PETER C. PHAN (ed.) | The Cambridge Companion to the Trinity | Cambridge University Press 2011


By Dennis Schulting

Given the centrality of the doctrine in Christian theology, it is fitting that in the prestigious long-running series of Cambridge Companions to Religion a volume is specifically dedicated to the Trinity. The Trinity is considered to be one of several aspects that uniquely characterise Christian theology but, given that Christianity is a monotheistic religion like Judaism and Islam, it is often also met with puzzlement and misunderstanding by outsiders or even by Christians. Apart from its constant place in public prayer and worship, the Trinity has until not so long ago also not been very central to the theological debate in modern Christian theology, but as the editor points out, at least since the work of mid-twentieth century theologians Karl Rahner (for Catholicism) and Karl Barth (for Protestantism) the Trinity is again ‘occupying center stage’ (p. xiii; cf. p. 11).

This Companion seeks to address the multiple theoretical facets of the Trinity, as well as some of its problems in the context of less directly associated fields of theology and religious studies. There is of course a range of historical essays (mainly in part II) reflecting on the origin of the doctrine of the Trinity in the early patristic theology, and the arduous road to its eventual orthodox formulation at the Council of Nicea (325), when Arianism was finally condemned and the Father and the Son were defined to be homoousios, of the same nature and equally fully divine (in contrast to homoiousios, which referred to them being merely similar, but not identical). (The divinity of the Holy Spirit was first proclaimed at the Council of Constantinople in 381.)

There are 23 chapters in total, divided up in 6 parts, including an introduction with two chapters by the editor, one of which addresses more general issues regarding methodology and directions in trinitarian theology, as well as defining central terms such as the ‘immanent’ and ‘economic’ Trinity. Part II addresses the sources in the New Testament (NT), the Greek fathers, and early Latin patristic theology. Part III expounds the Trinitarian accounts of two central figures of medieval theology, Thomas Aquinas and Bonaventure, as well as the formulations by the theologians of the Reformation, Luther and Calvin, and later Protestant appropriations such as in Pietism. The later heterodox accounts of Schleiermacher and Hegel are also briefly considered. I thought especially Hegel’s philosophical account merited a separate chapter written by a Hegel scholar, as his is one of the few sustained fully philosophically thought through versions of the doctrine of Trinity in existence. On the other hand, it is arguable whether Hegel’s appropriation of the doctrine is really relevant to scholars of the Trinity per se.

Part IV puts 20th century theological accounts centre stage: the obvious choices of Karl Barth, Hans Urs von Balthasar, Karl Rahner, Jürgen Moltmann and Wolfhart Pannenberg next to chapters on the Trinity in orthodox theology, feminist theology and “black” and Latin American/Hispanic theology. Part V considers the Trinity from the point-of-view of comparative religion, in relation to not just the obviously unitarian/monotheistic religions Judaism and Islam (Ch. 20), but also polytheist Hinduism (Ch. 18) as well as Buddhism, Confucianism and Taoism (Chs 17 and 18). The last part of the Companion (VI) considers systematic issues, namely how the Trinity relates to Christology (Ch. 21), liturgy, the sacraments and mysticism (Ch. 22) and to Christian ethics (Ch. 23).

It is impossible, of course, to consider the plethora of views expressed in all of these chapters in the short space of a review. Sometimes I got the impression that the editor wanted to have every conceivable topic that has at least some relation to the doctrine of the Trinity covered. But it is not always clear, from the accounts within some of the essays, whether all of what is broached has a direct bearing on the topic of the Trinity, and is not just motivated by obligatory politics or the academic predilections du jour. I also found those essays (it concerns Chs 15, 16, part V and some of part VI) the least satisfying and not always up to the same level of scholarship and clarity of writing as the more overtly theological parts of the Companion. I would have preferred to have one of the four (!) chapters dealing with comparative religious accounts substituted by a separate chapter on e.g. Augustine, whose De Trinitate is of course one of the intellectual pillars of the doctrine, but gets a measly four pages in the chapter on Latin patrology.

Traces of the doctrine of the Trinity can already be found in NT (incidentally, this crucial topic was badly served by a thoroughly disappointing Ch. 3). But the word Trinitas was first coined by Tertullian. The main challenge in understanding the Trinity is to reconcile the belief in a unitary God (monotheism) and the experience of the divine status of the Father, the Son and the Holy Spirit, as three separate persons, in other words, to ‘reconcile unity and plurality in God’ (p. 4). The various possible responses to this question make up the diverse theological traditions across many centuries of thought on the Trinity.

In Ch. 2, Peter Phan, the editor of the volume, helpfully addresses various general, systematic issues, the more important one being the pivotal contrast between the ‘economic’ Trinity and the ‘immanent’ Trinity, the first pointing to the relation the Trinity has to the created world, referring to God’s actions in history, the latter referring to the immanent life of God himself. Phan discusses ‘Rahner’s rule’, which states that ‘the “economic” Trinity is the “immanent” Trinity and the “immanent” Trinity is the “economic” Trinity’ (p. 17), which implies that the Trinity is only ‘in the fullness of history’ (p. 18), i.e. in the ‘economy’ of salvation. The second part of this rule is rejected by some, as it seems to collapse the ‘immanent’ trinity into the ‘economic’ one, ‘thereby compromising God’s freedom and transcendence’ (p. 17). But does that mean that the Trinity is eternally and ontologically prior to the ‘economic’ one? In the chapter on Moltmann and Pannenberg, this principle is again foregrounded.

Another central issue addressed by Phan is the distinction between the ousia or essentia of God and God’s hypostasis or substantia, in other words the distinction between the nature and persons of God respectively. Whereas God’s nature is one and indivisible, there are three numerically distinct persons, hypostases. The first (nature) addresses the question of what God is, the second (person) who God is. Modalism on the other hand represents the theory that the persons of the Trinity (Father, Son, Holy Ghost) are only modes of God, not distinct persons, i.e. modes of existing, not individuals (p. 19). It is important not to view the persons of God as psychologically distinct persons, that is, they are not three different consciousnesses. Hence, whilst steering clear of overt modalism, Barth preferred to talk about Seinsweise instead of person, and Rahner referred to Subsistenzweise. Further, the central term of perichoresis is introduced—first mentioned in the Christian vocabulary by Gregory of Nanzianzus—which signifies the idea of ‘mutual indwelling’; this idea explains the relations between the persons of God, as not being ‘marked by a linear and hierarchical descent but by a circular and inclusive movement or dance’ (pp. 21–2).

Chapters 4 and 5 discuss the patristic era of the Apostolic Fathers such as Clement,  Ignatius, and Irenaeus and, for the Latin period, Tertullian and Ambrose of Milan, and of course the Nicene and neo-Nicene parties. With the early Greek Fathers, trinitarianism is still very much seen in the light of the imminent eschaton. That Christ is divine is simply believed, apologetically stated, not debated as in later periods. The logos theology concerning Christ’s divinity is also still very much dyadic; the divinity of the Holy Spirit is considered only much later (p. 58). Nevertheless, Origen of Alexandria gives a new impetus to trinitarian theology in the early Christian church, by seeing the Trinity as ‘one of the key issues of all theology’ (p. 61). Origen argues that the Father, the Son and the Holy Spirit are the three hypostases of God, different realia of God (p. 61). He rejects however the concept of homoousios, which led eventually to the proclamation by the Nicene theologians that Christ is equally divine as the Father, and is eternally begotten, not made, in contrast to what Origen held. That is, Christ and the Father are not generically the same, but they are of the selfsame being (ousia). There is one essence, but three hypostases or persons. Tertullian, the most important figure in Latin patristics concentrates on Christ’s divinity, and has a weak pneumatology (p. 75), whereas Ambrose of Milan’s De spirito sancto is the ‘first lengthy Latin treatise on the third person’ (p. 77). And of course, the work of the illustrious Augustine is discussed, but, as said, with only four pages, the account in this Companion is rather short (for more on Augustine’s trinitarian theology refer to the chapter on De Trinitate, by Mary Clark, in The Cambridge Companion to Augustine).

Chapter 6 features the systematic work concerning the Trinity by another great, if not the greatest, theologian of the Christian church, namely Thomas Aquinas. I found this one of the intellectually most satisfying chapters in the book, perhaps also because Aquinas’s account of the Trinity is, as the author observes too, one of the most complex and elaborate accounts in trinitarian theology of the central question how there can be three distinct persons in God, whose essence and existence are identical. However, although the account given in the Companion was mostly compelling and illuminating, sometimes, perhaps due to the shortness of space in a paper dealing with such a vast work as Aquinas’s, there was a discouraging lack of clarity. A central question driving Aquinas’s account is: How can three persons originate or proceed from one at all? In order to be able to explain this, it is necessary to distinguish between transient and immanent action. Transient action is typically what happens when the effect of some cause is ontologically distinct from, or external to, that cause. By contrast, the immanent activity of the Trinity must be considered on the model of intellectual activity or intellectual emanation or procession, which typically causes effects by immanent action (p. 88).

It is further stressed that the origination of the Son is not by way of standard generation, but by way of inward procession, that is, by way of similitude with the Father. The Son and the Father are different persons, and so signify different real, subsisting relations, but they share the same divine essence. They are only relatively opposed. Thus, the Father is the ‘underived principle of the total divinity of the two other persons’ (p. 101), whereas the Son is ‘God as existing in the mode of the one begotten of the total self-communication of the Father in his divine nature in a procession of the intellect and therefore as Word and Image of the Father’ (p. 101). On the other hand, the Holy Spirit is ‘God as existing in the mode of one proceeding from the Father through the Son in a procession of the will and therefore also as Love and Gift between the Father and the Son’ (p. 101). The three persons are ‘mutually irreducible, intrinsically differentiated’ (p. 101). Aquinas’s sophisticated account is one which is able to circumvent the entrapments of both tritheism and extreme modalism.

Lastly, Aquinas is ‘thoroughly trinitarian’ both in the immanent and economic Trinity. Often, it is said that Aquinas’s God is unitarian ‘in her [sic] action on the world except by way of the “appropriation” of the common essential attributes to particular persons, which is not trinitarian enough’ (pp. 100–1). But, as the author of the essay points out, also in his creation, ‘the processions of the divine persons are “also in some way the cause and reason […] of creation”’ (p. 103), and the ‘power to create belongs to all three persons, but each person exercises that power according to his own personal mode’ (p. 103).

Chapter 8, dealing with the Trinity in the Reformation period, concentrates on the accounts of Luther and Calvin. Luther’s trinitarian theology is disposed towards de-emphasising the metaphysical distinctness of God’s transcendence from the natural world (p. 133), and towards a concentration on Christology; hence, ‘God’s nature and will are made known only in Christ the Word’ (p. 133). Although he largely eschews philosophical terminology, some have argued that Calvin is the most Trinitarian of the Reformation theologians (p. 136). Indeed, ‘the trinitarian doctrine is so integral to Calvin’s understanding of God that the whole Institutes has a trinitarian structure’ (p. 137).

In Chapter 10, the trinitarian theology of arguably the greatest theologian of the twentieth century, Karl Barth, is discussed. The Trinity, for Barth, defines his revelation theology: God reveals himself as triune, and is triune in his revelation. ‘Barth synthesizes the event of revelation and the doctrine of the Trinity by correlating the three forms of revelation with the three persons of the Trinity: God the Father is the revealer, the Son is the revelation, and the Holy Spirit is the revelation’s revealedness’ (pp. 175–6). The writers of this chapter emphasise a historical reading of Barth’s trinitarianism. They are interested ‘in what ways does Barth’s doctrine of the trinity ground his radical politics?’ (p. 174). Hence, Barth’s conception of the economic trinity is foregrounded, the priority of which seems already indicated by the strong correlation between revelation and Trinity. Given the correlation between revelation and the Trinity, it might seem that Barth reduces the immanent Trinity to the economic Trinity, in that one of Barth’s central theologoumena is that God is nothing beyond what he reveals of himself in revelation; hence, the economic Trinity is the immanent Trinity.

Among other issues discussed in this chapter, the question is considered how God’s triune being is to be correlated with the election, with his being pro nobis. In other words, is the decision of election constitutive of God’s triune being, or does it ‘confirm the antecedent triune being’ (p. 180)? Some scholars argue that God’s self-determination to be triune is one and the same as the act of election; others argue that the election confirms the pre-existence of the eternal triune communion of love between the three persons. The writers appear to play down this putative problem in Barth’s theology by entirely focussing on the aspect of the economic Trinity in relation to Barth’s social ethics, in which I thought they only half succeeded (for more on Barth and the Trinity see the excellent Ch. 5 in The Cambridge Companion to Barth).

Karl Rahner (Ch. 11) must be considered the one responsible for a rediscovery of the Trinity in twentieth century Catholic theology (p. 192). Rahner’s trinitarianism has its roots in his philosophical anthropology, in which he regards the human person as ‘spirit in world’ (p. 193). Although critical of Augustine’s psychological analogies of the Trinity, Rahner ‘invoke[s] the human acts of knowledge and love as intimations of the Trinity’ (p. 194). Rahner’s conception of the Trinity starts ‘from below’, that is, from ‘our concrete and historical experiences of God’s self-gift in the threefold modality of Father, Son, and Spirit’ (p. 194), which leads us to the immanent Trinity, so in a sense the explanatory regress is from the economic Trinity to the immanent Trinity. The Archimedean point in this explanation is God’s self-communication in history, in his gift of grace. The ‘intrinsical gracedness’ of the human being means that he ‘possess[es] a trinitarian constitution’, for grace is the indwelling in us of the Trinity (p. 195). Rahner’s real legacy however lies in the aforementioned ‘Rahner’s rule’, which simply says that the economic Trinity is the immanent Trinity and the immanent Trinity is the economic Trinity. For all its renown, one would be forgiven for thinking that one is none the wiser with this rule in hand as to how to answer the question regarding the relation between the immanent and economic Trinity. For Rahner, in any case, ‘God’s self-revelation and self-gift to us in history (the economic Trinity) is no other than or exactly the same as the […] immanent Trinity’ (p. 197). There is no hidden immanent Trinity behind or beyond the economic one, which is encountered in history (p. 198).

Jürgen Moltmann’s trinitarianism, expounded in Ch. 13, has a definite social orientation, which focuses on the ‘fellowship’ or perichoresis of the three persons in the unity of God (p. 228). ‘This perichoresis will be consummated in the eschaton in the coming union of God […] and the world’ (p. 228). Rather ingeniously, Moltmann argues that the apparent tension between the economic and immanent Trinity will be solved by the fact that the ‘economic Trinity completes and perfects itself to immanent Trinity when the history and experience of salvation are completed and perfected’ (p. 228); the economic Trinity is raised into the immanent one. What is one of the striking aspects of the great Protestant systematic theologian Wolfhart Pannenberg’s trinitarian theology is that he denies the death of God (p. 232). Death and humiliation are signs of the Son’s self-distinction from his Father (p. 233). Pannenberg’s views in this respect are undeniably complex and warrant further elaboration.

Lastly, I should like to note that the reference to God as ‘G*d’ (in Ch. 3) and as feminine (by the consistent use of the possessive pronoun ‘her’ when referring to God in Ch. 10, on Aquinas) is annoying, especially if this is done in sentences where also references to the Father or the Son are made by the use of the masculine ‘his’, which only leads to unnecessary confusion. This should have been edited out.

All in all, this is a fine compendium to many aspects of the Trinity, and recommended to anyone interested in this central doctrine of Christian theology.


Note: this review was originally intended for publication in Plurilogue, an online reviews journal, but retracted by the author, because there was a disagreement about not having agreed to having the review refereed. It was earlier posted on on 16th June 2014.

The author thanks Cambridge University Press for providing him with a review copy. 

© Dennis Schulting, 2014