Attributes

Dungeons & Dragons, and most D&D based retro-clones, divide attributes (stats, ability scores, traits, etc) into physical and mental groups, presumably on purpose. The physical attributes are Strength, Dexterity, and Constitution; while the mental attributes are Intelligence, Wisdom, and Charisma. The physical attributes are clearly beneficial with mechanical applications that passively enhance players who invest enough in them. Mental attributes are ultimately useful only for specific classes. As a result the mental attributes are typically deemed dump-stats where low scores can be placed to favor more useful attributes.

D&D Attributes

Listed in order of overall utility, notwithstanding class requirements or personal preference, including descriptions of the attributes and overviews of their mechanical advantages:

• Constitution measures physical resilience and overall health. It is universally important for the extra Hit Points a high score can provide.
• Dexterity measures physical agility and hand-eye coordination. It is also universally important for Armor Class, and to a lesser extent ranged combat, never mind the other advantages poorly armored thieves gain for a high dexterity.
• Strength measures physical capacity for lifting, pushing, and other exertion, namely combat. Its value for any potential combatant is undeniable, and it offers escalating advantages to fighters by way of the exception strength sub-attribute (1e & 2e).
• Intelligence reflects general knowledge, learning potential, and arguably thinking and reasoning. It grants extra languages in 1e, which converts to additional non-weapon proficiencies in 2e, making it useful, but not crucial; but does allow extra spells and easier spell training for magic-users.
• Charisma reflects leadership, charm, and social skills, and is erroneously used as a measure of physical appearance. It is useful for those who often parley with NPC's and intelligent monsters (bringing the extra languages of intelligence into play) or for those gamers who utilize retainers or followers.
• Wisdom is variously considered common sense, reasoning, judgement, spiritual awareness, perception, empathy, etc. It offers a boost to mental saving throws, an oft forgotten perk. It also grants clerics some extra spell capability.

The mental attributes, namely wisdom, are a bit muddled, and provide few overwhelming advantages that cannot be adjusted for via player agency. Most of the mental attributes tend to affect things that happen off the clock, like training time and cost between gaming sessions or the price of room and board and return on fenced spoils, all of which are easily written off as the cost of surviving. Up until non-weapon proficiencies were introduced in 2e, there were few meaningful mechanics that relied on mental attributes, and even those were not significant enough to warrant making an undue investment in mental attributes that were not core to the character's class.

Next Steps

Several steps need to be taken to address this dump-stat mentality and attribute irrelevance in actual play. I feel the first step is resolving the idiosyncratic nature of mental attributes by making their nature consistent with the physical attributes, which I observed followed a model of potency (strength), adaptability (agility) and vitality (endurance). Below is my first effort at uniform attributes following this model:

Type:	Physical	Mental        D&D Equivalent
Strength	Strength	Knowledge   Intelligence
Agility	Dexterity	Acuity           Intelligence/Wisdom
Endurance	Constitution	Will              Wisdom

The first obvious issue with this is charisma no longer is on the matrix, which is unacceptable as charisma provided some of the most obvious opportunities for mechanical application in the form of reaction checks for NPCs. Also, this breakdown illustrates the fickle double duty shared by intelligence and wisdom, and the latter, being full of so many intangible aspects, only compounds the problem. 

My first thought, and presumably the obvious idea, is to add Appeal as a fourth type:

Type:	Physical	Mental
Strength	Strength	Knowledge
Agility	Dexterity	Acuity
Endurance	Constitution	Will
Appeal	Comeliness	Charisma

The problem here is that the corresponding physical attribute is physical attractiveness. Even granting aspects of grace and poise to this, and not just passive 'beauty', it is a highly subjective trait that I don't see as a numerically relevant for adventure-based gaming. It is also practically guaranteed to become a dump-stat: An ugly warrior or haggard wizard? No problem!

So I reexamined the basic model, and it's assumptions, but focused on the mental attributes mutability, particularly the ill-defined boundary between intelligence and wisdom, and the nebulous hints of dominion wisdom claimed over so many other traits. The more I looked, the more clear it was Wisdom was doing too much work, which made defining the roles of other mental traits difficult.

Epiphany

This brought me back to thoughts of other systems that separate the supernatural from the natural aspects of intellect, usually in the context of one or two attributes. What if I added a category covering the more ephemeral aspects of human capacity? Charisma certainly falls into that category, the art of inspiring and manipulating is not a learnable thing so much as a gift. One can learn skills to augment poor charisma (oration, et al), but there are those who lack such skills that are remarkable leaders or confidence men.

So I narrowed the scope of the mental category to testable mental capacities like calculation speeds, knowledge, pattern recognition, etc; and put the fuzzy bits that were left over into the new spiritual category:

Type:	Physical	Spiritual	Mental
Strength	Brawn	Presence	Knowledge
Agility	Dexterity	Intuition	Acuity
Endurance	Constitution	Will	Focus

With the addition of a third category, I gain a set of attributes explicitly for all those things that wisdom, intelligence, charisma, or even dexterity (as luck!?) often got inconsistently tasked with resolving in the golden age of gaming, or were managed by other mechanics like saving throws, or handled as class-based abilities.

• Brawn (PS): raw muscular development and capability.
• Dexterity (PA): physical reaction speed and coordination.
• Constitution (PE): overall bodily health, and resilience.
• Presence (SS): strength of personality and charisma.
• Intuition (SA): instincts, luck, and non-tangible perceptions.
• Will (SE): personal resolve and resistance to trickery.
• Knowledge (MS): learning potential and recall of information.
• Acuity (MA): perception of details and problem solving.
• Focus (ME): attention span and concentration.

What Next?

The next step, now that I have this matrix locked down and documented, is to establish value ranges for these attributes, and flesh out the mechanics that handle how to apply those numbers for opposed and unopposed checks. 

This attribute matrix is robust enough that it, possibly combined with a level or skill mechanic, is sufficient for use as saving throws. I also intend to detail a tiered, broad-to-narrow scope skill system, wherein all applicable skills add to the applicable attribute and a dice roll, and are compared to either a target number or opposed roll. I want this system to rewards skills without making them mandatory to make an attempt. I also expect the combat mechanics to be a uniform part of the skill system, so no single aspect of game play has a mechanical advantage, giving it the impression that one behavior is preferred over others.

Although I have increased the number of attributes by 150%, by doing so I have made things simpler. By standardizing the nature of the attributes by type and category, I have made a uniform system where every attribute has a discernible purpose; unlike attribute systems with multiple arbitrary or ambiguous stats and setting specific jargon.

Attribute Naming

I have obviously adopting alternates to some standard attribute names, and conversely, kept several existing ones in place. These choices were not made lightly, no matter how capricious the results appear, and were all made respecting this rule:

No attributes, categories, or types can have similar names or abbreviations.

I wanted the names of both Attribute Categories and Attribute Types to be easily understood while also encompassing their entire domain. Physical, Spiritual, and Mental are practical givens, ideal for their categories. Strength, Agility, and Endurance; using the categories as modifiers make perfect sense in every case, capturing all applicable subsets while clearly communicating the nature of each type. Individual attribute names are provided for flavor and were selected for their descriptiveness and simplicity.

The D&D mental attribute names Intelligence and Wisdom were rejected because those attributes are no longer represented by a single attribute, but by the Mental and Spiritual categories, respectively. Charisma has been combined with some interpretive aspects of Wisdom to form Presence, and the name change reflects this. Strength became Brawn to avoid confusion with the type name, per the rule, above.