Pope Leo XIV urged governments and technology companies to slow the development of artificial intelligence in his first major encyclical, warning that the technology risks spreading misinformation, concentrating power and pushing the world toward more automated forms of war.
The document, titled “Magnifica Humanitas,” was released Monday and focuses on safeguarding the human person in the age of artificial intelligence. The Vatican said the encyclical was signed May 15, the 135th anniversary of Pope Leo XIII’s “Rerum Novarum,” the 1891 text that addressed labor and capital during the Industrial Revolution.
Leo, the first U.S. pope, used the text to frame AI as one of the central moral and political questions facing the world. He called for legal oversight, independent regulation and political accountability, arguing that ethical promises from technology companies are not enough when control over data and AI systems is concentrated in private hands.
The pope warned most sharply about the use of AI in warfare. He said decisions involving life and death must not be delegated to machines, describing the militarization of artificial intelligence as part of a destructive spiral. Reuters reported that Leo also rejected the continued use of “just war” theory as a justification for modern conflict, saying it had become too easily used to excuse violence.
The encyclical also criticized the political and commercial incentives behind the AI race. Leo said governments should not abdicate responsibility to private companies and warned that a “more moral AI” would not be enough if the definition of morality were left to a small number of powerful firms.
The Vatican presented the document at a launch event that included Christopher Olah, a co-founder of Anthropic and the company’s head of research on AI interpretability. The Vatican said other speakers included Cardinal Víctor Manuel Fernández, Cardinal Michael Czerny, theologian Anna Rowlands and Leocadie Lushombo, a professor of political theology and Catholic social thought.
The inclusion of an Anthropic executive underscored the Vatican’s effort to engage directly with the technology industry while also challenging it. AP reported that the Vatican’s decision reflected a continuing dialogue with AI leaders, even as Leo’s encyclical criticized the concentration of AI power and called for stronger protections for workers, children and vulnerable communities.
Leo’s message extended beyond regulation of software. He linked AI development to labor rights, democratic accountability, education, the environment and human relationships. Reuters reported that the 43,000-word document warned of the “gradual replacement of reality by its simulation” and criticized the environmental damage caused by the rush for rare earth elements used in modern electronics.
The pope also raised concerns about disinformation and digital manipulation, saying AI systems can distort public debate and weaken trust in democratic institutions. He called for informed users, transparent systems and political structures capable of holding developers and companies accountable.
The document places AI within the Catholic Church’s broader tradition of social teaching. Leo connected the issue to principles including human dignity, solidarity, the dignity of work and the common good, arguing that technological progress cannot be judged only by speed, profit or technical capability.
The encyclical also addressed global conflict more broadly. Reuters reported that Leo criticized military profiteering, the use of war as a political distraction and the erosion of moral restraint in modern warfare. His comments came after months in which he repeatedly warned that new technologies could intensify violence rather than reduce it.
In one of the document’s wider historical appeals, Leo apologized for the Catholic Church’s role in transatlantic slavery and its delayed condemnation of the practice, linking that history to his argument that human dignity must not be subordinated to economic systems or technological power.
The encyclical is likely to become a reference point in debates over AI regulation, particularly as governments weigh how to control automated decision-making, military use of AI and the dominance of major technology companies. Leo’s central argument is that AI should remain subject to human judgment, public oversight and moral limits.
For the Vatican, “Magnifica Humanitas” marks the clearest statement yet of Leo’s papacy on artificial intelligence. For governments and technology companies, it is a direct challenge: slow down, accept oversight and prove that AI development serves people rather than power.