Johannes Scotus Eriugena (c. 815–877) (also Johannes Scotus Erigena, Johannes Scottus Eriugena, John the Irishman), was an Irish theologian, Neoplatonist philosopher, and poet. He is known for having translated and made commentaries upon the work of Pseudo-Dionysius.

"Eriugena" is perhaps the most suitable surname form as he himself uses it in one manuscript. 'Scottus' in the Middle Ages was the Latin term for "Irish or Gaelic". The spelling 'Scottus' has the authority of the early manuscripts until perhaps the 11th century. Occasionally he is also named 'Scottigena' ("Irishborn" or "Gaelic") in the manuscripts.

Eriugena was highly proficient in Greek, which was rare at that time in mainland Europe, and was thus well-placed for translation work. Although he was born in Ireland, he later moved to France (about 845) and took over the Palatine Academy at the invitation of King Charles the Bald. He succeeded Alcuin of York (735 - 804) as head of the Palace School. The reputation of this school seems to have increased greatly under Eriugena's leadership, and the philosopher himself was treated with indulgence by the king. Whereas Alcuin was a schoolmaster rather than a philosopher, Eriugena was a noted Greek scholar. He was one of the most original thinkers of the entire Middle Ages.

William of Malmesbury's amusing story illustrates both the character of Eriugena and the position he occupied at the French court. The king having asked, Quid distat inter sottum et Scottum? (What separates a sot (drunkard) from a Scot?) Eriugena replied, Mensa tantum (Only a table).

He remained in France for at least thirty years. At the request of the Byzantine emperor Michael III (ca. 858), Eriugena undertook some translation into Latin of the works of Pseudo-Dionysius and added his own commentary. He was thus the first to introduce the ideas of Neoplatonism from the Greek into the Western European intellectual tradition, where they were to have a strong influence on Christian theology.

The latter part of his life lies in total obscurity. The story that in 882 he was invited to Oxford by Alfred the Great, that he labored there for many years, became abbot at Malmesbury, and was stabbed to death by his pupils with their styli, is apparently without any satisfactory foundation, and doubtless refers to some other Johannes. Eriugena probably never left France, and Haurau has advanced some reasons for fixing the date of his death about 877. From the evidence available it is impossible to determine whether he was a cleric or a layman, although it is difficult to deny that the general conditions of the time make it more than probable that he was a cleric and perhaps a monk.

His work is largely based upon Saint Augustine, Pseudo-Dionysius, Maximus the Confessor, and the Cappadocian Fathers, and is clearly Neoplatonist. He revived the transcendentalist standpoint of Neoplatonism with its "graded hierarchy" approach. By going back to Plato, he revived the nominalist-realist debate.

The first of the works known to have been written by Eriugena during this period was a treatise on the Eucharist, which has not come down to us. In it he seems to have advanced the doctrine that the Eucharist was merely symbolical or commemorative, an opinion for which Berengar of Tours was at a later date censured and condemned. As a part of his penance, Berengarius is said to have been compelled to burn publicly Eriugena's treatise. So far as we can learn, however, Eriugena's orthodoxy was not at the time suspected, and a few years later he was selected by Hincmar, archbishop of Reims, to defend the doctrine of liberty of will against the extreme predestinarianism of the monk Gottschalk (Gotteschalchus). The treatise De divina praedestinatione, composed on this occasion, has been preserved, and from its general tenor one cannot be surprised that the author's orthodoxy was at once and vehemently suspected. The Church was threatened by Gottschalk's position because it denies the inherent value of good works.

Eriugena argues the question entirely on speculative grounds, and starts with the bold affirmation that philosophy and religion are fundamentally one and the same. Even more significant is his handling of authority and reason. Eriugena offered a skilled proof that there can be predestination only to the good, in that all men are summoned to be saints. The work was warmly assailed by Drepanius Florus, canon of Lyons, and Prudentius, and was condemned by two councils: that of Valence in 855, and that of Langres in 859. By the former council his arguments were described as Pultes Scotorum ("Irish porridge") and commentum diaboli ("an invention of the devil").

Eriugena was a Christian universalist; he 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. To Eriugena, hell was not a place but a condition and punishment was purifying, not penal. He was a believer in apocatastasis, which maintains that all moral creatures--angels, humans and devils--will eventually come to a harmony in God's kingdom. He based his beliefs on the Greek writings of the early Christian fathers, like Origen, and considered himself an orthodox Christian thinker.

Eriugena's next work was a Latin translation of Dionysius the Areopagite undertaken at the request of Charles the Bald. This also has been preserved, and fragments of a commentary by Eriugena on Dionysius have been discovered in manuscript. A translation of the Areopagite's pantheistical writings was not likely to alter the opinion already formed as to Eriugena's orthodoxy. Pope Nicholas I was offended that the work had not been submitted for approval before being given to the world, and ordered Charles to send Eriugena to Rome, or at least to dismiss him from his court. There is no evidence, however, that this order was attended to.

Eriugena's great work, De divisione naturae (Periphyseon), which was condemned by a council at Sens by Honorius III (1225), who described it as "swarming with worms of heretical perversity," and by Gregory XIII in 1585, is arranged in five books. The form of exposition is that of dialogue; the method of reasoning is the syllogism. Natura is the name for the universal, the totality of all things, containing in itself being and non-being. It is the unity of which all special phenomena are manifestations. But of this nature there are four distinct classes (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 neither is 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 being the world of Platonic ideas or forms, and the third being a more pantheistic or pandeistic 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.

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 anticipates Thomas 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.

Eriugena's work is distinguished by the freedom of his speculation, and the boldness with which he works out his logical or dialectical system of the universe. He marks, indeed, a stage of transition from the older Platonizing philosophy to the later scholasticism. For him philosophy is not in the service of theology. The above-quoted assertion as to the substantial identity between philosophy and religion is repeated almost word for word by many of the later scholastic writers, but its significance depends upon the selection of one or other term of the identity as fundamental or primary. For Eriugena, philosophy or reason is first, primitive; authority or religion is secondary, derived.

His influence was greater with mystics than with logicians, but he was responsible for a revival of philosophical thought which had remained dormant in western Europe after the death of Boethius.

After Eriugena the next medieval thinker of significance was Berengar of Tours, professor at the monastic school in the French city. Berengar believed that truth is obtained through reason rather than revelation. St. Peter Damian agreed with Tertullian that it is not necessary for men to think because God has spoken for them. Damian was prior of Fonte Avellana and afterward Cardinal-Bishop of Ostia. He died in 1072. Lanfranc (1005 - 1089) was prior of Bec in Normandy. Like Damian he believed mostly in faith, but admitted the importance of reason. St. Anselm was a pupil and successor of St. Peter Damian.

Eriugena's work became known in the 1680s:

* Hiberno-Scottish mission * Christian mystics

* Stanford Encyclopedia of Philosophy entry *John Scottus Eriugena Criticism of Categories (Periphyseon Book I) *Annotated bibliography on Eriugena's philosophical work *