Siger of Brabant and Thomas Aquinas as Parties in the Dispute on the Unity of Reason

Miroslav Severa

The article analyzes the controversy concerning the unity of human intellect which erupted in the thirteenth century between Thomas Aquinas and Siger of Brabant, largely focusing on the differences in the approach to the human soul in these two thinkers. It is argued that the foundation which gives rise to the doctrine of the unique intellect for all humans in Siger of Brabant is the absence of creative causality, and that Siger of Brabant is unable to give any satisfying explanation of the fact that hic homo singularis intelligit (this singular human understands).