
In my preceding article “The Triune Good,” we followed St Bonaventure into the Holy of Holies, where the two cherubim gaze upon the mystery of God as Being and Good. Under the first name, we contemplated God in the unity and simplicity of his transcendent essence; under the second, we entered into the mystery of his Trinitarian life. The unbegotten Father is the highest Good (summum bonum) and is therefore supremely self-diffusive (bonum diffusivum sui), eternally communicating the fullness of his divine essence in the generation of the Son and the spiration of the Holy Spirit. Bonaventure’s language is surprisingly amatory. God is “loving in a loving way with love” (Itin. VI.2)—an eternal communion of Triadic Love.
A century earlier, Richard of St Victor argued for the plurality of the divine persons from the perfection of divine goodness in his classic work De Trinitate:
Now, where the fullness of all goodness is, the true and the highest charity cannot be missing. For nothing is better than charity, nothing is more perfect than charity. But no one can be said rightly to have charity in a private and own love of oneself. Therefore, love must be directed to another for being charity. Consequently, where there is not a plurality of persons there can certainly not be charity. (De Trin. III.2)
Perfect love requires another. The divine person must have a condignus, another of equal dignity whom he can love as much as himself. Supreme love cannot terminate upon an inferior beloved, for then the lover could not love another as much as himself. The fullness of charity therefore requires two persons equal in goodness and glory. Yet even this mutual love does not exhaust the perfection of charity. If the two possess together the supreme joy of their love, perfect generosity requires that they desire to share that love with another. There must therefore be a third, a condilectus, a co-beloved whom the first two love together and with whom they communicate the fullness of their common love:
It should now be noted about these divine persons that the perfection of one person demands the addition of the other [the eternal Son], and it follows that the perfection of the two persons demands the cohesion of the third [the Holy Spirit]. As it is already said above about the two persons that they must be perfect to the highest degree in order that both rightly can be loved to the highest degree by the other. Just as both have the same wisdom and the same power, both must truly have one and the same highest good will. And it belongs to the highest and totally perfect good will to share with others all the abundance of its fullness. But where there is an equal good will in both persons, it is necessary that they with the same wish and for a similar reason must want a partaker in their most high happiness. For where two mutually loving persons embrace each other with the highest desire and are delighted in each other with the highest love, then the one finds his highest happiness in the intimate love of the other, and, conversely, the other finds his highest happiness in the intimate love of the first. But as long as he only is loved by the other, he seems to own the highest sweetness of his pleasures alone; likewise, as long as the other does not have a partaker in his love he will be missing the fellowship in his highest happiness. In order that both can share these pleasures they must have a partaker in their love. (De Trin. III.15)
Divine charity thus reaches its perfection not simply in the mutual love of two persons, but in their generous communication of that love to a third. “Where there are three divine persons in mutual love,” comments Ilia Delio, “there is perfection.”1 The transcendent plenitude of love effloresces into Trinity.2 Readers unacquainted with Richard’s reasoning will no doubt be surprised by his arguments. He too, like the rest of us, affirms the Trinity on the basis of divine revelation. What he is offering here—and, as we will see, Bonaventure too—is what medieval theologians called rationes necessariae, “necessary reasons.”
The Franciscan masters who composed the Summa Halensis in the first half of the thirteenth century received Richard’s insight and incorporated it into their own Trinitarian reflections:
The highest goodness must contain the highest and most preeminent love; it is highest, insofar as one loves another as himself; and preeminent, since he wills that other person to be loved by a [third person] as that [third person] loves himself… Therefore, it is necessary to posit that the highest good loves another as himself and wills that this other be loved by [yet] another as that other loves himself; but this [love] is not able to occur in fewer than three persons; therefore, there are three persons; therefore, there is a Holy Spirit; but he does not have being unless by “proceeding”; therefore, his procession exists. (SH I, n. 304)
The Halensian theologians then joined Richard’s insight to the Dionysian principle of effluvious goodness. In their hands, writes Boyd Coolman, the bonum is imagined, as “flowing, self-diffusive, self-communicative, ecstatic plenitude, and of the summum bonum as maximally and perfectly such.”3 There are two principles of diffusion in things—nature and will. The highest natural diffusion is generation; the most perfect diffusion of the will is ecstatic love and therefore personal. Both must be found in God, for “it is essential for the highest good to be diffusive or communicative” (SH I, n. 304). The first gives us the eternal generation of the Son; the second, the procession of the Holy Spirit.
This is the theological inheritance that Bonaventure makes his own: God is the supreme Good; therefore he eternally communicates himself in his bounteous charity. Bonaventure embraces the maxim and unfolds its Trinitarian depths. Because each divine Person possesses the divine essence in mutual perichoretic indwelling, each Person’s love of himself embraces the other two; each eternally delights in and loves the others. The life of the Father, Son, and Holy Spirit is Love.4
The Fountain Fullness of the Father
What does it mean to say that Love is self-diffusive within the eternal life of God? Delio suggests that we begin with Bonaventure’s understanding of the innascible Father as primary and first principle within the Trinity and who is therefore the fontalis plenitudo, the fountain fullness of the Godhead. As Bonaventure writes in his Sentences: “By reason of primacy the person is born to produce another from itself; and I here call primacy innascibility, by reason of which, as the ancient opinion says, there is in the Father a fontal fullness toward every emanation” (1 Sent. d.2, art. 1, q. 2). The term innascible will no doubt be unfamiliar to most readers, but it has a twofold meaning for the Franciscan: (1) it signifies that the Father has no origin and is thus synonymous with ‘unoriginate’ and ‘unbegotten’; (2) it signifies the absolute primacy of the Father. The Seraphic Doctor elaborates in scholastic fashion:
Therefore, since the first principle, by virtue of the fact that it is the first being, is supremely one; and for this reason it is supremely simple and immense; and for the same reason it is eternal, unchangeable, and necessary as may be gathered from the above; and again, by the mere fact that it is the first being, it is most perfect in producing, most fontal in emanating, and most fecund in germinating, and this with respect to things that are equal, coeternal, consubstantial, distinct, original, and ordered, it follows that the first principle, because it is first, exists eternally with the fullness of all these perfect qualities. For this reason, it is in this principle, in as far as it is first, that all beings and all knowledge come to rest. (Disputed Questions on the Mystery of the Trinity q. 8, concl.)
Here Bonaventure joins together the themes of Being, goodness, fecundity, and eternal emanation that we have been tracing. Because the divine esse is supremely good, esse itself is supremely self-diffusive; and because God is eternal and fully actual, this self-diffusion is itself eternal:
This ‘to Be’ (esse) is supremely good, therefore ‘to Be’ supremely diffuses itself in a threefold diffusion: the most actual, the most complete, and the ultimate or most ultimate. Because most actual, it always is, always was, and always will be; it always generates, is always generated, and will always generate. A creature cannot have this, that it should always be, should always have been, and shall always be: therefore it is necessary that the eternal God must emanate in this way. (Hexaemeron XII.11)
Like the Halensian theologians who preceded him, the Seraphic Doctor incorporates the Dionysian principle into the Trinity. The self-diffusiveness of the divine Being comes to personal expression in the Father as the fontal fountain of the Son and Holy Spirit. Delio helps us to better understand the Bonaventurean view of the Father:
To understand the unity of persons in Bonaventure’s trinitarian theology is to locate their origin in the good. The very “source” of infinite goodness is the Father. Because the Father is unbegotten (that is, has no prior source), the Father is first or primal. As the infinite “first person,” the Father is absolutely fecund and, thus, the fountain-fullness of goodness. It is difficult for the human mind to conceive of an infinite source of goodness but we can compare it to one of the natural wonders in North America, Niagara Falls. Anyone who has ever seen the torrents of gushing waters bursting forth over the falls has never failed to gasp in awe and wonder at the magnificent power of these waters. Imagine that the source of these bursting torrents of waters is infinite. Such an image, although a limited one, gives us an idea of what the Father’s infinite goodness is like.5
If the Father is the inexhaustibly fecund and self-diffusive source of the Godhead, what then does he diffuse? His Son and Holy Spirit! As the eminent Bonaventurean scholar Zachary Hayes explains:
The divine nature is the rich fountain from which flows the entire created universe. But Bonaventure pushes beyond this to argue that the concept of primacy may be traced into the depths of the divine nature itself, where it may be seen as the characteristic of the first divine Person. As the divine nature is absolutely prior with respect to all other essences, and thus is a se in the fullest sense of the word, so the Father, as that Person who is non ab alio [not from another], is first with respect to the other Persons. Hence, there is in God one in whom resides the fullness of divine fecundity with respect to the Persons. But since whatever God is in himself he is in act, it follows that the divine fecundity with respect to God himself must be in act, and hence there must be a plurality of Persons in God… God is the infinitely rich and fecund mystery whose eternal being is a dynamic ecstasy of goodness and love. The divine nature is not a static, monadic being, but is to be conceived more as a unifying power which, in the unity of the divine fecundity, produces a plurality without multiplying the nature. The Trinity of Persons is the fruit of the most perfect unity which, while subsisting in a multiplicity of Persons, is yet not multiplied in itself.6
In stressing the monarchy of the Father, Bonaventure locates his theology of the Trinity within the Eastern patristic construal of the Trinitarian emanations,7 perhaps drawing upon St John of Damascus’s On the Orthodox Faith, which he knew well. This makes his position distinctive within Latin scholasticism, distinguishing it from the more characteristically Augustinian presentations.
Since the fourth century, the Church catholic has confessed the eternal generation of the Son and Holy Spirit by the unbegotten Father. The early creeds focused on the divine identity of Jesus Christ and his relationship with God. Consider these lines proclaimed by the Council of Nicaea in A.D. 325: “And in one Lord, Jesus Christ, the Son of God, begotten from the Father, only-begotten, that is, from the essence (οὐσίας) of the Father.” If you recite the “Nicene Creed” every Sunday, you may be startled by the phrase “from the essence of the Father.” “I don’t remember that.” And that’s because our liturgical creed dates from the 381 Council of Constantinople. The dogmatic intent of the Nicene phrase is clear: the eternal Son is homoousios with the Father because he is begotten from the ousia of the Father. Like produces like. And so with the Holy Spirit. The same divine consubstantiality belongs to the Paraclete, whom the Second Ecumenical Council would confess as “the Lord and giver of life, who proceeds from the Father.”
Why the Good Must Be Triune
We have seen that the goodness of the Father is superabundantly fecund, flowing forth in the Son and Holy Spirit. But Bonaventure presses the matter further. Could God be the infinite Good and yet exist eternally as a solitary person? His answer is no. As with Richard, the very perfection of divine goodness requires that God be Triune. For if it belongs to the nature of the good to diffuse and communicate itself, then the supreme Good must communicate himself supremely. And the highest possible self-communication is not the creation of something less than God, however glorious that creature might be. It is the eternal communication of the fullness of the divine being to another who is equal, coeternal, and consubstantial. As Bonaventure explains in the Breviloquium:
Since faith is the first condition of divine worship and the foundation of doctrine which is according to godliness, it requires that our thinking about God be of the loftiest and most devout order. Now, our thought would not be of the loftiest order if we did not believe that God can supremely communicate Himself; and it would not be of the most devout order if, believing Him able, we believed Him unwilling to do so. Thus, if we are to think of God most loftily and most devoutly, we are to hold that He supremely communicates Himself by eternally possessing One who is beloved and One who is Mutual Love, so that He is both one and trine. (Brev. 1.2.4)
We can succinctly (inadequately as it must be given the complexity and subtlety of his thought) lay out Bonaventure’s argument in four premises.
First, the perfection of divine beatitude requires that supreme goodness and love be communicated to another:
If there is the highest beatitude; but wherever there is the highest beatitude, there is the highest goodness, the highest charity, and the highest joy. But if there is the highest goodness, since it belongs to goodness to communicate itself in the highest degree, and this is most of all in producing from itself an equal and giving its being… If the highest charity, since charity is not a private love but is directed to another: therefore it requires plurality. Likewise, if the highest joy, since “of no good is the possession joyful without a companion” [Seneca], therefore for the highest joy a society and so a plurality is required. (I Sent. dist. 2, art. 1, q. 2)
Note that here Bonaventure argues from the perfection of the divine beatitude and includes the communicability of divine goodness and love within it, right alongside the highest joy. God delights in his love.
Secondly, within the oneness of the Godhead, perfect divine love requires personal plurality: lover and beloved:
Unity is more perfect in which, together with the unity of nature, there remains the unity of love. But “love tends toward the other.” Therefore it includes the distinction of the lover and the beloved. Therefore, if the most perfect unity exists in God, it is necessary that He possess an intrinsic plurality for He has nothing outside Himself that is supremely lovable. (Disp. Quest. q. 2, a. 2, fund. 9)
The perfection of divine love therefore requires an other within God himself: one who loves and one who is beloved, distinct in Person yet one in nature. Bonaventure here is echoing Richard of St Victor.
Thirdly, perfect love requires a third: the co-beloved:
Perfect love is both generous and shared: because it is generous, it tends toward another; because it is shared, it wills that the beloved be loved by another, and that the other be loved as itself and by itself: therefore there is love and co-love; but this cannot exist with fewer than three. (I Sent. d. 2, a. 1, q. 4)
The love of lover and beloved reaches its perfection in co-love: their shared love of a third. Thus the perfection of divine love requires neither one nor two, but at least three Persons—another Victorine echo.
Fourthly, divine fecundity has two—and only two—intrinsic modes of procession; therefore there cannot be more than three divine Persons:
Supreme primacy in the supreme and highest principle demands the highest actuality, the highest fontality, and the highest fecundity… Therefore since the perfect production, emanation and germination is realized only through two intrinsic modes, namely, by way of nature and by way of will, that is by way of the word and of love, therefore the highest perfection, fontality, and fecundity necessarily demands two kinds of emanation with respect to the two hypostases which are produced and emanate from the first person as from the first producing principle. Therefore, it is necessary to affirm three persons. (Disp. Ques. q. 8, concl.)
The possibility of more than three Persons is excluded by the fact divine fecundity admits only two intrinsic modes of emanation: by nature and by will. These are eternally and perfectly realized in the generation of the Son and the spiration of the Holy Spirit. Since divine simplicity permits no further personal distinction apart from these modes of emanation, there can be no fourth Person.
What Bonaventure means by these two modes of emanation cannot be adequately explained in passing. “Nature” does not signify a mechanical or involuntary production, nor does “will” signify a divine decision to produce the Holy Spirit. The divine processions are simultaneously “natural and voluntary, free and necessary” (Itin. 2). The distinction takes us into the heart of Bonaventure’s understanding of the eternal processions of the Son and the Spirit, which will be the topic of our next article.
(Cont)
- Ilia Delio, Simply Bonaventure, 43. ↩︎
- For an Orthodox appreciation of Richard of St Victor’s contribution, see Kallistos Ware, “The Human Person as an Icon of the Trinity,” Sobornost 8 (1986): 6-21. “In this way,” Ware writes, “Richard sees God, as the Cappadocians do, in terms of interpersonal community. In his argument there is a movement from self love (the Father alone) to mutual love (Father and Son), and so to shared love (Father, Son and Holy Spirit).” ↩︎
- Boyd Taylor Coolman, “The Comprehensive Trinitarianism of the Summa Halensis,” in The Summa Halensis: Doctrines and Debates, ed. L. Schumacher, 120-121. ↩︎
- See Thomas Piolata, “God Is Love: An Investigation of Bonaventure’s Theology of the Essential Love of God,” Nova et Vetera 23, (2025): 237–261. ↩︎
- Delio, 43. ↩︎
- Zachary Hayes, “Bonaventure’s Trinitarian Theology,” in A Companion to Bonaventure, ed. J. Hammond et al., 209-210. ↩︎
- Excepting the Filioque, of course. 😎 ↩︎








