For other uses, see trichotomy (mathematics).

A trichotomy is a three-way classificatory division. Some philosophers pursued trichotomies.

Important trichotomies discussed by Aquinas include the causal principles (agent, patient, act), the potencies for the intellect (imagination, cogitative power, and memory and reminiscence), and the acts of the intellect (concept, judgment, reasoning), with all of those rooted in Aristotle; also the transcendentals of being (unity, truth, goodness) the requisites of the beautiful (wholeness, harmony, radiance).

Kant expounded a table of judgments involving four three-way alternatives, in regard to (1) Quantity, (2) Quality, (3) Relation, (4) Modality, and, based thereupon, a table of four categories, named by the terms just listed, and each with three subcategories. Kant also adapted the Thomistic acts of intellect in his trichotomy of higher cognition—(a) understanding, (b) judgment, (c) reason—which he correlated with his adaptation in the soul's capacities—(a) cognitive faculties, (b) feeling of pleasure or displeasure, and (c) faculty of desire[1]—of Tetens's trichotomy of feeling, understanding, will.[2]

Hegel held that a thing's or idea's internal contradiction leads in a dialectical process to a new synthesis that makes better sense of the contradiction. The process is sometimes described as thesis, antithesis, synthesis. It is instanced across a pattern of trichotomies (e.g. being-nothingness-becoming, immediate-mediate-concrete, abstract-negative-concrete); such trichotomies are not just three-way classificatory divisions; they involve trios of elements functionally interrelated in a process. They are often called triads (but 'triad' does not have that as a fixed sense in philosophy generally).

Charles Sanders Peirce built his philosophy on trichotomies and triadic relations and processes, and framed the "Reduction Thesis" that every predicate is essentially either monadic (quality), dyadic (relation of reaction or resistance), or triadic (representational relation), and never genuinely and irreducibly tetradic or larger.

Examples of philosophical trichotomiesEdit

Plato's Tripartite Soul Rational. Libidinous (desiring). Spirited (various animal qualities).
Plotinus' three principles The One. The Intellect. The Soul.
St. Augustine's 3 Laws[3] Divine Law. Natural Law. Temporal, Positive, or Human Law.
St. Augustine's 3 features of the soul[4] Intellect. Will. Memory. (St. John of the Cross, OCD follows this also, but may erroneously identify them as 3 distinct powers.[5])
St. Thomas Aquinas, OP's 3 causal principles[6] (based in Aristotle) Agent. Patient. Act.
Aquinas's 3 potencies for intellect[6] (based in Aristotle) Imagination. Cogitative power (or, in animals, instinct). Memory (and, in humans, reminiscence).
Aquinas's 3 acts of intellect[6] (based in Aristotle) Conception. Judgment. Reasoning.
Aquinas's 3 transcendentals of being[6] Unity. Truth. Goodness.
Aquinas's 3 requisites for the beautiful[6] Wholeness or perfection. Harmony or due proportion. Radiance.
St. Albertus Magnus's 3 Universals[7] Ante rem (Idea in God's mind). In re (potential or actual in things). Post rem (mentally abstracted).
Sir Francis Bacon's 3 Tables[8] Presence. Absence. Degree.
Thomas Hobbes's 3 Fields Physics. Moral Philosophy. Civil Philosophy.
Johannes Nikolaus Tetens's 3 powers of mind[2] Feeling. Understanding. Will.
John Dryden's 3 ways of transferring Metaphrase. Paraphrase. Imitation.
Korzybski's 3 types of life. Chemical-binder (i.e. plants). Space-binder (i.e. mammals). Time-binder (i.e. humans). Each one up the scale requires the previous one.
Kant's 3 faculties of soul[1] Faculties of knowledge. Feeling of pleasure or displeasure. Faculty of desire (which Kant regarded also as the will).
Kant's 3 higher faculties of cognition[1] Understanding. Judgment. Reason.
Kant's 3 judgments of quantity Universal. Particular. Singular
Kant's 3 categories of quantity Unity. Plurality. Totality
Kant's 3 judgments of quality Affirmative. Negative. Infinite
Kant's 3 categories of quality Reality. Negation. Limitation.
Kant's 3 judgments of relation Categorical. Hypothetical. Disjunctive.
Kant's 3 categories of relation Inherence and subsistence. Causality and dependence. Community.
  In other words:
Substance and accident. Cause and effect. Reciprocity.
Kant's 3 judgments of modality Problematical. Assertoric. Apodictic
Kant's 3 categories of modality Possibility. Existence. Necessity
Hegel's 3 dialectical moments Thesis. Antithesis. Synthesis.
Hegel's 3 Spirits[9] Subjective Spirit. Objective Spirit. Absolute Spirit.
Charles Sanders Peirce's 3 categories Quality of feeling. Reaction, resistance. Representation, mediation.
C. S. Peirce's 3 universes of experience Ideas. Brute fact. Habit (habit-taking).
C. S. Peirce's 3 orders of philosophy Phenomenology. Normative sciences. Metaphysics.
C. S. Peirce's 3 normatives The good (esthetic). The right (ethical). The true (logical).
C. S. Peirce's 3 semiotic elements Sign (representamen). Object. Interpretant.
C. S. Peirce's 3 grades of conceptual clearness By familiarity. Of definition's parts. Of conceivable practical implications.
C. S. Peirce's 3 active principles in the cosmos Spontaneity, absolute chance. Mechanical necessity. Creative love.
R. Steiner more threefold aspects. Body, soul and spirit. Imagination, inspiration and intuition.
Gottlob Frege's 3 realms of sense[10] The external, public, physical. The internal, private, mental. The Platonic, ideal but objective (to which sentences refer).
Karl Popper's 3 worlds[11] Physical things and processes. Subjective human experience. Culture and objective knowledge
James Joyce's 3 aesthetic stages[12] Arrest (by wholeness). Fascination (by harmony). Enchantment (by radiance).
Louis Zukofsky's 3 aesthetic elements[13] Shape. Rhythm. Style.
Søren Kierkegaard's 3 Stages[14] Aesthetic. Ethical. Religious.
Edmund Husserl's 3 Reductions Phenomenological. Eidetic. Religious.
Maurice Merleau-Ponty's 3 fields[15] Physical. Vital. Human.
Maurice Merleau-Ponty's 3 categories[15] Quantity. Order. Meaning.
Alan Watts's 3 world views Life as machine (Western). Life as organism (Chinese). Life as drama (Indian).
Saint Paul's tripartite nature of man (I Thes. 5:23) Body, soul, and spirit
Sigmund Freud's structural model Id, ego, and superego
Eric Berne's transactional analysis Parent, adult, and child
Jacques Lacan's 3 orders Real, Symbolic, and Imaginary

See alsoEdit


  1. ^ a b c Kant, Immanuel, The Critique of Judgment, 2007 edition, Cosimo Classics, pp. 10-11.
  2. ^ a b Teo, Thomas (2005), The critique of psychology: from Kant to postcolonial theory, p. 43.
  3. ^ Augustine through the Ages (1999), p. 582.
  4. ^ St. Augustine of Hippo, De Trinitate, 10, 11; Encyclopedia of Christian Theology, Volume 1 (2004), page 54. See St. Augustine of Hippo, De Trinitate, 14. St. Thomas Aquinas, OP explains that St. Augustine does not identify these 3 features as "powers" of the soul. St. Thomas Aquinas, OP, Summa Theologiae, Prima Pars, Q. 79, A. 7, ad 1.
  5. ^ St. John of the Cross, OCD, Doctor, The Ascent of Mount Carmel, Book 2, Chapter 6, §1.
  6. ^ a b c d e See The Pocket Aquinas (1991).
  7. ^ "St. Albertus Magnus" in the Catholic Encyclopedia. Eprint.
  8. ^ "Francis Bacon, Viscount Saint Alban", Eprint
  9. ^ Redding, Paul (1997, 2006), "Georg Wilhelm Friedrich Hegel" in the Stanford Encyclopedia of Philosophy. Eprint.
  10. ^ Klement, Kevin C. (2005), "Gottlob Frege (1848—1925)", Internet Encyclopedia of Philosophy.
  11. ^ Popper, Karl (1982), The Open Universe: An Argument for Indeterminism.
  12. ^ Joyce, James (1914-1915), A Portrait of the Artist as a Young Man, see Chapter 5, especially (but not only) lines 8215-8221.
  13. ^ Zukofsky, Louis, "A" – 12 (1966), and Prepositions (1967, 1981), p. 55.
  14. ^ McDonald, William (1996, 2009), "Søren Kierkegaard" in the Stanford Encyclopedia of Philosophy. See Section 6.
  15. ^ a b Merleau-Ponty, Maurice (1942), La structure du comportement, and published in English as The Structure of Behavior.