According to various technical analyses, a considerable part of the encyclical "Magnifica Humanitas" recently issued by Pope Leo XIV and focusing on the impact of artificial intelligence on mankind is suspected to be generated by AI. Linch Zhang published an analysis on the LessWrong forum, saying that based on the results of the mainstream AI detection tool Pangram, some passages in the encyclical were judged to be 40% to 100% written by AI.

Another user ran the encyclical through Pangram, paragraph by paragraph, and found that about 62% of the first chapter was marked as AI-generated text. "The Verge" reporters then extracted about 2,000 words of the encyclical content for retesting, and Pangram determined that 46% of it was AI text.

The analysis pointed out that some typical AI writing style features appeared in "Glorious Humanity", such as the frequent use of the word "genuinely" (really, truly), and this wording habit is particularly common in the output of Claude, a large model owned by Anthropic Company. However, the test results also show that not the entire encyclical is suspected to be written by AI. Zhang noted that Pangram judged some passages to be “almost 0% AI texts,” while the first 20 natural passages in the Holy See’s last four encyclicals were all determined to be 100% human-written texts after Pangram detection. In addition, the actual transcript of Pope Leo XIV’s speech when delivering the encyclical was assessed by Pangram as 100% human creation.

It’s important to stress that AI text detection itself is not foolproof. There are often differences in the conclusions between different testing tools. Even if multiple tools give similar results, they cannot be regarded as absolutely reliable evidence. However, among the AI ​​research community, Pangram is now generally regarded as one of the relatively reliable detection tools. In notes published in March 2025, the company said it estimated the rate of "false positives" in which human-written text was mistakenly reported as AI-generated, at about one in 10,000.

Encyclicals are lengthy open letters issued by the Pope, often teaching on important moral or social issues of the day. According to the New York Times, "Human Nature" is Leo XIV's first encyclical after his accession to the throne, and the last encyclical was issued by Pope Francis in October 2024. This is also the first encyclical to focus on artificial intelligence and its widespread impact. At the launch ceremony, Leo XIV rarely invited Christopher Olah, co-founder of the AI ​​company Anthropic, to appear on the same stage, highlighting the interaction between the Vatican and the technology community on AI issues.

As of press time, the Vatican has not officially responded to whether AI was used in the writing process of the encyclical.

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