the same logic to work out how damage should get an equivalent DC, 1 HP of damage to a 1st level character is equivalent to 10 points of damage to a 10th level character. From that theory, a damage-based DC should start by taking damage and dividing by character level.

Either of these look pretty awkward. Its hard to get them to work when the HP figure can get so inflated.

Another idea, without straying too far off standard D&D might be the SAGA/Unearthed Arcana system (much like Rifts) where you have two HP tracks - a'serious damage' HP number that increases very slowly and a minor damage HP number that goes up quickly with level ('shucks ma'am, its just a flesh wound'). The serious damage track might modify Fortitude saves etc. etc. Or serious damage, taken off criticals or after all normal HP are lost, might directly come off CON.

This is all pretty speculative. When building an RPG myself (something that tends to sort of explode partway, mostly) it tends not to look much like D&D. After discussion here, I'm leaning more toward having not bothering with any sort of condition system but trying to make damage from individual attacks easily convertible to a difficulty number somehow.

[tussock]

Regarding the logic of D&D's hit point model, one just needs to note that all attacks are of a type that is lethal.

Taking just 1 or 2 damage can kill /anyone/, if they've run out of the ability to not be killed that. "What's that ability represent" you ask? Why, it's your luck, skill, resilience, the favour of the gods, or whatever makes the most sense for your character at the time; you just get clipped by the Giant's club, barely feel all the Kobolds arrows in your armour, Selune shields you from harmful magic: whatever.

But, just because you're not killed by those lethal attacks doesn't mean they don't hurt. Cosmetic it may seem from outside, it's gradually eating into your ability to not be killed by that. Sure, everyone compensates as best they can, but a 9th level Fighter with 10 hp left can't beat near as many things as one with his full 100. They know it too, going all out in a blaze of glory.