The Secular and Post-Christian Frontier

Some of the world’s most Christian-looking landscapes are also sites of profound Christian decline.

Cathedrals dominate city centers. Christian holidays structure calendars. Biblical phrases survive in language. Churches helped shape universities, welfare systems, art, music, law, and national memory. A person can live surrounded by Christian inheritance and remain personally distant from Christian faith.

This is the post-Christian frontier.

It differs from the classic unreached-peoples map because access may be high even where Christian commitment is low. Bibles are available. Churches exist. Christian history is visible. The problem is not primarily whether the gospel has ever entered the society.

The problem may be whether Christianity remains credible, trusted, understood, or socially plausible.

Europe and the End of Christendom

Europe remains the region most commonly associated with post-Christian change.

Pew estimates that Europe’s Christian population declined to roughly 505 million in 2020, a decrease of about 9 percent from 2010. Christians still represented about two-thirds of the regional population, but their share declined substantially during the decade.¹

Those numbers do not mean Europe has become non-Christian in one uniform sense.

Roman Catholicism remains institutionally important in countries such as Poland, Italy, Spain, Portugal, Croatia, Austria, and elsewhere, though levels of practice vary.

Orthodox Christianity remains deeply associated with national and cultural identity in much of Eastern and Southeastern Europe.

Protestant state-church traditions remain institutionally visible in northern Europe even where regular attendance is low.

Evangelical, Pentecostal, immigrant, independent, and free churches operate across the continent.

The secularization story therefore differs dramatically between Sweden, Poland, France, Romania, Germany, and Portugal.

One “secular Europe” category is almost as blunt as one “Muslim world.”

Secularization Is Several Processes. The word secularization can refer to different phenomena.

Declining affiliation

Fewer people identify as Christian.

Declining practice

People may retain Christian identity while attending worship less often.

Declining belief

Traditional doctrines become less widely accepted.

Declining institutional authority

Churches exercise less influence over public morality, education, law, or political life.

Religious privatization

Faith continues but becomes increasingly detached from public institutions.

Religious switching

People raised Christian identify differently as adults.

These processes interact but do not move at the same rate.

A society can remain culturally Christian while institutional practice collapses.

Another can retain church attendance among a minority while public Christian authority declines.

Missionary diagnosis therefore needs more precision than saying “Europe is secular.”

Religious Switching

Pew’s recent international research defines religious switching as a difference between the religion in which adults say they were raised and the religion they currently identify with. Across many of the countries studied, Christianity experiences substantial net losses through switching, usually toward religious nonaffiliation.²

This is especially important because it changes the missionary question.

The person who has never seriously encountered Christianity and the person who was baptized, attended Christian education, became disillusioned, and left church do not begin in the same place.

The second person may know Christian vocabulary very well.

The barrier may be trust rather than information.

Mission to post-Christian societies therefore often includes listening to why people left.

Nominal Christianity. Christian identity can remain strong after Christian practice weakens.

Someone may identify as Catholic, Orthodox, Lutheran, Anglican, or simply Christian because of:

• family heritage;
• baptism;
• nationality;
• holiday practice;
• moral values;
• community identity.

Evangelical missionary rhetoric sometimes treats such people as essentially non-Christian and therefore no different from populations with no Christian background.

That can be theologically and sociologically crude.

A nominal Christian may possess substantial Christian knowledge and institutional access even if personal faith is weak or absent. Historic churches may preserve Scripture, sacraments, theological tradition, and pastoral life even where participation is low.

The missionary challenge is therefore renewal, evangelism, catechesis, or re-discipleship within an existing Christian environment—not pioneer entry into a blank religious space.

High Access, Low Response. The Gospel Access Framework helps clarify the distinction.

A secular European may possess:

very high informational access — Christianity is easy to research;

very high linguistic access — Scripture and theological material exist in the dominant language;

moderate to high relational access — Christians are easy to meet in principle, though practicing Christians may be less common in some networks;

high geographic ecclesial access — church buildings and congregations exist, though cultural or generational fit may be weak.

The central challenge can therefore be plausibility rather than availability.

Does Christianity appear intellectually credible?

Does it appear morally trustworthy?

Does church life seem capable of answering the person’s deepest questions?

Does anyone the person respects embody Christian faith attractively?

No missionary statistic can answer these questions globally.

Institutional Scandal and Credibility

Post-Christian mission cannot ignore the failures of churches.

Sexual abuse scandals, institutional cover-ups, financial corruption, political manipulation, and hypocrisy have damaged Christian credibility in many societies.

The missionary temptation is to treat these as public-relations obstacles external to the gospel.

Often they are failures within the church that require repentance before apologetics.

A person who distrusts Christian institutions because leaders concealed abuse does not need a clever argument explaining why media coverage is unfair.

The church must tell the truth.

Mission and institutional repentance belong together because the witness is embodied by a community.

Political Christianity. Christianity can also become closely associated with political identity.

The phenomenon differs across countries. In some contexts, Christianity becomes associated with conservative nationalism. Elsewhere churches are associated with progressive politics. Historic state churches may appear linked with old establishment power. Minority evangelical churches may become associated with imported American culture.

The missionary problem is not that Christians must avoid political convictions.

It is that the gospel can become socially indistinguishable from one political tribe.

Then rejecting the tribe feels like rejecting Christianity, and entering the church feels like changing political identity as much as religious allegiance.

This is another form of unnecessary cultural distance.

France and Laïcité. France illustrates a particularly strong form of secular public culture shaped by the history of Catholic Church-state relations, republicanism, and laïcité. Religious symbols and institutions are interpreted through a political history different from the more church-friendly public culture of the United States.

Missionaries who import American assumptions about religion in public life can therefore misread French secularism as simple hostility to God.

A better approach begins with history.

What social problem is secularism trying to prevent?

Why are religious institutions distrusted?

Which forms of Christian presence are credible?

The answer requires contextual learning, not just apologetic confidence.

Germany

Germany presents another complex post-Christian environment.

Historic Protestant and Catholic churches remain institutionally significant through tax systems, charities, schools, theological faculties, hospitals, and public structures. At the same time, formal membership has declined, especially in former East Germany, where several generations experienced state socialism and unusually high religious nonaffiliation.

A church-planting strategy in Cologne therefore confronts a different environment from one in Leipzig.

Even within one country, post-Christianity has several histories.

Eastern Germany: Secularity Across Generations. The former German Democratic Republic is particularly important for theories of secularization because nonreligion became deeply normalized across generations. Many people are not angry former church members. They may simply inhabit families in which religion has been socially absent for decades.

This creates a missionary environment surprisingly different from both strongly Christian societies and highly religious non-Christian societies.

The evangelist cannot assume people possess even the Christian questions that older apologetics answer.

Biblical literacy may be weak.

Yet there is no rival religious system to study in the conventional sense.

Mission must learn how secular lives make meaning.

The Czech and Estonian Examples. Other European societies frequently cited for high nonaffiliation, such as Czechia and Estonia, likewise have distinctive histories involving empire, church-state relationships, nationalism, Communism, and institutional distrust.

The common outcome—low formal religious affiliation—can arise through different historical paths.

The same rule applied to Islam and South Asia therefore applies to secularization:

similar statistics do not guarantee similar causes.

The United Kingdom. Britain’s Christian history remains highly visible, yet church affiliation and participation have undergone major change. The established Church of England continues to occupy formal public roles while Christian practice has become far less universal. Catholic, evangelical, Pentecostal, Black-majority, immigrant, and independent churches complicate any simple narrative of national decline.

London in particular illustrates the interaction between secularization and migration. It is simultaneously one of Europe’s most religiously diverse and internationally connected cities.

The post-Christian city is not necessarily nonreligious.

It may contain intense religious plurality alongside secular institutions.

Immigration Changes Secular Europe

Migration means Europe’s religious future cannot be extrapolated from secularization alone.

Muslim communities have grown through migration and demographic change. African, Asian, Eastern European, and Latin American Christians have established congregations. Orthodox communities expand through migration. New religious movements and Hindu, Buddhist, Sikh, and other communities contribute to pluralization.

Therefore Europe is not simply becoming less religious.

It is becoming differently religious while much of the historic majority population becomes less institutionally Christian.

Mission in Europe increasingly requires both:

• evangelism among post-Christian populations;
• cross-cultural engagement with religious minorities.

These tasks can occur in the same neighborhood.

North America. Post-Christian dynamics also appear in North America.

Pew’s 2020 reconstruction estimated a sharp decline in Christian share in North America between 2010 and 2020, driven substantially by religious switching. The United States remains much more religiously active than many European societies, but the long-term direction of Christian affiliation has changed significantly.³

This matters for mission because the United States remains one of the world’s largest missionary-sending and mission-financing environments.

A sending center can itself become a growing mission field.

Again, the old binary breaks down.

South Korea as a Post-Christian Warning

South Korea provides a non-Western example of similar complexity.

The country still contains major Protestant and Catholic populations and substantial missionary sending. Yet Pew’s East Asian survey reports very high religious switching, and younger generations show weaker affiliation than older Christian-growth narratives might suggest.⁴

The implication is significant for newer sending movements.

Missionary strength is not permanent.

Churches that focus almost entirely overseas can neglect evangelistic and discipleship crises at home.

The solution is not to retreat from global mission.

It is to reject the idea that sending regions and receiving regions are fixed identities.

Japan: Low Christianity Without Post-Christendom. Japan helps distinguish post-Christianity from low Christian presence.

Christianity has existed in Japan for centuries, including the dramatic sixteenth-century Catholic mission, later persecution, hidden Christian communities, and modern Protestant and Catholic institutions. Yet Japan has never experienced national Christendom comparable to much of Europe.

Its low Christian percentage therefore arises from a different historical trajectory than France or Sweden.

The missionary challenge cannot simply be described as secularization after Christianity.

Religious practice, social conformity, ancestor obligations, Buddhism, Shinto-related customs, and modern secular life interact in distinctive ways.

Again, low Christian response does not have one universal cause.

What Does “Post-Christian” Actually Mean? The term should therefore be used carefully.

A post-Christian society is not simply one in which Christians form a minority.

It describes a social environment significantly shaped by Christianity in the past where Christian institutions, beliefs, or practices have lost their former cultural centrality.

The term works well for some European contexts.

It works less well for societies where Christianity never held comparable dominance.

Even within Europe, Christian history remains active enough that “post” should not imply Christianity has disappeared.

Apologetics and Plausibility

Post-Christian mission often places renewed emphasis on apologetics.

Intellectual objections matter:

Does God exist?

Why believe the resurrection?

How can Christianity make exclusive truth claims?

What about science or suffering?

But intellectual argument alone rarely explains religious change.

People also ask whether the church is trustworthy, whether Christianity belongs to a rejected social identity, whether Christian ethics seem good, and whether religious commitment fits modern life.

Missionaries need what Lesslie Newbigin called a missionary encounter with culture, not merely a collection of arguments detached from social imagination.⁵

Christian Community as Apologetic. In post-Christian societies, the local church can itself become part of the plausibility structure for belief.

A community practicing:

• hospitality;
• sexual integrity;
• generosity;
• reconciliation;
• intellectual seriousness;
• care for vulnerable people

makes Christian claims visible in a way arguments alone cannot.

Conversely, an unhealthy church can make Christianity less plausible even where the preaching is technically orthodox.

Mission therefore returns again to ecclesiology.

Digital Abundance and Spiritual Distance

Post-Christian societies possess enormous Christian informational access.

This can tempt churches into believing that everyone already knows the gospel.

Online abundance can produce the opposite effect: people encounter enormous quantities of fragmented religious content, caricature, scandal, debate, and algorithmically amplified controversy.

Information quantity is not understanding.

A person may have heard about Christianity constantly without ever encountering a coherent account of Christian belief within a trusted relationship.

Even high-access societies can therefore contain forms of informational confusion.

The Problem of Response Metrics. Post-Christian mission demonstrates why the church must distinguish faithfulness from numerical control.

A population may possess excellent gospel access and respond weakly.

Mission cannot solve this through increasingly manipulative techniques.

The church’s responsibility is:

• faithful proclamation;
• credible life;
• patient discipleship;
• institutional repentance;
• contextual communication.

The response remains beyond missionary control.

This is one reason strategic priority should not be based simply on low Christian percentage. A 1 percent Christian population with extensive relational and informational access may represent a different pioneer need from a 1 percent population where no local church or Scripture access exists.

High Access Can Still Be Unfinished

The post-Christian frontier therefore broadens the book’s definition of unfinished mission.

The church’s universal responsibility includes societies where Christian access has become abundant but fragile, distrusted, or declining.

Yet strategic missionary priority may still belong especially to populations where access itself remains weak.

Those two truths can coexist.

Every person matters equally.

Every missionary situation is not identical.

The next chapter returns to one of the clearest measurable access barriers: language. Even in an age of instant translation technology, hundreds of language communities still lack Scripture translation work, and thousands have only partial access. The language frontier shows both how much Christian mission has accomplished and why availability alone never completes the task.

Footnotes

1. Pew Research Center, “Christian Population Change,” June 9, 2025: Europe contained an estimated 505 million Christians in 2020, down about 9 percent from 2010. ↩

2. Pew Research Center, Around the World, Many People Are Leaving Their Childhood Religions, especially “Religious Switching Into and Out of Christianity” (March 26, 2025). ↩

3. Pew Research Center, How the Global Religious Landscape Changed From 2010 to 2020, regional findings for North America. ↩

4. Pew Research Center, Religion and Spirituality in East Asian Societies (2024), findings on religious switching in South Korea. ↩

5. Lesslie Newbigin, The Gospel in a Pluralist Society (Eerdmans, 1989); Grace Davie, José Casanova, Charles Taylor, and Callum G. Brown provide different major frameworks for understanding secularization and post-Christian change. ↩