What is sacred music? If we simply mean music that assists liturgy or prayer, the category includes Protestant hymns, Christian rock, church chant, musical aids for the memorization of sacred texts, and countless other kinds of music. Much music provides indispensable assistance to divine service, but so do the pastor’s trousers, which cannot be called sacred, indispensable though they may be.

Music that carries an association with liturgy may evoke religious feelings, whatever its provenance. Musicologists have proved that the “ancient chant” promulgated in the nineteenth century by the Benedictines of Solemnes was, in fact, their own invention rather than a historical reconstruction, but its associations are no less compelling for many Catholics.

There is music, though, that seems inherently sacred in character. “Whether it is Bach or Mozart that we hear in church, we have a sense in either case of what Gloria Dei , the glory of God, means. The mystery of infinite beauty is there and enables us to experience the presence of God more truly and vividly than in many sermons,” wrote Benedict XVI in his book The Spirit of the Liturgy (2000). Simpler music can foster camaraderie among worshipers and even communal joy. Authentically sacred music does more: It inspires awe, even fear.

The question, of course, is what makes it possible for music to convey a sense of the sacred in the way that Benedict avers. And the answer should be sought first in our perception of time. Because we are mortal, and because all religion responds to mortality, our intimations of the sacred arise from our experience of the tension between the mortal existence of humankind and the eternal life of God. In revealed religion, God’s time stands in contrast to the earthly time of days and years and the corporeal time of pulse and respiration. A creator God who stands outside nature also stands outside time itself. Eternity is incommensurate with natural time. God made the world ex nihilo before time existed and he will bring it to an end.

Eternity breaks into the temporal world through revelation. For Jews, the sanctification of the Sabbath introduces an element of eternity into natural time; for Christians, the eschaton breaks into the natural time of human history through Christ’s birth, death, and resurrection. God’s time, the time of salvation in the coming of the Messiah or the second coming of Christ, stands in contrast to the natural time of ordinary existence.

Music unfolds in time. The rhythms of the music of all cultures arise from the natural rhythms of respiration and pulse. Unique to the tonal music of the West, however, is its capacity to create a perception of time on two distinct levels, that is, the natural time of systole and diastole, and the plastic time of tonal events. The coincidence or conflict of durational and tonal rhythm, that is, between metronome time and the pace of tonal motion, gives composers the tools to depict higher orders of time. That is what makes possible the sacred in music, for our perception of the sacred involves a transformation in our perception of time.

Music begins with respiration and pulse, the inborn rhythms of human life. We may intensify these rhythms with percussive accents and electronic amplification and, through this intensification, achieve the momentary sort of exaltation that seems to buoy the audience at rock concerts. As Benedict has written, this is the opposite of Christian worship: “It is the expression of elemental passions, and at rock festivals it assumes a cultic character, a form of worship, in fact, in opposition to Christian worship. People are, so to speak, released from themselves by the experience of being part of a crowd and by the emotional shock of rhythm, noise, and special lighting effects. However, in the ecstasy of having all their defenses torn down, the participants sink, as it were, beneath the elemental force of the universe.”

We know, no matter what we do, that the rhythms of respiration and pulse will cease at the moment of death. But we do not know what eternity is. At best we can say what it isn’t, as in Psalm 90:4, through poetic hyperbole: “For a thousand years in thy sight are but as yesterday when it is past, and as a watch in the night.” Eternity manifests itself to us as an irruption of the divine into the temporal world, as a singularity, a moment that interrupts the procession of years and days, of systole and diastole.

Music can no more depict eternity than can ordinary language. The use of lengthy repetition in music or dance to empty our minds aims not at eternity but rather at timelessness. In Judeo“Christian terms, timelessness is the antithesis of eternity, for God’s time is not an absence but rather a content so full that our minds cannot absorb it.

Music cannot represent eternity”no human artifice can”but it can direct the mind’s ear to the border line at which eternity breaks into temporality. This is the argument of St. Augustine, whose theory of time at the end of the Confessions is cited in textbooks as the precedent for the phenomenological and existential theories of time that flourished at the turn of the twentieth century. Music is one of the examples Augustine uses to expound his theory of time, but that theory reaches back to inform his account of music. His purpose was not to make time relative but to show how we perceive eternity’s intrusion into mortal experience. Thus, in Book VI of his De Musica , the theory of time becomes a theory of music, for music is Augustine’s laboratory for temporal investigation.

Eternity, as the Psalmist taught, is beyond our capacity to conceive, but eternity lurks in the perception of time as such. Our time is not commensurable with God’s time, Augustine writes: “Nor do you by time precede time: or else you should not precede all times. But you precede all things past, by the sublimity of an ever-present eternity; and you surpass all future because they are future, and when they come, they shall be past; but you are the same, and your years fail not.”

Augustine is not concerned with time in the abstract, but rather with the possibility of communication between God and humankind. “Lord, since ­eternity is yours, are you ignorant of what I say to you? Or do you see in time, what passes in time?” Aristotle’s Prime Mover has no need to communicate with humans and, for that matter, no means of doing so. Aristotle’s static time can have no interaction with the eternity of the biblical God”which means that if Aristotle’s description of time as a sequence of moments were adequate, we could not hope to commune with an eternal being.

But Aristotle’s theory, in Augustine’s view, leads to absurdities. To consider durations in time, we must measure what is past, for the moment as such has no duration. Events that have passed no longer exist, leaving us in the paradoxical position of seeking to measure what does not exist. Augustine’s solution is that memory of events, rather than the events themselves, is what we compare. “It is in you, my mind, that I measure times,” he concludes. If the measurement of small intervals of time occurs in the mind, then what can we say about our perception of distant past and future? If our perception of past events depends on memory, then our thoughts about future events depend on expectation, and what links both is “consideration.” For “the mind expects, it considers, it remembers; so that which it expects, through that which it considers, passes into that which it remembers.”

Expectation and memory, Augustine adds, determine our perception of distant past and future: “It is not then future time that is long, for as yet it is not: But a long future, is ‘a long expectation of the future,’ nor is it time past, which now is not, that is long; but a long past is ‘a long memory of the past.’” This is the insight that allows Augustine to link perception of time to the remembrance of revelation and the expectation of redemption.

An extensive literature connects the Confessions to the relativizing theories of time in Edmund Husserl and Martin Heidegger. But Augustine’s “long memory” and “long expectation” are not relative, for they presume the ontological primacy of revelation. Memory and expectation arise as eternity breaks into mortal time. In Judeo“Christian teleology, revelation demarcates the “long memory of the past,” and the Eschaton informs the “long expectation of the future.” As Franz Rosenzweig put the matter in The Star of Redemption : “Revelation is the first thing to set its mark firmly into the middle of time; only after Revelation do we have an immovable Before and Afterward. Then there is a reckoning of time independent of the reckoner and the place of reckoning, valid for all the places of the world.”

Our memory of redemption in the past, however distant, and our expectation of salvation in the future, however remote, are the fixed points by which we judge time. As individual moments flee past, we struggle to keep them in memory so that our faculty of “consideration” can order them and judge them. Superior to our perception of these fleeting moments is memory. Memory in turn is understood through the expectation of events in time, through our faculty of “consideration.”

Augustine returns to the problem of time, memory, and expectation in De Musica . Although there is no consensus as to the date of De Musica , it seems likely that it was composed well after the Confessions , for Augustine weaves his earlier ideas about time into a better-developed theory of musical rhythm.

In De Musica , Augustine seeks to portray “consideration” as a form of musical number, that is, numeri iudiciales , “numbers [or perhaps rhythms] of judgment.” These “numbers of judgment” bridge eternity and mortal time; they are eternal in character and lie outside of rhythm itself, but act as an ordering principle for all other rhythms. They stand at the head of a hierarchy of numbers that begins with “sounding rhythms””the sounds as such”which are in turn inferior to “memorized rhythms.”

Only the “numbers of judgment” are immortal, for the others pass away instantly as they sound, or fade gradually from memory over time. They are, moreover, a gift from God, for “from where should we believe that the soul is given what is eternal and unchangeable, if not from the one, eternal, and unchangeable God?” For that reason the “numbers of judgment,” by which the lower-order rhythms are ordered, do not exist in time but order time itself and are superior in beauty; without them there could be no perception of time. Memory and expectation are linked by the “numbers of judgment,” which themselves stand outside of time, are eternal, and come from God.

Augustine here proposes not merely a psychology of music but also an ontology: He seems to think that the “numbers of judgment” with which we evaluate rhythm exist eternally and were given to us by God. A thousand years later, the Renaissance philosopher most influenced by Augustine’s treatise, Nicholas of Cusa, put the matter somewhat differently: “Creative art, which the happy soul will attain, is not of its essence that art which is God, but rather participation and sharing in it.” The great composers never imagined that they were participating in creation, only imitating it. Sacred music is not revelation, just the next best thing.

We know almost nothing about the music that so deeply moved Augustine in Milan, so much so that he feared that its beauty might distract him from devotion. But ideas that seem obscure, for example his rhythmic hierarchy, do not suffer from transposition into the framework of modern music theory. On the contrary, they become clearer. Augustine’s hierarchical theory of rhythm fits uncannily well into the musical world that emerged in the fifteenth-century West.

Starting in Paris during the fourteenth century, and coming to full realization during the fifteenth, Western musicians found means to create tonal expectations so compelling that the hearer’s perception of the flow of musical time is guided by a sense of the musical future. Tonality”the system in which the horizontal unfolding of melody in time integrates with vertical consonance”has the unique capacity to generate a sense of the future.

Once musicians discovered how to link musical rhythm to the resolution of dissonance into consonance, Western music acquired a teleology. Every tonal work has a goal, the resolution of tonal tension in the return to the tonic by way of a final cadence from the dominant. The Austrian music theorist Heinrich Schenker identified a fundamental structure underlying each movement of a classical composition that guides a great passage away from and back to the tonic. All the elements of composition are there to fulfill this journey. Once the composer has created an expectation, it is possible to create tension by prolonging it, or create surprise and even humor by leading in an unexpected direction. Deep expectations of the future act upon memory through the judgment of our mind’s ear. Thus, for instance, the Schenkerian theorist Carl Schachter introduced the distinction between durational and tonal, and identified higher-order rhythms in tonal music”work consistent with Augustine’s teaching in the De Musica .

The two kinds of rhythm in Western music”durational and tonal”arise from a practice first described explicitly by the Flemish contrapuntalist Johannes Tinctoris in 1477, although (as musicologist Sarah Fuller has shown) the embryo of the idea can be found in the treatise De Mensurabili Musica , attributed to John of Garland at Paris in the late thirteenth century. All Western theory had taught that music was founded upon consonance, the intervals that nature had provided in simple proportions that created a sense of stability for the ear. To sound two melodies together in counterpoint, the pitches intoned simultaneously must be at consonant intervals. But the musicians of Paris learned that not all notes had to be sung in consonant relation, only those that sounded at points of rhythmic stability. Dissonances were permitted so long as they occurred at points of rhythmic instability and led to a consonance.

The resolution of dissonance into consonance in the context of rhythm gave music a powerful means to create deep expectations. From the rhythmic alternation of dissonance and consonance in the note-by-note progression of late medieval counterpoint, fifteenth-century composers learned to prolong the tension and resolution of dissonance and consonance in longer musical forms. In late medieval counterpoint, a single dissonant note could be accommodated at a point of rhythmic instability; by the sixteenth century, tonality made possible whole regions of relative instability within a longer form.

Western music sprang into life in full armor, like Athena from the head of Zeus, once the musicians of the fifteenth century learned to integrate rhythmic and tonal emphasis on a broader scale than note-by-note setting. Tinctoris remarked in 1470 that all the music worth listening to had been written in the preceding forty years”at the only moment in music history when a leading musician would have made that remark, and when it would have been true. This uniquely Western art came into full flower in the last third of the fifteenth century in the Flemish school of Dufay, Ockeghem, and Josquin and was adopted by the Catholic Church in the middle of the sixteenth century during the generation of Palestrina and Victoria.

The fundamentals of rhythmic and tonal emphasis are perceptible to anyone who can hum a tune. Even the simplest rhythm creates expectations; we assume that the pattern we hear will continue, and that one verse will be like the next. We judge the time of individual syllables and feet within that rhythm according to our expectations. Just as Augustine argued, we do not grope our way blindly from beat to beat; on the contrary, we hear the individual beats with our mind’s ear. Tonality allows the composer to create yet another level of expectations.

Take a melody everyone knows: Stephen Foster’s “Old Folks at Home.” The first two strophes”“Way down upon the Swanee River/Far, far away ””occupy four measures and end on the dominant in the bass (supporting the second scale step in the treble).

We expect that another four measures will follow, and bring us back to the tonic, or home key, and that is just what Foster does. Our mind’s ear demands that the second scale-step on which we lingered at the word “away” descend to the tonic at “That’s where the old folks stay .” The ear also wants the fifth degree, or dominant, in the bass to descend back to the tonic.

This garden-variety melodic structure is called antecedent-consequent and links a rhythmic expectation (a second four-bar phrase to follow the first four-bar phrase) to a tonal expectation (a move from the tonic to the dominant at the end of the first phrase sets up a cadence on the tonic at the end of the second eight-bar phrase). We know where each beat should fall and how the voice-leading should return us to the tonic, because our mind’s ear forms a judgment about the structure of the song.

The expectations evoked by the first eight bars of “Old Folks at Home” and countless other songs require no musical training to understand. But simple tunes as such do not evoke the sacred, whatever their sacred associations might be. Fortunately for students as well as teachers of music, the most pedagogical of composers, J.S. Bach, left us more than 150 works of sacred music whose purpose is to show how a simple hymn-tune can be prolonged in a more complex structure in a way that evokes the sacred. These are the chorale preludes and related chorale settings, which embed church hymns in a longer work. By choosing hymns as raw material for transformation, Bach is making a programmatic statement as well as a musical one.

Consider another melody in antecedent-consequent form, the Bach chorale “ Jesus bleibet meine Freude ” from Cantata 147. In the familiar work known in English as “Jesu, Joy of Man’s Desiring,” Bach embedded this hymn in an orchestral setting, extending the time frame in which the expectations of tonal and rhythmic resolution are realized. Our expectations work on two levels. On the simpler level, we have the same sort of antecedent-consequent we heard in the Foster song; and on the more complex, we have the expansion in time of the chorale through a florid accompaniment. The intrusion of a higher order of expectations on the hymn tune is what evokes the sacred.

Even more poignant is the celebrated setting of the chorale “Sleepers, Awake” in Cantata 140. In this case, what appears to be an accompanying counterpoint not only extends in time the musical and rhythmic expectations of the chorale melody but also alters these expectations.

The expected resolution of the hymn-tune, with its four-square phrasing, is displaced in time by the florid counterpoint played by the strings. The quotidian sense of time associated with the hymn-tune encounters a second set of expectations that subsume the first. The two interlocking themes transform each other, shifting the rhythmic placement of voice-leading resolution. Bach, in effect, has introduced a higher order of time, in which a second set of expectations breaks in on the first.

The tension between the two sets of expectations, the simple hymn-tune and the overlaid counterpoint, generates a sense of the sacred. Bach cannot put the infinite into notes, but by transforming our perception of time, he can attune our mind’s ear to a higher order of time. The sense of the sacred arises from the response of our mind’s ear (Augustine’s “consideration” or numeris judicialis ) to the juxtaposition of two temporal frameworks.

Pace Benedict, there really is nothing mysterious about it after the fact. Miraculous, maybe. It seems simple, but only a Bach could do it.

The chorale prelude was a venue for Bach to spell out the prolongation of the hymn-tune in schoolmasterly fashion. Bach is not more lawful than other ­composers (he fudged to fit melodies together when ­convenient); what delights us in the chorale from Cantata 140 is not mathematical fit but rather artistic surprise. In fact this method of transforming expectations informs all Western counterpoint starting in the mid-fifteenth century. It subordinates an individual melody to a voice-leading structure that also accommodates other melodies (or the same melody sung with displacement in time or pitch). Imitative counterpoint is not mathematical but rather programmatic. It begins with one set of expectations embodied in a single line of music and subsumes them in a larger voice-leading structure.

The tonal music of the West began with a teleology learned from Christianity, though, to be sure, the ­compositional ­techniques invented to evoke the sacred were employed later for secular purposes. Possibly the most astonishing example of a supervening rhythm occurs in the last movement of Robert Schumann’s piano collection Kreisleriana. Schumann moved within a musical culture whose spiritual mission was taken for granted (he composed a Mass and a Requiem).

The ordering of musical time by tonal teleology broke down with the so-called new German music of Liszt and Wagner. Writing in 1919, Franz Rosenzweig admonished the musicians to return to the Church and to the demarcation of time by revelation and redemption. In the chapter on Christianity (“The Eternal Rays”) in The Star of Redemption , he wrote: “What is sacrilegious in music is idealized time, with which it subverts real time. If it is to be made clean of its willful sacrilege, it must be removed from the Beyond, and brought to this side of time, and its ideal time must be made real. For music, that would mean to make the transition from the concert hall to the church.”

Revelation, he continues, “makes fast its point of reference in the middle of time.” Humanity can best understand it in the Church year, particularly in “the festivals of revelation,” which, “pointing backward toward the creation of revelation and forward toward revealed redemption, incorporate the immeasurable eternity of the day of God into the annual cycle of the Church year.”

By integrating itself into these festivals and in the Church year as a whole, the individual piece of music alights from the artificial frame of its ideal time and becomes wholly alive . . . . He who joins in singing a chorale, or who listens to the mass, the Christmas oratorio, the passion . . . wants to make his soul stand with both feet in time, in the most real time of all, in the time of the one day of the world of which all individual days of the world are but a part. Music is supposed to escort him there.

Western composers abandoned teleology in music at the same time they turned away from Christianity. Tonality enabled music to create deep expectations about the future. With the abandonment of tonality, listeners lost their map of the musical future, and found themselves trapped in a sort of Blind Man’s Bluff of a perpetual musical present. Churchgoers shunned twentieth-century composers as resolutely as they had embraced Bach or Mozart. As in other venues, churchgoers turned to popular music, the last bastion of the old tonality. Classical music played a diminishing role in religious life. Not even Benedict XVI’s advocacy has had much effect on church music. The music that attends worship of all Western denominations has little to do with the sacred in the sense that Benedict perceives it.

But it is too early to relegate Western sacred music to the museum. More children are studying classical music than ever before, and more people are converting to Christianity. I do not know to what extent the estimated 140 million Christian converts in China overlap with the estimated 60 million students of classical music. But the potential surely exists for revival of sacred music on a scale that humanity never before has seen.

Music, as Rosenzweig said, is there to escort the Christian to the time of the one day of the world of which all days are a part. Jews have a different sense of sacred time, for God sanctified the Sabbath, the last day of creation and creation’s goal. Sabbath observance is radically unique to Judaism and is the pivot of Jewish worship. Rather than journey to “the one day of the world of which all individual days of the world are but a part,” the Jews live in the seventh day, which God planted in temporality as a foretaste of the world to come.

Sacred time has a different meaning for Jews than Christians. Augustine believed that deep expectations of the future acting through memory create our perception of the flow of time. For Jews, as Abraham Joshua Heschel put it, time is merely the mask of eternity, which does not need to be recreated through musical artifice but is planted among us in the Sabbath. Melismatic chant that enhances recitation of the text remains the characteristic music of Jewish worship. The ordering of musical time through classical composition would be alien to the spirit of Jewish liturgy.

David P. Goldman is associate editor of First Things . He has written on Renaissance music theory and taught history of music theory at the Mannes College of Music, where he serves on the board of governors.