Relation as a Condition of Diversity: The Order of “processio” in Eriugena and Gundisalvus

The medieval ontology of relation is linked to the issue of the multiple and diverse as a result of a causal unity, which therefore presupposes a certain reformulation of the classical category of relation. This implies a reflection on the model of first unity as a source of a hierarchical order of beings that constitutes the vast web of relations that we call the world. In this context one has to show that processio indicates the relation between the first principle, which is a unity of simplicity, and the different realities that proceed from it. In this article, I will discuss a similar issue that we encounter in understanding creatio as processio, in Eriugena’s Periphyseon and in the metaphysical works of Dominicus Gundisalvus (De unitate et uno and De processione mundi).