Emmanuel Carrère set out to write about the origins of Christianity and spent a whole winter falling unexpectedly in love with Seneca. What that detour reveals about empathy — and about the limits of wisdom — is the most revealing.

There is a forged correspondence, fabricated in the fourth century by an enterprising Christian apologist, in which Paul and Seneca exchange admiring letters. Paul congratulates Seneca on his eloquence; Seneca expresses his esteem and hints at an openness to the new faith. The letters are, Carrère notes, false and rather flat — but Augustine thought highly of them, and you can see the appeal. The desire to make these two men speak to each other, to imagine a dialogue between the apostle and the philosopher who were near-contemporaries moving through the same imperial world, is itself an act of wishful empathy. It keeps recurring, across centuries, because the gap between them is so productive and so impossible to close.

Le Royaume begins as an investigation into the origins of Christianity — into Paul, into Luke, into the historical and human conditions under which a small Jewish sect became a world religion. It ends, as Carrère's books tend to, somewhere more uncomfortable: inside himself, examining the years when he was a practising Catholic, the faith he lost, the question of what he owes to the belief that shaped him and that he can no longer access. The Christianity he is trying to understand is not foreign territory. It is a room he once lived in and can no longer enter.

Seneca arrives in the middle of the book as a foil to Paul — the representative of everything Paul rejected. Where Paul proposed a faith that made no sense to the cultivated Greco-Roman world, Seneca embodied that world at its most refined: Stoic philosophy as self-management, wisdom as the achievement of inner equilibrium, happiness as making yourself invulnerable to fortune. Carrère's early treatment of him is dismissive, even mocking. The rich man who preaches detachment while eating off gold plates; the philosopher who justifies his fortune with the argument that one can enjoy the wind without being attached to it. Familiar hypocrisy, elegantly dressed.

Then something shifts. Carrère spends a whole winter reading the Letters to Lucilius and arrives at admiration he hadn't expected. The late Seneca, writing in retirement after decades of compromise at Nero's court, is no longer performing wisdom from above. He has dropped the oratorical posture. The letters find their register in a single sentence Carrère quotes and clearly can't stop thinking about: " I am sick and won't play the doctor. We are neighbours in the same hospital ward, so I talk with you about the illness we share and I pass you my remedies, for what they're worth.”

This is also, precisely, Carrère's method in Le Royaume — and in all his books. Not the writer dispensing insight from a position of achieved understanding, but someone working through the same confusions as the reader, from the same hospital bed, offering what he has. The identification with Seneca is personal before it is intellectual: both men are constitutionally attached to the pleasures and textures of life, both find the Stoic ideal of the self as thermostat — maintaining constant temperature, purging desire and novelty and emotion in the service of inner peace — finally uninhabitable.

And yet the insufficiency of Stoicism is not Paul's argument to make. Paul's rejection of wisdom is theological and violent — he calls it the wisdom of the world and dismisses it in terms that neither Seneca nor his brother Galion could have begun to understand. Carrère finds himself in the uncomfortable middle: unable to follow Paul into faith, unable to settle for Seneca's equilibrium, drawn to both and satisfied by neither.

Robert Schwentke's film Seneca — On the Creation of Earthquakes (2023) arrives at these questions from an angle Carrère doesn't take. Where Carrère finds in the late Seneca of the Letters something genuinely moving — the sermoniser finally dropping his pretensions — Schwentke asks what happened when the moment of actual reckoning came. The film is set on Seneca's last day: a decadent party at his farmhouse, a lover, friends, the staging of his own dark tragedy — the cultivated, self-sufficient life still being lived. Then the messenger arrives with Nero's order. He must be dead by morning.

What follows, in Malkovich's performance, is not the noble death of philosophical tradition. It is a man discovering the distance between the philosophy he built and the fear he actually feels. He talks — he keeps talking, at length, as the blood drains — but the words no longer quite reach the terror underneath them. The stoic as thermostat fails to maintain its temperature at the one moment the system was designed for. Carrère, characteristically, would probably find himself on both sides of it. He admires the Seneca who said we are neighbours in the same hospital ward — the one who gave up the performance of wisdom for something more exposed and more true. But he is also the writer who has spent his career examining the gap between what we profess and what we discover about ourselves under pressure. The film, for all its theatrical strangeness, is asking his question. It just refuses his answer.