Siger of Brabant

Works

• c. 1269Questions on the Third Book of On the Soul

  Lecture questions that defend, with Averroes, one separate intellect for all humans – most likely the target of Aquinas’ treatise of 1270.

• c. 1273On the Intellective Soul (De anima intellectiva)

  A reply to Aquinas: what did Aristotle really hold about the intellect? Siger admits that the question remains doubtful for him and that in doubt he holds to faith.

Position

As an arts master Siger’s task was to explain Aristotle, and he took the task literally. In his Questions on the third book of On the Soul, probably from the late 1260s, he followed Averroes in holding that Aristotle taught a single intellect, separate from bodies and shared by all humans, which thinks in each person by means of that person’s images. Aquinas’ On the Unity of the Intellect against the Averroists (1270) was almost certainly aimed at this teaching, and it accused its defenders of saying that by reason they concluded one thing while holding the opposite by faith. Siger also treated the eternity of the world, the necessity of what the heavens cause and similar theses as conclusions of philosophy. In On the Intellective Soul, written in reply to Aquinas, he presented the question as still doubtful and declared that in doubt he held to faith, which is above all reason; in later works, such as his questions on the Book of Causes, he came closer to Aquinas. The charge that he taught a “double truth”, that something can be true in philosophy and false in faith, goes back to the prologue of the 1277 condemnation. Most historians think it does not fit his own statements, in which philosophy reports what Aristotle and the philosophers held while truth lies with faith; whether this was sincere or a protective formula is still debated. The condemnation of 1277 shaped Paris teaching for decades. Pierre Duhem’s thesis that it opened the way for modern science, by insisting that God can do what Aristotle declared impossible, is now treated with caution.

Life & context

Siger was born around 1240 in the duchy of Brabant. By the mid-1260s he was a master in the arts faculty at Paris, teaching Aristotle’s philosophy. In 1266 the papal legate Simon of Brion threatened him with sanctions after disturbances between the “nations” of the faculty, and in the early 1270s he led a minority party in a disputed election of the rector that was settled only in 1275. On 10 December 1270 Bishop Étienne Tempier of Paris condemned thirteen propositions, among them the unity of the intellect and the eternity of the world. In November 1276 the inquisitor of France, Simon du Val, summoned Siger and two other masters, who had by then left the kingdom. On 7 March 1277 Tempier condemned 219 propositions taught in the arts faculty – some of them close to positions of Aquinas, who had died in 1274; eleven days later Archbishop Robert Kilwardby condemned thirty propositions at Oxford. According to the traditional account Siger went to the papal court in Italy and died at Orvieto before November 1284, stabbed by a secretary who had lost his mind; this account rests on late and indirect evidence and has recently been questioned. Dante placed him in the heaven of the Sun, introduced by Aquinas, his former opponent (Paradiso X 133–138).

Further main works

• On the Eternity of the World (early 1270s)
• Questions on the Metaphysics (1270s)
• On the Necessity and Contingency of Causes
• Questions on the Book of Causes (mid-1270s)

Appears in

• Debate ‘Thomas Aquinas and Siger of Brabant: One Intellect for All?’