Why do scholars question whether St. Paul wrote some letters attributed to him?

While 13 or 14 books in the New Testament are traditionally attributed to St. Paul the Apostle, scholars generally accept only seven as being entirely authentic and dictated by Paul himself. The authorship of the remaining letters is widely debated, and they are often classified as "deuter-Pauline" or "trito-Pauline," suggesting they were written by followers in Paul's name after his death.1

Scholars question the authenticity of these works based on several key factors:

• Linguistic and Stylistic Differences: Many disputed letters exhibit vocabulary, syntax, and stylistic patterns—such as the use of different words for the same concepts or unique connectives—that are inconsistent with Paul’s known writings.12
• Theological and Historical Discrepancies: Some letters reflect a level of church organization, specific heresies, or theological developments that appear to belong to a later, post-apostolic period rather than Paul’s own lifetime.12
• Literary Dependence: Certain epistles, such as Ephesians, show a heavy reliance on other Pauline letters (like Colossians), suggesting they were composed by later authors who had access to Paul’s earlier works.31