philosophy and religion are fundamentally one and the same
Eriugena believed that all people and all beings, including animals, reflect attributes of God, towards whom all are capable of progressing and to which all things ultimately must return
At the request of the Byzantineemperor Michael III (ca. 858), Eriugena undertook some translation into Latin of the works of Pseudo-Dionysius and added his own commentary
Eriugena's great work, De divisione naturae (Περί φύσεων), which was condemned by a council at Sens byHonorius III (1225), who described it as "swarming with worms of hereticalperversity,"
Nature (Natura in Latin or physis in Greek) is the name of the most comprehensive of all unities, that which contains within itself the most primary division of all things, that which is (being) and that which is not (nonbeing). The Latin title refers to these four divisions of nature: (1) that which creates and is not created; (2) that which is created and creates; (3) that which is created and does not create; (4) that which is neither created nor creates. The first is God as the ground or origin of all things, the last is God as the final end or goal of all things, that into which the world of created things ultimately returns. The second and third together compose the created universe, which is the manifestation of God, God in process,Theophania; the second is the world of Platonic ideas or forms, and the third is a more pantheistic world, depending on the interference of God. Thus we distinguish in the divine system beginning, middle and end; but these three are in essence one; the difference is only the consequence of our finite comprehension. We are compelled to envisage this eternal process under the form of time, to apply temporal distinctions to that which is extra- or supra-temporal. It is in turn through our experience that the incomprehensible divine is able to frame an understanding of itself.
The Division of Nature has been called the final achievement of ancient philosophy, a work which "synthesizes the philosophical accomplishments of fifteen centuries." It is presented, like Alcuin's book, as a dialogue between Master and Pupil. Eriugena anticipatesThomas Aquinas, who said that one cannot know and believe a thing at the same time. Eriugena explains that reason is necessary to understand and interpret revelation. "Authority is the source of knowledge, but the reason of mankind is the norm by which all authority is judged
For Eriugena, philosophy or reason is first, primitive; authority or religion is secondary, derived.
His influence was greater with mysticsthan with logicians, but he was responsible for a revival of philosophical thought which had remained largely dormant in western Europe after the death of Boethius.
Leszek Kołakowski, a Polish Marx scholar, has mentioned Eriugena as one of the primary influences on Hegel's, and therefore Marx's, dialectical form. In particular, he calledDe Divisione Naturae a prototype of Hegel's Phenomenology of Spirit.[9]