I

Recently, analytic philosophers have considered how religious practice shapes attitudes and commitments that constitute faith.Footnote ¹ Such work appropriately recognises that liturgical and moral actions are fundamental to the life of faith. Through unbalanced focus on the content and justification of religious beliefs, and failure to examine praxis, philosophy can present a picture of religion which many practitioners might find one-sided.

Yet attention to religious practice can tempt philosophers to conclude that faith is reducible to practice, or to non-doxastic attitudes which it fosters. John Cottingham, for instance, argues that ‘religious understanding’ is to be conceived of ‘adverbially, as it were, as referring to a certain mode or manner of understanding the world’. Such knowledge is gained through religious ‘involvement and commitment’, and does not involve belief in metaphysical propositions which serve as explanatory hypotheses.Footnote ² Cottingham overlooks the teaching of many Christian (and other) traditions that propositional belief in revelation is a necessary constituent of salvific faith. Many believers would find the claim that propositional belief is peripheral to ‘religious understanding’ as misguided as analyses which reduce faith to propositional assent.

By contrast, this paper illustrates how philosophical examination of religious practice can enrich discussion of the rationality of religious belief. I argue that the experience of liturgical music can provide distinctive evidence for the truth of Christian orthodoxy. Claims that musical experience can provide justification for Christian beliefs (or, for theism) receive anecdotal endorsement from believers. Pope Benedict XVI, for example, recalls attending a Bach concert:

Benedict's experience may have provided epistemic justification for his belief in God (or Christianity) in several ways. Perhaps Bach's Cantata served as appropriate ‘grounds’ for the functioning of Benedict's sensus divinitatis,Footnote ⁴ or maybe his experience caused him to form a subconscious argument for theism from aesthetic realism. In arguing that liturgical music provides evidence for Christian orthodoxy, I will not survey every way in which musical experience may contribute to the justification of religious belief.

However, I intend to avoid one common shortcoming of proposals that Christian beliefs receive epistemic support from musical experience. Frequently, musical experience is introduced as evidence that we recognise objective standards of beauty. Philosophers then use aesthetic ‘realism’ as a premise in transcendental arguments for the existence of absolute Beauty,Footnote ⁵ or argue that our knowledge of objective beauty renders God's existence probable.Footnote ⁶ Others simply assert that experiences of beautiful music render theism rational.Footnote ⁷ Whatever their value, these arguments ignore the particularities of Christian liturgical music, and ways in which musical experience might provide justification for distinctively Christian beliefs. This is surprising, since liturgical music is often composed to portray Christian narratives and doctrines. My argument that liturgical music can provide evidence for Christian orthodoxy will examine salient aesthetic features of music and their relationship to Christian doctrine.

I first argue that liturgical music possesses two properties: the ability to express and generate emotion (Section II), and to embody narratives and doctrines (Section III). In Section IV, I use these claims to develop an Aesthetic Argument for Christianity (AAC), explaining how its premises can receive support from musical experience. I then further develop one version of AAC: the Aesthetic Argument for Trinitarianism (AAT) (Section V), before defending both argument from objections (Section VI). This paper will only provide an introductory defence of AAC and AAT, but I aim to show that these arguments have dialectical promise. I primarily discuss examples from traditional, Western Christian music. This is largely because of my familiarity with the latter musical tradition, although as I shall argue there are musical forms common to Western Christian music which convey the particular beauty and moral relevance of Christian narratives and doctrines. I do not intend to imply, though, that other forms of Christian music cannot do likewise.

II

Augustine's Confessions recounts that he was especially moved by religious texts sung in church to appropriate melodies. Augustine asserts that ‘there are particular modes in song and in the voice, corresponding to my various emotions and able to stimulate them because of some mysterious relationship between the two’.Footnote ⁸ We can distinguish two claims here: that there is a correspondence between musical forms and particular emotions (perhaps, that music can be emotionally expressive), and that music can produce emotional responses. Yet these intuitive suggestions are contested by ‘formalists’, who hold that ‘pure music’ (instrumental music, performed in concert) cannot be emotionally expressive, or evoke emotional responses in virtue of its expressive qualities. Although liturgical music is not ‘pure’, formalists suggest that it can only express and evoke emotions because of its lyrics, setting, or other non-musical properties. Since it is important for my later arguments that liturgical music can be emotionally expressive and evocative (or minimally, resemble and generate emotional states), I now argue that these claims are plausible.

Given the complexity of debates about music and emotion, I explore just one credible account of how music expresses and generates emotion (‘contour theory’). I do not argue that contour theory provides a uniquely credible or comprehensive account of music's emotional nature. My later arguments may be compatible with other accounts of music's emotional expression, but I lack space to demonstrate that here.

Philosophers dispute the nature of emotion. Jeremy Begbie discerns three constituent elements typically taken to characterise emotions: conscious experience (‘feeling’ angry), bodily behaviour (clenching one's fists), and physiological activation (increased heart-rate).Footnote ⁹ Emotions are also dispositions to action. ‘Cognitivists’ further insist that emotions involve cognitive judgements about intentional objects. Thus whilst ‘fear’ possesses a distinctive phenomenology and involves bodily changes and dispositions to action, it necessarily includes the judgment that something is dangerous. ‘Non-cognitivists’ demur, holding that emotions are reducible to bodily or phenomenological changes (or their perception), or that bodily changes can constitute non-cognitive appraisals of intentional objects.Footnote ¹⁰

Hereafter, ‘emotion’ refers to any state which combines distinctive phenomenology, physiological activation, expressive behaviour, and disposition to action. Even cognitivists recognise that that one can possess emotions lacking any intentional object, or which are directed towards everything which one perceives. Perhaps this is how we should understand the emotional aspect of (e.g.) depression. Following convention, I term objectless emotions ‘moods’.

We can now examine the suggestion that music can be emotionally expressive. What might this mean? Peter Kivy distinguishes ‘expressing’ from ‘being expressive of’.Footnote ¹¹ An action, facial expression, or object (etc.) expresses an emotion by indicating the presence of a (token) emotion in its subject or author. Thus my smile expresses my joy. By contrast, actions or objects which are expressive of emotion somehow indicate an emotion (type) which is not necessarily experienced by its subject, author, or anyone else. Weeping willows might be expressive of sadness, but this does not entail that any trees or gardeners are melancholy.

Given this distinction, we can see why formalists deny that music is emotionally expressive. Fundamentally, one might wonder how actions or objects can be ‘expressive of’ emotion. One can understand how actions or objects express emotion: roughly, they indicate occurrent emotions of their subjects or creators. But music cannot thus express emotion, because it is not a conscious subject.Footnote ¹² Moreover, suggestions that music is emotionally expressive because it indicates the emotions of composers and performers, or because it emotionally affects listeners, are uncompelling.Footnote ¹³ The emotions of composers, performers, or audiences seem accidental to music's emotional expression. Intuitively, emotion exists ‘in’ the music, rather than external subjects. Eduard Hanslick famously raised another problem: if (as ‘cognitivists’ urge) emotions necessarily possess intentional objects, what are the objects of emotions expressed in music?Footnote ¹⁴ Finally, some formalists complain that music is wholly intelligible without description in emotional terms. Emotional descriptions of music can always be paraphrased in technical, non-emotional language.Footnote ¹⁵ This might support suggestions that attributing emotional properties to music involves projection or irreducibly metaphorical description.Footnote ¹⁶

Fortunately, one account of music's emotional expression answers formalist worries. According to the ‘contour theory’ developed by Kivy and Davies, pieces are emotionally expressive because their perceptible features (‘contours’) resemble features or behaviours exhibited when humans experience emotions.Footnote ¹⁷ Several features of music have parallels in human emotional expression. Firstly, there are similarities between vocalisations which typically accompany human emotions, and the volume and pitch of emotionally expressive music. Sad speech and tunes are often quiet and faltering; joyful people and pieces are usually loud, with rising pitch. Secondly, there are rhythmic parallels between the movement of humans experiencing emotion and emotionally expressive music. The slow movement of sad people matches the speed of melancholy pieces. Lastly, harmonic progressions involving ‘tension’ and ‘resolution’ can mirror physical or mental patterns of stress and release which characterise emotional experience, as when mounting anger turns to calmness.

Although contour theory faces criticism,Footnote ¹⁸ it resists arguments that music cannot be emotionally expressive. Crucially, it explains what it means for music to be ‘expressive of’ emotion. An object, artwork, etc. is expressive of some emotion if it bears structural resemblance to human actions or mannerisms which express that emotion. Admittedly, any musical piece bears structural resemblance to innumerable entities or processes, but since music is widely regarded as emotionally expressive, this resemblance is not accidental to its nature or value. Accordingly, a piece's emotional expression is important to its nature as music, even if pieces can be described in purely technical, non-emotional terms.

I assume hereafter that contour theory plausibly explains some musical expression of emotion. Pieces are expressive of emotion because (inter alia) their perceptible features resemble those of emotionally expressive human behaviours. But contour theory's key insight for my later argument is that music can resemble emotionally expressive human behaviour.

One might object that this resemblance does not supply intentional objects which are – cognitivists maintain – necessary to individuate emotions proper. Perhaps only some coarse-grained ‘moods’, such as sadness or restlessness, are associated with sufficiently precise patterns of human behaviour to have perceptible analogues in musical ‘contours’. Some ‘contour theorists’ therefore claim that music can only be expressive of certain moods, and not emotions (e.g. love, regret).Footnote ¹⁹ But liturgical music is not ‘pure’. Its lyrics and setting can provide intentional objects for the emotions of which it is expressive (e.g. Christ, sin). Indeed, in liturgical context, sacred music often expresses the emotions of performers or congregants. Pitoni's ‘Cantate Domino’, sung at Mass, is both ‘expressive of’ a joyful mood and ‘expresses’ the Church's jubilant praise of God.

Despite objections,Footnote ²⁰ contour theory also renders it plausible that listeners are often moved to feel emotions expressed in music. As Julian Perlmutter shows, extensive experimental evidence supports this suggestion,Footnote ²¹ and defenders of contour theory offer explanations of how this happens. Perhaps on noticing the expression of emotion in music, listeners are moved by imaginative sympathy; or maybe physiological mechanisms directly induce bodily manifestations of emotion (and eventually, emotions themselves) when one hears their musical analogues.Footnote ²² Moreover, because in liturgical context music can express emotions with intentional objects, it can likewise inspire listeners to experience emotions with those same objects. Lotti's eight-part ‘Crucifixus’, for example, can provoke both the mood of anguish portrayed in its opening, and sorrow at Christ's death in particular.

In sum, given ‘contour theory’, claims that liturgical music is emotionally expressive and affective remain credible.

III

If for music to be emotionally expressive is (partly) for its perceptible properties to resemble those of emotionally expressive human behaviours, music can plausibly likewise express – or ‘embody’ – objects or events other than emotions, including Christian narratives and doctrines.

Yet suggestions that music ‘represents’ non-musical objects face criticism.Footnote ²³ Accordingly, I should explain how my assertion that music embodies narratives and doctrines differs from the claim that it represents them. By affirming that liturgical music can embody Christian narratives and doctrines, I mean that there is sufficient resemblance between the perceptible properties of the music and properties of the narratives or doctrines (or, their “truthmakers” – i.e., the extra-mental realities in virtue of which these narratives and doctrine are true, such as God and His actions) that listeners can perceive the narratives and doctrines ‘in’ the music. That is, because perceptible properties of the music resemble properties of the narratives and doctrines, the former can bring the latter to mind for informed listeners – in a phenomenologically distinctive manner.

A non-musical example illustrates such ‘embodiment’. Mark Wynn discusses the experience of viewing a cathedral designed to resemble the ‘heavenly city’.Footnote ²⁴ Because its architecture resembles a cityscape, one can perceive the New Jerusalem as embodied in the cathedral, ‘as when I see the dots of a puzzle picture as a face’. As Wynn explains, ‘we can reflect upon and be moved by the idea of the heavenly city not only insofar as we reckon with that idea in abstractly conceptual terms, but also insofar as we encounter the idea in sensory form, as embedded in the sensory appearances’.Footnote ²⁵

Perhaps unlike the claim that liturgical music represents narratives and doctrines, this does not mean that composers intend liturgical music to bear these resemblances, or that these resemblances are important for musical analysis. Equally, I do not maintain that competent listeners should hear liturgical music as representing narratives, as critics should see abstract sculptures as representing their subjects.

Given ‘contour theory’, it is intuitive that music can embody scenes from narratives. Many Christian narratives – paradigmatically, Christ's passion and resurrection – are emotionally rich: their characters experience intense emotions. Through its setting and lyrics, liturgical music frequently depicts the emotions of protagonists in Christian stories. Famously, Christ's suffering is portrayed in many pieces, including Bach's Passions and Renaissance Tenebrae responsories. Psalms give musical expression to the emotions of unnamed subjects, who can be interpreted as historical individuals and/or voices personifying the collective feelings of God's people. Listening to Tallis’ ‘Lamentationes Jeremiae’ at Tenebrae, for example, one might simultaneously perceive the music as expressing the mourning of conquered Jerusalem, the sorrow of Christ's disciples at His death, and Jesus’ own suffering.

Christian narratives are also emotionally evocative: some emotional reactions to salvation history are normative. Recalling the enslavement of God's People in Egypt, one should feel sorrow; hearing of the Exodus, one should feel something of the joy that Israel expressed in song.Footnote ²⁶ Accordingly, narratives or doctrines can be musically ‘embodied’ in an extended sense, when liturgical music (given its lyrics or context) depicts some narrative whilst being ‘expressive of’ the emotional reaction that God's People should have to that narrative. Thus, for example, joyful Easter hymns embody Christ's resurrection.

Further, music can also embody doctrines which do not involve or provoke emotions, by bearing structural resemblance to their truthmakers. Saliently, music can embody the doctrine of the Trinity. To see this, we might first recall the essence of orthodox Trinitarianism.Footnote ²⁷ According to the latter, God exists as Father, Son and Holy Spirit: three persons (persones, hypostases) who share one divine substance. These persons are equally valuable and co-eternal, but related in an order which bears some (perhaps, remote) analogy to causation. The Father eternally ‘begets’ the Son, and the Spirit eternally ‘proceeds’ from the Father (and, in Latin tradition, from/through the Son). Father, Son and Spirit are united in knowledge, will, and actions towards creatures.Footnote ²⁸ The doctrine of perichoresis further maintains that the Persons are somehow present within one another.Footnote ²⁹

Several commentators find echoes of the Trinity in Western musical structures.Footnote ³⁰ Here, I explore how polyphony can function as a (limited) structural analogue of the Trinity. David Cunningham explains that in polyphony, we ‘hear more than one melody played simultaneously: thus, we hear not only multiple tones (as in a chord) but also entirely different sequences overlapping one another’. Polyphony's ‘chief attribute is non-excluding difference: that is, more than one note is played at a time, and none of these notes is so dominant that it renders another mute’.Footnote ³¹

We can consider how polyphony structurally resembles the Trinity – insofar as Christians understand the latter. A delicate interplay between unity and diversity characterises both polyphony and God's (putative) Triune life. In polyphony, individual lines retain melodic integrity, whilst combining to form coherent harmonies or dissonances. Indeed, Stephen Davies claims that musical pieces can resemble persons, since they present dynamic, diachronic unfoldings of emotional expression.Footnote ³² If lines of polyphony can be imaginatively perceived as expressive individuals, one can further perceive them as persons in relationship. Such lines exist ‘in conversation’, echoing themes and joining to produce chords. Moreover, as Chiara Bertoglio observes, in polyphonic compositions – particularly, ‘canons’ – the manner in which leading voices generate responses in subsequent parts resembles the Father generates the Son and Spirit.Footnote ³³ In canons, the initial line is necessarily re-echoed, just as the Son and Spirit necessarily proceed from the Father, whose nature they share.

Chords themselves likewise resemble the Trinity. As Begbie argues, notes in chords can sound so closely united in musical space that, without losing their identities, they encompass one another in perichoretic unity.Footnote ³⁴ Moreover, Bertoglio and Bradley Broadhead describe how the relations between the divine Persons are (imperfectly) mirrored by the relationship between the root, third and fifth of a triad.Footnote ³⁵ Like the Father, the root is the triad's foundation, which gives rise to the consonant fifth (the Son). Meanwhile, the third resembles the Spirit by linking the root and fifth, and giving the chord ‘life’ and its distinctive nature.

Finally, performers of liturgical music can themselves embody the doctrine of the Trinity.Footnote ³⁶ Terence Cuneo argues that it is appropriate that liturgical prayers for peace are sung, because singing produces a state of peace. Biblical peace is not mere absence of violence, but the state in which humans co-operate to act justly towards God, creation, and one another. It is therefore noteworthy that communal singing is a co-operative activity that involves close attention to one's own voice and to the voices of fellow singers. Cuneo describes this as paying ‘full divided attention’.Footnote ³⁷ Singing involves particularly intimate co-operation, as it requires constant and continuous attention to one's own performance and that of fellow singers. Successful choral performance necessitates immediate reaction to other singers’ vocal changes, in pursuit of a common goal. Cuneo dubs this process of feedback between attention and action ‘real-time responsiveness’. By instilling full divided attention and real-time responsiveness in singers, group singing unites the congregation in the co-operative ‘peace’ for which congregants pray, affording singers and listeners an intimate experience of peace and its value.Footnote ³⁸

Through full divided attention and real-time responsiveness, in which singers carefully attend to themselves and to one another to produce a combined sound, singers resemble the divine persons. This is obvious on ‘social’ accounts of the Trinity, in which the Persons are understood as distinct centres of consciousness which know and love one another perfectly, co-operating in actions ad extra. However, even on interpretations of Trinitarian doctrine wherein the Persons are not characterised as centres of consciousness, there is an analogy between singers and the Persons, insofar as the latter exist in perfect (non-conscious) relationship with one another, or as mutually constituting subsistent relations.

IV

Since liturgical music can express and evoke emotions, and embody Christian narratives and doctrines, I argue that it provides distinctive evidence for Christianity's truth.

John Henry Newman once suggested that ‘Revealed religion should be especially poetical- and it is so in fact. While its disclosures have an originality in them to engage the intellect, they have a beauty to satisfy the moral nature’.Footnote ³⁹ Newman's remark can be developed into an ‘Aesthetic Argument for Christianity’ (AAC), which – like familiar probabilistic arguments for theism – attempts to raise Christianity's epistemic probability for its audience:

So,

How should one understand (AAC1)’s assertion that Christian narratives and doctrines are aesthetically and morally compelling? The claim that Christian narratives and doctrines are aesthetically compelling principally means that their truthmakers (chiefly, God and His actions) are beautiful, as described by Christian orthodoxy.Footnote ⁴¹

Admittedly, the beauty of God and His wonderful acts of creation and redemption contrasts with the occasional ugliness of fallen creatures. According to Christianity, it is primarily God and His actions, rather than human properties or accomplishments, which evince beauty. Secondly, Christian narratives and doctrines are plausibly themselves beautiful (as narratives and doctrines), by exhibiting features which make stories or theories attractive (dramatic tension, parsimony etc.).

Finally, the claim that Christian doctrines and narratives are morally compelling means, very broadly that they have (positive) relevance for our moral lives. Principally, they provide (sometimes, novel or surprising) insight into our ethical situation and suggest avenues for moral development. Theological narratives and doctrines are especially morally compelling if they present plausible understandings of human moral dignity, flourishing, and purpose – including ways in which humans can make moral mistakes and receive moral healing. Moreover, reflection on Christian doctrines and narratives sometimes directly contributes to the moral transformation of their audience. Reading Scripture, for example, can lead to intense conversion experiences, as experienced by Augustine and John Wesley.Footnote ⁴² Doubtless, one can give a fuller analysis of what it is for doctrines or narratives to be morally compelling, but this characterisation should suffice to introduce AAC.

Having parsed (AAC1), we can see why (AAC2) is plausible. Christianity claims that in Christ, God has revealed His plan of salvation. God is concerned to restore creation's beauty and moral rectitude; indeed, creation already reflects His glory.Footnote ⁴³ Further, it is necessarily true on Christianity that Christian doctrine is morally significant, given that the Christian kerygma is the ‘good news’ of humanity's liberation from Sin and Death, and God's promise to wonderfully re-make creation. Moreover, according to Patristic theologians (e.g. Augustine, Pseudo-Dionysius), the link between divinity and beauty runs deep, since God is the Form of Beauty, in which all beautiful creatures participate.Footnote ⁴⁴ It is consequently unsurprising that Christian doctrine presents God and His actions as beautiful and morally compelling, if it is true and divinely revealed. Moreover, since according to Genesis we bear God's ‘image and likeness’, Christians might particularly expect that their doctrine of God will reveal something about human nature or value.

What is the comparative probability that Christian narratives and doctrines are beautiful and morally compelling if Christianity is false? I assume that if Christianity is false, its narratives and doctrines are human inventions, excluding exotic hypotheses on which Christianity is (e.g.) inspired by deceptive supernatural forces. Accordingly, unless we suspect that Christian theology has developed doctrines for their aesthetic or moral value (see Section VI), it is less epistemically probable that Christian teachings possess particular beauty or ethical relevance, if Christianity is false.

One can develop AAC further, by examining the particular appeal of different Christian doctrines or narratives. I shortly argue that Trinitarian doctrine's beauty and moral relevance provides evidence for the truth of Christian orthodoxy. But first, I illustrate how music might generally provide evidence for (AAC1), and for a claim closely related to (AAC2).

We can begin by examining three ways in which experiences of liturgical music can support (AAC1). Firstly, Christian narratives and doctrines can be musically ‘embodied’, such that they can be perceived as embedded in music's sensory appearances. Accordingly, one who perceives the beauty of a liturgical piece may be helped to perceive that the narrative or doctrine which it embodies is likewise beautiful. Because one perceives the relevant narrative (or doctrine) as ‘embodied’ in the piece, in noticing the music's beauty, one might also see the narrative's attractiveness – at least, if beautiful elements of the music are mirrored in the embodied narrative. Upon hearing Bach's ‘Passion Chorale’, listeners might see a correspondence between the tune's beauty sad, poignant beauty and the aesthetic and moral value of Christ's sorrowful death; listening to Palestrina's ‘Sicut Cervus’, one might perceive the beauty of confident yearning for God. In experiencing Christian narratives or doctrines through the ‘medium’ of music, listeners may therefore be encouraged to notice aesthetic properties of the former.

Secondly, music can be emotionally expressive. In hearing liturgical pieces that express the emotions of protagonists in religious narratives which they recount – or, normative emotional responses to those narratives – listeners are encouraged to notice the emotions of characters and their own emotional reactions. Similarly, drama uses music to highlight characters’ emotions, or to encourage emotional responses from the audience. Such appreciation of the emotional nature of Christian narratives is key to grasping their moral or spiritual relevance. Paradigmatically, understanding the sorrow and shame of Christ's death is necessary to appreciate God's condescension in the Passion, and the depths of human sinfulness which it likewise reveals.

Finally, liturgical music can emotionally affect listeners. As Mark Wynn argues, this allows listeners to ‘try out’ emotions or moods proper to Christian life (e.g. joy and gratitude towards creation).Footnote ⁴⁵ If liturgical music can directly induce emotional states, it might enable non-Christian listeners to experience emotions which are normative (for Christians) as responses to Christian narratives. Accordingly, music might teach one something of Christian narratives’ ability to positively shape human experience.

If liturgical music provides evidence for (AAC1), it likewise supports (AAC2) – or rather, a nearby claim. Even if Christian narratives and doctrines are aesthetically and morally compelling, this does not guarantee that they are perceptible as compelling through musical experience. The fact that Christian doctrines and narratives are often perceptible as compelling through musical experience constitutes an additional piece of evidence. We can consider its relative epistemic likelihood on Christianity's truth and falsity.

If Christian orthodoxy is true, God has commended liturgical music in Scripture and guided the Church to make music central to liturgical practice. If certain musical forms disclose Christianity's beauty and relevance, God possesses motivation for ensuring that they persist in Christian worship, if He desires to provide non-coercive evidence for Christianity. This raises the epistemic probability that if Christianity is true, liturgical music providing evidence for (AAC1) is widely incorporated into Christian liturgy. By contrast, if Christianity is false, it is likely a historical accident that such music is widely performed. Admittedly, many religions use music in worship, so if music can express emotion and represent doctrines or narratives, it is not entirely surprising that Christian liturgy frequently features music which provides evidence for (AAC1). But it remains noteworthy that particular forms of music including polyphony and harmony – which, as argued below, offer special evidence for (AAC1) – remain common in Christian liturgy, despite efforts to outlaw them. The presence of such music in Christian liturgy therefore provides modest, additional reason to affirm a claim adjacent to (AAC2), which likewise supports (AAC3): that it is (epistemically) more probable that Christian narratives and doctrines are perceptible as attractive through liturgical music if Christianity is true, than if Christianity is false.

V

I now defend one version of AAC – the ‘Aesthetic Argument for Trinitarianism’ (AAT):

So,

Since (AAT2) is plausible for the reasons given to support (AAC2) above, I focus on defending (AAT1). I survey two representative modern discussions of Trinitarian doctrine's value, before examining evidence for (AAT1) which musical experience supplies.

Richard Swinburne argues that God is Triune on a priori grounds, given love's moral value.Footnote ⁴⁶ Swinburne highlights the value of two species of loving action: sharing (and receiving) love, and co-operation in sharing love. These types of love are illustrated in marriage: spouses share love with one another and co-operate in loving their children. It is therefore good (‘great-making’) for God to be Triune, because this allows the Father to share His ousia and life (experiences, choices) with the Son, and permits the Father and Son to co-operate in sharing their nature and lives with the Spirit. Swinburne's argument does not appeal to aesthetic considerations. But it suggests that the Triune God is doubly beautiful. Firstly, possession of any great-making properties plausibly makes entities somehow attractive. Secondly, simplicity contributes to beauty. On Swinburne's account, the Trinity evinces parsimonious beauty, since God exists as the minimum number of persons necessary to instantiate the valuable properties of sharing and co-operation in love within the Godhead.

Despite critiques of Trinitarianism as ‘masculine’ theology, Catharine Mowry LaCugna and Hannah BaconFootnote ⁴⁷ have attempted to reclaim Trinitarian doctrine as congruent with feminist concerns. According to LaCugna, whilst Trinitarian doctrine does not afford detailed guidance for political theorising, it undermines attempts to justify patriarchal systems through theological appeal to God as a paradigm of male, individual superiority. According to orthodox Trinitarianism, God's rule is always shared by a community of persons, of equal value. Contra Arianism, the Father necessarily exists in relation to other Persons, and cannot function as an analogue for an absolute monarch or pater familias who exists independently of and in superiority to his inferiors. Consequently, in human affairs, ‘subordination is not natural but decidedly unnatural, because it violates both the nature of God and the nature of persons created in the image of God’.Footnote ⁴⁸

Similarly, Bacon argues that Trinitarian doctrine supports efforts to foreground the diversity of human experienceFootnote ⁴⁹ in rejection of ‘phallocentric logic’, which understands women and female experience as aberrations from a masculine norm.Footnote ⁵⁰ Bacon summarises:

These suggestions that Trinitarian doctrine is beautiful and morally compelling do not appeal to musical experience. But by experiencing Trinitarian doctrine as embodied in music, listeners can more readily grasp its appeal. To see this, first consider Swinburne's claim that it is good for God to exist as Triune, because the Trinity instantiates two species of loving relationship. Earlier, I parsed Cuneo's argument that by entering states of ‘full-divided attention’ and ‘real-time responsiveness’, singers can experience the phenomenology – and value – of open, co-operative relationship and action. In liturgical context, such relationships might be experienced as an analogue of the relationships and actions of the divine Persons, who are fully open to one another and co-operate through love. Whilst liturgical singers are not (necessarily) motivated by or engaged in love for one another, if full-divided attention and real-time responsiveness are intrinsically valuable, it is a fortiori plausible that they are valuable between persons who co-operate through love. On Swinburne's account, the Trinity paradigmatically intantiates such co-operative love. Experiences of liturgical singing therefore partially reveal the value of God's Triune life.

Secondly, the diversity of divine ‘perspectives’ within the Trinity – which LaCugna and Bacon argue renders the Trinity a valuable model for human relationships – can also be perceived as valuable through experience of the Trinity in music. I argued above that polyphony, in which musical ‘perspectives’ form a unity whilst preserving individual integrity, illustrates the relations between the divine persons. Likewise, one can perceive the Trinity as embodied in triadic chords because of the manner in which the third and fifth are generated by the tonic, and since notes in chords form a harmonious unity whilst remaining distinct. But both polyphony and triads appear beautiful because of their unity-in-diversity. So again, by experiencing the Trinity as embodied in polyphony or triads, one might appreciate its beauty.

VI

Having defended (AAT1), and (AAT2), I examine objections to both premises, which also attack (AAC1) and (AAC2).

Firstly, one could reject (AAT1) by arguing that Trinitarian doctrine is ugly or morally harmful. One could argue that it is logically incoherent, and consequently false and conceptually unattractive. Alternatively, one might endorse feminist worries that because the Trinity contains no ‘female’ persons, Trinitarianism is socially harmful.

Yet such objections seem superable. Firstly, recent metaphysical models of the Trinity give reason to hope that the doctrine is logically coherent.Footnote ⁵² Further, as Bacon argues,Footnote ⁵³ feminist worries about the doctrine often focus on how the Persons are named. They overlook Trinitarianism's metaphysical claims, which are plausibly attractive to feminists.

One might undercut arguments for (AAT1), by claiming that modern suggestions that Trinitarian doctrine is beautiful or morally perspicacious are theologically naïve. ‘Social’ models of the Trinity advanced by Swinburne and LaCugna, which suggest that God exists as a community of separate centres of consciousness, face theological criticism. Saliently, Karen Kilby advances two objections to the analysis of the Trinity developed by Swinburne, LaCugna, and Bacon which support (AAT1). Firstly, Kilby alleges that using the Trinity as a model for human relationships involves problematic projection of human concerns onto God.Footnote ⁵⁴ Secondly, she draws on Gregory Nyssen and Aquinas to argue that Trinitarian doctrine gives Christians no positive (kataphatic) knowledge of what God is like in se.Footnote ⁵⁵ If, as Kilby urges, Trinitarian doctrine does not hold that God exists as three centres of consciousness with perfect knowledge and love of one another, and that God thereby instantiates loving relationships through His Triune existence, the arguments canvassed above for Trinitarian doctrine's fittingness and moral relevance are undermined.

Yet Kilby's case is overstated. LaCugna and Bacon do not claim that Trinitarian orthodoxy supports detailed ethical proposals. They hold that the Trinity presents a broad guide for human relationships because it reveals that God – however unintelligible His nature, or three-fold personhood – evinces internal unity-in-diversity. Moreover, pace Kilby's apophatic criticism of ‘social Trinitarianism’, it remains plausible that experience of the Trinity through music allows us to see the beauty of God's Triune life, even if our understanding of what Christians refer to as the divine ‘persons’ or ‘nature’ is limited. One can perceive the Trinity as embodied in polyphony or triads because of the structural relationships between different musical lines or notes, and their resemblance to the relationships between the persons of the Trinity. Famously, structural similarities can exist between entities with vastly different intrinsic properties. Kilby might reply that the Trinitarian doctrine teaches us nothing about God in se, so that it does not even licence the claims that (e.g.) there are distinct referents in God which Christians call Father, Son, and Spirit, and that these referents are related in some quasi-causal manner. But (briefly) this suggestion runs contrary to Christian tradition and empties Trinitarianism of much meaningful content.

(AAC2) and (AAT2) also face potential objections. Firstly, perhaps it is unsurprising (epistemically insignificant) that Christian doctrines or narratives are beautiful or compelling even if they are false, because the latter may have been developed for (or, became popular through) their attractiveness. By analogy, it is unremarkable that many fictional works are aesthetically or morally compelling, because we know that their authors aimed to compose compelling narratives. Maybe, in elucidating doctrine, early Christian theologians aimed to arrive at beautiful and morally relevant descriptions of God and His actions. If Christian doctrines and narratives were developed for beauty and moral relevance, their attractiveness is unsurprising even if Christianity is false.

But the claim that Christian narratives and doctrines were developed or selected for their beauty or moral value is false, at least concerning some core doctrines. Narratives and doctrines were often accepted and elaborated by the Church because early Christians believed that they were true, divinely revealed, or entailed by revelation; not because they were considered aesthetically or morally compelling. The doctrine of the Trinity, for example, emerged from Patristic debates over Scriptural interpretation, metaphysics, and liturgical practice.Footnote ⁵⁶ Besides appeals to the soteriological importance of Jesus’ divinity, defenders of orthodox doctrine did not emphasise Trinitarianism's beauty or moral import, and there was no discussion of its political implications or musical embodiment. Admittedly, as a reviewer notes, coherence (internal, and with other Christian teachings) is an aesthetic virtue of doctrines, and defenders of Trinitarianism did attempt to form a doctrine of God which was beautiful qua coherent. But as argued above, Trinitarian doctrine's beauty and relevance extends far beyond its coherence. Because – unlike some works of fiction – some central Christian narratives and doctrines were not developed or selected for their attractiveness (beyond coherence), it is surprising that they are so attractive, especially in their abstruse metaphysical or theological details.

Another objection to (AAC2) and (AAT2) protests that it is trivial (hence, unsurprising) that Christian narratives and doctrines are attractive. All doctrines of God have some beauty and moral value, which can become evident through musical embodiment. For instance, a striking piece – say, against Messaien's intention, the fourth movement of ‘La Nativité du Seigneur’ (‘Le Verbe’), in which the opening chords emerge almost ‘ex nihilo’ – might embody Arius’ understanding of the Son's relationship to the Father in a way which makes Arianism seem attractive.

However, one can reply that although many religions offer attractive theologies, Christian doctrine is particularly beautiful and morally relevant. Whilst there is perhaps no ‘baseline’ of aesthetic or moral value which one should expect the average, non-veridical doctrine of God to exhibit, one can show that the Christian doctrine of God is significantly compelling by showing that it is more beautiful and morally relevant than most rival theologies.

Similarly, whilst alternative doctrines of God are capable of attractive musical portrayal, one can argue that because Trinitarianism posits unity-in-diversity in God, it can – unlike other doctrines of God – be portrayed in especially beautiful and sophisticated musical forms, including polyphony. Consider two alternatives to Trinitarianism: strict monotheism (on which God is a single person) and polytheism. Perhaps the God of strict monotheism is best portrayed musically by monody. Although monody is beautiful, with harmonic or polyphonic compositions often incorporating monodic sections, it is arguably less rich and compelling than harmony or polyphony. Moreover, monody can also portray the Trinity, by illustrating the unity of God's ousia. But by parallel, it hard to see how the interplay of parts in polyphonic or harmonic compositions can have an analogue in the life of a single divine person – especially if, as many strict monotheists claim, God is simple. By contrast, polytheistic deities might resemble the diverse parts in polyphony. But on many forms of polytheism, gods do not necessarily stand in quasi-causal relations, share a mental life, or perfectly co-operate in action. These versions of polytheism therefore lack several of features of Trinitarianism which are discernible as beautiful through its embodiment in polyphony. So whilst all doctrines of God have attractive features which are perceptible through music, the doctrine of the Trinity is arguably particularly attractive, and perceptible as such through especially beautiful music. Thus (AAT2) is hardly trivial.

I lack space to rebut every objection to AAT or AAC. But these arguments appear promising, and might be supported by the experience of liturgical music.

VII

We can now review my argument. I have not described every way in which liturgical music might contribute to the epistemic justification of Christian beliefs. Rather, I have advanced discussion of this topic in two ways. Firstly, I have highlighted existing work on music's expression and generation of emotion, and further explored liturgical music's ability to embody Christian narratives and doctrines, thereby drawing attention to their beauty. These properties give liturgical music particular epistemic value. Secondly, I have introduced two probabilistic arguments for Christian orthodoxy (AAC and AAT), which claim that Christian doctrine's beauty and relevance provide evidence for its truth. Liturgical music can supply distinctive support for these arguments.

But liturgical music only provides useful evidence for Christianity for those willing and able to receive it. To receive this evidence, one must participate in Christian worship, and attend to salient properties of liturgical music: its beauty, emotional expression, and relationship to Christian narratives and doctrines. Further, appreciation of the beauty and moral relevance of both music and doctrine requires a prior sense of beauty and goodness. In short, appropriating music's rational support for faith requires co-operation with grace. ‘Let those who have ears to hear, hear…’.Footnote ⁵⁷