Person

Eric Kaufmann

Canadian political scientist and demographer (b. 1970), professor of politics at the University of Buckingham and previously at Birkbeck, University of London. He is cited in this codex for a single empirical thesis with substantial apologetic relevance: that the demographic assumptions underlying the secularisation narrative are wrong.

Kaufmann is not writing as an apologist. He has described himself as a secular liberal, and the argument is presented as demography rather than advocacy, which is what makes it usable.

Shall the Religious Inherit the Earth? (2010)

The thesis, in outline:

Religious populations have substantially higher fertility than secular ones, and the gap holds across countries, income levels and educational levels rather than disappearing with development.
The gap is widest among the most observant. Kaufmann's cases include Haredi Jews, whose share of the Israeli Jewish population has grown from a small minority in 1948 to a large and rising fraction, and comparable patterns among Laestadian Lutherans in Finland, conservative Anabaptist groups in North America, and Salafi Muslims in Europe.
Retention rates matter as much as birth rates. Where highly observant communities keep a large majority of their children in the faith, the compounding effect over generations is decisive.
Secularism has no comparable reproduction mechanism. It grows principally by defection from religious populations rather than by births, which makes it dependent on the very populations it is replacing. Once the religious remainder is concentrated among the most committed, defection rates fall and the mechanism weakens.
The conclusion is a projection, not a prophecy: on current trends the religious share of the world population, and of several Western populations, rises rather than falls through the twenty-first century.

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Why it matters apologetically

The standard secularisation thesis, that modernisation produces religious decline as a matter of course, has been the background assumption of a great deal of popular atheist writing, which treats religion as a residue that education and prosperity will dissolve. Kaufmann's work is part of a broader scholarly reassessment of that thesis, alongside Rodney Stark and Peter Berger, the latter of whom publicly repudiated his own earlier secularisation position.

Two cautions on deployment:

It is a sociological observation, not an argument for truth. That a belief is growing says nothing about whether it is correct, and treating demography as evidence for Christianity would be the same fallacy as treating decline as evidence against it. Its proper use is narrowly defensive: it answers the claim that religion is inevitably disappearing, and nothing more.
The thesis is about religion generally, not Christianity specifically. The fastest-growing groups in his data include Muslim and Jewish populations, and within Christianity the growth is in the global South and among conservative denominations rather than in Western liberal ones. Using the work honestly means reporting that.