Mercurius
Legend
In regards to Hit Points - I have always assumed that they are a hold over from D&D's wargaming roots - a man at arms had one hit point, a character model had more.
In D&D the assumption remains kind of the same - a man at arms has D8 Hit Points, and a longsword does D8 Damage.
They then modified up and down from there - a wizard is twice as likely to die from a hit by a longsword than a man at arms is. A fighting man somewhat less.
It is also why a combat round used to be a full minute - trying to correlate a tabletop wargames passage of time with that of a role playing game.
So, consider the Hit Point a wavicle - it behaves as an abstract unless you are observing it, then it behaves as a concrete.... The concept is abstract, but the game effects need to be empirical.
In other words, they are both abstract and concrete, so game mechanics on some level echo quantum mechanics.
The Auld Grump
Interesting thinking here, although the problem is that it starts falling apart the higher level you go, or at least the more abstract hit points become. A 1st level character can be slain by a single weapon strike from an opponent of any level; a 10th level cannot, unless it is from a very powerful opponent. But what happens when an orc scores a critical hit on a 10th level character? They lose HP, but not a devastating amount. What then is a "critical hit"? In the rules as written--in pretty much any edition, afaict--an orc can never deal a death-blow to a high level character. It just isn't possible with some sort of house rule. Why? Because hit points don't represent merely physical damage capacity, and this becomes even more so the case at higher levels.
I don't have a problem with hit points not being realistic--it fits the epic feeling of D&D. The 3rd edition of Talislanta was re-designed by none other than Jonathan Tweet, one of the main designers on 3E D&D. Talislanta, especially 3e (and later editions) has a very similar basic structure to D&D 3E and d20 games in general. But in Talislanta, characters have armor points, and less hit points, and HP represent actually bodily damage capacity.
I would suggest that HP-as-body points requires something akin to armor points or damage reduction. In a sense, damage reduction and HP as they are, are redundant--might as well just give a creature more HP. But if we want HP to represent the body and the body only, then we would need to tease out skill (via increased defense), damage reduction (perhaps armor points or an armor protection value to reduces damage), and perhaps even some kind of X-Factor, like a fate/karma/luck mechanism that allows a PC to ignore damage of a given attack once-every-so-often.
Just thinking aloud here.