Pope Leo XIV writes an open letter to 'all people of good will' warning about AI; says: Ensure that humans, not AI remain responsible for all decisions regarding…

Pope Leo XIV has issued the first major teaching document of his papacy, and he spent it on artificial intelligence. The 42,300-word encyclical, titled "Magnifica Humanitas" ("Magnificent Humanity"), released on May 25, is addressed not just to Catholic bishops but to "all the Catholic faithful, to all Christians and to all men and women of goodwill"—which is to say, everyone. The first US-born pope used it to warn that AI, left to private companies chasing profit and power, could deepen inequality, hollow out human work, and make war easier to wage. He signed it on May 15, exactly 135 years after Pope Leo XIII published "Rerum Novarum," the landmark text on workers' rights during the Industrial Revolution. The parallel is the whole point. Leo XIV sees AI as the new industrial revolution, and he wants safeguards before, not after, the damage is done.In an unusual move, the Pope presented the document himself at the Vatican, sharing the dais with Christopher Olah, a co-founder of AI developer Anthropic. "What a great sign of hope it is that in our differences we can listen to one another," Leo said.Leo frames the entire encyclical around a single decision. "Humanity, created by God in all its grandeur, is today facing a pivotal choice: either to construct a new Tower of Babel or to build the city in which God and humanity dwell together," he writes in the opening line. Babel, in his telling, is the trap—what he calls the "Babel syndrome," meaning "the idolatry of profit that sacrifices the weak, a uniformity that neutralizes differences, and the pretense that a single language—even a digital one—can translate everything, including the mystery of the person, into data and performance."He's careful not to sound like a technophobe. "Technology should not be considered, in itself, as a force antagonistic to humanity," he writes, adding elsewhere that it is not "inherently evil." But here's his catch: "technology is never neutral, because it takes on the characteristics of those who devise, finance, regulate and use it." So the real question, he argues, isn't yes or no to AI. It's about who controls it and what they're building toward.A big chunk of Leo's worry is about concentration. He repeatedly returns to the idea that AI power sits with a handful of private players whose resources now outstrip many governments. When data, computing power and regulatory influence stay "in the hands of a few," he warns, the gap widens between those who can join the digital revolution and those left on the margins. His proposed fix is not subtle: "It is not enough to invoke ethics in the abstract; robust legal frameworks, independent oversight, informed users and a political system that does not abdicate its responsibility are required." And a line that lands hard: "A more moral AI is not enough if that morality is determined by a few."He also rejects letting markets sort it out on their own. "More than ever, in the age of AI and robotics, it is no longer possible to rely solely on the 'invisible hand' of the market," he writes, arguing politics has to steer economies and technology toward the common good.On work, Leo echoes his namesake from 1891—machines should serve people, not the reverseThe labor sections carry the clearest fingerprints of "Rerum Novarum." Leo treats work as far more than a paycheck. "Work is not simply an instrument; it expresses and enhances the dignity of our lives," he writes. "It is a requirement of the human condition, a normal path toward maturity, development and personal fulfilment."His central warning to employers and AI builders is blunt: "The pursuit of greater profits cannot justify choices that systematically sacrifice jobs, because the human person is an end, not a means, and the economic order must remain subordinate to human dignity and the common good."He's skeptical of the standard pitch that automation simply makes everything better. The "new ways" of working, he writes, aren't necessarily better, because "while AI promises to boost productivity by taking over mundane tasks, it frequently forces workers to adapt to the speed and demands of machines, rather than machines being designed to support those who work." The result, he argues, can be the opposite of what's advertised—de-skilling, automated surveillance, and rigid, repetitive tasks.Then comes one of his sharpest formulations. A society that gives work to only a small slice of people, even while sitting on advanced technology, "risks exposing many to forced inactivity." That, he writes, "creates a paradox of material progress and anthropological regression that undermines the foundations of a just and stable social peace." His practical asks include continuous retraining made accessible to all, social criteria attached to every rollout of automation, and companies treating dignified work as a measure of success rather than a cost to cut.Children get a dedicated focus too. Leo points to "psychological and psychiatric literature" documenting how early, unsupervised exposure to devices and social media can hurt sleep, attention, emotional control and relationships during the most vulnerable years, "at times with tragic consequences." He calls for age limits, accountability for platforms instead of dumping the burden on parents, and protections against online sexual exploitation of minors.If there's a section where Leo's tone hardens, it's the one on conflict. He argues the digital revolution is changing the very nature of war, with cyberattacks, information manipulation and the automation of strategic decisions blurring the line between defense and aggression.His core demand is that humans, not machines, stay in charge of lethal choices. Citing the Holy See's earlier observations, he writes that "the growing ease with which autonomous weapons systems can be deployed" makes war "more 'feasible' and less subject to human control." That, he says, violates the principle that armed force should be a last resort in cases of legitimate self-defense.He goes further, declaring it "not permissible to entrust lethal or otherwise irreversible decisions to artificial systems." And in a line that functions as the encyclical's moral floor: "No algorithm can make war morally acceptable." AI doesn't remove the "intrinsic inhumanity" of conflict, he writes—it can only "bring about conflict more quickly and render it more impersonal, lowering the threshold for resorting to violence, transforming defense into threat prediction and thus reducing victims to data."That reasoning leads him to a striking conclusion about Catholic doctrine itself. The "just war" theory, he writes, "which has all too often been used to justify any kind of war, is now outdated," given how far weapons technology has advanced. In its place he urges dialogue, diplomacy and forgiveness, plus an international framework to curb the AI arms race and protect civilians.This is where Leo's signature word arrives. AI, he writes, must be "disarmed." He knows it's a loaded term and picks it on purpose. "To disarm does not mean rejecting technology, but preventing it from dominating humanity," he writes. "It means freeing technology from monopolistic control and opening it to discussion and debate, therefore making it human-friendly and restoring it to the plurality of human cultures and ways of life." Disarming AI, in his framing, means stripping it of the "armed" competition logic that drives a race for ever more powerful algorithms and bigger datasets in pursuit of dominance.Leo also issues a "special appeal" directly to the people building these systems. "Developers bear a particular ethical and spiritual responsibility, for every design choice reflects a vision of humanity," he writes—calling for transparency, responsibility toward affected communities, and genuine attention to whether what they're cultivating is actually good.Threaded through it all is a separate, historic note: Leo offers one of the strongest Vatican apologies yet for the Catholic Church's role in legitimizing slavery, drawing a deliberate line between that historical failure and the risk of normalizing "new digital slaveries" today—from the hidden labor of data labelers and content moderators to the children mining the rare earth elements that power our devices. "I sincerely ask for pardon," he writes.For all the policy detail, Leo keeps circling back to one idea: machines can't replace what makes us human. "No computational system, however sophisticated, can create a heart that gives itself, or a conscience that discerns good from evil," he writes. His closing plea is for what he calls slowing down. "What is needed," he writes, "is a more active political involvement that is capable of slowing things down when everything is accelerating, and of protecting the opportunities for communities still to be able to participate and ask questions."