Wednesday, January 25, 2012

The meaning of Hit Points

I just finished reading a series of posts on hit points.  I'm not going to bother to link it, because there are many such posts and discussions and they are all more or less the same.

Hit points are a thorny issue and have been so since way back when.  The barbs jabbing at the minds of so many involve the realization that characters with high hit points can survive seemingly impossible situations - a hail of arrows for example.  After all, if a single arrow can kill a peasant, why does it take 10 to kill a fighter?

This question popped up often enough that Gygax wrote several essays about it, including the description in the DMG, p82.  His explanation is always the same: Hit points represent fatigue, luck and physical toughness, all three, and a trick or two besides. 

Folks have wrestled with this answer ever since.  Some have tried to break it down into some kind of fatigue damage, vs. physical damage, etc.  Others have argued that there are contradictions in this explanation, particularly as regards monster HP. 

Despite the messiness, I never let it worry me much as a game mechanic, but the thread I just read wondered how Constitution should or should not affect Hit Points at each level, given the physical vs. fatigue aspect, and that seemed like a really legitimate question, given Gygax's definition.

The course out of this muddle begins with a simple realization:

Gygax was wrong.

Now, to those crying foul, I would point to a simple fact: Gygax had no more authority to talk about the meaning of Hit Points than Traci Hickman, Monte Cook, or Mike Mearls do.   What I mean is that while he was certainly a very involved game designer - almost certainly the most involved in the '70s - in the D&D world, he didn't invent the concept of Hit Points.  His explanation is his opinion.  It is not the explanation of the designer.

Dave Arneson created the idea (and the label) of Hit Points.  Dave Arneson didn't have a lot to say about what Hit Points meant.  Luckily, if we look closely, its not too hard to figure out what he thought about them.

In the FFC he wrote "As the player progressed, he did not receive additional Hit Points, but rather he became harder to Hit"

For Dave, Hit points were a fixed number.  It wasn't long (by 1972) before Dave changed the above so that while characters still received a fixed number of points, it grew greater at each level, but the principle in the second part of that statement "became harder to Hit" is really the most interesting.  Dave's thinking was that going up in level equaled increased ability to survive.  Ability to survive - the characters defense against death - is wrapped in three stats: Saving Throws, Armor Class, and Hit Points.

Armor Class has its limits.  It's not much fun if characters and monsters are statistically invulnerable to being hit.  The same limitations apply to saving throws.  Hit Points are a lot more flexible.

For Dave, all three of these were subject to situational modification.  Armor Class and Saving Throws could get a bonus of +1 to +4, and that's still common in D&D.  Hit Point "values" (as he sometimes wrote it) were even more fluid; they changed from situation to situation.  Arneson’s early gaming material often mentions "double (or more) values".  the 1975 version of Temple of the Frog makes it clear that the key "defense value" of Hit Points could be doubled, trebled, even sextupled; ToTF: Pg 45. Breeding pond frogs “fight at Double value for 2-12 rounds” – but 3 hit points are the only value given; Pg 47. “double strength and HIT POINT VALUES”. (emphasis mine)

When Arneson created Hit Points for monsters and characters he didn't intend them to represent a one to one amount of physical damage a creature could take, or a one to one amount of luck or fatigue.  They didn't represent anything concrete and interchangeable at all.  Hit Points were a fluid abstraction for how many dice pips it took to turn it from living to dead or free to subdued.   This amount could change from situation to situation based on the creatures willingness and ability to fight, mostly.

In short, 1 Hit Point does not equal 1 Hit Point.  The value of a point is circumstantial and fluid and not the same from situation to situation or creature to creature. 


  1. Interesting points. I don't think anyone buys into Gygax's explanation anyway. Most people I ever played with always thought of hit points as representing toughness and closeness to death only, and enjoyed seeing their (and their opponents) reduced HPs as a sign of encroaching death.

    Gygax's explanation doesn't fit with the introduction of curative magic either. Why would luck be healed by a cure spell? It's contradictory.

    The explanation also doesn't hold up against another mechanic from AD&D onward: multiple attacks. Many monsters had multiple attacks even in OD&D, and from AD&D onwards so did PCs. If HPs represent just luck and fatigue, etc., why should anyone get multiple chances to reduce them, with each chance explicitly representing a different weapon? Why not just increase the monster's damage from its single attack? (This especially applies to PCs, who only ever use the one weapon).

    Gygax conceived as a round as a series of feints, parries and attacks, and even the "successful" hit doesn't necessarily hit the target, but backs them into a corner, reduces their energy to avoid the killing blow, etc. This doesn't seem to square with the use of multiple attacks with the same weapon, which instead implies multiple chances to hit from separate, discrete, defined attacks.

  2. Great points Faustusnotes! I don't think I heard that argument regarding multiple attacks before. Very interesting.

  3. In regards to faustusnotes, I'd always considered the healing spells to be more similar to faith healing when thinking of hit points as luck, combat skill and fatigue. That itself doesn't seem contradictory, though it may breed other issues if the "healed" doesn't follow the cleric's force of personality.

    As for Arneson's view of hit points, I must say I'm tickled right by that. A simple, flexible and fluid abstraction. Nothing more and nothing less.

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  5. I know this blog post is a bit old and all but I'm still having trouble seeing what is wrong with Gygax's explanation.

    If HP is luck, skill, fatigue and toughness... then CON should certainly affect HP since that ability score definitely affects toughness and fatigue. Luck comes from the value you roll when gaining HP. Skill results from Level. Its all there.

    Even the Cure Wounds spells still make sense. Healing closes minor wounds, removes fatigue and lays a blessing upon you (luck). All of which encourages you to do live up to your potential (skill).

    Iterative attacks represent multiple blows that cause surface damage, force you to engage in more elaborate parries (fatigue), whittle away at your fortune and hamper your ability to do your best (skill).
    (this isn't to say that I'm a supporter of massive iterative attacks or anything)

    To be honest I think the weirdest thing is that Armor doesn't add to HP. The "To-Hit Value" should be based on the character's ability to straight up dodge so I'd use Dexterity as a base "Evasion value" then apply a solid bonus based on class. Everything else is HP and saving throws based on ability scores.

    1. Ah, well the real issue is that HP are a very poor way to model both luck and fatigue. They were never intended to, and there are other rules - fatigue rules and saving throws - that already handle luck and fatigue. So there's redundancy if HP also does that. If HP are to represent fatigue, then you would really need to develop rules about how many HP you lose for loss of sleep, for forced marches, for being affected by a sleep spell or working too hard, etc. I don't even know how you would model good luck and bad luck using HP.
      Suppose for example your tenth level lord steps into the dungeon of doom and immediately falls into a 50' pit lined with spikes of sharpness +2, (whatever), and takes a massive amount of damage, leaving but 1 HP left. He isn't the least bit fatigued and luck only goes so far when you are being impaled on a bed of spikes. The damage is physical, but the 10th level fighter is able to take it because he is tough and experienced and knows how best to protect himself.

    2. In my own games I use HP penalties to represent fatigue so I think it works pretty well. That said, I don't use very detailed rules for such things anyways.

      I don't believe that embedding the idea of luck into multiple stats is necessarily a bad thing. Much of literature features Destined heroes and Lucky heroes. HP isn't static, it rises and falls. To me that is a good model for luck "running out" and also showing off the GAME aspect of a rpG as players mechanically manipulate their luck.

      Also, didn't you already say that HP should be fluid? It represents all of those things, some of those things and maybe even one of those things in any given situation. It doesn't make sense to track each HP loss in its own category because this isn't a simulation of life. It is a game. We forgo realism with abstraction for the sake of fun, right?

      Maybe the real problem is modeling what 0 HP means. Death? Not in my games. It is unconsciousness. An additional blow is required to deal death. (I'm not really a "hardcore" DM I guess)