John Scotus Eriugena (c. 800-877) - the greatest philosopher of the early medieval West and arguably of any medieval Christian thinker before Aquinas - wrote the Periphyseon (known in Latin as De Divisione Naturae, 'On the Division of Nature') between roughly 862 and 866 CE at the Carolingian court. It is the most ambitious philosophical system produced between Augustine and Aquinas: a comprehensive account of all reality grounded in a Neoplatonic interpretation of the biblical creation narrative that anticipates later idealist philosophy and pantheistic mysticism.
The Thinker and His World
Eriugena ('from Ireland') came to the court of Charles the Bald in France around 845 CE, bringing with him not only the Latin learning of the Irish monastic tradition but, unusually, the ability to read Greek. He translated the works of Pseudo-Dionysius the Areopagite, Maximus the Confessor, and Gregory of Nyssa into Latin - introducing the riches of Greek patristic theology to a West that could not read them in the original. His translation of Pseudo-Dionysius was particularly consequential: it made available to the Latin West the most sophisticated account of divine transcendence and mystical theology in the early Christian tradition.
Eriugena's independence of mind was remarkable and occasionally dangerous. Twice condemned - once for his views on predestination, once for the Periphyseon itself (condemned in 1210 and 1225 by papal councils) - he nevertheless continued to be read, cited, and influential throughout the medieval period. Meister Eckhart's German mysticism, the Rhineland speculative tradition, and eventually Hegel's absolute idealism all show traces of Eriugenian influence.
Biblical Texts Engaged
Genesis 1:1 - 'In the beginning, God created the heavens and the earth' - is the foundational text for Eriugena's entire metaphysical system. But Eriugena reads it through a Neoplatonic lens: the 'beginning' is not a temporal starting point but the eternal Logos or Word in which God expresses himself and creates the primordial causes of all things. Creation is not a discrete event in time but an eternal process of divine self-expression (exitus) and return (reditus) - the going forth of all things from the divine One and their ultimate return to it.
John 1:1 - 'In the beginning was the Word, and the Word was with God, and the Word was God' - provides the Trinitarian framework for this cosmology. The Logos (Word) in whom 'all things were made' (John 1:3) is the second person of the Trinity and simultaneously the primordial cause of all created reality: the realm of divine ideas in which the essences of all things exist eternally before they are expressed in the created world. Eriugena's Christian Neoplatonism reads John 1 and Genesis 1 as complementary accounts of the same reality: the eternal self-expression of God that is the foundation and goal of all created existence.
Romans 11:36 - 'For from him and through him and to him are all things. To him be glory forever. Amen' - provides the Pauline formula for Eriugena's circular ontology: all things come from God (exitus), are sustained by God, and return to God (reditus). This circulation is not merely a metaphor for religious piety but a metaphysical structure: reality itself is constituted by the movement from divine unity through differentiation to restored unity.
Core Argument
The Periphyseon divides 'Nature' (all reality) into four categories. First, Nature that creates and is not created: God as the source of all things, who transcends all categories and can only be spoken of negatively (apophatic theology). Second, Nature that is created and creates: the primordial causes, the divine ideas in the Logos in which all created things pre-exist eternally. Third, Nature that is created and does not create: the temporal, spatial world of individual created things as we experience them. Fourth, Nature that neither creates nor is created: God as the goal of all things, to whom all things return.
This four-fold division structures a comprehensive account of reality as the self-expression of God. God, as pure Being that transcends all categories, cannot properly be said to 'create' anything separate from himself; creation is rather the divine self-expression, the externalization of the divine nature in multiplicity and particularity. The return of all things to God - the apocatastasis - will be the restoration of all created nature to its source, not the destruction of individuality but its transformation and elevation.
Eriugena's most controversial claim is that God does not know himself except through his creation: the divine self-knowledge is the knowledge of God through his creatures, in whom he expresses himself. This comes perilously close to pantheism - the identification of God and the world - though Eriugena insists on the distinction: God exceeds the world even as he is expressed in it. The boundary between theism and pantheism is thin here, which explains the later condemnations.
Intellectual Context
Eriugena's primary sources were Pseudo-Dionysius (whose negative theology provided the framework for his account of divine transcendence), Maximus the Confessor (whose cosmic theology of exitus and reditus provided the circular structure of the Periphyseon), Gregory of Nyssa (whose account of the soul's infinite progress toward an inexhaustible God influenced Eriugena's eschatology), and Augustine (whose Neoplatonic theology of divine illumination and the eternal ideas underlay the entire system).
Reception and Critique
Eriugena's influence, though underground, was persistent. Meister Eckhart's speculative mysticism - his account of the soul's 'birth of God' in the ground of the soul - draws on Eriugenian themes. The Rhineland mystical tradition, the fifteenth-century Neoplatonism of Cusanus (who owned a manuscript of the Periphyseon), and eventually Hegel's Phenomenology of Spirit (which follows the same circular structure of Absolute Spirit's self-expression and return) can all be read as developments of the Eriugenian vision.
Legacy
Eriugena established speculative Christian philosophy as a legitimate genre - the attempt to think through the deepest implications of biblical theology with the full resources of philosophical reason. His conviction that negative theology (knowing what God is not) is the most adequate theological method anticipated Maimonides, Aquinas, and the entire apophatic tradition.
Key Passages
'We must not understand God and the creature as two things distant from one another, but as one and the same thing.' (Periphyseon III.17 - a statement that generated the pantheism charges)
'Every visible and invisible creature is a theophany, that is, an appearance of God.' (Periphyseon I.10)
Contemporary Relevance
Eriugena's vision of creation as divine self-expression - of the natural world as the eternal Word made visible in time and space - has found unexpected resonance in contemporary theology's engagement with ecology and the natural sciences. If every creature is a theophany, then the destruction of species and ecosystems is not merely environmental harm but a theological impoverishment: the extinction of modes of divine self-disclosure that can never be recovered.