Magnifica humanitas calls for breaking up monopolistic control of the technology, rules out algorithmic warfare, and is being presented alongside Anthropic co-founder Chris Olah.
Pope Leo XIV used the first encyclical of his pontificate, published in Rome on Monday, to call for the disarmament of artificial intelligence.
The 245-paragraph document, titled Magnifica humanitas, frames AI as a technology that has begun to dominate the people it was built to serve, and argues that disarming it means restoring the moral primacy of the human over the algorithm.
“To disarm means discrediting the assumption that technical power automatically confers the right to govern,” the pope wrote.
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“To disarm does not mean rejecting technology, but preventing it from dominating humanity.”
The encyclical is the most consequential act of his year-old papacy, and the first time a pope has organised an entire foundational letter around an emerging technology rather than a doctrinal or social question.
Leo, the first American pope and a former Villanova mathematics major, signed it on May 15, the 135th anniversary of Leo XIII's Rerum novarum, which set out Catholic social teaching for the industrial age.
The framing is deliberate: this encyclical is offered as its successor for the AI age.
Its central targets are concentration and warfare. The pope called for AI to be made more “human-friendly” and freed from “monopolistic control”, language that lands directly against the half-dozen US firms that now define the technology's frontier.
On war, he was sharper. “No algorithm can make war morally acceptable,” he wrote. “AI does not remove the intrinsic inhumanity of conflict, indeed it can only bring about conflict more quickly and render it more impersonal.”
The choice of speaker for the launch underlined the line. Christopher Olah, Anthropic's co-founder and head of interpretability research, presented alongside cardinals at the Vatican Synod Hall on Monday morning.
Anthropic has spent the past two months at the centre of a separate global debate over the security implications of Mythos, its autonomous vulnerability-discovery model that has found thousands of zero-days across every major operating system.
The company has clashed with the Trump administration over the use of its technology in war and surveillance.
On that last point, the encyclical now sits directly across from the White House. Vice president JD Vance, a Catholic convert close to early OpenAI investor Peter Thiel, was asked about the document at a press briefing on May 19.
“When the leader of the world's largest Christian denomination speaks on an issue like that, it's certainly going to have some influence,” he said.
“And I'm sure it'll contain a lot of insights, some of which I'll probably agree with, some of which I may not.”
In the same briefing he restated that president Donald Trump “wants us to win the AI race against all other countries in the world”.
The proximate tension is older than this week. Thiel spent part of March in Rome delivering closed-door lectures at Palazzo Taverna on the figure of the Antichrist, drawing on a thesis that a one-world technocratic government would emerge under the pretext of averting AI, nuclear, or climate-driven catastrophe.
Father Paolo Benanti, the Vatican's adviser on AI, responded in an op-ed describing the lectures as “a sustained act of heresy” against the liberal consensus. Leo and Trump have separately sparred over the war in Iran.
An encyclical, by design, is not a policy document but a moral framing under which subsequent policy gets argued. Magnifica humanitas places “human dignity” and “shared standards of social justice” at the centre of any future regulatory architecture and rules algorithmic warfare out of it.
Pope Leo XIV presented it personally rather than delegating it to cardinals, a break with tradition. He addressed the world's 1.4 billion Catholics. The wider audience was understood.