Why Protestants Convert, Pt. III: The Theology of Conversion

In our previous post, we considered the dynamics of the soul that give rise to conversion—psychological motives that draw evangelicals, especially younger ones, toward Roman Catholicism. The soul’s longings draw the convert into a fresh encounter of the Holy, a new vision of God and the Christian story. No doubt such movement is shrouded by a veil of mystery that cannot be fully penetrated. As G. K. Chesterton quipped, “The church is a house with a hundred gates; and no two men enter at exactly the same angle.”

But it’s not completely shrouded. Even a religious conversion such as Augustine’s—with its multilayered complex of friendships and philosophical turning points—relied upon progressive engagement with divine revelation. Yes, one’s personal experiences and expectations are important, but, as any convert will tell you, they are no substitute for theological thought. The contemporary temptation to bracket Godward reality and focus exclusively on the psychology or sociology of converts may expose the fine texture of personal faith journeys, but it represents a myopia that misses the bigger picture. In other words, we need both phenomenology and theology.

Below, I discuss three theological factors that drive conversion.

1) Quest for Certainty

When pilgrims traverse the Via della Conciliazione (“the way of conciliation”)—the primary route into the Vatican—they are greeted by the embracing arms of Bernini’s Colonnade, a convex of columns that enfolds travelers into Saint Peter’s Basilica. More than an architectural masterpiece, the magnificent dome of St. Peter’s symbolizes the Roman Church’s authority, a grandeur that imbues Catholic faith with confidence and supremacy. The top of the Billy Graham Center just can’t compare.

The authority of Rome is often among the main reasons converts leave Protestantism. Even for those who never visit Vatican City—whose experience is limited to the ordinary life of a local parish—the quest for magisterial certainty and substance is cited as a chief reason for Rome-ward journeys. However, as we suggested in our first post, it is never simply an attractive pull without a corresponding push.

In this case, the compelling push is “biblicism.” For example, in his sermon entitled “Unreal Words” (1840), John Henry Newman conveys his frustration with the ever-growing number of Protestant interpretations: “Let us avoid talking, of whatever kind,” he pleaded, “whether mere empty talking, or censorious talking, or idle profession, or descanting upon Gospel doctrines, or the affectation of philosophy, or the pretense of eloquence.” Over against such “private interpretation,” Newman was drawn to a thick magisterial authority that promised doctrinal and ethical certainty.

In our day, this feature of Protestantism is called “pervasive interpretive pluralism,” a term coined by sociologist Christian Smith, a convert to Rome who thinks Protestant hermeneutics are discredited by the “entrenched, ubiquitous disagreements among biblicists about what scripture teaches on most issues.”[1] While Smith locates the source of this problem in the Protestant doctrine of sola scriptura, it is also clear that the unending choices in modernity—from which television programs to watch to which form of Christianity one prefers—compounds the problem, shifting religious affiliation from an inheritance received at birth to a series of personal decisions. Indeed, as Peter Berger suggests, modern life universalizes choice by creating “a new situation in which picking and choosing becomes an imperative.”[2]

Beset with intellectual chaos, uncertainty, and choice, converts look to Rome to resolve the struggle, a struggle that some believe is an outworking of the Protestant Reformation, unintended as it may have been. Peter Kreeft writes, “Protestantism shows a massive and natural slide toward modernism and liberalism and relativism and historicism concerning scripture.” Against this slide, Kreeft presents the Roman Catholic magisterium as the bulwark never failing, “the rock of Peter that stands up against the floods of history.” Again, “That rock does not exist outside of Rome. It is the only dike against the ocean of relativism that never springs leaks. Never has, never will.”

But Kreeft’s account is too neat. A friend who borrowed my copy of Kreeft’s book scribbled in the margins: “Pope Francis?” A bit cheeky, but it makes the point. If there’s one thing the pontificate of Francis has demonstrated, it’s the imperspicuous nature of the Roman Catholic magisterium. As Onsi Kamel explains in his recent First Things article, “Catholicism Made Me Protestant,” the infighting among traditionalist, conservative, and liberal Catholics highlights the sizable dent in Rome’s claim to speak with the living voice of divine authority, revealing that interpretive certainty cannot be realized in the sola magisterium position of Rome any more than in one’s private interpretation. The proper path, rather, is an acknowledgement that in Scripture alone we have the inspired Word of God commanding our allegiance above all earthly powers and authorities (including that of Popes and councils), a word that is rightly understood in the community of faith, the church, with her biblically chastened theological judgments (or “catholic tradition”), retrieved and renewed from centuries of church history. In the words of Kevin Vanhoozer:

“The norm of Christian wisdom remains the Word of God (biblicism), yet the corporate confessions of the church—the sum total of its creedal, conciliar, and confessional theological judgments (catholicity)—have testimonial authority as to Scripture’s meaning. Hence, counterintuitive though it may be, ‘Catholicity is the only option for a Protestantism that takes sola scriptura seriously.’”[3]

2) In Touch with History

Hillsdale College is an extraordinary place. Protestants and Roman Catholics read Cicero and Milton together, fall in love, and sometimes attend a school sponsored event titled “Coffee with Castaldo” to better understand the dynamics of their ecumenical relationship. “Why did you convert to Catholicism?” I asked one former Protestant. He looked into the autumn brown eyes of his beloved, took a deep breath, and then, without missing a beat, quoted Newman: “To be deep in history is to cease to be Protestant.” The halting smile on her face suggested she wasn’t in quite so deeply.

It’s true; Newman’s study of the post-Nicene fathers provoked uncertainty about whether Anglicanism was truly “catholic.” Such doubts took root in 1839, when he read an article by Cardinal Nicholas Wiseman in the Dublin Review in which Anglicans were compared to African Donatists during the time of Augustine. Reflecting on this question, Newman began to correlate the Church of England with the heretical Arians of the fourth century. In Newman’s mind, Anglicanism failed the Catholic test. Roman Catholicism’s offer of continuity with the past, and a robust, lasting intellectual tradition helped him to give an answer for his historical hope within.

There is a valuable lesson here for Protestants concerning the importance of catholicity. Our historical awareness of the Christian faith must rise above the popular Protestants tropes of the “Ditch Theory.”[4] According to this error, the Apostles understood and practiced devotion to Christ in all of its purity and depth. Such fidelity to the apostolic tradition continued until Emperor Constantine elevated Christianity as the official religion of the empire, at which point the Church promptly fell into the ditch of compromise and heresy. From Constantine through the Medieval Age, the gospel was immersed in unbiblical tradition and therefore largely misunderstood, apart from a small remnant of believers who somehow managed to get it right. Eventually, God empowered Martin Luther to confront these errors, which he initiated in 1517 when he nailed his Ninety-Five Theses to the castle church door at Wittenberg. With Luther and the reform movements that followed, Christianity was elevated three quarters of the way out of the ditch. In this nearly-restored condition, biblical Christianity remained until the founding of one’s particular denomination or church, at which point pure, biblical faith was finally returned to its original condition. Hopefully, the absurdity of this view is apparent.

To be sure, the Ditch Theory is a caricature; and yet, its storyline is implicit in much Protestant teaching. As Tom Howard, a Protestant-turned-Catholic, writes, “[Evangelicals] speak of the ancient faith as though the Bible had swum into view just this morning and as though one’s approach to it is simply to open it, read, and start running.” And the more independent and separatist a church, the deeper the ditch, and, conversely, the more attractive will be the Catholic claim to an unbroken and historic church.

While the Ditch Theory characterizes much of evangelical Protestantism from the middle decades of the twentieth century to the present, it fails to capture the historical sensitivity of Protestants from the sixteenth-century to that period. Consider, for example, Peter Martyr Vermigli’s Romans locus on justification. In addition to supporting each point with Scripture, he devotes considerable attention to the church fathers and councils, parading a great host of ancient voices before the reader as evidence of support for his position.[5]

In other words, the Ditch Theory was emphatically not the theory of the magisterial Reformers or their descendants. Ken Stewart addresses this matter in his book, In Search of Ancient Roots, connecting the Reformers with those who came before them. After all, the works of Bucer, Vermigli, Calvin, Zanchi, and Bèze are brimming with citations of church fathers, councils, and medieval thinkers. Far from trying to break with tradition, the Reformers were seeking to recover it, a legacy that we must recapture and emulate in our own day.

We are still confronted by the question of whether the Roman reading of history is the proper route out of the ditch and into the Promised Land of catholicity. In their book Roman but Not Catholic, Ken Collins and Jerry Walls offer a respectful and emphatic “no,” objecting to Rome’s self-referential claim to the exclusive center of the catholic Church. Collins and Walls examine a range of distinctively Roman Catholic doctrines (e.g., sacraments, priesthood, papacy, Mariology, and justification), and conclude that such teaching is more indebted to an inbred development of Roman tradition than a genuinely catholic Christianity.

Ken Stewart takes a similar approach, considering the historical coherence of Protestantism, a wholeness centered not on an imperial structure (Rome) but on an ancient Word (Scripture). It’s noteworthy that both of these books address Newman’s aphorism concerning the necessity of going deep in history, and both reach the same conclusion: to go deep in history requires Christians to go to the Church of history, but then also to go beyond it: to Jerusalem, to Haran, to Mount Ararat, and back to Eden. It goes to the places where God’s redemptive promise has been proclaimed and received. This catholicity reaches beneath the structural forms that so captured Newman’s imagination into the substance of our common evangelical faith.

3) Tangible Grace

The third motivating factor behind Protestant conversions to Rome is the anti-sacramental impulse of many evangelical churches. Against churches which offer unadorned preaching of the word and a means of grace that is either overly cerebral or subjective, Christian Smith writes:

In reality, the mental world you inhabit as a Protestant is powerfully shaped by a disenchanting modernity. The monasteries have been dissolved and plundered, the saints have been driven away, and prayers with the dead are abolished. All of the embodied mumbo-jumbo of the medieval sacramental world has been stripped away. The statues have been smashed, the faces of holy images scraped away. The material world is now emptied of spiritual occupation and meaning. Material substances no longer offer ties to the “great cloud of witnesses,” to celestial realities, to world unknown. Your beliefs reside in your head….[6]

Smith speaks for many converts to Rome who find something constricting in the heavily cognitive patterns of spirituality often found in Protestant worship and devotion. Such individuals have grown tired of divine encounter centered on teaching, preaching, and small group curriculum—information that feeds one’s mind but offers little to the rest of one’s being. It’s the “via pulchritudinous” about which Bishop Robert Barron often speaks, the “way of beauty,” found in the consecrated host, cathedrals, holy water, incense, candles, and various sacramentals that bespeak of the mysterious presence of Christ. In short, it is a sacramental system and incarnational ethos that appeals to one’s physicality and not simply one’s rationality.

Once again, Newman is a great example. As mentioned previously, the desire to experience embodied dimensions of Christian worship was central to his conversion. Over against the low-church experience of his younger brother, Francis, John was drawn to the sacramental system of Rome for its objectivity and materiality. Writing to a friend after his conversion, Newman says:

[I am writing beside the chapel]—It is such an incomprehensible blessing to have Christ in bodily presence in one’s house, within one’s walls, as swallows up all other privileges… To know that [Jesus] is close by—to be able again and again through the day to go in to Him…[7]

It’s important to note that Newman didn’t move from his Bible-centered faith to his sacramental theology all at once. At first, he was deeply troubled by Roman Catholicism’s sub-biblical “superstition,” religious accretions such as papal primacy, devotion to the Blessed Virgin and the saints, veneration of relics, Purgatory, and the like. For instance, he writes the following impression of the Catholic Church during his visit to Italy as an Anglican:

Oh that thy creed were sound!
For thou dost soothe the heart, Thou Church of Rome
By thy unwearied watch and varied round
Of service, in thy Saviour’s holy name

In time, however, Newman would reconcile himself to these concerns, understanding them in light of the development of doctrine. This enabled Newman to embrace the external elements of Catholic tradition which lacked clear witness in the Bible and church history. And so it is for many Protestants who converts to Rome. The materiality of the sacraments and surrounding liturgy wins them over. As Tom Howard puts it, “To be Catholic, then, is to have the Mass at the center of one’s whole existence and consciousness. It is to be a ‘eucharistic’ man or woman.”[8]

There is a valuable insight here for contemporary Protestants. God is redeeming the whole person–body and soul–not simply the mind. In addition to our rationality, God also takes captive our kardia and splagchna (inner parts) from which holy affections arise (Col 3:12; Philemon 1:7). But as Protestants, we maintain the conviction that God works through the intelligibility of His Word, and we do so without ceding sacramental “objectivity” to Rome. After all, even the Sacraments are Words: “We say with Augustine that the sacramental symbols are visible words,” wrote Vermigli.[9] In our celebration of the Lord’s Supper, we truly feed on Christ, and not only do we recognize baptism as a sign and seal of our engrafting into Christ, we believe, contrary to Rome, that its effects endure forever. Word and sacrament together are the God-ordained means for spiritual life, and they are necessary to protect the church from sub-biblical accretions, whether they have developed over time or were invented yesterday. These living words ought to enliven our music, poetry, confession, preaching, sacraments, and prayers–forms that constitute the rich birthright of our “catholic” Christian heritage, a birthright that we dare not allow to be sold for a lentil stew of fog machines, hypnotic choruses, and biblically feeble sermons. God help us.


Conversion always entails a personal pursuit of the sacred, a primal longing for transcendence and desire to find one’s rest in a loving relationship with the Almighty. Personal experiences of joy, the sting of evil, a longing for hope, and glimpses of the pneumenal in the rhythms of life lead us to wager belief against doubt, lifting our sights above the horizon. More than a sacred canopy that provides a plurality of religious options to deal with life’s pain and chaos, such faith is a pathway toward addressing the deep, inner yearnings of the human heart, the path from Athens to Jerusalem, where pilgrims discover that Israel’s God has rolled back the stone of the empty tomb.

The difference between Roman Catholics and Protestants in this pursuit centers on the question of how we encounter the risen Christ, a lesson that recently came into focus while I was visiting the land of Israel. During one excursion, our guide mentioned that Catholic and Protestant tours are never combined. The reason comes down to the way our respective traditions understand materiality. For Protestants, the aesthetic dimensions of Christian faith are secondary to the Word. For Catholics, on the other hand, the sacred is primarily connected to the material—to oil, water, shrines, relics, chapels—a sensory experience that involves ritual. A short while after the conversation with my guide, I looked on as my friend Michael preached a sermon on the shore of Tabgha. Meanwhile, directly beside him was a Mass in which a vast number of Filipino Catholics were kneeling before the altar in eucharistic adoration. I quickly snapped a photo, realizing that I was observing something of the difference between Catholics and Protestants. In the words of Peter Martyr Vermigli,

“Therefore the first principle according to which all true theological truths are determined should be this: ‘The Lord has spoken’ [DOMINUS DIXIT]. This clarity is not to be looked for from the light of human understanding or our reason, but from the light of faith which should be most persuasive to us, and which is contained in the sacred writings [of Scripture].”[10]

Why Protestants Convert, Pt. I: Conversionitis

Why Protestants Convert, Pt. II: The Psychology of Conversion

Why Protestants Convert, Pt. IV: The Sociology of Conversion

Why Protestants Convert, Pt.V: A Way Forward

This essay was originally published on The Davenant Institue’s main website in 2019, but has been republished here for Reformation Day 2021. The series was written by Dr. Brad Littlejohn and Dr. Christ Castaldo. It has been lightly updated. Part III is by Dr. Castaldo.

Dr. Brad Littlejohn (PhD, University of Edinburgh) is the President of The Davenant Insitute.

Dr Chris Castaldo (PhD, London School of Theology) is pastor of New Covenant Church in Naperville, IL.

  1. Christian Smith. The Bible Made Impossible: Why Biblicism Is Not a Truly Evangelical Reading of Scripture. Grand Rapids: Brazos, 2012), 67.
  2. Peter Berger, The Heretical Imperative: Contemporary Possibilities of Religious Affirmation (Garden City, NY: Anchor Books, 1980), pp. 14, 25

  3. Kevin J. Vanhoozer. Biblical Authority After Babel: Retrieving the Solas in the Spirit of Mere Christianity. (Grand Rapids, Brazos, 2017), 146. Vanhoozer is quoting Peter Leithart from his First Things article, “Sola Scriptura, Una Ecclesia” (May 1, 2014).

  4. I am indebted to Professor Greg Quiggle for this term.

  5. Pietro Martire Vermigli. In epistolam S. Pauli apostoli ad Romanos D. Petri Martyris Vermilii Florentini, professoris divinarum literarum in schola Tigurina, commentarii doctissimi, cum tractatione perutili rerum & locorum, qui ad eam epistolam pertinent. (Basel: Apud Petrum Perna, 1560), 1236-1252, 1296-1311, 1323-1324.

  6. Christian Smith. How to Go from Being a Good Evangelical to a Committed Catholic in Ninety-Five Difficult Steps. (Eugene: Cascade Books, 2001), 35.

  7. The Letters and Diaries of John Henry Newman, ed. Charles Stephen Dessain et al. (London: Nelson, 1961-72; Oxford: Clarendon Press, 1973—) xi, 129.

  8. Thomas Howard. On Being Catholic. (San Francisco: Ignatius Press, 1997), 89

  9. Joseph McLelland, The Visible Words of God: An Exposition of the Sacramental Theology of Peter Martyr Vermigli, A.D. 1500–1562. Edinburgh: Oliver & Boyd, 1957), x.

  10. Peter Martyr Vermigli. The Peter Martyr Reader. Edited by John Patrick Donnelly, Frank A. James III, and Joseph C. McLelland. Kirksville: Truman State University Press, 1999), 70.


Related Articles

Other Articles by

Why Protestants Convert, Pt. 5: A Way Forward

People have more than one reason (whether they know it or not) for changing their religious commitments. Conversion is usually a multilayered process. In this series, we have examined the (1) psychological, (2) theological, and (3) sociological dimensions of conversion.

Join our Community
Subscribe to receive access to our members-only articles as well as 4 annual print publications.
Share This