Was this medieval theologian’s massive, unfinished masterpiece truly as heavy as a horse?

Ideas & Philosophy · Published 3 October 2026 Swipe more like this →

In short: Alexander of Hales was a towering figure of scholasticism who became the first Franciscan to hold a university chair in Paris. Known as the Irrefutable Teacher, he revolutionized theological study by turning Peter Lombard’s Sentences into a foundational textbook, though his own massive Summa remains a subject of intense scholarly debate.

Born in Shropshire between 1180 and 1186, Alexander of Hales rose to prominence at the University of Paris. His academic career was marked by a pivotal shift in 1236 or 1237, when he joined the Franciscan Order at age 50. This transition established the Franciscan school of theology, with Alexander serving as its first chair. His influence was profound, shaping the minds of later thinkers like Bonaventure, who regarded him as a master.

Alexander is best remembered for his systematic approach to theology, particularly his use of Aristotle and his revival of Anselm of Canterbury. He introduced the Sentences of Peter Lombard as a core teaching text, a move that standardized scholastic training. His own major work, the Summa fratris Alexandri, was an ambitious attempt to organize theological knowledge. However, the text was left incomplete at his death in 1245. Because it was finished by his students, including William of Middleton and John of Rupella, its authorship and internal consistency remain contentious topics among historians.

The work’s sheer scale drew both praise and sharp criticism. While an assembly of seventy doctors once declared the Summa infallible, the philosopher Roger Bacon famously mocked its size, claiming it weighed as much as a horse and was riddled with errors in logic and metaphysics. Despite these critiques, Alexander’s contributions were foundational. He explored complex issues, such as the nature of original sin and the criteria for a just war, which required authority, proper intention, and the ultimate goal of peace for all.

Beyond his writing, Alexander was a master of the disputation, a rigorous academic event where he would engage with any question posed by students or faculty. His legacy persists not only in his surviving manuscripts but in the intellectual tradition he inaugurated, bridging the gap between early medieval thought and the more systematic scholasticism that would define the later Middle Ages.

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