The term 'Fourth' occupies a position of extraordinary conceptual density within the depth-psychology corpus, functioning simultaneously as a structural, symbolic, and transformative category. Its primary locus is the Jungian theory of the four psychological functions, where the inferior — or fourth — function stands apart from the three differentiated functions as the threshold between consciousness and the deeper strata of the unconscious. Von Franz's Lectures on Jung's Typology establishes that the fourth function cannot simply be raised to consciousness; rather, contact with it precipitates a reorganization of the entire psychic economy, dissolving the tyranny of the dominant function. Jung's own writings situate the 'fourth' within a far broader symbolic field: the axiom of Maria Prophetissa, the Platonic question in the Timaeus ('where is the fourth?'), the Gnostic and alchemical quaternities, and the space-time quaternio of Aion all converge on the same structural insight — that wholeness requires the addition of an incommensurable, often shadowed, fourth term to any triad. The persistent tension between three and four — trinitarian thinking versus quaternary completion — is identified by Jung and amplified by von Franz and Edinger as a wound running through Western religious and intellectual history. The fourth is characteristically feminine, chthonic, and archaic; it corresponds variously to the devil, to Mary, to Mercurius duplex, to the inferior function contaminated by the collective unconscious. Its integration is the sine qua non of individuation.
In the library
21 passages
the fourth, undifferentiated, "inferior" function is undomesticated, unadapted, uncontrolled, and primitive. Because of its contamination with the collective unconscious, it possesses archaic and mystical qualities
This passage directly identifies the fourth function as the psychologically primitive, unconscious-contaminated complement to three differentiated functions, grounding the Jungian typological schema in the Platonic axiom of Maria Prophetissa.
Edinger, Edward F., The Psyche in Antiquity, Book One: Early Greek Philosophy From Thales to Plotinus, 1999thesis
The Other, the fourth, corresponds in the Gnostic quaternities to the fiery god, 'the fourth by number,' to the dual wife of Moses... to the fire in the alchemical quaternio of elements, to Mercurius duplex
Jung demonstrates that across Gnostic, alchemical, and cosmological schemas, the fourth term consistently represents an incommensurable and paradoxical Other necessary for the mutual determination of any quaternary totality.
Jung, Carl Gustav, Aion: Researches into the Phenomenology of the Self, 1951thesis
one cannot bring the fourth function up to this same level. On the contrary, if one tries too hard, the fourth function will pull ego-consciousness down to a completely primitive level.
Von Franz articulates the structural asymmetry of the fourth function: unlike the first three, it resists assimilation into civilized consciousness and threatens regressive dissolution of the ego if approached naively.
Marie-Louise von Franz, James Hillman, Lectures on Jung's Typology, 2013thesis
side by side with the distinctive leanings of alchemy (and of the unconscious) towards quaternity there is always a vacillation between three and four which comes out over and over again
Jung, cited by von Franz, identifies a persistent oscillation between trinitarian and quaternary models in alchemy and the unconscious, with the fourth element — often earth or fire — occupying a specially ambiguous, isolated position.
von Franz, Marie-Louise, Aurora Consurgens: A Document Attributed to Thomas Aquinas on the Problem of Opposites in Alchemy, 1966thesis
People who stick in this phase never quite understand what Jung means by the problem of the fourth, and they never quite understand what individuation really means.
Von Franz equates genuine confrontation with the fourth function — rather than brief forays into its territory — with the very meaning of individuation, making avoidance of the fourth a failure to complete the transformative process.
Marie-Louise von Franz, James Hillman, Lectures on Jung's Typology, 2013thesis
the problem of the four functions in the consciousness of an individual is one of the many manifestations of this more general archetypal disposition... it would therefore be dangerous to reduce the dogma of the Trinity and the problem of the fourth
Von Franz argues that the quaternary archetype — including the problem of the fourth — is a more fundamental psychic orientation pattern than the functional typology derived from it, warning against reductive equation of the two.
von Franz, Marie-Louise, Psychotherapy, 1993thesis
The 'fourth' is something special, ambivalent — a daimonion. A good example of this is in Daniel 3: 24f., where the three men in the burning fiery furnace are joined by a fourth, whose form was 'like a son of God.'
Jung identifies the archetypal quality of the fourth as inherently ambivalent and daemonic, illustrated through the Naassene Euphrates symbol and the biblical fourth figure in the furnace, both of which carry numinous and paradoxical significance.
Jung, Carl Gustav, Aion: Researches into the Phenomenology of the Self, 1951thesis
the step from three to four appears too difficult, we often find in the unconscious material a doubling of these numbers, and the problematical step is then from seven to eight, so that the inferior function appears to have been reduced by half.
Von Franz describes how the psyche can displace the difficult step from three to four by doubling all numbers, so that the confrontation with the inferior fourth function is deferred to the threshold between seven and eight.
von Franz, Marie-Louise, Aurora Consurgens: A Document Attributed to Thomas Aquinas on the Problem of Opposites in Alchemy, 1966supporting
Jung, moreover, says that the step from three to four is painful, because in the psyche it is associated with painful insights into ourselves... the number four can, by the very fact of the confrontations, be a powerful step toward wholeness.
Drawing on Jung, Hamaker-Zondag frames the number four as the locus of painful but potentially wholeness-generating self-confrontation, noting that four's own internal duality (2+2, 2×2) mirrors the tensions inherent in the inferior function.
Hamaker-Zondag, Karen, Tarot as a Way of Life: A Jungian Approach to the Tarot, 1997supporting
the inferior function is really the bridge to the experience of all the deeper layers of the unconscious. Going and staying with it... effects a radical change in the whole setup of the personality.
Von Franz characterizes the inferior — fourth — function as the bridge to the collective unconscious, whose sustained engagement, rather than mere transient contact, produces a radical transformation of the entire psychic structure.
von Franz, Marie-Louise, Psychotherapy, 1993supporting
the number four symbolizes man's orientation to reality as a human being. One pictorial representation of the number four is a square, symbolic of the order superimposed by Logos
Nichols situates the number four within the broad symbolic tradition of human orientation — four elements, four seasons, four functions — arguing that the square geometry of four represents the imposition of rational order upon lived reality.
Nichols, Sallie, Jung and Tarot: An Archetypal Journey, 1980supporting
Von Franz emphasizes that within Jungian psychology three constantly recurs as a dynamic process... The form does not come into being until the following number: four.
Hamaker-Zondag, following von Franz, presents three as dynamic process and four as the attainment of stable form, establishing the structural logic by which the fourth term completes and consolidates what three has set in motion.
Hamaker-Zondag, Karen, Tarot as a Way of Life: A Jungian Approach to the Tarot, 1997supporting
Like the four seasons and the four quarters of heaven, the four elements are a quaternary system of orientation which always expresses a totality.
Jung identifies the quaternary structure — manifested in seasons, spatial directions, and elements — as a universal orienting schema that expresses psychic totality, linking Paracelsian cosmology to the archetypal pattern of the Self.
Jung, C. G., Collected Works Volume 3: The Psychogenesis of Mental Disease, 1907supporting
the quaternity and the cross signify wholeness. Thus Paulinus of Nola says: Extended on the four arms of the wood of the cross, he reached out to the four quarters of the world
Jung traces the apotropaic and cosmological significance of the cross as a quaternary symbol of wholeness, connecting the fourfold extension of Christ's crucifixion to the archetypal pattern of orientation across the four world-directions.
Jung, C. G., Collected Works Volume 3: The Psychogenesis of Mental Disease, 1907supporting
Touching the inferior function resembles an inner breakdown at a certain crucial point of one's life. It has the advantage, however, of overcoming the tyranny of the dominant function in the ego complex.
Von Franz describes the encounter with the fourth inferior function as a crisis that liberates the ego from the tyranny of its dominant function, enabling a more flexible, tool-like relationship to all four functions.
Marie-Louise von Franz, James Hillman, Lectures on Jung's Typology, 2013supporting
The driving forces that work themselves out in this thinking are not conscious motives; they spring from an historical occurrence rooted, in its turn, in those obscure psychic conditions for which one could hardly find a better or more succinct formula than the 'change from father to son'
Jung's analysis of trinitarian thinking as driven by impersonal collective psychic forces — representing a movement from unity to duality — provides the historical-psychological background against which the problem of the missing fourth becomes intelligible.
Jung, Carl Gustav, Psychology and Religion: West and East, 1958supporting
Nature herself, deriving her origin from the Godhead, also lays claim to this number as to her fundamental principle.
Pauli's alchemical source presents the quaternary as Nature's own foundational principle, derived from the divine Tetragrammaton, supporting the Jungian claim that the number four reflects an archetypal ordering pattern permeating both psyche and cosmos.
Pauli, Wolfgang, Writings on Physics and Philosophy, 1994supporting
we see, first of all, an indication of the quaternary in the cross, four lines being arranged so as to meet in a common point. Joined with the number 3, which denotes the moon, the sun, and fire, this [quaternary] will produce the number 7
Pauli's symbolic image of the cross demonstrates how the quaternary and the Trinity interact to generate further symbolic structures, illustrating the mathematical-archetypal relationship between three and four in Keplerian natural philosophy.
Pauli, Wolfgang, Writings on Physics and Philosophy, 1994supporting
The lapis quaternity, which is a product of alchemical gnosis, brings us to the interesting physical speculations of alchemy... the four spheres are filled with fire.
Jung identifies the alchemical lapis quaternity — illustrated by Maier's four elemental fire-spheres — as a product of Gnostic speculation that encodes the same quaternary totality operative in psychological and cosmological symbolism.
Jung, Carl Gustav, Aion: Researches into the Phenomenology of the Self, 1951supporting
The fourth house, related to the Moon and the sign Cancer, traditionally represents such matters as your home, mother, base of security, and heredity or parental influence.
Cunningham's astrological treatment assigns the fourth house to lunar, maternal, and security themes, offering an analogous quaternary structure in the horoscopic wheel that parallels — though does not directly engage — depth-psychological conceptions of the fourth.
Donna Cunningham, An Astrological Guide to Self-Awareness, 1982aside
history was divided into three great aeons: the period of the Old Testament, which was the time of the Father... the first
Von Franz's summary of Joachim of Fiore's three-aeon historical schema illustrates the trinitarian framework that Jung's psychology identifies as structurally incomplete without a fourth term.
von Franz, Marie-Louise, Psyche and Matter, 2014aside