Zusammenfassung / Summary
Siger of Brabant (who died in 1281/84) considered in an early phase of his work the human intellect to be a single one. After the condemnation of 1270, he abandons this theory and holds an interpretation of Aristotle which is mainly geared to Thomas Aquinas. The essay aims to introduce a differentiation between a “primary” and a “secondary authority” and to apply this to the analysis of the arguments from authority used by Siger in the several stages of his development. This way, it is possible to describe systematically the graduation of different loci from where philosophical knowledge can be imparted. Historically, Siger’s change can be interpreted as a profound shift of epistemological authorities.