Siger of Brabant
Siger of Brabant was a thirteenth century philosopher and theologian who taught at the University of Paris. He was a prominent member of a group of teachers, mostly at the Faculty of Arts in Paris, known to historians as the 'Latin Averroists', who aimed at a secular interpretation of Aristotle.
Siger was born about 1240 in the Duchy of Brabant. He attended the University of Paris about 1255-7. At that time the full range of Aristotle's work were being incorporated into the curriculum, after being initially banned in 1215 . By 1266 he was probably a master of arts, in which position he remained until the end of his career. He was a prominent member of a group of teachers, mostly at the Faculty of Arts in Paris, known to historians as the 'Latin Averroists' or 'secular Aristotelians', who aimed to interpret Aristotle in a secular way. They taught the eternity of the world, the unity of the passive intellect in men, collective immortality, determinism and the absence of free will.
These interpretations were felt by many to challenge Christian faith, and Siger was exposed to persecution from the Church as well as from purely philosophical opponents. Averroism was denounced by Bonaventura in 1267, and in December 1270 was condemned by the ecclesiastical authorities. In the same year, Thomas Aquinas  challenged the Averroistic interpretation of De Anima proposed by Siger.
In 1276 the French Inquisition summoned Siger to appear before a tribunal at Noyon, although he seems to have been acquitted. In 1277 there was a general condemnation of Aristotelianism, instigated by the Archbishop of Paris, Stephen Tempier (known as the 'Parisian Condemnations'). These included a special clause directed against Boethius of Dacia, and Siger. Both fled to Italy.
It is not known exactly how Siger died, and there are various stories about his death. According to John Pecham, archbishop of Canterbury, he perished miserably . A Brabantine chronicle says that he was assassinated by an insane secretary (a clerico suo quasi dementi) [. Dante, in the Paradiso (x. 134-6), says that he found 'death slow in coming'. A 13th century sonnet by Durante (xcii. 9-14) says that he was executed at Orvieto .
He is supposedly mentioned in Dante's Divine Comedy - (Paradiso, canto X, 133-8), where he is located within Paradise, beside Aquinas and Isidore of Seville (a curiosity, given that Siger was a secular Aristotelian, Dante a Thomist, but perhaps Dante only knew of Siger as a persecuted philosopher, or perhaps, as Van Steenberghen has suggested, Siger's position was closer to Aquinas than his surviving works imply).
his search for a truthful interpretation of Aristotle, Siger discovered inconsistencies between Aristotelian doctrine and orthodox Christian belief. This brought him into conflict with Thomas Aquinas, whose object was to reconcile Aristotle and the Church. Aquinas argued in On the Unicity of the Intellect that the Averroistic reading of Aristotle was altogether contrary (repugnare omnino) to their true meaning. Siger replied with his treatise On the Intellective Soul, saying his intention was to determine what was said according to the texts of the philosophers, not what he thought on his own behalf. Historical truth should not be hidden, even if it contradicts the truth and wisdom which has been given to us by revelation. Aristotle is not the only authority in philosophy and is su bject, like all philosophers, to error.
Siger is sometimes credited with the 'double truth' doctrine. This has different versions. According to one verson, we can affirm contradictory propositions, first as a philosopher, then as a Christian. For example, I can hold as a philosopher that the world is eternal, but as a Christian that the world is created. According to another version, we can express what Aristotle taught, without expressing our own views.
Aquinas was suspicious of the second view, accusing its adherents of bad faith. 'Among those who labour in philosophy, some say things that are not true according to faith, and when told that what they say goes against faith, they answer that it is the Philosopher who says so; as to themselves they do not affirm it, they are only repeating the philosopher's words'. .
Mandonnet rediscovered Siger's work in the 1890's. This was of some importance to our understanding of medieval philosophy, suggesting it could no longer be viewed simply as theology, although it is still not clear how we should interpret his work. According to Mandonnet, he was an Averroist who endorses Christian doctrine only because it is expedient. Van Steenberghen, by contrast, regards him as a sincere Christian whose position was close to that of Aquinas.
His works include logical works (Impossibilia, Quaestiones logicales, Sophismata); commentaries on Aristotle (In III De Anima, De generatione, Physics, Metaphysics), and the Treatises De Necessitate et contingentia causarum, De aeternitate mundi, and De anima intellectiva, some of which were published by Mandonnet in 1899.
- MANDONNET, Siger de Brabant et l'averroisme latin in Philosophes belges, VI, VII part i: Etude critique (Louvain, 1910), part ii, Textes (Louvain, 1909), contains all the works of Siger;
- BAUMKER, Die Impossibilia d. Siger von Brabant, eine philosoph Streitschr. aus. d. XIII Jahrh. in Beitr. z. Gesch. d. Philos. Mitt. II (1888), 6
- IDEM, Zur Beurteilung Sigers von Brabant in Philosophisches Jahrbuch (1911)
- MANDONNET, Autour de Siger de Brabant in Rev. thomiste, XIX, 1911. .
- Bazan, B.C., Article 'Siger of Brabant', in A Companion to Philosophy in the Middle Ages, ed. Gracia & Noone, Oxford 2006.
- Mandonnet, P., Siger de Brabant et l'Averroisme latin du XIII e siecle (Fribourg, 1899); G. Paris, "Siger de Brabant" in La Poesie du moyen age (1895); and an article in the Revue de Paris (Sept. 1st, 1900).
- Van Steenberghen, F., (1977), Maitre Siger de Brabant, Paris: Publications Universitaires, Louvain, Vander-Oyez S.A