Periphyseon (The Division of Nature)

A long dialogue in five books between a teacher and a student, written in the 860s by an Irish scholar at the court of Charles the Bald. Eriugena, who had translated Pseudo-Dionysius from Greek, builds a single system from Greek and Latin Christian sources. Book I defines nature as everything that is and is not, and divides it four ways: what creates and is not created (God as source), what is created and creates (the primordial causes, or divine ideas), what is created and does not create (the world in space and time), and what neither creates nor is created (God as the end to which all returns). It argues that none of Aristotle's ten categories applies properly to God, who so exceeds all things that he can even be called 'nothing'. Books II–IV treat the primordial causes, creation and human nature, read through the opening of Genesis. Book V describes the return of all things into God. The work was condemned in 1225.

It is the most ambitious philosophical system written in Latin between Augustine and the thirteenth century, and a striking attempt to think of God, nature and humanity as one movement of going out and return.