Why did Francesco Borromini prefer geometric configurations over human-body proportions in architecture?

Francesco Borromini’s preference for geometric configurations over human-body proportions was rooted in his specialized training and his connection to medieval building traditions. Rather than rejecting anthropometry entirely, he utilized a method likely learned in Lombardy, where architectural procedures were passed down through generations. This approach involved establishing a primary geometric figure for a space and articulating it through smaller geometric subunits.1

While contemporaries like Gian Lorenzo Bernini argued that architecture should derive its proportions from the human body—viewing the body of Adam as a divine model—Borromini’s focus on geometry was seen by critics as a departure from the anthropometric basis of architecture. Despite this, Borromini did not completely divorce his work from human references; for instance, he described the concave facade of the Oratory of St. Philip Neri as representing the welcoming gesture of outstretched arms, with the central unit acting as the chest and the wings as the arms. Ultimately, his reliance on geometry reflected his desire to move beyond being a mere copyist of antiquity, favoring novel, complex, and dynamic structural interpretations.1