Cracking the Code: The Logic Behind Model L's Dichotomy Names

Model L, developed by Kimani White and Aleesha Lowry, introduces a precise system of codes for its sixteen function dichotomies: names like G3, U1, R2, I4. Once you see the logic behind them, the whole architecture snaps into focus.

Why bother with the codes at all?

Model L splits each of Model A's seven function dichotomies into two separate dichotomies, giving fourteen in total, plus a fifteenth that Model A treats as a background assumption. That's a lot of dichotomies to keep track of. The code system is how Kimani keeps them organised: not arbitrary shorthand, but a genuine map of where each dichotomy sits in the architecture and what kind of work it does.

Each code has three components: a class prefix, OD or CD; a letter, G, U, R, or I; and a number from 1 through 4. All three mean something.

The numbers: where in the architecture does this sit?

The simplest piece first. The number just tells you which of the four paired sections the dichotomy belongs to.

Model L organises its dichotomies into four pairs of sections, from most fundamental to most peripheral:

• Level 1: Parameter and Facet dichotomies. The bedrock: what exists in the system at all, and how strong or accessible each function is.
• Level 2: Vector and Tract dichotomies. How things appear in awareness, and what a type values as metabolic ends.
• Level 3: Perspective and Complex dichotomies. The perspective from which a type outputs information, and how it reaches assessments and decisions.
• Level 4: Orientation and Purview dichotomies. How attention is distributed, and what domains consistently occupy a type's focus.

G1, U1, R1, and I1 all belong to Level 1: the most foundational. G4, U4, R4, and I4 all belong to Level 4: the most peripheral. The number is simply a depth marker.

OD and CD: two different kinds of work

Within each level, the dichotomies divide into two classes.

OD, Ordinal Dichotomies, deal with the intrinsic conditions of the system: the structural properties that define what functions fundamentally are at that level. They're about states and axes: what condition things are in, what axis they operate on.

CD, Capacity Dichotomies, deal with how types characteristically use those functions: orientations, tendencies, and styles that differentiate one type from another. Kimani names the tetrachotomy produced by crossing the two CD I dichotomies the Capacity groups, A, B, C, D, which gives the game away. CD means Capacity Dichotomy.

Think of OD as describing the terrain, and CD as describing how a type moves through it.

G and U: the two ordinal flavours

Within each OD section, there are always two dichotomies, labelled G and U.

G, Global, dichotomies set the broadest condition of the functional field at that level. They describe the state of the system:

• G1 asks: does this function belong to the socion at all? Valid or Null.
• G2 asks: what state is information in when it reaches awareness? Dynamic or Static.
• G3 asks: what is the overall frame from which a type dispenses its outputs? Pivotal or Contingent, roughly the J/P distinction at the function level.
• G4 asks: how is conscious focus distributed? Intensive, narrowing to depth, or Extensive, spreading to breadth.

U, Universal, dichotomies set the underlying axis or mode that runs through the system at that level:

• U1 is the big one: the 15th Reinin dichotomy itself, the Metabolic Axis, Conduct/Transduction, the axis that defines whether a type's specialisation runs through the Central functions of Model A or the Radial functions unique to Model L.
• U2 asks: what is a type's universal mode of engaging with information? Divergent, expanding outward, or Convergent, consolidating inward.
• U3 asks: what does composing a metabolic output require? Constitutive, where the process itself is the thing, or Extrinsic, where the result is defined separately from the process.
• U4 asks: what universal kind of concern draws a type's attention? Constructive, reinforcing favoured conditions, or Corrective, addressing problems.

G names tend to describe conditions or fields: Identity, State, Frame, Concentration. U names tend to describe axes, modes, and prerequisites: Axis, Engagement, Requisite, Concern. Both are ordinal because they describe the structure itself, not how a type navigates it.

R and I: the two capacity flavours

Within each CD section, the two dichotomies are labelled R and I, and these carry a deliberate double meaning.

In socionics, the eight aspects divide into two families. The Rational aspects are the Judging functions: Laws, Pragmatics, Relations, and Emotions. The Irrational aspects are the Perceiving functions: Senses, Force, Telos, and Ideas.

R and I map directly onto those families.

R, Rational, dichotomies govern the Rational/Judging dimension of capacity. The very first R dichotomy, R1 Longitudinal Facing, has poles Objective (T.) and Subjective (F.). Those are exactly the two Rational aspect families. Cross R1 with I1 and you get the four clubs: Rational x Irrational = four combinations. That's the Capacity tetrachotomy. The derivation is right there in the structure.

I, Irrational, dichotomies govern the Irrational/Perceiving dimension. I1, Latitudinal Facility, has poles Concrete (S.) and Abstract (N.): the two Irrational aspect families.

The R and I labels aren't just filing codes. They identify which family of aspects each dichotomy is fundamentally about.

Putting it together: G3 and U3

Take the Level 3 ordinal pair as a concrete example.

Level 3 is the Perspective level, corresponding to the Accepting/Producing, or Necessitating/Supplying, distinction in Model A: the question of how types handle the input and output of metabolic information.

G3, Dispensatory Frame, sets the global frame from which a type primarily outputs metabolites. A Pivotal type dispenses from a Perceptual perspective, channelling inputs and outputs. A Contingent type dispenses from a Judicious perspective. The word "Dispensatory" tells you it's about output; "Frame" tells you this is the G-type question: the broad framing condition of the field.

U3, Compositive Requisite, sets the universal requirement for how a type goes about constructing those outputs. Constitutive types deal in the process itself as the thing of value. Extrinsic types treat the result as defined separately from the process. "Compositive" tells you it's about construction; "Requisite" tells you this is the U-type question: the underlying mode or prerequisite.

Cross them and you get the Ensemble groups: the four combinations of output-frame and compositive-requirement that sit beneath what Model A calls the Necessitating/Supplying split. Two of those combinations have Model A equivalents, the Accepting and Producing functions. The other two are Radial positions that only become visible in Model L.

That's the payoff. Once you know what the code means, you know not just what a dichotomy does but why it belongs where it does.

The map in full

Once you see it, you can't unsee it. Model L's code system isn't notation layered over a theory: it is the theory, compressed into two letters and a number. Every dichotomy tells you its class, its family, and its depth, all at once.

Model L was developed by Kimani White and Aleesha Lowry. Visit tetratypes.org.uk for a full reference.