Being as Communion in Aquinas’s Trinitarian Theology

Abstract

A number of thinkers in recent decades have argued that, in light of the Trinity, we can see that God's being is communion. Particularly effective was John D. Zizioulas, whose Trinitarian ontology centered on communion. Some skeptical of this claim have invoked Aquinas as a source for countering an ontology of communion. I argue that, while Thomas never explicitly affirms that the divine being is communion, he can give us deep resources for reaching this conclusion. Indeed, he can ultimately lead us towards a divine being which is more thoroughly a matter of communion—and towards an ontology which is more radically Trinitarian—than anything we find in Zizioulas.

Trinitarian ontologies seem to be at a crossroads. On the one hand, Trinitarian ontologies came into vogue in a big way during the twentieth century's ‘Trinitarian revivals’¹—revivals which have come under heavy fire of late.² Anti-revivalist pushback takes many forms, but a prominent strain of it features calls for a more ‘modest’ and ‘apophatic’ Trinitarian theology. The revivalists had thought that we can know an awful lot about the Trinity, and they had assumed that the Trinity can tell us an awful lot about everything else—including ontology. More recent thinkers have argued otherwise: they have expressed reservations about the prospect of looking to the Trinity for insights into things like anthropology, political programs, or ontology.³ On the other hand, 2020 saw the translation into English of Klaus Hemmerle's Theses Towards a Trinitarian Ontology,⁴ and 2019 saw such luminaries as Rowan Williams, John Milbank, David Bentley Hart, and Emmanuel Falque gather for a conference at Cambridge titled ‘New Trinitarian Ontologies’.⁵ Trinitarian ontology is both on the defensive and on the rise.

The question of whether Thomas Aquinas's ontology is Trinitarian, or whether he can provide support for the recent swell of Trinitarian ontologies, has been similarly contentious. Some proponents of Trinitarian ontology have drawn heavily on him.⁶ Others, however, have cast Thomas as an obstacle to the sort of ontological revolution they are after.⁷ Some critics of Trinitarian ontologies have agreed: they have appealed to Thomas as an antidote to the excesses wrought by Trinitarian ontologies.⁸

In what follows, I will not speak to Aquinas's stance on Trinitarian ontologies in general. Instead, I will focus on just one claim which has figured prominently in those ontologies: that the divine being is communion.⁹ To this point, I know of only one sustained attempt to put Thomas in conversation with this claim. Back in 2004, Matthew Levering drew on Thomas in order to respond to John D. Zizioulas's Being as Communion. Summarizing greatly, Zizioulas had argued that, in God, the divine Persons—along with the freedom, love, and communion proper to persons—are not merely layered atop a pre-personal ontological substratum. Instead, in God, ‘person’ is identical with ‘hypostasis’. Person, freedom, and communion, therefore, sink down to the most basic of ontological categories: in God, ‘being is identical with an act of communion’.¹⁰

Levering remained unconvinced. He charged that, for Zizioulas, ‘the divine unity is simply perichoretic communion’, to the point that ‘it becomes unclear how the “unity” of God is to be fully upheld’, for this unity ‘seems reducible to threeness’.¹¹ Levering then appeals to Thomas as a corrective to the confusions Zizioulas had introduced. And Levering is right, at least in part: he identifies a number of commitments which are bedrock to Zizioulas's proposal and which have no place in Thomas's thought.¹² Yet he also presents Thomas as inimical to any reading of the divine being in terms of communion. Levering puts the matter starkly: for Thomas, ‘God's being is not a communion, because being is not what relates in God’.¹³ To claim that God's being is communion would be to claim that this being relates to itself—and it would therefore be to shatter the unity of the divine being.

To be clear, Levering by no means denies that there is communion in God. Indeed, he had spoken earlier in the same work of the ‘thoroughly relational communion that is the subsisting Persons’.¹⁴ Yet he clarifies that, while the divine Persons may be communion, the divine being is not communion, ‘because being is not what relates in God’. Of course, Levering recognizes that the divine Persons are really identical to the divine being. In this sense, he would affirm that God's being is communion. The question, however, is whether the divine being or essence, insofar as it is logically distinct from the divine Persons, is communion.¹⁵ And, to hear Levering tell it, Thomas's answer is ‘no’.

Zizioulas would agree with Levering on at least one point: he too reads Thomas as an obstacle to an ontology of communion.¹⁶ In what follows, I will argue that both Levering and Zizioulas misread Thomas on this score. For it is true that Thomas, unlike Zizioulas, never explicitly affirms that the divine being is communion. Yet it is also true that Thomas, unlike Levering, never explicitly denies that this being is communion. In fact, Thomas never directly asks or explicitly answers this question at all. He does, however, associate the divine being with communion in a number of ways, and he even opens up certain respects in which God's being is communion.¹⁷ Even more, we will see that, for all their ostensible disagreement, Levering and Zizioulas actually share a key assumption—and we will see that this assumption is foreign to the mind of Thomas. Most importantly, we will see that this assumption prevents Zizioulas from affirming, in the most radical way possible, that the divine being is communion—and we will see that, because Thomas does not share this assumption, he can go further than Zizioulas in affirming that God's being is communion.¹⁸

We will see, in other words, both that Thomas can help to prepare the way for contemporary attempts at a Trinitarian ontology and that he can even give us resources for an ontology which is more Trinitarian than Zizioulas's is. In showing as much, I hope to suggest, first, that Thomas can offer support, at least in broad strokes, for contemporary calls for a Trinitarian ontology. Second, I hope to show that Thomas can help to correct certain imbalances to which some recent Trinitarian ontologies have been prone, and of which Zizioulas is a good example.¹⁹ I hope, that is, to encourage the current interest in Trinitarian ontologies, but I also hope to help those involved to steer clear of paths which could prevent them from being as fruitful as they might otherwise be.

To do so, we will begin in section I with passages where Thomas speaks more directly to the place of communion in his Trinitarian theology. From there, in section II, we will introduce definitions of Trinitarian communion which have emerged more recently, and we will ask whether Thomas's divine being would qualify as communion on the terms of these newer definitions. Finally, we will spend section III putting Thomas more directly in dialogue with Levering and Zizioulas, and we will draw out a way in which Thomas can go further than Zizioulas in affirming that the divine being is communion.

I. ‘COMMUNION IN THE SAME NATURE’

A. Common, Communion, Community

We can begin with a point on which there is very little controversy: for Aquinas, the Father communicates the divine essence and existence to the Son, the Father and the Son together communicate this same essence and existence to the Holy Spirit, and the three Persons hold the divine essence and existence in common.²⁰

These claims are very basic. Yet they carry implications for the question of ‘being as communion’. For ‘communion’, or ‘communio’, is tightly related etymologically to ‘communication’, or ‘communicatio’. In Adrea Di Maio's study of Thomas's use of the word ‘communicare’, she writes, ‘In its use, “communio” is more or less equivalent and interchangeable with “communicatio.”’²¹ ‘Communio’ is also tied to the word ‘common’, or ‘communis’: the main difference between ‘communio’ and ‘communicatio’ is that ‘“communio” derives directly from “communis,” while “communication” is derived through the verb “communico.”’²² The word ‘communion’, then, is roughly interchangeable with the word ‘communication’, and it is derived from the word ‘common’. It therefore seems reasonable to suppose that, because the divine being is communicated by the divine Persons, and because it is common to Them, it might be bound up with Their communion.

On their own, of course, these etymological considerations would yield little in the way of concrete conclusions. Yet they can help to account for other texts where Thomas ties the divine being more directly to communion. Before diving directly into communion, we can begin with a related passage. Thomas writes that

there are two kinds of community: real community and rational community. Real community exists when one and the same numerical thing belongs to many; and a community of nature of this sort does not exist except in the divine Persons, nor is there any community of this kind in the Trinity except in the essence, and in those things which belong to the essence.²³

We saw above that, for Levering, the divine Persons are communion, whereas the divine essence in not. This passage can already help us push back on such a scheme. Thomas, admittedly, speaks not of ‘communion’ but of ‘community’. Communio and communitas, however, are closely related.²⁴ And, in this passage, Thomas does not keep community at arm's length from the divine essence. Nor does he associate it exclusively with the divine Persons. Instead, he teaches that, insofar as Persons and essence are logically distinct, the divine essence is the only site of real community: real community exists only in the divine Persons, and those Persons have community only in the divine essence. Even more, this one divine essence is the site of Their community because it is common to all three Persons.²⁵

We will pursue these points further as we continue. For now, we can note that, as Thomas's work matures, he continues speaking of the divine essence as locus site of ‘real community’ in God.²⁶ More importantly for us, he also speaks of the essence in terms of communion. He does so rarely; yet he does so plainly. He speaks of ‘the communion of the divine nature in the three Persons’,²⁷ and he writes that there is a ‘communion in the same nature’ in God.²⁸ He seems to have in mind the meaning of ‘communion’ which was suggested by our notes on etymology above: to say that the Persons have ‘communion’ in Their nature is to say that this nature is common to the Persons. For Thomas, at least in these passages, communion means first and foremost being common to multiple persons, or being one in multiple persons. It is no surprise, therefore, that the divine Persons should have communion in the one divine nature. Indeed, Gilles Emery is comfortable writing that the divine essence is ‘constitutive of Trinitarian communion’,²⁹ and that ‘communion’ in Thomas's Trinitarian theology ‘principally signifies the communion of the Persons in the divine essence, that is to say Trinitarian consubstantiality’.³⁰ It is not merely that communion is first a matter of the distinct Persons, but that it is also, in some derivative and less intense way, a matter of the one essence. Instead, communion is principally a matter of the essence which the Persons share.

If, finally, communion is a matter principally of the divine essence, then communion must be a matter principally of the divine being as well. For the divine essence is really identical to the divine act of being.³¹ Indeed, even insofar as essence and being are logically distinct, the divine being—like the divine essence—is communicated between, is common to, and is numerically identical in the divine Persons. All of the reasons which make the divine essence the site of divine communion, therefore, would make the divine being the site of divine communion as well. For Thomas, God's being has everything to do with communion.

B. ‘Distinct and Incommunicable’

We can take things deeper if we turn from the divine being to the divine Persons. For it is not merely that the divine Persons have communion in the one divine essence. It is also that They do not have communion in Their personhood. In the same passage where Thomas affirms that there is ‘communion in the same nature’ in God, he continues by clarifying that there is not a ‘communion in the same Person’ in God.³² Thomas puts the matter more strongly elsewhere: ‘there can be no communion of any kind’ in the divine Persons’ properties.³³ The personal properties are, by definition, proper to each Person; they are not held in common. And, if something is not common, then no one can have communion in it. More basically, Thomas teaches that all personhood is incommunicable. As he writes, ‘person formally signifies incommunicability or individuality of one subsisting in a nature’.³⁴ The same goes for the meaning of ‘hypostasis’: ‘a divine hypostasis will be that which is subsistent through itself, distinct and incommunicable’.³⁵ Persons and hypostases can certainly hold things in common with others; but personhood itself is incommunicable.³⁶ It should therefore be no surprise that, for Thomas, there is no ‘communion in the same Person’ in God.³⁷

These points can allow me to begin responding to Levering's reading of Thomas. For we have seen that the divine Persons do not have communion in Their properties because They do not share Their properties, whereas They do have communion in the divine nature and being because They do share this nature and being. To say that eternal communion is a matter of God's being and essence, therefore, is not to blur the conceptual boundary between the common and the proper in God.³⁸ Nor is it to reduce oneness to threeness, or to dissolve substantial unity into perichoretic union.³⁹ Instead, the role of the essence and being in eternal communion depends both on consubstantial unity and on the logical distinction between the essence and the Persons: it is because the divine essence and being, and not the Persons, is numerically one that the essence and being is the principal locus of eternal communion.

C. Being is Communion?

To say that eternal communion is principally a matter of the divine being, however—or to say that the divine being is the principal locus of divine communion, or that the divine Persons have communion in it—is not yet to say that the divine being is communion. Indeed, Levering might admit all of the points we have mentioned so far, but he might still draw the line at saying that the divine being is communion. And, as we admitted above, Thomas never explicitly writes that God's being is communion. Yet he also never explicitly writes—as Levering claims—that the divine Persons are communion. Instead, all he writes is that the Persons have ‘communion in the same nature’⁴⁰ and that They have ‘communion of the same nature’.⁴¹ He never, in these contexts, calls our attention to the logical distinction between Persons and nature, and he never tells us whether the divine communion is the divine Persons as logically distinct from the nature, whether it is the nature as logically distinct from the Persons, or whether it is both.

Elsewhere, however, Thomas suggests that, when persons have communion in a common thing, the thing which they hold in common, or the thing in which they have communion, is itself communion. The Father and the Son, for example, have communion in breathing forth the Holy Spirit. Yet Thomas never writes that the Father and the Son are communion; he writes that the Holy Spirit, in Whom They have communion, is communion.⁴² Similarly, the Eucharist is that in which Christians have communion. Yet the Christians who have communion are not themselves straightforwardly named ‘communion’; it is the Eucharist itself, in which they have communion, which is called ‘communion’.⁴³

None of these points, of course, prove that the divine being is communion. Yet they are the strongest clue I know of into how Thomas would answer the question of divine being and communion: given that he elsewhere teaches that the thing in which persons have communion is communion, it seems reasonable to infer that the divine being in which the divine Persons have communion is Their communion. There therefore seem to be at least some grounds for saying that, even insofar as Persons and being are logically distinct, the divine being is communion.

That said, we are still a long way from an explicit affirmation from Thomas that the divine being is communion. Yet I hope we have seen enough to show that Levering is overhasty in denying that Thomas's divine being is communion, or in claiming that his divine Persons are communion whereas Their being is not. Indeed, it should be enough to show that, if communion exists in Thomas's God—which it very clearly does—then it cannot be the Persons alone Who are communion. Instead, because the Persons have communion in the essence, it seems that this essence, as logically distinct from the Persons, is the divine communion in a privileged way.

Whatever the finer points, however, we have seen enough to conclude that an ontology of communion is not foreign to Thomas's Trinitarian theology. Instead, Thomas can at least help pave the way for, even if he cannot explicitly affirm, the claim that the divine being is communion.

D. ‘We must Shun the Term “Singularity”’

All that said, my aim is certainly not to suggest that, for Thomas, divine communion is the essence or being instead of the Persons. Instead, it will be central to our conclusions that both Thomas's divine being and his divine Persons are communion. First of all, Thomas teaches that the divine Persons have communion not only in the divine essence, but also in the Holy Spirit. As Emery puts it, ‘Trinitarian communion takes on two principal dimensions: first, it is the communion of three persons in the one divine substance which is numerically one, that is the consubstantiality of the Holy Trinity; and, secondly, it is the communion of the Father and the Son in their Bond of Love who is the Holy Spirit’.⁴⁴ The Holy Spirit, no less than the divine essence, is communion.⁴⁵ So, too, the Father and the Son: because of simplicity, if the Father and the Son have communion in Their essence and in the Holy Spirit, then They must be the communion They have. All three Persons, then, are communion.⁴⁶

Perhaps more basically, we have seen that communion only exists when one thing is shared by multiple persons. Yet it is just as true that communion only exists when one thing is shared by multiple persons. A single person can neither communicate anything to himself nor hold anything in common with himself—which means that a single person cannot enjoy communion with himself. Thomas suggests this point at least indirectly when he writes, ‘To avoid the heresy of Sabellius, we must shun the term ‘singularity’ [in our speech of the divine Persons], lest we take away the communicability of the divine essence’.⁴⁷ To claim that divine personhood is ‘singular’—that is, to deny that there are multiple divine Persons—would be to make the divine essence incommunicable. Yet, if the essence were incommunicable, or if no one held it in common, then there could be no communion in it. Communion, therefore, depends just as much on the distinction of the divine Persons as it does on the unity of the divine essence: without distinct Persons, eternal communion evaporates.

II. COMMUNION, BEING, PERSONS

To this point, I have either focused on passages where Thomas speaks of communion in God or considered other aspects of his thought which can help us to better appreciate those passages. What we have seen can already open up a dialogue between Thomas and contemporary champions of God's being as communion. For we have seen that communion in Thomas's Trinitarian theology is a matter of commonness: God's being is communion because it is common to the divine Persons. Some contemporary talk of communion has unfolded along similar lines. For some contemporaries, as for Thomas, communion in general is a matter of sharing. Hans Urs von Balthasar, for example, writes that all human beings enjoy ‘a communion in their common human nature’.⁴⁸ Joseph Ratzinger, a longtime advocate of a Trinitarian ontology of communion,⁴⁹ even casts divine communion in these terms. Drawing on Augustine, he writes that the Holy Spirit is ‘the communion of the Father and the Son’ because the Spirit's ‘particular characteristic is obviously being what is shared by the Father and the Son’: ‘his particular quality…is in fact that of being shared in common’.⁵⁰ For Ratzinger, merely because the Holy Spirit is eternally shared by the Father and the Son, He is Their eternal communion. If we extend Ratzinger's logic to what we saw above, it seems safe to say that, because Thomas's divine being is shared by all three Persons, this being is communion as well. If Ratzinger's definition of communion is allowed to stand, then Thomas's divine being is communion.

These brief reflections on Ratzinger are enough to show that Thomas's working definition of communion, along with the ways in which he speaks of communion in God, can find a foothold in contemporary conversations. Other contemporaries, however, define communion differently: when they say that God's being is communion, they do not merely mean that it is shared by three Persons. None of these further definitions will map as cleanly onto Thomas's use of ‘communion’ for the Trinity as Ratzinger's does. Yet we can take a step deeper by asking to what extent Thomas can affirm that, on the terms of these newer definitions, the divine being is communion. First, Antonio López defines communion as a ‘unity among equals who remain distinct in their unity’.⁵¹ Twenty years after Being as Communion, Zizioulas had spoken in similar terms. With direct reference to the Trinity, he wrote, ‘Communion does not threaten otherness; it generates it’.⁵² Indeed, Zizioulas devoted a whole book—titled Communion and Otherness—to the place of otherness in communion. For some contemporaries, then, communion is a union which protects otherness.

For Thomas, of course, the divine being is one. One might therefore think that it has no place for otherness, and that Thomas's divine being cannot be communion on López and Zizioulas's definition. In fact, however, Thomas's divine being is itself shot through with otherness. For Thomas, there is no divine essence or existence lurking before, behind, or beneath the distinction of the divine Persons. Instead, the one divine essence and existence only ever exists as the divine Persons, and it exists according to the relations which distinguish the divine Persons. As Thomas puts it, ‘the same essence is fatherhood in the Father and sonship in the Son’.⁵³ In more detail, he writes that ‘[it is true that] whatever the Father has the Son has, but not that the Son has it in the same order as the Father. For the Son has as receiving from another, while the Father has as giving to another’.⁵⁴ Everything shared by the Persons exists as giving in the Father, as receiving in the Son, and as receiving in the Holy Spirit.⁵⁵

For our purposes, we can focus on ways in which Thomas extends this pattern to the divine esse. First, he speaks of each Person's distinct ‘way of existing [modus existendi]’. As he puts it, ‘Though the same nature is in Father and the Son, it is in each by a different mode of existence, that is to say with a different relation’.⁵⁶ The one divine being is not a bare unity set apart from—much less poised to suffocate—the distinction of the Persons. Instead, the one divine being exists according to the distinction of the Persons: it exists according to the relations by which each Person is distinguished from the others. Similarly, Thomas speaks of the Son as ‘the generated He-Who-is’.⁵⁷ Elsewhere, Thomas clarifies that the divine essence, as essence—and so the divine existence, as existence—neither generates nor is generated.⁵⁸ Yet, in the Son, the divine esse is generated esse. The divine esse, then, is one and undivided: it is that which unites the distinct Persons. Yet it also preserves Their distinction. It is a unity which exists according to distinct relations. If communion is a ‘unity among equals who remain distinct in their unity’, we therefore have good reason to say that Thomas's divine being is communion.⁵⁹

We can go deeper if we turn to Emery, who has helpfully compiled a set of themes which are often operative in contemporary talk of ‘Trinitarian communion’: ‘By “Trinitarian communion,” one generally understands the mutual exchange of the divine Persons, their interrelationality, their communication of all divine goods in their mutuality, their reciprocal interaction in an interpersonal life of knowledge and of love, [and] their “perichoresis”’.⁶⁰ We will see that, for Thomas, some of these notes are a matter first and foremost of the divine Persons, whereas others are principally a matter of the divine essence and being. All of them, however—even those which are first a matter of the distinct Persons—are at least very closely associated with the divine being.

I already spoke of the ‘interrelationality’ of the divine Persons. In reality, the divine being is this interrelationality: it is really identical to all of the divine relations. Yet, even insofar as it is rationally distinct from the Persons and Their relations, it exists according to these relations. ‘Interrelationality’, therefore, is not set at a remove from the divine being. Instead, it determines the modes in which the divine being eternally exists. Insofar as divine communion is divine interrelationality, therefore, the divine being is shot through with communion: it is a being which exists according to communion.

Similarly, the Persons’ ‘communication of goods’ is principally a matter of the Persons Themselves—at least insofar as one takes ‘communication’ to be an act of communicating. For Thomas's divine Persons are identical to the notional acts by which They give and receive all They have to or from each other.⁶¹ Insofar as the divine being is really identical to the Persons, this being simply is these acts of giving and receiving. Even insofar as it is logically distinct from the Persons, however, the divine being is intimately involved in this giving and receiving. For the divine Persons may be acts of giving and receiving. Yet it is the divine being which is given and received. There can be no communication unless something is communicated, and we just saw in section I that, insofar as Persons and being are logically distinct, the Persons are not communicated. It is the divine being which is communicated. Insofar as ‘communion’ means an act of communication, therefore, it might be too much to say that the divine being is communion. Yet it would be even more misleading to simply remove the divine being from communion. For the divine being is necessary for divine communion-as-communication: there would be no divine communion-as-communication if there were no being which was communicated.

The next two themes can take us further. First, the communion of the divine Persons could mean Their ‘reciprocal interaction in an interpersonal life of knowledge and of love’. Knowledge and love, of course, are essential terms: insofar as Persons and being are logically distinct, knowledge and love fall on the side not of Person but of being. Within his Trinitarian theology, however, Thomas shows that this knowledge and love is reciprocal knowledge and love: it is the knowledge and love of three Persons Who cannot know or love Themselves or Their own essence without knowing and loving the others.⁶² The point to emphasize, however, is that this knowledge and love is no less essential or common for being interpersonal. It is a single act of knowledge and love which exists in three Persons Who know and love each other. This reciprocal interpersonal knowledge and love, therefore, is a matter first not of the distinct divine Persons but of the one divine essence and being: insofar as ‘communion’ means interpersonal knowledge and love, Thomas's divine being is communion.

Similar conclusions follow if we take on the final theme Emery introduces, the ‘perichoresis’ of the divine Persons, or Their intimate reciprocal indwelling. As Emery himself has shown, the reciprocal interiority of the divine Persons in Thomas's Trinitarian theology is a matter chiefly of the divine essence and existence.⁶³ Because the one divine being is in the Son, and because the Father is identical to this being, the Father Himself must be in the Son. Perichoresis is a fruit first of consubstantiality.⁶⁴ Yet perichoresis is also a matter of the distinct divine Persons and Their relations. Thomas explains that ‘one relative opposite is in the notion of the other’: one cannot be a father unless one has a son, and so the idea of sonship is included within the idea of fatherhood. The Father, therefore, must be in the Son to Whom He is relatively opposed.⁶⁵ Insofar as communion means reciprocal indwelling, communion is a matter both of the one divine being and of the distinct divine Persons. Yet it is a matter first of the divine being.

Taking all these points together, we can say that, on some definitions of ‘communion’, Thomas's divine being is communion. Insofar as ‘communion’ means that which is shared, insofar as it points to a unity which preserves otherness, and insofar is it stands for interpersonal knowledge and love, the divine being, even as logically distinct from the divine Persons, is communion. On other definitions of ‘communion’, we cannot identify being as straightforwardly with communion. Yet, even on these latter definitions, the divine being is intimately involved with communion. If communion is interrelationality, then the divine being exists according to communion. If communion is communication, then the divine being is communicated in communion, and communion would be impossible without the divine being which is communicated. If communion is perichoresis, then communion is first and foremost a matter of the Persons’ unity in a single act of being. In Thomas's Trinitarian theology, there are many respects in which being is communion, and even when being is not communion, being has everything to do with communion.

At the very least, then, we would misread Thomas considerably if we concluded that ‘being is not communion, because being is not what relates in God’.⁶⁶ Insofar as being is really identical to the Persons Who relate, both being and Persons are communion in every way. Yet even insofar as being is logically distinct from the Persons, and even insofar as being does not relate—that is, insofar as being is one and is common to the Persons Who are distinct—there are many respects in which it is communion, and every respect in which it is not communion is a respect in which it is intimately bound up with communion.

III. NOTHING LEFT OUT

I ended the last section by alluding to Levering's denial that being is communion in Thomas's Trinitarian theology. Beginning with Levering, we should join him in affirming that ‘being is not what relates in God’: the divine being is really related neither to itself nor to any of the divine Persons. Yet Levering reasons that, because the divine being is not really related to anything in God, it cannot be communion: he writes that ‘God's being is not a communion, because being is not what relates in God’.⁶⁷ We have already seen that, for Thomas, it is ‘because being is not what relates in God’—that is, it is because being is numerically identical in the distinct Persons—that the divine being is communion in some respects and is bound up with communion in others. Put differently, we have seen that, on Thomas's terms, Levering is right to associate communion with distinction and relation, and therefore with the distinct divine Persons. Yet Levering breaks with Thomas in associating communion with distinction and with the distinct divine Persons instead of with unity and with the one divine being. Levering assumes that the unity of the divine being sets it apart from communion. In fact, this unity immerses the divine being in communion. If the divine being were not one, then it could not be common to the Persons, and it therefore could not be communion as Thomas himself uses the term. Nor could it be a unity which preserves the Persons’ otherness, for it would not be a unity at all. Nor again could it be Their reciprocal knowledge and love, for this knowledge and love is one and undivided in Them. Nor still could it be communicated in Their interpersonal communication, for whatever is communicated must be common. Nor, finally, could it serve as the principle of Their reciprocal indwelling, for it only secures Their indwelling because it is identically the same in all of Them. Whether one defines communion as being-shared, as unity-in-otherness, as the communication of goods, as interpersonal knowledge and love, or as perichoresis, it is because the divine being is one that it either just is communion or is steeped in communion. The reason Levering gives for distancing being from communion—and for doing so in Thomas's name—is the very reason Thomas is able to bind being to communion.

Again, Levering articulates his position—which he presents as Thomas's position—in response to Zizioulas. And Levering and Zizioulas certainly differ on any number of fundamental points. Yet we saw above that they agree in their reading of Thomas: they both hold that, for Thomas, being is not communion. We will see now that they also agree on deeper points. As we mentioned above, Levering argues that the distinct divine hypostases are communion, whereas the one divine essence is not. Zizioulas, for all his ostensible disagreement with Levering, argues the same. Specifically, Zizioulas holds that ‘being is communion’ insofar as, in God, ‘Person’—and so the communion proper to persons—is identical to ‘hypostasis’. He makes no mention, however, of ‘Person’—or of the divine communion—as identical to the divine essence. Instead, he starkly opposes the communion of the divine Persons to the divine essence. He contrasts ‘the fact that [God's] being is identical with an act of communion’ to ‘the ontological necessity which His substance would have demanded’.⁶⁸ He continues that ‘this communion is a product of freedom as a result not of the substance of God but of a Person, the Father’, and that God ‘is Trinity not because the divine nature is ecstatic but because the Father as a person freely wills this communion’.⁶⁹ Thomas would certainly agree that the communication of the divine essence springs not from a pre-personal divine nature, but from the Person of the Father.⁷⁰ Yet, in contrast to Thomas—and like so many of the Trinitarian Revivalists⁷¹—Zizioulas opposes the divine Persons to the divine nature or substance. For Zizioulas, communion is a matter of the divine Persons or hypostases instead of the divine nature or substance.⁷²

This point is important, first of all, because it can shed light on the disagreement—and on the hidden agreement—between Zizioulas and Levering. For it shows that, when Zizioulas and Levering ask whether ‘being’ is communion, they are actually asking different things. They are using the word ‘being’ differently. When Zizioulas says that ‘being’ is communion, he is talking about the distinct divine hypostases; he is not talking about the one divine nature—indeed, he opposes this nature to communion. When Levering says that ‘being’ is not communion, he is talking about the one divine nature; he is not talking about the distinct divine hypostases—indeed, he identifies these hypostases with communion.⁷³ ‘Being’ means ‘hypostasis’ for Zizioulas and ‘essence’, ‘nature’, ‘ousia’, or ‘esse’ for Levering.⁷⁴

Once this terminological confusion is cleared up, it becomes clear that Zizioulas and Levering actually agree on one of the deepest points: they both hold that the distinct divine Persons and hypostases are communion, whereas the one divine esse, essence, nature, or ousia is not communion. Zizioulas concludes that being is communion—but only because, by ‘being’, he means hypostasis. Levering concludes that being is not communion—but only because, by ‘being’, he means essence, esse, and nature. These opposed conclusions mask almost identical positions.

The most important point is that this shared position sets both Zizioulas and Levering apart from Thomas. We saw above that, for Thomas, both the divine essence and the divine Persons are communion in some respects and are bound up with communion in other respects. Depending on how one defines communion, the emphasis might fall either on the essence or on the Persons. Yet, taking together all the definitions we surveyed, and taking into account Thomas's own use of ‘communion’ in his Trinitarian theology, we certainly cannot say that communion is the Persons instead of the essence. We cannot even say that communion is a matter more of the Persons than of the essence. Instead, in light of everything we have seen here, we can say that, for Thomas, hypostases and Persons and nature and essence and esse are all communion. Communion encompasses everything; nothing is left out.

Taking a step back, Levering attempts to respond in Thomas's name to Zizioulas's proposal. I can respond to Levering by noting that, perhaps surprisingly, he ends up internalizing—and he ends up reading into Thomas—one of the basic assumptions by which Zizioulas breaks with Thomas: he argues that Thomas, like Zizioulas, restricts eternal communion to the divine hypostases. Things become most interesting, however, when we turn to Zizioulas. For, on Thomas's terms, the problem with Zizioulas is not that he goes too far in affirming that the divine being is communion. The problem is that he does not go far enough. It is not—as Zizioulas seems to suggest—that Zizioulas blazes boldly beyond Thomas by claiming that the divine being is communion, whereas Thomas more soberly raises reservations or qualifications which would wall the divine being off from communion. Instead, it is Zizioulas who limits communion to the divine being-as-hypostases instead of extending it also to being-as-ousia, and it is Thomas who is able to extend communion to the divine being as a whole: to hypostases and to Persons to be sure, but no less to essence, to nature, to ousia, and to esse. It is not that Zizioulas insists that the divine being is communion whereas Thomas denies that it is so. Instead, it is Thomas who can hold that the divine being as a whole is communion, and it is Zizioulas who denies that it is so.

For Thomas, then, the problem with Zizioulas is not merely that he opposes the divine Persons to the divine nature. Nor is the problem merely that he fractures the divine unity—though these dimensions of his thought may, in fact, be problems. The problem is also that he fails to affirm that the divine being as a whole is communion. The problem with his ‘being’ is that it is not communion; the problem with his ontology is that it is insufficiently Trinitarian.

Most basically, however, I hope that my main conclusion has been established: even though Thomas never explicitly claims that the divine being is communion, he gives us deep resources for saying that it is. Indeed, he gives us resources for saying it more fully than some recent champions of Trinitarian ontologies have said it. Contemporary proponents of Trinitarian ontologies, therefore, might look to Thomas as a source of support. For Thomas can agree with their most basic intuition: both for Thomas and for more recent champions of Trinitarian ontologies, the fact that God is Triune matters for the meaning of being. Thomas, therefore, can serve as proof that the claim at the foundation of Trinitarian ontologies can find a foothold in the tradition. More deeply, however, Thomas can help advocates of Trinitarian ontologies steer clear of unhelpful patterns of thought to which they have been prone in the recent past, and he can thereby help them be more radically Trinitarian—that is, he can help them be more faithful to their own fundamental insights and commitments—than they might otherwise be.