It appears that artificial intelligence may have played a role in the creation of sections of Pope Leo XIV’s recent encyclical discussing AI’s impact on humanity. Linch Zhang’s analysis on the LessWrong forum revealed that certain passages in Magnifica Humanitas were determined to be between 40 percent and 100 percent AI-generated, as detected by the popular AI tool Pangram.
The text exhibits characteristics commonly found in AI-generated content, such as an increased usage of the word “genuinely,” a trait associated with writing by Anthropic’s Claude, compared to previous encyclicals. Another individual conducted a section-by-section analysis using Pangram, determining that 62 percent of the initial chapter was identified as AI-generated. When The Verge tested approximately 2,000 words from the document, Pangram estimated that 46 percent of the content was produced by AI.
AI detection methods are not infallible
However, certain sections within the encyclical were identified as being authored by humans. Pangram flagged some portions as having “essentially 0% AI” involvement. Notably, the first 20 paragraphs of the past four encyclicals were confirmed by Pangram to be 100 percent human-written. Additionally, a Pangram analysis of a transcript of Pope Leo’s speech also indicated a 100 percent human origin.
While AI detection methods have their limitations, Pangram is highly regarded among AI researchers. In March 2025, Pangram stated that its false positive rate for misidentifying human-written content as AI-generated was estimated to be around 1 in 10,000.
Encyclicals are lengthy letters published by the pope, aimed at addressing important moral and social issues of the time, as reported by The New York Times. This particular encyclical marks the first from Pope Leo, following the most recent one penned by Pope Francis in October 2024. It is also the first to delve into the topic of AI and its broad impacts, with Pope Leo presenting it in collaboration with Christopher Olah, a co-founder of Anthropic.
The Vatican has not yet responded to requests for comments on this matter.
