In recent years, the doctrine of the Trinity has been frequently invoked as a model for the Christian life.Footnote 1 However, there are different views on what is involved in the participation of human beings in the divine life. In some cases, moreover, the very nature and entailments of this participation are not always rendered entirely perspicuous. The purpose of this paper is to explain in broadly Thomist terms how the doctrine of the Trinity might be said to afford a model for life in God, and critically to situate this account within the context of a larger discussion on the topic.
In his well-known treatise on The Trinity, Karl Rahner famously bemoans the fact that the doctrine of the Trinity is treated quite separately from that of the Incarnation in treatises like Aquinas’ Summa Theologiae, which both represents and establishes the agenda of the Western theological tradition.Footnote 2 In practice, Rahner contends, this separation renders Christianity a monotheist religion. Furthermore, it deprives Christians of a robust understanding of what it means to share in Christ's life or imitate him, who is, after all, the Image of the Trinity.
In an attempt to remedy the existing theological situation, Rahner takes great pains to forge a connection between the economy of salvation through Christ and the inner life of the Triune God. In this connection, he formulated his well-known rule, according to which, ‘the economic Trinity is the immanent Trinity, and the immanent Trinity is the economic Trinity’.Footnote 3 The upshot of this rule is that, from the human point of view, there is no knowledge of the Trinity outside of the Incarnation of Christ—even if there is knowledge along these lines for God. Thus, the doctrine of the Trinity is inextricably linked to Christian faith; conversely, Christian faith cannot be practically monotheist.
The delineation of ‘Rahner's rule’ is largely to credit not only for instigating a revival of Trinitarian theology but also for inspiring inquiries concerning the practical ramifications of Trinitarian theology for an understanding of Christian life, which remain the subject of intense theological interest to this day. Of course, many scholars have gone further than Rahner in the development of his rule, arguing that God is ‘for us’ or nothing at all—that the immanent Trinity is or collapses into the economic Trinity, even, on some level, for God.Footnote 4 In many such accounts, a preliminary to this understanding of the Trinity, to which I will return momentarily, is an account of God's general nature, which breaks down the presumably Thomist divide between deus unus and deus trinus by depicting the nature of the one God in already more ‘personal’, even human terms, which are supposedly more compatible with the personal conception of God any worthy doctrine of the Trinity would presuppose.
According to the critics of Aquinas and other proponents of traditional theology, the general western conception of God's nature is nothing but a recycled version of the Greek conception of an utterly immovable and detached God who makes contact with his creatures only through intermediaries, and is in no way willing or able to empathise with the exigencies of their situation.Footnote 5 So conceived, the western Christian God is not only fundamentally monotheist, with the Trinity remaining something of a theological afterthought. He is, at best, a mere philosophical construct, at worst, an idol that falls short of the personal God of Christian worship.
In the attempt to rectify, in fact, replace, this notion of God, many have resorted to some version of process theology, which is inherently amenable to the task of rendering God capable of relating to human beings. According to process theology, also known in some guises as ‘panentheism’ or ‘dialectical theism’,Footnote 6 systems of thought which are nonetheless subject to considerable diversity, God takes on and pervades creaturely and specifically human modes of being like temporality, transience, and finitude, to the point of experiencing evil and suffering. At the same time, however, he ‘prehends’ or subsumes all things in himself, thus preserving his transcendence, albeit in a highly attenuated or qualified way. On this showing, consequently, God emerges as capable of empathizing with the exigencies and even the horrors of the human condition. He is affirmed as personal in the fullest sense of the term.
In many instances, a panentheist account sets the stage for the development of a social doctrine of the Trinity, which completes the aforementioned project of casting God as ‘for us’, to the point of being like us.Footnote 7 That is not to say that all panentheists are social Trinitarians or vice versa. A fair number of thinkers seem interested in only one of the positions, without much or any reference to the other. Although some do not take advantage of it, there seems nevertheless to be a natural partnership between panentheism and social Trinitarianism which is celebrated in accounts like that of Jürgen Moltman and Paul Fiddes, who hold the positions together.
Whereas panentheism in many respects renders God similar to his human subjects, social Trinitarianism builds on this foundation implicitly or explicitly to contend that human beings must aspire to relate to one another after the manner of the three persons that constitute the divine being. That said, it is worth noting that social doctrines of the Trinity are subject to as much diversity as characterizes uses of panentheism, and may be found in the work of philosophers as well as theologians.Footnote 8 In an effort to preserve the uniqueness and individuality of those persons, social Trinitarians tend to define them in quasi-modern terms as distinct or autonomous centres of agency and consciousness, a view that has invited charges of tritheism.
In response to such charges, social Trinitarians have tended to emphasize that the three persons mutually inter-penetrate, co-inhere, indwell, even define one another, in a mode of relating that is referred to as perichoresis.Footnote 9 Because the three persons are thus effectively rendered a function of their relationships with one another, their unity is ultimately maintained. As one critic has noted, however, ‘any notion of perichoresis strong enough to mitigate the accusation of tritheism is too strong to maintain full personhood within the Trinity.’Footnote 10 Thus, social Trinitarianism seems to entail a contradiction in terms.
After the manner of the persons of the Trinity, social Trinitarians tend to argue, human persons are or ought to be seen as constituted by their relations with one another. This understanding, they say, is the condition for subject-subject, as opposed to subject-object relationships, which function on the principles of mutual or reciprocal equality and respect. By the same token, it is necessary for checking the authoritarianism, patriarchalism, and oppressive structures that dominate many human societies, including churches, and for overcoming modern individualism, which has fostered an unhealthy sense of personal autonomy from social relations.Footnote 11
Perhaps one reason why social Trinitarianism and panentheism have gained such considerable theological sway in recent years concerns the fact that they operate with a view to accomplishing what is at face value at highly commendable socio-political agenda—indeed, an agenda which it would be politically incorrect to oppose. Whereas panentheism presumably purports to render faith in the divine relevant and intelligible for contemporary society, which is alienated from God in so many ways, not least because of the atrocious forms of human evil and suffering that have been witnessed in the past century, social Trinitarianism focuses on forging a way past modern individualism into a more communal form of life which is free of all forms of oppression and in which all persons are truly treated as equals.
While I have no interest in anything but affirming such goals, I would submit that there is reason to question the tendency to confuse the divine with the human, and the human with the divine, that appears to underlie many of the aforementioned strategies for their realization. This tendency could conceivably defeat the very purposes for which the strategies are developed. In that sense, those strategies might prove not only unsuited to accomplishing their goals; they could go so far as to undermine them.
Bracketing for the moment the problems that may arise from defining divine and human beings in a univocal way, however, I shall turn presently to take up my main project of illustrating how the doctrines of divine unity and Trinity, as well as the Trinity and Christian life, may be naturally linked in a broadly Thomist account. As will become evident through the ensuing discussion, this account holds great potential for accomplishing the goals stated above, which has not been sufficiently appreciated in recent years, particularly by those who have read it in the perhaps somewhat uncharitable or unsympathetic manner outlined above.
A Broadly Thomist Account of the One-in-Three God
In turning to Aquinas’ treatise on the one God, it becomes clear that his first and foremost concern is to establish the divine simplicity.Footnote 12 Though the doctrine of divine simplicity is affirmed by diverse monotheist religious philosophies and religions, including the three Abrahamic faiths, these systems of belief are united in the claim that the doctrine confirms God's total otherness to all known objects. While nature and creatures as Aquinas calls them are composed of parts, finite, temporal, and therefore subject to development, God is not divided nor limited nor tensed in any way. He always completely is what he is, which is to be one being which is and knows and wills and does all things good, and who is perfect in that sense.
Though human beings, for instance, may imitate or participate in the unity or simplicity of God—the tendency to be one thing rather than another—by becoming the finite entities they are, it is precisely by these means that they illustrate that God is utterly transcendent and cannot be said in any way to share their characteristics or a common form of life. Indeed, the qualities of infinity, omnipresence, immutability, eternity, unity, and perfection which Aquinas invokes in developing his conception of divine simplicity, and which evidently unfold from it, serve not to disclose direct knowledge of God, as in a ‘philosophical’ or ‘idolatrous’ analysis of his nature. Rather, they confirm that he is a kind of being that is above our knowledge.Footnote 13
By contrast to the way it is commonly understood, Aquinas’ account of the one God does not undermine but anticipate the connection between the oneness and threeness of the divine. In order to see how this is so, it is necessary to consider how Aquinas unpacks his understanding of the two processions, three persons, and four relations that subsist in the one God. The first principle of the two processions—that is, of generation and spiration—and therefore of the Trinity itself is God the Father. He alone is unbegotten: not produced by another. By contrast, the second person of the Son proceeds from the Father by way of knowledge or intellect. This is because his relationship to the Father is like that of one known by a knower.Footnote 14
When the Father knows the Son, on Aquinas’ account, he generates a thought of himself, that is, his image, or a word of self-expression.Footnote 15 As God is the highest object of knowledge, his supreme knowledge as God consists simply in the knowledge of himself. Since the Father's knowledge of the Son is reflexive, it can be likened to self-knowledge. Thus, the Son can conversely be said to know and make known the Father in the very experience of being known by him.
With the proviso that a good withheld is not truly good, Aquinas argues that a good incapable of communicating itself along these lines could not be considered the highest good. Because the communication of goodness is an expression of love, Aquinas identifies love as the ultimate attribute of the Trinity in which the Father and the Son communicate God's goodness to one another.Footnote 16 This brings us to the role in the Godhead of the Holy Spirit, who proceeds from the Father and the Son not by way of intellect but by way of the will—or love and desire—for that which is known, namely, the Son by the Father, and the Father, in turn, by the Son.Footnote 17
In Aquinas’ account, the Father's knowing of the Son and the Son's knowing of the Father ultimately reflect their mutual desire to know one another, that is, God's desire, consisting in the Holy Spirit, to know himself and make himself known as the highest good that he is. Since the Spirit is indicative of the Father's will to make himself known in the Son, and the Son's will to know and make known the Father, he is generally described as the ‘Love’ or the ‘Gift’ exchanged between the Father and Son.Footnote 18 In this connection, the Spirit is said to be spirated or breathed out by the Father and the Son (filioque), thus binding them in unity.Footnote 19 Because this spiration enacts the knowledge shared by the knower and the known, the Spirit is said to constitute the very life or indeed the Spirit of the Trinity, which consists in honoring or loving God as the highest good or object of devotion and adoration, which he is known to be.
As the discussion above suggests, an appeal to the processions of the Son and Spirit from the Father generates an account of one God who does not merely exist as God but also knows and names or communicates himself as God, wants to act and indeed acts like God. Since a God incapable of knowing himself and acting as the supreme being could scarcely seem like such a being in the first place, it seems to follow that the doctrine of the Trinity delineates how the one God can be described as worthy of the name ‘God’. This is the upshot of Aquinas’ affirmation that God is his act of understanding, such that whatever is understood by God is the very living or life of God:Footnote 20 God always completely is what he is, which is to be and to know and to say and to desire and to do all that is good, or consistent with love, because there is in him a perfect correspondence between who he is, what he knows, what he communicates, what he wants, and what he does.
Against the supposition of many contemporary thinkers, therefore, Aquinas’ work is not plagued by a sharp division between accounts de Deo uno and de Deo trino—and the tendency to demote the doctrine of the Trinity. When the two treatises are interpreted on their own terms, the doctrine of the Trinity emerges as the condition for explaining fully how the one God may be described as the simple or supreme good monotheists believe him to be. That is not to undermine monotheisms that reject the teaching that God is Triune. Rather, it is to offer a rationale behind beliefs in one God that affirms them in the strongest possible terms. In offering this rationale, Aquinas’ treatise on the Trinity further corrects any sense that he might endorse a detached and uncompassionate God. For in affirming the intrinsically communicative or relational and thus personal nature of this God, the doctrine of the Trinity establishes his fundamental feature as that of love.
The loving or compassionate nature of God comes into even fuller relief when we consider the fact that there is for Aquinas no knowledge—at least for us—of the Trinity apart from the revelation of God at the Incarnation of his Son. Thus, it remains to explain how the ‘known unknown’ made himself known as such to humanity by assuming human personhood at the Incarnation. On a broadly Thomist conception of this event, Christ relayed the knowledge of the Triune God by continuing the work he eternally accomplishes within the Godhead.Footnote 21 That is to say, he operated in the awareness of God as the highest good and with a view to accomplishing God's good purposes. In that sense, the Son underwent no change in his nature as God in order to become Incarnate.Footnote 22 If he had done so, it would follow that he became inconsistent or fickle with regard to the fulfilment of the Father's will, not least to show compassion for and enable unfailingly the thriving of human beings.
In that light, it appears that proponents of the view that God undergoes change even to the point of experiencing human suffering may have misunderstood the implications of the traditional doctrines of divine immutability and impassibility which they forcefully reject. Furthermore, they may have undermined the very objectives they set out to achieve when they described God as mutable and passible or capable of feeling, including suffering. In doing so, after all, they rendered him so like us as to make it theoretically impossible for him to show love by helping us in times of need in the way only God can.
As rendered by the early Christian tradition, by contrast, the aforementioned doctrines were designed to guarantee God's unfailing love and fidelity to his covenant with human beings—his commitment to make it possible for them to thrive through participation in his life, notwithstanding their general unfaithfulness thus to participate. For the sake of divine empathy with human suffering, the traditional account further posits in this connection that it sufficed for God to assume the human nature in which human beings actually suffer. He did not have to suffer as God, because it is irrelevant to human beings that he does so in a nature unfamiliar to our own. As already mentioned, moreover, it is contrary to the interests of humanity for God to suffer in this regard, since a God plagued by his own plights cannot rescue us from ours.Footnote 23
In Aquinas’ understanding, consequently, the Incarnation rather than an untraditional teaching about divine suffering is the answer to the question how God meets us in the hour of our deepest need. As Kathryn Tanner notes, there is in that light something telling and even worrying about the surprising lack of emphasis in panentheist and social Trinitarian accounts on Christology as the key to questions about what it means to participate in God and how this becomes possible for human beings.Footnote 24
Because Jesus Christ was as much human as he was God, he was able to reveal God to human beings by bringing his direct knowledge of God to bear in an indirect manner, that is, by assessing how to go about ordinary human life and activities and confront distinctly human situations in light of the knowledge of God as the highest good. By these means, he might be said to have expressed his Spirit (life, mind, personality, etc.) of love for the Father, that is, his desire to please the Father, and thus to have established implicitly the Triune nature of God. Since he was a human person, Christ's revelation of the Trinity in the same instance confirmed that all human beings are made in the image of the Trinity to do as Christ did, namely, to express their spirits—lives, abilities, personalities—given through the creative work of the Son with a view to glorifying God the Father in every single circumstance.
By thus operating in the light of the knowledge of God as highest good, human beings are safeguarded from the sinful human tendency to attribute too much significance to temporal objects and experiences—to treat them as though they could make or break human happiness. They are empowered instead to see all things in terms of the actual value or threat they pose and deal with them accordingly. In short, they are enabled to maintain an untainted—divine—perspective on reality. Although this perspective does not afford the direct knowledge of God, which Christ enjoyed, it does provide a sort of indirect knowledge of the maker, which comes by discerning the difference belief in him makes to the way we think and live in ordinary ways.
The more consistently human beings operate in the light of the knowledge of God in ordinary circumstances and thus see God through the mediation of them, Aquinas believes, the more they predispose themselves to see him as he really is: the being who remains constantly the highest good. Since human beings were evidently made to factor the knowledge of God as highest good into all their ordinary activities, it stands to reason that there is no dichotomy between the two natures of Christ. For the divine nature simply enabled Christ to do infallibly and infinitely what human beings do falteringly and finitely. That is why Christ is appropriately referred to as the most human or universal ‘human being’.
Through his own paradigmatic example and atoning work—which it falls outside the scope of the present discussion to treat—Christ enabled us to participate in precisely the way it is possible for us as humans who are not also God to participate in the paradigmatic human life he led on account of his divinity. This brings us to the question as to what it means for human beings to participate in the life of the Trinity, which is another way of referring to the imitation of Christ.
A Broadly Thomist Account of Participation
On the basis of the account of the Trinity outlined above, I would submit that human participation in the divine life turns on efforts gradually to achieve the unity of being, knowledge, word, will, and action that characterizes the divine. The point of participation, in other words, is to come to a place of personal maturity. As the notion of self-knowledge suggests, achieving this maturity means learning accurately—neither excessively nor deficiently—to assess personal capacities, which at once represent limitations, and to employ them accordingly. This effort can take a good deal of experience, as well as some trial and error, to accomplish, precisely because human beings are temporal and therefore simply cannot know themselves fully straightaway, or perhaps even at any point in time.
Furthermore, it is complicated by the sin of pride, which may manifest in extreme forms of hubris or false humility that nurse in persons desires to be something more, less, or altogether other than they actually are. By doing the most they can at any given stage to discover and actualize personal potential, in contrast, human beings overcome sin and achieve by grace through faith the highest level of maturity that is subjectively possible for them at the time. In that sense, they may participate fully in the life of the Trinity, in the way possible for them, while nonetheless falling short of the objective state of personal maturity towards which they still strive.
While all human beings possess individual abilities and interests, I suggested above that many are hindered when it comes to using them—and fully realizing their potential—by the desire to be something they are not. As this suggests, a will to be the person God made one to be—no more, no less—to accept oneself in one's state of finitude and feebleness—is in many respects the pre-condition of identifying and utilizing personal abilities. After all, it is impossible to know oneself and communicate about oneself appropriately, let alone act in accordance with accurate self-knowledge, while resenting the particular constraints of one's own limited existence—either by trying to transcend them, as in hubris, or reducing oneself to them, as in false humility.
The failure of the will in terms of self-acceptance inevitably generates a failure of the intellect in respect of self-knowledge. It is the reason why some individuals undertake activities for which they are not particularly well suited; why others neglect their potential; and why still others spend an excess of time wondering what they should be doing with their lives or second-guessing their decisions on this score. As this suggests, the first step towards overcoming sin involves regaining a proper love or appreciation for the persons God made us to be. That desire situates us not only to come gradually to a better understanding of ourselves but also to improve in the way we communicate ourselves and define our personal boundaries before others, and ultimately, engage in self-actualization: acts that accord with right self-knowledge and self-love.
As we come by these means to a place of heightened continuity between who we are, who we know ourselves to be, who we want to be, how we relate to others or express ourselves, and how we act, I have noted that we increasingly imitate or participate in the fullness of being that characterizes the Triune God in an utterly simple and supreme manner which nevertheless remains foreign to us. Thus, it is through the ordinary operations of the human intellect, will, language, and life that we are formed after the image of God in Christ, in a way made possible by Christ, and come to reflect that image with increasing clarity and consistency. From this, it follows that there is no bifurcation between a life of participation in God and one that turns on participation in ordinary human activities. By this account, participation represents the rationale or formality under which human beings engage in their ordinary lives, namely, from a standpoint of faith in God as the highest good.
Although it is only possible to know God indirectly, that is, by perceiving the difference belief in him makes to our way of evaluating ourselves and our world, while this life of ceaseless learning and self-discovery is ongoing, I have hinted that it is by achieving the highest possible level of personal maturity with respect to self-awareness, self-acceptance, self-expression, and self-actualization at any stage, that we become predisposed to see the divine being who is mature in the fullest and truest sense of the term. Of course, it remains impossible to attain maturity along these lines in the way that is proper to God.
On account of the fundamental difference between the Creator and his creatures delineated above, human beings cannot share in the divine life in the way God is fit to participate in what is by definition his life. Rather, I have shown that we do so in ways that accord with our finitude and created natures. This difference between God and us bears further on our understanding of how we ought to develop in the context of a community life. While the very fact that the three individual persons of the Trinity enact divine unity through their community suggests that human individuality should be nurtured in a communal context as well, the Creator-creature distinction already clues us in to the fact that the way in which our individuality is consummated in community will differ qualitatively from the way in which this happens in God.
On Aquinas’ seemingly plausible understanding, the Father, Son, and Spirit are unlimited, albeit distinct, as persons, precisely on account of the unbounded nature of God. Since their distinctive ‘personalities’, as it were, predispose them to enter into relations, the three persons are accordingly unlimited, albeit distinct, in terms of their capacity to relate to one another. Because of this unlimitedness-in-difference, there is nothing about the Father that is not made known to the Son in the Spirit and vice versa. So construed, the three persons of the Trinity are ‘personal’ and correspondingly ‘relational’ in the fullest sense of the terms. Indeed, the persons are a function of their relations, which render God the one genuinely and supremely personal being.Footnote 25
By contrast to the divine persons, human persons are limited in their personalities and thus in their ability to relate to others. While this means that it is impossible for human beings to experience complete fulfilment in any given relationship, or in relationships overall, it also means that human beings are not and cannot rightly be defined by their relations. Though many social Trinitarians have argued to the contrary in their enthusiasm to promote human community and combat an unhealthy sense of autonomy, they seem not to have noticed that their position logically entails human confinement to circumstances of personal upbringing, social status, gender stereotypes, and instances of authoritarian or oppressive control which are all too common in human societies, not least within the Church. In trying to counteract individualism, in other words, they seem to pose a significant theoretical threat to the most vulnerable individuals.
The present account steers a middle course between the individualism which rejects community and the communitarianism that potentially harmfully reduces individuals to a function of their social circumstances, however oppressive, by affirming that while we are like God in that our individuality can only flourish within community, we are unlike him in the sense that we are not ultimately defined by our communities.Footnote 26 Although human personalities can be called out through relationships, in other words, they remain prior to those relationships, as predispositions for engaging in them.Footnote 27 Although a community poses a context in which to use our gifts, which are relatively useless apart from beneficiaries with whom to share them, as well as a responsibility to use those gifts to the benefit of others, its purpose by this account is therefore ultimately to facilitate the development of individuals, and to enable them to transcend gender stereotypes, disadvantage, and forms of oppression to this end.
As the persons of the Trinity are equal though different, so a community should serve its members equally when it comes to helping them realize their potential in this way, even though operating to this effect may require different forms of service, to accommodate different human natures and needs. Moreover, a community should be overhauled, or even abandoned, if it fails to do so, since it is precisely in such a failure that a community fails in its purpose and is transformed into a perverse and potentially oppressive ‘pseudo-community’. This is all the more true if we consider the fact that the neglect of individuals to realize their potential—perhaps in part because of the constraints of a problematic community—represents a form of neglect that is not simply neutral in its effect but which has detrimental consequences for other living beings and especially human beings whose flourishing individuals may be gifted to foster in different ways and which is undermined when those gifts are not employed.
Thus, the communitarian insistence that individuals conform to the ‘collective personality’Footnote 28 or ‘group identity’ of a particular community, and whatever personality stereotypes this might entail, and the corresponding failure of individuals to ‘become themselves’ with the support of a community creates a vicious cycle in which communities hinder the thriving of individuals and vice versa. By sharp contrast, the account delineated above casts the process of achieving self-knowledge and self-actualization, for example, as intrinsically social. Yet it does not do so in a way that destroys but uphold the integrity of individuals, and correspondingly, communities.
Although I cannot in the space provided here delineate in greater detail what might be regarded as the problems with process thought and social doctrines of the Trinity, the arguments that have been developed thus far should at least suffice to show that a broadly Thomist understanding of the Trinity and human participation in the life of the Triune God does not fall prey to the problems that have been associated with it and that have motivated the development of untraditional theologies like those just mentioned. In fact, the traditional theology outlined here appears to resolve the very problems such theologies purport to solve without resorting to what might be regarded as a deeply concerning tendency to efface the difference between God and humans, and humans and God; upon which the integrity of the above account and theology in general turns.
