Experience is not divided at first. Sensation, expectation and feeling mingle in a changing whole.
Intensity gives an impression its outline. What grows stronger stands out against what remains faint.
An impression becomes conscious when it enters a relation with the ego. The ego is the centre from which we are aware.
We can distinguish different activities within the same experience. Jung calls their separation and development differentiation.
Sensation perceives what is present through the senses. A flower has colour, texture and scent. We mark this function S.
Intuition perceives possibilities through unconscious processes. The same flower may suggest a connection before we can explain it. We mark this function N.
Thinking brings experience into conceptual relations. We recognise the flower as a kind of plant and explain how it grows. We mark this function T.
Feeling judges value: whether something matters, pleases us or is worth preserving. It is distinct from emotional intensity. We mark this function F.
S and N perceive. T and F judge. Within each pair, the two functions offer opposing approaches to the same experience.
One function can become especially developed and available to conscious direction. When it habitually leads, it is the dominant. Here, N leads.
The opposing function tends to remain less differentiated. Jung calls it inferior. With N leading, S occupies this less conscious position.
A second function supports the dominant with another kind of activity. Here thinking, T, helps judge what intuition, N, perceives.
Experience involves both a subject and an object: the one who experiences, and what is experienced.
In extraversion, the object and outward conditions carry greater determining weight. The arrow marks this outward orientation.
In introversion, the subject’s inner response carries greater determining weight. Both orientations occur in everyone.
Each function can be introverted, i, or extraverted, e. Four functions in two attitudes give eight forms. A habitual dominant gives each of Jung’s eight types its character.
To describe a dominant and auxiliary together, we need one perceiving function and one judging function: S or N, with F or T.
These two distinctions give four pairings: SF, ST, NF and NT. Along each edge, one answer changes and the other stays fixed.
NT contains intuition and thinking. Either can lead: N supported by T, or T supported by N. The pair alone leaves their order open.
Each pairing occurs in two orders. One square holds perception first; the other holds judgment first. Follow our NT pair into both.
Join corresponding corners. Four pairings in two orders give eight arrangements. The new edges change which function leads.
This face contains the four arrangements in which perception leads. Its corners differ in their perceiving function, S or N, and their supporting judgment, F or T.
The six faces hold six answers fixed: S, N, F, T, perception first or judgment first. They open around their shared edges.
The cube is now open. Each face contains four arrangements. Some corners appear more than once because their shared edges have been cut.
The faces close. Their repeated corners meet again. Eight arrangements form one cube.
The dominant can face inward or outward. Each of our eight arrangements therefore has two attitudes. The later model gives its auxiliary the complementary attitude.
Join the matching corners of these two cubes. Eight arrangements in two attitudes give sixteen. This fourth distinction completes the construction.
The result is a tesseract: sixteen corners and thirty-two edges. Each corner records perception, judgment, which leads and its attitude.
Follow the highlighted corner. Intuition leads inwardly, Ni. Thinking supports it outwardly, Te. We can now name this arrangement.
I names its inward dominant; N and T name its preferred functions. J says its outward function judges. Ni supported by Te is INTJ.
All sixteen arrangements receive four-letter names. J or P describes the outward function: judging or perceiving. For introverts, this is the auxiliary.
INTJ shares N with seven other types. Four lie on the inward cube, four on the outward cube. These are the two highlighted faces.
The faces and their connections form one cubic cell. All eight members share N; the other three distinctions remain open.
The inward cell contains the eight I types. We keep this cube fixed while the other seven open around it.
The tesseract has eight cubic cells. Its boundary opens into a three-dimensional net, just as the cube opened into a flat net.
Each cube holds one answer fixed. A type belongs to four cubes, one for each of its four answers. Their shared faces join the whole.
The eight cells close through the fourth dimension. Their shared positions meet. We see the folding through a projection.
The later four-function convention extends INTJ to Ni · Te · Fi · Se. Fi opposes Te; Se opposes Ni. These are the third and fourth positions.
INTJ and INFJ share Ni as dominant. Te supports one; Fe supports the other. This relation pairs the sixteen arrangements around eight dominant forms.
INTJ is Ni supported by Te. ENTJ is Te supported by Ni. The same two forms exchange leading and supporting roles.
INTJ is Ni with Te. ENTP is Ne with Ti. Their functions keep their order while both attitudes reverse.
Now compare the same types by their letters. The four distinctions become I/E, S/N, F/T and J/P. In this map, an edge changes exactly one letter.
Changing F to T carries INFP to INTP. Ne and Si retain their places; Fi and Te become Ti and Fe. One letter changes two function forms.
INTJ and ESFP differ in all four letters. Their function orders reverse: Ni · Te · Fi · Se becomes Se · Fi · Te · Ni.
Four edge steps connect these opposite corners. The straight diagonal joins the same endpoints through the centre.
Turn the view toward that diagonal. Its two endpoints approach the same place in the drawing. They remain distinct in the structure.
Eight positions surround the centre: four differ from INTJ by one letter, four by three. Their projected positions form a cube.
The remaining six positions differ by two letters. They form an octahedron within the same view.
Two cube corners and two octahedron corners share a plane. Four equal edges enclose a rhombus.
Twelve such rhombi enclose the crystal. Its form follows from the view we have constructed.
The original sixteen positions and thirty-two edges remain. We have changed the view, while preserving the connections.
Turn slightly. The two central positions separate. What appeared to be one was an overlap in the drawing.
A dominant gives consciousness a direction. Unconscious activity can compensate for its one-sidedness: neglected functions and possibilities begin to matter.
Individuation develops the particular person through a more conscious relation to these differences. The person becomes less identified with a single function.
Jung calls the conscious and unconscious personality together the Self. The ego belongs within this larger whole. A type describes a standpoint within it.