VATICAN CITY — Pope Leo XIV has called for the “disarming” of artificial intelligence in his first encyclical, warning of “new forms of slavery” behind the rapid development of the technology.

The American-born pontiff warned against “a race for ever more powerful algorithms and larger datasets, driven by the desire to secure geopolitical or commercial dominance” during the presentation of “Magnifica Humanitas” (Magnificent Humanity) at the Vatican on Monday.

Leo presented the manifesto alongside AI experts including Christopher Olah, co-founder of US technology company Anthropic, which is currently in a legal dispute with the US military over the use of its technology for autonomous warfare and mass surveillance.

At the presentation, Olah said AI companies operate “inside a set of incentives and constraints that can sometimes conflict with doing the right thing”. He welcomed input from organisations like the Catholic Church to “push events in a better direction”, saying that “the questions raised by AI are bigger than the AI research community”.

Leo said he had confidence that “together, we can discern the major questions of our time, and so, the future of humanity”.

The pope said he had consulted scientists, engineers, political leaders, parents and teachers in preparing his manifesto, and had heard “very troubling voices” as well as “the silence of those who have no voice”.

AI must be “freed from logics that turn it into an instrument of domination, exclusion and death”, he said.

Lethal technology concerns

In his encyclical, Leo raised concerns about AI-directed weaponry, saying it was “not permissible to entrust lethal” decisions to technology.

The pope, who has repeatedly clashed with the White House over the Iran war and its use of religion to justify conflict, wrote that the “just war” theory recently referenced by the Trump administration was “outdated”, adding that “no algorithm can make war morally acceptable”.

AI could be worth up to $4.8 trillion by 2033, a 25-fold increase in a decade, whilst concentrating its profits in the hands of a limited few, according to the United Nations.

“Disarming AI means freeing it from the mentality of ‘armed’ competition,” the pope wrote. “To disarm does not mean rejecting technology, but preventing it from dominating humanity.”

Leo said AI should be “human-friendly”, accessible to all and open to discussion and debate.

The head of the world’s 1.4 billion Catholics has made the issue a cornerstone of his papacy by dedicating his first encyclical to it. An encyclical is a document which lays the basis for Church teaching and longer-term debate.

The manifesto references cultural figures ranging from Greek philosopher Plato to composer Beethoven and his Ninth Symphony, and even cites a character from JRR Tolkien’s “The Lord of the Rings”.

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Hidden exploitation

“Magnifica Humanitas” was signed on 15 May, the 135th anniversary of an 1891 encyclical by Leo XIII which laid the foundations of the Church’s social doctrine during the Industrial Revolution.

Leo warned of new forms of slavery fuelling the technological revolution, noting “nothing in the world of AI is immaterial or magical”.

“Every seemingly immediate and flawless response relies on the silent work of millions of people”, from content moderators forced to watch disturbing material to children who extract the rare earth elements on which AI depends.

They are “scarred, injured and worn down so that computational flow may continue uninterruptedly”, he wrote.

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Greater efficiency or innovation did not excuse “a chain of exploitation that remains deliberately hidden”, he wrote, whilst more must be done to reduce AI’s environmental impact and “protect our common home”.

The pope also issued an unprecedented apology for the Vatican’s role in the slave trade and in helping to justify slavery, saying it was “a wound in Christian memory”.

“For this, in the name of the Church, I sincerely ask for pardon,” Leo wrote.

The release of the text follows several years of study by the Church on AI-related technologies.

As early as 2020, the Holy See launched the “Rome Appeal for an AI Ethic”, which called for new technologies to respect human dignity.

Experts say “Magnifica Humanitas” could prove as influential as Pope Francis’s “Laudato Si”, a 2015 climate manifesto that triggered political and civic reactions worldwide.

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