Divine Simplicity and the Trinity Explained

Below is a piece explaining my contribution to Catholic theology. In a nutshell, I reconfigure the classic concept of divine simplicity by reinterpreting the internal distinctions of the Trinity as irreducible relational modes – a perspective partly informed by Aquinas’s and St. Augustine’s foundational insights on the unity of God. Drawing on Jiri Benovsky’s work on primitives and their relations, my model demonstrates how an undivided essence can be fully compresent in distinct modes without implying any compositional parts. I also attempt to echo Jean‑Luc Marion’s phenomenology of givenness-albeit in language that is still evolving form me-to underscore that the complete act of self‑donation by a divine Person is fundamental to understanding divine nature. Additionally, my approach incorporates elements of Ratzinger’s emphasis on the relational nature of the divine, thereby bridging classical scholasticism with modern metaphysical insights; ultimately, my synthesis unites the classical notion of full actuality (God’s complete, undivided being) with dynamic relationality, demonstrating that divine self‑givenness manifests as both absolute perfection and a living, interpersonal exchange among the divine Persons.

Please note, I wrote this before I developed “The Principle of Relationality.” The references to the SSGO are what I now call the principle. You can read more about said principle on my main page where I’ve written two comprehensive papers on the subject.

[6,000 words, 20 minutes read time]

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Reconciling Divine Simplicity with Trinitarian Relationality

Introduction

One of the most profound theological challenges is holding together two bedrock truths of Catholic doctrine: Divine Simplicity (the teaching that God is absolutely one and has no “parts”) and Trinitarian Relationality (the reality that the one God is Father, Son, and Holy Spirit-three distinct Persons in loving communion). At first glance these truths seem in tension-how can God be utterly one and simultaneously a triune communion of distinct relations? Critics have long pointed to an apparent contradiction: if each divine Person is fully God, does this not divide God’s nature, or conversely, does a simple God leave no room for real interpersonal relations? Catholic theology, however, has developed a nuanced synthesis over the centuries that affirms both God’s indivisible unity and God’s tri-personal life without compromise. This paper provides a rigorous examination of that synthesis, engaging classical formulations and modern insights to show that God’s simplicity and God’s triune relationality not only coexist but mutually illuminate each other. We will survey the historical foundations of divine simplicity, the Church’s understanding of Trinitarian relations, the scholastic solution of subsistent relations, and more personalist approaches that emphasize communion. Contemporary philosophical critiques (such as the “modal collapse” or identity objections³⁰) will be briefly addressed alongside recent theological developments-including insights from Jean‑Luc Marion and the Self‑Standing Givenness Ontology (but full treatments or “questions” are dealt with my other work on this site). By integrating these perspectives, we will see that the Catholic doctrine of God’s triune life maintains God’s perfect oneness even as Father, Son, and Spirit exist in eternal self‑giving love. In short, the Trinity does not undermine divine simplicity-it reveals the fullness of God’s one being as an infinite act of relational love.¹

Divine Simplicity in Classical Doctrine

Divine Simplicity means that God is not composed of parts, properties, or any internal divisions-God is the fullness of being, utterly unified and indivisible. The Catholic tradition has affirmed this dogmatically from an early date. For example, the Fourth Lateran Council (1215) taught that God is “an absolutely simple substance or nature.”² In God there is no composition of form and matter, essence and existence, or substance and accidents.² In essence, God’s attributes (goodness, wisdom, power, etc.) are not “pieces” that make up God; each is identical with the one simple essence of God. The Catechism of the Catholic Church summarizes this succinctly: “In God, the divine nature is one and the same… Each of the persons is that supreme reality, viz., the divine substance, essence or nature.”² Because God is the ultimate reality (ipsum esse subsistens) and “pure actuality” with no unrealized potentiality, nothing in God can be added, subtracted, or divided.²

This absolute oneness does not imply that God is a featureless monolith; rather, it safeguards God’s self‑existence and independence. Created beings are composites (matter–form, soul–body, essence–accidents, etc.), which is why they can change or fall apart. But God is actus purus, with no parts needing assembly and no traits that could be lost-God is One in the most radical sense of unity. Scripture itself hints at this when declaring “the LORD is one” (Deut 6:4); there is no suggestion of an “assembled deity” or a divisible godhead.³ Any conception of God as composed of lesser components would fall short of the biblical and philosophical understanding of the Almighty. Thus, Catholic theology insists that whatever is in God is God. As one medieval slogan puts it, “Everything in God is God,” meaning all that is in the divine nature is identical with the divine essence (with the sole exception of the distinct relations between the Persons, as we shall see).² Moreover, the Fourth Lateran Council expressed this by declaring, “there is only one true God… eternal, immense, unchangeable, incomprehensible, omnipotent, ineffable,” and that this one God is Father, Son, and Holy Spirit without “any division.”² In short, divine simplicity upholds that God’s nature is undivided and indivisible-the one absolute being upon which all else depends.

Trinitarian Relationality in Scripture and Tradition

Alongside God’s oneness, Christianity proclaims that the one God is a Trinity of Persons. The Father, Son, and Holy Spirit are really distinct from one another-not merely different names or roles.² The New Testament reveals this tri‑personal reality: the Father and Son love one another; the Son speaks to the Father; the Holy Spirit is sent by the Father and Son; etc. Yet the Bible equally insists there is one God. For example, in 1 Corinthians 8:6, St. Paul deliberately echoes the (Septuagint) Shema: “For us there is one God, the Father… and one Lord, Jesus Christ,” thereby including Jesus in the unique identity of the one Yahweh.⁴ The early Church was careful to include the Son and Spirit in the Godhead “without fragmenting the one God.”⁴ They “insisted upon [the Son and Spirit’s] shared divinity, yet without” dividing God’s unity.⁴ This “triadic” understanding of the one God was present long before formal councils-the New Testament’s portrayal of Father, Son, and Spirit constitutes a “proto‑Nicene” Trinitarianism organically rooted in Scripture.⁴

Over the centuries, Church doctrine clarified this mystery. The classic formula is one divine ousia (essence or substance) in three hypostases (Persons). The three Persons are not three separate beings or three gods, nor are they simply roles played by a single Person-they are true interpersonal relations within the one Godhead. The Father is God, the Son is God, and the Spirit is God-each is fully, equally, and eternally the one God in substance.² And yet the Father is not the Son, nor is the Son the Spirit.² How is this possible? The key lies in the nature of the relations of origin: the Father is God as the unbegotten source; the Son is God as begotten of the Father; and the Spirit is God as proceeding from the Father (and Son). These relations are the only distinctions in God. “Fatherhood” and “Sonship” (and the spiration of the Spirit) distinguish the Persons relative to one another but do not divide the divine nature. As the Catechism states, “The real distinction of the persons from one another resides solely in the relationships which relate them to one another… While they are called three persons in view of their relations, we believe in one nature or substance. Indeed ‘everything (in them) is one where there is no opposition of relationship.’”² In other words, Father, Son, and Spirit are “two” or “three” only in their mutual relations, not in their essence. Apart from their relational opposition (e.g. Father versus Son), all that they are is the one infinite being of God-one power, one wisdom, one will, one substance. This crucial principle, drawn from St. Augustine and centuries of reflection, allows theology to affirm real distinctions (the Father is not the Son) without positing any parts in God. The divine Persons are not partitions of the divine essence but the personal manner in which the one essence subsists.

The Church Fathers employed analogies such as mind, word, and love-or the sun, its radiance, and its warmth-to illustrate how three can exist in unity. Yet they always fell short of fully capturing God. St. Gregory of Nazianzen, one of the great Cappadocian Fathers, famously insisted that when we contemplate God, “Nothing then is peculiar [to one Person], because all things are in common. For Their Being itself is common and equal, even though the Son receive it from the Father.”⁵ He further concluded that “it is impossible and inconceivable that the Son should do anything that the Father doeth not… for all things that the Father hath are the Son’s.”⁵ This patristic testimony reinforces that the Trinity is not a division of labor or essence-everything the one God is and does is fully present in each Person, albeit in the mode proper to each (as source, as begotten, as proceeding). Later councils (such as that of Florence in 1442) echoed this with the formula: “Each of the three persons is one and the same God… because of this unity the Father is wholly in the Son and wholly in the Holy Spirit.”² In sum, Trinitarian relationality means that the one indivisible divine essence exists in three relational ways. God is “one but not solitary”²-the unity of God is a living, communicative unity of Father, Son, and Holy Spirit.

Scholastic Reconciliation: Subsistent Relations and Unity

Medieval scholastic theologians-especially St. Thomas Aquinas-provided the classic resolution to the paradox by teaching that the divine Persons are the mutual relations in God and that these relations subsist as the Persons. In God, “Person = Relation.”⁶ The Father is paternity, the relation of giving existence to the Son; the Son is filiation, the relation of being begotten; and the Spirit is the spiration-the relation of proceeding love. These relations of origin are not qualities that God acquires; they are the eternal outgoing and incoming of the one divine essence. Aquinas argued that relation in God, unlike in creatures, does not introduce accident or composition because, in an infinite, simple being, relation is identical with the divine essence (that is, it is the essence as oriented toward another). In technical terms, these are “subsistent relations” – real relations that are the Persons themselves. Thus, the Father is “God in the mode of Fatherhood,” the Son is “God in the mode of Sonship,” and the Spirit is “God in the mode of proceeding.”⁶ Crucially, this means that the Father is not a “part” of God or a piece added onto the divine nature; the Father just is the one divine nature existing as Father. Likewise, the Son isn’t “God plus begottenness”-his very sonship is the one simple Godhead received from the Father. As one modern explainer puts it, “The Father… is not ‘God plus fatherhood,’ but simply God’s entire essence in the stance of unbegotten. The Son is God’s entire essence in the stance of begotten, and the Spirit is God’s entire essence in the stance of proceeding.”⁶ Because these relational “stances” add no extra content or parts to God (they are ways the one essence is lived, not additions to it), God remains absolutely one and noncomposite.⁶ Each Person fully is the simple divine essence, differing only in the relational orientation inherent to their identity.

Aquinas’ solution can be summed up in an axiom-like phrase roughly: “What is distinct in God is only the relations; what is not relational is not distinct.” In God, everything that does not involve the opposition of Father versus Son (or procession) is literally the same single reality. This preserves divine simplicity impeccably: the divine power, knowledge, goodness, and essence are one across Father, Son, and Spirit. They do not each have a third of the power or knowledge; each one is the one omnipotence, the one omniscience-the one God. The only differentiation is that the Father possesses the divine nature as Source, the Son as Begotten of the Father, and the Spirit as proceeding from the love of Father and Son. Thus, any property that would imply division or inequality (e.g., being Creator, almighty, eternal) belongs equally to all Persons and is identical with the one essence. The distinctions remain solely in how they relate to one another: the Father is unbegotten (has no origin), the Son is begotten by the Father, and the Spirit proceeds from the love of Father and Son-relations that, by definition, contrast each Person relative to the others but do not partition God’s essence.

This relational distinction without compositional difference is a unique type of reality-unlike anything in the created order-and is part of the divine mystery. God is uniquely unique, and Joseph Ratzinger (Pope Benedict XVI), engaging St. Augustine and Aquinas, phrased it beautifully: “In God, person is the pure relativity of being turned toward the other… the person is relation, not substance. God remains one substance, while as person‑in‑relation is ‘Tri‑Unity.’”¹⁷ In other words, the very meaning of “Person” in God is different from that in creatures: a divine Person is not a separate center of being but exists only in relation to another Person. The Father exists as Father for the Son; the Son as Son of the Father; and the Spirit as the bond of Father and Son. Each is that relation of self‑giving and receiving-and nothing more. Ratzinger further notes that “the person exists only as relation… Father, Son, and Holy Spirit are real, existing relations, and… they are that one God.”⁷ This remarkable idea means that the highest form of unity-God’s unity-contains relationality within itself as identical with itself. Far from relations “adding” something to God, the relations are God; each one constitutes a distinct Person precisely by being entirely constituted by relation. This scholastic (and post‑scholastic) consensus-that the Trinity is one nature in three subsisting relations-became the cornerstone of Catholic teaching. It allows theologians to say, for example, that “the Father = God,” “the Son = God,” and “the Holy Spirit = God” without implying that Father, Son, and Spirit are conflated into one Person. The phrase “Father = God” is understood to mean that “the Father fully possesses the one divine essence.”⁸ (The same holds for the Son and the Spirit.) In logical terms, the strict identity laws that apply to created beings (where if A = the one God, then no one else can be the one God) are nuanced by the fact that God is infinite and transcends creaturely modes of identity.⁸ Thus, the Father, Son, and Spirit are distinct whos but not distinct whats. Classical theology avoids the fallacy of treating “Father = God” as a solitary equivalence that would exclude the Son by recognizing that three distinct whos can share the one infinite what of God.⁸ In summary, Catholic scholasticism achieved a reconciliation: the Trinity of Persons does not break the unity of God’s being because the personal distinctions are nothing but the eternal relations of origin inherent in the one being of God, fully possessed in three modes. As one saying goes, “All in God is God”-except for the mutual relations, which constitute the Persons.² Thus, divine simplicity remains intact: God has no parts or composition, only the self‑relational life of Father, Son, and Holy Spirit-which itself is the indivisible divine essence.

Personalist and Eastern Approaches: Being‑as‑Communion

While scholastic theology articulated the Trinity in terms of relations of origin and essence, Eastern Christian and modern personalist theologians have approached the mystery from another angle-starting with the Persons and their communion. The Cappadocian Fathers of the fourth century (Basil, Gregory Nazianzen, Gregory of Nyssa) famously emphasized that the one God is not an abstract essence but the Father, from whom the Son is begotten and the Spirit proceeds. In Eastern thought, personhood (hypostasis) has primacy-seeing the Father as the personal source of the Godhead. Although this risks being misread as making the essence secondary or divided, the intention is to underline that God’s being is intrinsically relational and communal. Metropolitan John Zizioulas, a contemporary Orthodox theologian, explains: “God exists as a Trinity of persons, and His Trinitarian existence does not follow logically from His essence, but determines it ontologically, since the divine essence is hypostasized only as persons‑hypostases; without the persons the essence remains ‘non‑hypostasized’ (anhypostatos), i.e. non-existent. God’s being is understood only as communion.”⁹ In this view, it is not that an impersonal essence “decides” to be triune; rather, God is Father, Son, and Spirit-and thus communion-from all eternity, and this communion of Persons is precisely God’s one being. Zizioulas contrasts Eastern and Western approaches: whereas Latin theology (from Augustine onward) tended to give logical priority to the one essence over the three persons, Greek theology identifies the Person of the Father as the starting point of unity: “God is first and foremost the Father… But the concept of Father is (by definition) relational… Thus, the unity, the ‘one’ (the divine essence), does not ontologically precede the ‘many’ of the Trinity. The concept of ‘many’ is integrated into the concept of ‘one,’ since ‘one’ is the Father-a relational concept by definition.”⁹ In other words, the monarchy of the Father (the Father as sole source of Son and Spirit) does not undermine unity but grounds it dynamically: the oneness of God is the loving communion of the Father with Son and Spirit.

Eastern Fathers like St. Gregory Nazianzen also guarded simplicity while speaking in these terms. Nazianzen insists that the Son possesses the same Being as the Father-even as He receives it eternally from the Father.⁵ Nothing is “held back” by the Father; the entirety of the Godhead is communicated in the act of generation. Therefore, even though the Father alone is “uncaused,” the Father does not have a “greater share” of the divine nature-the Son is that same simple nature in filial mode, and likewise for the Spirit. As one modern Orthodox writer explains, the Father eternally generates the Son by complete self‑giving: “God the Father gives… his divinity away in such a manner that it is not merely ‘lent’ to the Son: the Son’s possession of it is ‘equally substantial’.”¹⁰ The result is that Father and Son “give themselves to one another eternally,” and the Holy Spirit is the unity of love between them.¹⁰ This presents a very personalist interpretation of the inner life of God: God is Love (cf. 1 John 4:8), and that love is an eternal kenosis (self‑emptying) and mutual gift-the Father pouring out His entire being in begetting the Son, the Son returning all in love to the Father, and the Spirit proceeding as that very bond of love.¹⁰ This dynamic picture complements the scholastic account by highlighting that the one essence of God is not a static unity but a living, active unity of love. Yet it still holds that what is given and received is one and the same divinity-the Son is not “another god” derived from the first, but the very same God as the Father, communicated in a new personal way. Relationality in this framework does not conflict with simplicity; rather, it manifests it. The fact that the Father, Son, and Spirit “each wholly give and receive the one essence without dividing it” shows that God’s simplicity is robust enough to include interpersonal love.¹⁰ If God were not simple (for instance, if the Father had “his own part” of deity), then giving divinity to the Son would divide God. But because the divine essence is indivisible and infinite, it can be fully possessed by more than one Person without being apportioned or diminished.³ In an eternal sense, the Father’s generating of the Son is like one candle lighting another-the same flame exists in two without the first losing anything. Father and Son “co‑eternally possess and express the same infinite being,” and the Spirit, proceeding from them, likewise shares “the entire divine essence lived as ‘proceeding fullness’.”³ The Eastern monarchy of the Father thus operates within divine simplicity: the Father is the personal source-not a separate source of a separate essence, but the source of Persons. As one recent Catholic essay puts it, each divine Person is “the complete divine essence lived out in its own distinctive relational expression.”¹¹ The Father in His unbegottenness is the font of divinity; the Son in being begotten is that same divine fullness now in filial relation; the Spirit as proceeding is the same fullness as the bond of love-all without “diminishing the fullness” in any Person.¹¹

Modern Catholic theologians such as Karl Rahner and Joseph Ratzinger have also stressed a personalist understanding of God that reinforces simplicity. According to Rahner (as noted by Kobus, 2007¹²) we must not reduce God’s unity to a barren, unmediated self‑identity. Rahner warned that if one were to imagine God as a unitary being devoid of any internal mediation-lacking an intrinsic Word or Love-then divine perfection would be diminished to a lifeless abstraction, a “false conception of God’s simplicity.”¹² In his view, true divine simplicity does not negate relationality but instead guarantees that all internal relations remain perfectly one in being. Moreover, Rahner maintained that the immanent Trinity-that is, God’s self‑communication within Himself-is identical with the economic Trinity, in which the way God reveals Himself to us (for example, through the Father sending the Son) fully discloses His inner nature.¹² The Father is eternally the “communicator,” the Son the “communicated Word,” and the Spirit the communion-and God’s unity is not some fourth thing behind them but the very fact that Father, Son, and Spirit are one God. Thus, Rahner can say: “God is simplicity, unicity, oneness in the most absolute manner… When considering the relative distinctions of the Trinitarian members, we must remember that there is really only one Godhead and no mathematics can add to it or subtract from it.”²⁵ In that vein, Ratzinger’s insight that ‘person’ means relation guards against any notion that the Trinity is three independent substances (which would violate simplicity). Instead, ‘Father, Son, and Holy Spirit are real, existing relations… and person‑in‑relation is Tri‑Unity, not three [gods].'”¹⁷ We see an intriguing convergence: scholastic theology ensured that relation is not something added to God, and personalist theology ensured that relation is not omitted from God. Both meet in the same place: the very being of the simple God is tri‑personal relation. God’s simplicity, rather than being a barrier to relational life, is what makes the communion of Persons fully one and thus truly divine.

Synthesis: Unity in Distinction – The Coherence of Simplicity and Triune Love

Bringing these threads together, we can finally appreciate where synthesis emerges in Catholic thought on one of its greatest mysteries: God’s simplicity and God’s triune relationality are not merely compatible-they mutually illumine the nature of divinity. God’s simplicity tells us that God’s essence is undivided and wholly itself; Trinitarian relationality tells us what that one essence is in act: an eternal communion of love. The distinct Persons are the modes in which the one essence exists (the Father as origin, the Son as begotten, the Spirit as proceeding).⁶ And because the one essence is fully present in each, the relations do not compromise unity.¹⁴

Consider an analogy from modern metaphysics: Jiri Benovsky speaks of using different “primitives” to solve identity puzzles-sometimes a new primitive relation (such as “compresence” or “bundle”) is posited to explain how two things share one nature.⁴ In Trinitarian ontology, the “primitive” that solves the puzzle is precisely the concept of person‑as‑relation. Instead of three gods or one Person only, we have one essence “compresent” in three relational modes of being. My Self‑Standing Givenness Ontology (SSGO) stands as a contemporary example building on such ideas, explicitly framing each Person as an irreducible “relational mode” of the one essence-a “distinct vantage” on the whole of God.⁶ SSGO maintains fidelity to classical doctrine while using fresh terminology: “each divine Person-Father, Son, and Holy Spirit-fully and indivisibly possesses the one divine essence in a ‘relational mode.’ Rather than seeing Father, Son, and Spirit as partial shares of deity or as superficial ‘modes,’ SSGO contends that each Person is the entire essence ‘from a distinct vantage’ (unbegotten, begotten, proceeding)… a mode in SSGO is not an addition to God, but an irreducible way the one divine being is fully lived in each Person.”⁶ This restates in modern philosophical language what the tradition has always implied: Fatherhood, Sonship, and Spirit‑hood are essential, irreducible ways of being God-not attributes tacked onto an underlying thing.

Exploration of Dryer’s Contribution

My own Self‑Standing Givenness Ontology thus provides a synthesis by demonstrating that the tension between divine simplicity and the threefold personal distinctions is resolved in the very nature of God’s self‑givenness. SSGO posits that the divine essence is not only undivided but is fully actualized in each divine Person by means of an eternal act of self‑donation. In this framework, the one divine nature is “lived” in three irreducible modes-each corresponding to the relational roles of Father, Son, and Holy Spirit.⁶ The ontology asserts that there is no division of the divine substance; rather, the distinctions arise solely from the internal dynamics of self‑gifting, which, being the only process in God’s unchanging life, maintains complete unity.

Philosophically, SSGO is rooted in the conviction that relation is ontologically primary and that the self‑givenness of God is a primitive, uncaused reality. It is not an accidental feature added to an otherwise static substance; instead, it is the very manner in which the divine essence subsists as a personal being. Each divine Person is the full expression of the infinite act of being-shared entirely among Father, Son, and Spirit. What I am doing with SSGO is re-imagining God’s very being as a self‑giving relational act. It aims to uphold the classical truth that God is pure act (actus purus)-fully actual, with no unrealized potential or parts-and to affirm that God’s triune identity is constituted by primitive relationality, the most basic fact about God being the eternal giving and receiving of the divine being in Father, Son, and Spirit. This perspective not only answers the classic objection that a simple God might be too “thin” or impersonal to relate to creatures but also asserts that divine simplicity is the source of all relationality in the Godhead. It is only by being utterly simple that God can give Himself in full to another without any loss or diminution.

Primitive talk here is with the help of Professor Benovsky’s work on said topic, specifically his work around the notion of “Problem Solvers.” Benovsky’s work teaches on that irreducible relational elements, as in terms of primitive here, does in fact provide a conceptual framework for understanding identity and compresence without resorting to compositional analysis (see footnote 30). This insight resonates with my view of a relational cosmos through and through, and the SSGO’s depiction of God by affirming that relational distinctions are fundamental, not additive. Bukovsky’s work mirrors the idea that the divine is self‑given in distinct, irreducible relational modes rather than being partitioned into separate parts. However, I respectfully diverge by asserting that, while Benovsky’s primitives enrich our metaphysical vocabulary, they must be appropriated within a theological commitment. As such in this case the appropriation is to divine simplicity. In my view, the tools Benovsky allows illuminates the mystery of God’s self-givenness without reducing the relational distinctions to mere abstract properties detached from faith. Speaking of God’s reality in primitive terms is to appeal to reason in balance with faith. What is more primitive than the divine nature? This kind of talk helps us frame said nature reasonably, but we can never do justice to the Creator’s grandeur. The “problem-solving” aspect of Benovsky’s work is a helpful mean. It would take too much to space here to revisit this element of the theory in detail, as we cover enough throughout this piece. For those who need more, I have a whole page dedicated to defending SSGO in the context of divine simplicity here: Defending Divine Simplicity – RobertDryer… See Questions #38 and #39, as that’s where I directly engage with Benovsky’s work and his use of primitives as problem solvers. In Q#38, I explore the Self‑Standing Givenness Ontology (SSGO) and how it defends divine simplicity—drawing on Benovsky’s insight into using primitives to explain identity without composition. Q#39 further delves into the concepts of “mode” and “vantage,” which are informed by the idea of primitives as irreducible relational elements. These questions, together, show how SSGO employs Benovsky’s metaphysical tools to articulate a relational understanding of the divine without compromising its simplicity. The goal here is to appropriate reasonably.

What needs to be said here, at this juncture is that SSGO deepens our understanding of traditional Catholic Trinitarian formulations by making explicit what has long been held implicitly: the relations of origin (unbegotten, begetting, proceeding) are not external attributes but are identical with the divine essence itself. In SSGO, these relations are reinterpreted as “self‑standing relational modes” – the distinctive ways in which the one, indivisible divine nature is dynamically expressed. The Father exists as the source of the divine life, the Son as its mediator (being begotten and returning the divine gift), and the Spirit as the bond that unites and perfects this mutual self‑donation.⁶ This reading reinforces the Church’s teaching that each Person is “the complete divine essence lived out in its own distinctive relational expression.”⁶

Participation and Mixed Relations in and through and to the Fully Given

By articulating that each Person is the full self‑actualization of the divine essence “from a distinct vantage” (unbegotten, begotten, proceeding), SSGO shows that the one God is completely present in each Person without any division or multiplication of the essence. This insight enables us to affirm with confidence that there is no additive or subtractive process at work in the Trinity. Instead, the one divine nature is entirely “compresent” in Father, Son, and Holy Spirit, with the distinctions arising solely in the way that each Person gives and receives the divine gift.⁶ God is his own self‑ordering principle and holds himself in perfect Spiritual unity. Thus, God’s self‑donation, as the complete expression of His undivided unity, manifests in the Trinity as the harmonious interplay of distinct Persons—expressing both “Trinity in Unity” and “Unity in Trinity” in a fully realized perfection of love and grace. For example, in the Eucharist, the bread and wine are transformed into the Body and Blood of Christ, enabling the faithful to experience the full, living presence of the divine Person while maintaining the distinction between Father, Son, and Holy Spirit. This sacramental participation mirrors the relational dynamics of the Godhead—where each Person fully shares in the one divine nature, yet preserves its unique relational identity. Thus, sacraments mediate an intimate union with God, embodying the mystery of divine simplicity and triune relationality by conveying God’s self‑donation in a manner that is both concrete and transcendent. In doing so, they offer a model for human participation that reflects how the divine grace is communicated without mixing or diminishing the distinct natures within the Trinity because God’s standard is to hold himself to consubstantiality, or self‑standing givenness if you will.¹³

Finally, by framing the Trinity as an eternal, self‑giving communion, SSGO provides a robust ontological explanation for the classic theological formula: “All in God is God.” This means that the unity of the Godhead is realized in the dynamic, self‑communicative life of the Persons-a life in which each act of self‑givenness is both the source of divine energy and the guarantee of undivided being. There is no “fourth thing” beyond the three Persons; the only reality is the one, simple essence expressed in three eternal modes of self‑donation.⁶ SSGO’s framework can be described as a relational ontology grounded in the doctrine of the Trinity: being-as-communion elevated to the first principle without abandoning the classical notion of the plenitude of being.

In sum, SSGO drives home a powerful conclusion: Divine Simplicity and Trinitarian Relationality are not opposing truths but two facets of the same divine reality-an infinite act of self‑giving love. The one God subsists as Father, Son, and Holy Spirit, not by partitioning the divine essence but by expressing it in three irreducible relational modes. This synthesis not only preserves the Church’s traditional affirmations but also provides a compelling, philosophically rigorous account of the mystery of the Trinity.⁶ This allows us to incorporate the personalist and patristic intuition that “God is love” (1 John 4:8) into a more powerful theological and spiritual context-love inherently implies lover, beloved, and the love between them, yet true love makes the many one. The Father eternally imparts everything to the Son (and, by extension, the Holy Spirit), so that lover, beloved, and the love between them exist in perfect unity. This mutual indwelling and sharing means that the three divine Persons are “one” God not by a solitary metaphysical essence alone, but by the communion of love in which they give and receive the entirety of divine life.

Conclusion

The reconciliation of divine simplicity with Trinitarian relationality stands as a testament to the depth and coherence of Catholic theology. Through careful distinctions and profound insights, the Church proclaims that God is one and God is three without contradiction. The one simple essence of God is not a barren unity but the unity of the Father, Son, and Holy Spirit. The three Persons are not independent parts of God but are the one God, each fully. Classical doctrine achieved this balance by identifying the Persons with the eternal relations of origin in the Godhead, ensuring that nothing divides the unity of nature. Personalist and Eastern perspectives have enriched this understanding by showing that the one divine nature is nothing other than an eternal communion of self‑giving-in other words, the highest unity includes relationship as its very heartbeat. Modern theological developments, such as SSGO and analogous philosophical frameworks, have translated these ancient truths into new idioms, confirming that even under rigorous analysis the mystery holds together logically and metaphysically. Every objection-whether about God’s freedom, the logic of identity, or the dynamic liveliness of a simple God-finds its resolution in the doctrine of the Trinity rightly understood. There is no competition between God’s unity and God’s tripersonal life: unity belongs to God’s essence, and relational plurality belongs to God’s Persons; and since the Persons are of the essence, the plurality lives within the unity without shattering it.²

In the end, the Trinity teaches us who the one God is: an eternal Father loving a Son in the Spirit, an eternal Son receiving all from the Father and returning all in the Spirit, and an eternal Spirit who is the love and life of Father and Son. Likewise, the doctrine of simplicity teaches us that this God is wholly and perfectly God-“I AM who AM,” one Lord. Our exploration has shown that these teachings, far from undermining one another, together give us the fullest picture of the God of Christian faith. As 1 John 4:8 implies, “God is love”-in God’s innermost being there is Lover, Beloved, and the Love that unites them; yet Love is one. Love, by its nature, is self‑gift, and in God this self‑gift occurs in a way that does not split the giver and receiver into separate beings, but rather maintains the unity of the Godhead. This is why Christianity can claim that God is communion without ceasing to be monotheistic. It is a sublime mystery-inherently consistent and richly meaningful: Divine Simplicity and Trinitarian Relationality are two ways of expressing that God’s one being is an infinite act of triune love.⁹ Finally, the Catholic synthesis upholds that the Trinity is One God. The Fathers of the Church and the councils safeguarded this truth, and no later development has surpassed its clarity: “We do not confess three Gods, but one God in three Persons, the consubstantial Trinity.”² In that consubstantial (common substance) Trinity, each Person is the simple divine substance-not a part of it-and each Person exists only in relation to the others. Thus, God’s unity and God’s tripersonal life interpenetrate completely. The mystery remains, but it is not a contradiction. By embracing both truths, we approach the threshold of divine life with reverence-perceiving, however dimly, that the very reality of God is a unity of self‑giving communion. This realization not only resolves an abstract doctrinal puzzle but also invites us into awe and worship. We began with a philosophical problem and conclude with a vision of love: unus Deus, Trinitas-the One God who is Trinity, simple in substance and rich in relationship, forever to be praised.²⁹

The distinctiveness of the Father, Son, and Spirit comes solely from their unique, undivided act of self‑donation rather than from any fragmentation of whatever is God’s essence. Thus, the Trinity is not a plurality of parts but a unity expressed in three unique relational modes: too one to be many, yet too given to be merely one among many. In the end SSGO says this is simplicity in the Trinity and Trinity in its simplicity.

Footnotes

See discussion of the synthesis in that section near the end.
Catechism of the Catholic Church | Catholic Culture. Retrieved from: https://www.catholicculture.org/culture/library/catechism/index.cfm?recnum=610.
Scriptural Testimony: κοινωνία (koinōnía) and πλήρωμα (plērōma) – RobertDryer. Retrieved from: https://robertdryer.com/defending-divine-simplicity/scriptural-testimony-%CE%BAοινωνία-koinonia-and-%CF%80λήρωμα-pleroma/.
Why the Bible is Trinitarian – RobertDryer. Retrieved from: https://robertdryer.com/blog/why-the-bible-is-trinitarian/.
Nicene and Post-Nicene Fathers: Series II/Volume VII/Orations of Gregory Nazianzen/Oration 30 – Wikisource. Retrieved from: https://www.newadvent.org/fathers/310230.htm#:~:text=make%20both%20four%20and%20ten%2C,by%20the%20Father%3B%20not%20as.
What is SSGO and How Does It Defend Divine Simplicity? – RobertDryer. Retrieved from: https://robertdryer.com/defending-divine-simplicity/what-is-ssgo-and-how-does-it-defend-divine-simplicity/.
Modal Collapse & Classical Simplicity Revisited – RobertDryer. Retrieved from: https://robertdryer.com/defending-divine-simplicity/modal-collapse-classical-simplicity-revisited/.
The Premier Case Against Unitarianism – RobertDryer. Retrieved from: https://robertdryer.com/defending-divine-simplicity/the-premier-case-against-unitarianism/.
Analysis of the Opus – John Zizioulas Foundation Official Website. Retrieved from: https://zizioulas.org/theology/analysis-of-the-opus#:~:text=This%20work%20builds%20on%20his,understands%20communion%20as%20generating%20otherness.
Rethinking Divine Simplicity: A Meta Metaphysical Reconfiguration – RobertDryer. Retrieved from: https://robertdryer.com/rethinking-divine-simplicity-a-meta%e2%80%91metaphysical-reconfiguration/.
The Monarchy of the Father and Divine Simplicity – RobertDryer. Retrieved from: https://robertdryer.com/defending-divine-simplicity/the-monarchy-of-the-father-and-divine-simplicity/.
Kobus, M. M. (2007). The Doctrine of the Trinity according to Karl Rahner [Doctoral dissertation, Graduate Theological Foundation]. Retrieved from: https://rdtwot.files.wordpress.com/2007/10/kobus_the-doctrine-of-the-trinity-according-to-karl-rahner.pdf.
Hans Urs von Balthasar, Theo‑Drama IV: The Action, section III, C, 1 (San Francisco: Ignatius Press, 1980): “It follows that the Son, for his part, cannot be and possess the absolute nature of God except in the mode of receptivity: he receives this unity of omnipotence and powerlessness from the Father. This receptivity simultaneously includes the Son’s self-givenness… and his filial thanksgiving (Eucharist) for the gift of consubstantial divinity.” This was originally sourced and accessed from here: Life of the Trinity: Self-Giving Love – Lucas Hattenberger (Blog Post). Retrieved from: https://lucashatt.wordpress.com/2015/04/06/life-of-the-trinity-self-giving-love/. Hattenberger is helpful here.
Benovsky, J. (2020). Primitives. In R. Bliss & J. T. M. Miller (Eds.), The Routledge Handbook of Metametaphysics. Routledge. Professor Jiri Benovsky speaks of using different ‘primitives’ to solve identity puzzles—sometimes a new primitive relation (such as ‘compresence’ or ‘bundle’) is posited to explain how two things share one nature. You can read more here: https://robertdryer.com/defending-divine-simplicity/jiri-benovsky/
Ratzinger, J. C. (n.d.). Credo for Today: What Christians Believe (M. J. Miller, H. Taylor, S. M. McCarthy, A. Walker, J. R. Foster, G. Harrison, & M. J. O’Connell, Trans.). Ignatius Press.
What Does It Mean to Say God Has No Parts? – RobertDryer. Retrieved from: https://robertdryer.com/defending-divine-simplicity/what-does-it-mean-to-say-god-has-no-parts/.
Ratzinger, J. (1990). Concerning the Notion of Person in Theology. Communio, 17 (Fall). Retrieved from: https://www.communio-icr.com/files/ratzinger17-3.pdf#:~:text=Let%20us%20summarize%3A%20in%20God,affirma%02tion%20into%20anthropology%20by%20attemptingto. Albeit, Ratzinger is more in an anthropological mode here, I think the reappropriation of a coherent framework like SSGO allows for his implied metaphysics, a metaphysics in principle he’s committed to for his whole life, is salvageable if we use SSGO as a hermeneutics for him when he’s in this vein. If we take him naively, he’s probably wrong because he’s criticizing Aquinas here and doesn’t get him right if Dr. Gaven Kerr is right: https://www.youtube.com/live/Q22JnpTQbnI?si=LUbbMXpnC6tjHfq1
(Repeated; see footnote 3.)
(Repeated; see footnote 11.)
(Repeated; see footnote 8.)
Rahner, K. (1970). The Trinity (Trans. by Joseph Donceel). Burns & Oates. Retrieved from: https://www.cambridge.org/core/services/aop-cambridge-core/content/view/BE2C834D14502FAEBA2E4C86DAAB2F1A/S0036930600027435a.pdf/trinity_by_karl_rahner_translated_by_joseph_donceel_burns_and_oates_1970_pp_120_30s.pdf#:~:text=The%20Trinity,the%20concept%20of%20God%27s%20personality.
(Repeated; see footnote 16.)
(Repeated; see footnote 6.)
(Repeated; see footnote 4.)
Rahner, K. (2015). Foundations of Christian Faith: An Introduction to the Idea of Christianity. Crossroad Publishing.
Lateran 1215 – Hosted at RobertDryer.com (IV Lateran Council 1215).
Retrieved from: https://robertdryer.com/defending-divine-simplicity/lateran-council-1215/.
Marion, J.-L. (2012). Being Given: Toward a Phenomenology of Givenness (J. L. Kosky, Trans.; New preface by the author). Stanford University Press.
(Repeated; see footnote 14.)
Meta-note: This footnote refers to the closing synthesis and is supported by repeated citations from the Catechism of the Catholic Church and the overall theological synthesis.
This characterization (by Milbank) of Aquinas comports well with my view. But, you can see my 50 questions on defending simplicity to see how I deal with this directly https://robertdryer.com/defending-divine-simplicity/ This piece deals with something more fundamental than the identity problem so it’s not deeply addressed here. The stance here is that, in God, the distinctions among Father, Son, and Spirit are not additional substances but the ways in which God self-gives: transcending finite, creaturely criteria of identity.
:

Bibliography

Analysis of the Opus – John Zizioulas Foundation Official Website.
Retrieved from: https://zizioulas.org/theology/analysis-of-the-opus#:~:text=This%20work%20builds%20on%20his,understands%20communion%20as%20generating%20otherness
Catechism of the Catholic Church | Catholic Culture.
Retrieved from: https://www.catholicculture.org/culture/library/catechism/index.cfm?recnum=610
SSGO and Information Theory – RobertDryer.
a. Retrieved from: https://robertdryer.com/ssgo-and-information-theory/#:~:text=One%20of%20the%20central%20claims,shapes%20their%20identity%20over%20time
b. Retrieved from: https://robertdryer.com/ssgo-and-information-theory/#:~:text=SSGO%20would%20allow%20for%20a,informational%20integrity%20through%20relational%20interactions
Does Hyperintensionality Challenge Divine Simplicity? – RobertDryer.com.
Retrieved from: https://robertdryer.com/defending-divine-simplicity/does-hyperintensionality-challenge-divine-simplicity/
Divine Givenness and Divine Attributes in Catholic Theology – RobertDryer.com.
Retrieved from: https://robertdryer.com/divine-givenness-and-divine-attributes-in-catholic-theology/
What is SSGO and How Does It Defend Divine Simplicity? – RobertDryer.com.
Retrieved from: https://robertdryer.com/defending-divine-simplicity/what-is-ssgo-and-how-does-it-defend-divine-simplicity/
Modal Collapse & Classical Simplicity Revisited – RobertDryer.com.
Retrieved from: https://robertdryer.com/defending-divine-simplicity/modal-collapse-classical-simplicity-revisited/
The Premier Case Against Unitarianism – RobertDryer.com.
Retrieved from: https://robertdryer.com/defending-divine-simplicity/the-premier-case-against-unitarianism/
Scriptural Testimony: κοινωνία (koinōnía) and πλήρωμα (plērōma) – RobertDryer.com.
Retrieved from: https://robertdryer.com/defending-divine-simplicity/scriptural-testimony-%CE%BAοινωνία-koinonia-and-%CF%80λήρωμα-pleroma/
Rethinking Divine Simplicity: A Meta Metaphysical Reconfiguration – RobertDryer.com.
Retrieved from: https://robertdryer.com/rethinking-divine-simplicity-a-meta%e2%80%91metaphysical-reconfiguration/
The Monarchy of the Father and Divine Simplicity – RobertDryer.com.
Retrieved from: https://robertdryer.com/defending-divine-simplicity/the-monarchy-of-the-father-and-divine-simplicity/
Kobus, M. M. (2007). The Doctrine of the Trinity According to Karl Rahner [PDF file].
Retrieved from: https://rdtwot.files.wordpress.com/2007/10/kobus_the-doctrine-of-the-trinity-according-to-karl-rahner.pdf
Life of the Trinity: Self-Giving Love – Lucas Hattenberger (Blog Post).
Retrieved from: https://lucashatt.wordpress.com/2015/04/06/life-of-the-trinity-self-giving-love/
Benovsky, J. (2020). Primitives. In R. Bliss & J. T. M. Miller (Eds.), The Routledge Handbook of Metametaphysics (pp. [insert page range]). Routledge.
Ratzinger, J. C. (n.d.). Credo for Today: What Christians Believe (M. J. Miller, H. Taylor, S. M. McCarthy, A. Walker, J. R. Foster, G. Harrison, & M. J. O’Connell, Trans.). Ignatius Press.
(Replace “n.d.” with the publication year, if available.)
What Does It Mean to Say God Has No Parts? – RobertDryer.com.
Retrieved from: https://robertdryer.com/defending-divine-simplicity/what-does-it-mean-to-say-god-has-no-parts/
Ratzinger, J. (1990). Concerning the Notion of Person in Theology. Communio, 17 (Fall).
Retrieved from: https://www.communio-icr.com/files/ratzinger17-3.pdf#:~:text=Let%20us%20summarize%3A%20in%20God,affirma%02tion%20into%20anthropology%20by%20attemptingto
Rahner, K. (1970). The Trinity (Trans. by Joseph Donceel). Burns & Oates.
Retrieved from: https://www.cambridge.org/core/services/aop-cambridge-core/content/view/BE2C834D14502FAEBA2E4C86DAAB2F1A/S0036930600027435a.pdf/trinity_by_karl_rahner_translated_by_joseph_donceel_burns_and_oates_1970_pp_120_30s.pdf#:~:text=The%20Trinity,the%20concept%20of%20God%27s%20personality
Rahner, K. (2015). Foundations of Christian Faith: An Introduction to the Idea of Christianity. Crossroad Publishing.
Lateran 1215 – Hosted at RobertDryer.com (IV Lateran Council 1215).
Retrieved from: https://robertdryer.com/defending-divine-simplicity/lateran-council-1215/
Marion, J.-L. (2012). Being Given: Toward a Phenomenology of Givenness (J. L. Kosky, Trans.; New preface by the author). Stanford University Press.
Jean Luc Marion – RobertDryer.com.
(Replaced by entry 21.)
(Consolidated with entry 6.)
(Consolidated with entry 4.)
Rahner, K. (2015). Foundations of Christian Faith: An Introduction to the Idea of Christianity. Crossroad Publishing.
(This entry duplicates entry 19; please consolidate into one entry.)
Lateran 1215 – Hosted at RobertDryer.com (IV Lateran Council 1215).
(Duplicate; see entry 20.)
(Jean Luc Marion entry is now updated as entry 21.)
Benovsky, J. (2020). Primitives. In R. Bliss & J. T. M. Miller (Eds.), The Routledge Handbook of Metametaphysics. Routledge.

TLDR:

After synthesizing the whole of the tradition we can say the Axiom like phrasing of the SSGO than is this, the Divine self‑givenness is the primitive, irreducible act by which the Father, Son, and Holy Spirit relate–establishing unique, non‑compositional distinctions among the Persons without dividing the one undivided essence, and thus forming the very ground of divine self‑communication and unity. In a more principled way of saying this with depth: The self‑gift among the Father, Son, and Spirit is an irreducible act of givenness that structures divine actuality not by dividing the essence but through each Person’s unique relational mode of origin. This framework permits genuine, non‑compositional distinctions among the divine Persons while preserving the absolute unity of God’s undivided nature. Moreover, this primitive relational givenness forms the very ground of divine life, establishing the ultimate reality in which self‑communication and unity are inherently realized.

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