Proclus

Not to be confused with Procles.

This article is about Proclus Diadochus, the Neoplatonist philosopher. For other people named Proclus, see Proclus (disambiguation).

Proclus Lycius
The beginning of Proclus' Fundamentals of Physics in the manuscript London, British Library, Harley 5685, fol. 133r (12th century)
Born	8 February 412 Constantinople, Thracia, Eastern Roman Empire (now Istanbul, Turkey)
Died	17 April 485(485-04-17) (aged 73) Athens, Achaea, Eastern Roman Empire (now Athens, Greece)
Other names	"The Successor"
Era	Ancient philosophy
Region	Western philosophy
School	Neoplatonism
Main interests	Metaphysics
Notable ideas	Platonic theology
Influences Plotinus Iamblichus Aristotle Plato Plutarch Syrianus
Influenced Damascius Pseudo-Dionysius Ammonius Hermiae Al-Kindi Marinus Marsilio Ficino St. Thomas Aquinas Nicholas of Cusa

Proclus Lycius (/ˈprɒkləs laɪˈsiəs/) (410/411/ 7 Feb. or 8 Feb. 412 –17 April 485 AD), also called Proclus the Successor, Proclus the Platonic Successor, or Proclus of Athens (Greek: Προκλος Διαδοχος Próklos Diádochos, or διάδοχος Πλατωνικός), is one of the most influential philosophical commentators of antiquity and is regarded by some scholars as the greatest Neoplatonic philosopher of the 5th century AD. The title of Successor (Greek: διάδοχος) was given to the head of the School of Plato in Athens and signified that Proclus was the successor of his predecessor and also the latest successor of continuous Platonic scholarship going back to Plato, the founder of the School of Plato in Athens.

Proclus was a prolific writer of ancient Greek philosophy leaving behind extensive commentaries on Plato, Aristotle, Porphyry and Plotinus, books and treaties on Neoplatonic theology, epigrams and hymns. He set forth one of the most authentic and systematic expositions of Neoplatonism and his works represent the most complete statement of Platonism we possess. Proclus stands at the end of ancient Greek philosophy and at the beginning of Middle Ages philosophy and is hence historically significant as he is a major connection between those two ages of philosophy.

Biography

The Byzantine Empire c. 476 AD showing the major cities in which Proclus lived, Constantinople, Alexandria and Athens.

Proclus was born in Constantinople, formerly Byzantium, now Istanbul, Turkey, to a wealthy Lycian family. The name his family gave him was probably Proklos, a Greek form of the Latin Proculus, which reveals that he was born procul a patria, or "far from home". There is confusion about the exact date of his birth, but the one given as February 8, 412 AD was educed from a horoscope cast by his biographer Marinus of Neapolis.

Constantinople and Alexandria

Soon after his birth, his mother Marcella and his father Patricus, a lawyer in the Byzantium courts, moved from Constantinople, where Patricus was working, back to their home district Lycia. Proclus received his early education in Xanthus, (now Kinik, Turkey) a city in Lycia, where he also studied rhetoric and law.

Between c. 427–428 AD, when he was 15 or 16 years old, his parents sent him from Lycia to Alexandria to study rhetoric, Roman law, mathematics and philosophy with the intent of pursuing a judicial position like his father. In Alexandria his teachers were the sophist Leonas of Isauria and the grammarian Orion of Thebes. Proclus was introduced by Leonas to distinguished members of Alexandrian society, including Alexandria's 'Governor', Theodorus. After a few years in Alexandria he accompanied his rector and principal instructor Leonas to Constantinople because he wanted to continue his guidance from him.

In Constantinople there were professors and students who had studied philosophy in Athens, in particular the Athenian Neoplatonists Empress Eusocial and her father Leontius. Whilst in Constantinople, and possibly due to the influence of professors and students there, Proclus turned his attentions to the study of philosophy and returned to Alexandria.

In Alexandria, he began determinedly studying the works of Aristotle under the guidance of the 5th century Neoplatonic philosopher Olympiodorus the Elder and, dropping rhetoric, studying mathematics under the guidance of the 5th century Alexandrian mathematician Heron (or Hero). Proclus was a brilliant student with a remarkable memory that helped him to quickly comprehend the logical works of Aristotle. Olympiodorus the Elder was sufficiently enough impressed by Proclus to offer him his daughter in marriage. However, like Plotinus, and other philosophers in the Roman Empire prior to him, Proclus travelled extensively to try and find the right teacher, and that might have led him to depart Alexandria.

Athens

In c. 430 or 431 AD, before he was 19 or 20 years old, he sailed from Alexandria to Athens where, in a parable recounted by Proclus' biographer Marinus of Neapolis, upon his arrival to Athens, and after being received at the Piraeus (a port city within Athens) by fellow-countryman Nicolaus of Myra and escorted into the city, he was met by the gatekeeper ready to close the city for the night, who said: "Certainly unless you had come, I should have closed the gates."

Plutarch of Athens and Syrianus

In Athens he lived with the late 4th to early 5th century Greek Neoplatonic philosopher Plutarch of Athens, who had officially retired and was in the last years of his life. Plutarch of Athens instructed Proclus on Aristotle's De Anima and Plato's Phaedo. After Plutarch's death in 432 AD, Proclus was under the guidance of the 5th century Greek Neoplatonic philosopher Syrianus, the head of the School of Plato in Athens. Two students studying alongside Proclus and also under the guidance of Syrianus were Hermias and Domninus of Larissa. Proclus is also said to have been taught, and initiated into, Chaldaean wisdom by the 5th century Greek philosopher Asclepigenia, wife of Theagenes, and the daughter of Archiades and Plutarch of Athens.

Proclus lived in Syrianus' house and was under his guidance for five years, two of which he spent studying the complete works of Aristotle and afterwards, the works of Plato. He also studied Syrianus' commentary on Orphic theogony, the works of Porphyry and works by Iamblichus on the Chaldean Oracles. Later in his life he was to spend five years writing a commentary on the Chaldean Oracles.

Whilst in Syrianus' house, Proclus was arranged to marry Aedesia, a relative of Syrianus, an arrangement that Proclus declined. Aedesia later married Hermias with whom she had two children, Ammonius Hermiae and Heliodorus of Alexandria; both children eventually became students of Proclus. It is likely that the house of the head of the School of Plato in Athens was bequeathed, so that the house of Plutarch of Athens became the house of Syrianus and then the house of Proclus and it was also a school where the head of the school held discussions and taught. The school operated financially much like a private school with revenue from a substantial bequest that paid teachers and was supplemented by student payments.

Head of School of Plato

After Syrianus' death, c. 437 AD, Proclus, at about the age of 25, became the head of the School of Plato in Athens, where amongst his students were:

1st century BC mosaic of the School of Plato in Athens. Proclus was head of the school from c. 437–485 AD

• Agapius of Athens,; who later set up his own school of philosophy in Constantinople where he taught John Lydus;
• Archiadas, grandson of Plutarch of Athens;
• Ammoniums Hermias, who in c. 470 AD became head of the Neoplatonic school in Alexandria;
• Anthemius, later to become a Western Roman Emperor;
• Asclepiodotus of Alexandria, who was one of Proclus' best students and later left Athens to become a senator in Aphrodisias;
• Hegias, son of Theagenes;
• Heliodorus of Alexandria, brother of Ammoniums Hermias, and who went on to become a philosopher in Alexandria;
• Isidore of Alexandria, who was the head of the neoplatonic school in Athens after Marinus of Neapolis;
• Marinus of Neapolis, who succeeded Proclus as the head of the neoplatonic school in Athens, and was his biographer;
• Nicolaus the Rhetor;
• Pericles;
• Severianus of Damascus, later to become Anthemius' chief minister in Rome;
• and Zenodotus.

Scholars of the 19th, 20th and 21st century also say that Pseudo-Dionysius the Areopagite was probably a student of Proclus or a student of the late Neoplatonic school of Athens or a hearer of Proclus' lectures. During his directorship of the school, the Proclean curriculum included Orphic Theogony, Homer, Hesiod, Chaldaean Oracles, Plato, Aristotle, Euclid and Plotinus. Proclus, like Porphyry, had an extensive literary education and was deeply committed to language, style, and literary matters which might explain why allegorical reading is so strongly yoked to Neoplatonism.

"It is manifest however, that the elements are every where bound to each other by analogy. For analogy, as we have said, imitates divine union, and is a demiurgic bond."—Proclus, Commentary on Timaeus II.51.3–5

A 42 ft. replica of Athena Parthenos in the Nashville Parthenon, Centennial Park, Tennessee, USA. Proclus was a devotee of the goddess Athena and was in Athens when the original statue was removed from the Parthenon possibly between 450–470 AD.

Marinus of Neapolis, a mathematician, student of Proclus and Proclus' eventual biographer or hagiographer, says Proclus lived in Athens as a predominantly vegetarian scholar, prosperous and generous to his friends and that Proclus had a great devotion to the goddess Athena, and believed the goddess guided him at key moments in his life. A particularly striking incident of that devotion was after Roman authorities removed a colossal statue of the goddess Athena from the Acropolis, near where Proclus lived. Soon after, Proclus recounted a dream he had to Marinus, in which the goddess Athena told him to quickly build a temple in his house dedicated to her.

There is confusion between scholars about which particular statue of Athena, Marinus says was removed in his 5th century biography of Proclus (Greek title: ΠΡΟΚΛΟΣ η περι ευδαιμονιας). Scholarly publications in the 19th, 20th and 21st century plus one late 18th century English translation of Marinus' biography of Proclus, say that the statue of Athena inside the Parthenon, 26 cubits high and made of ivory and 40 to 50 talents of gold; called the Athena Parthenos, is the statue that Marinus says was removed. However, some 21st century scholars say that it was the bronze statue of Athena outside the Parthenon, which was about 50 ft. to 70 ft. high including the pedestal, called the Athena Promachos, that Marinus, in his biography of Proclus, says was removed. 20th and 21st century scholarly publications date Marinus' account of the removal of a statue of Athena between 450–470 AD.

Marinus reports Proclus was a prominent member of Athenian society, remained unmarried, despite numerous noble and wealthy alliances offered to him, and that he had no children. He also says Proclus took the liveliest interest in the welfare of his friends, their wives and their children; promoted and increased literary studies, and at times took part in politics despite the inimical Christian atmosphere. On occasion he also gave advice to magistrates, composed letters for noblemen, took part in public education and was under the protection of a distinguished member of Athenian society called Rufinus. Marinus also reports Proclus usually gave five lectures a day, held informal evening conversations, spent nights writing hymns, employed himself in Orphic and Chaldaic devotions, and that in his prime, Proclus was writing, or dictating to a scribe, 700 lines a day.

Sabbatical

During his entire time in Athens, Proclus left only once, and that was to Lydia for a year-long sabbatical designed to lessen the pressure put on him by his political, religious and philosophical activity. During his sabbatical, he spent time traveling and being initiated into various local Greco-Roman mysteries and put to good use the knowledge he gained in Lydia later in his career. Scholars are unsure about when Proclus went on his year-long sabbatical, but they suppose it was when he was an established scholar, possibly when he was about 40 years-old in c. 450 AD. Whilst in Lydia, Proclus met the philosopher Pericles of Lydia, whom he addressed in his work Outline of Astronomical Hypotheses, and may be the same Pericles cited in his works Commentary on Parmenides and Platonic Theology.

Succession

Proclus was head of the School of Plato in Athens for nearly fifty years until his death in 485 AD. He died in Athens at about the age of 73 and was buried near Mount Lycabettus in the same tomb as Syrianus. His inheritance was given to Athens and to his native city of Xanthus. He was succeeded by Marinus of Neapolis, and then by Isidore of Alexandria, a young and much admired former student of Proclus, chosen by Marinus of Neapolis, and a pallbearer at Proclus' funeral.

House of Proclus and Epitaph

The covered ruins of the House of Proclus on Dionysiou Areopagitou Street with the walls marked.

The ruins of Proclus' house in Athens were first discovered in 1879, but it was not until 1955 that the excavator Giannis Meliades claimed the site to be the 'House of Proclus', a claim also supported by the publications of American Byzantine scholar Alison Frantz in 1975 and 1988, Finnish Professor Arja Karivieri in 1994 and Finnish Professor Paavo Castrén in 1994. The excavations are well documented and the archaeological finds from the House of Proclus are on display at the Acropolis Museum in Athens. The ruins are now covered, but the walls are clearly marked on Dionysiou Areopagitou Street where the street meets the steps coming down from the south of the Acropolis, opposite the Theatre of Dionysus.

The following translated epitaph, composed by Proclus, is engraved in Greek on the single tomb of both Proclus and Syrianus:

Mount Lycabettus, a limestone hill in Athens near where Proclus and his teacher Syrianus were buried.

"I Proclus, here the debt of nature paid,

(My country Lycia) in the dust am laid;

Great Syrianus form'd my early youth,

And left me his successor in the truth.

One common tomb, our earthly part contains,

One place our kindred souls, —th' aetherial plains."

Influence

Proclus was greatly received in the centuries after his death. He was a very influential 5th century Neoplatonic philosopher and left a vast philosophical legacy to Western philosophy, Christianity, Byzantine philosophy and Islamic philosophy and theology. In the Middle Ages, for about 900 years from the 6th to the 15th centuries, Proclus's Neoplatonic doctrines, through the various Arabic and Latin translations of his Elements of Theology, treaties and commentaries on Plato's Timaeus and Parmenides, were very influential and disseminated and studied more than the Platonic doctrines of Plato and the Neoplatonism of Plotinus.

5th century

Proclus' immediate reception in the late 5th century was by way of the Greek Neoplatonist Ammonius Hermiae's commentary on Aristotle's De Interpretatione. That Greek commentary included a lot of Proclus' doctrines taken from notes Ammonius Hermiae (a student of Proclus) made when he was reading the text with Proclus. It was shown, in a 1987 work by English Professor Anne Sheppard, how closely Ammonius' work followed Proclus' commentary on Plato's Cratylus. Ammonius recognizes his debt to Proclus in the beginning of his commentary.

Middle Ages Greek reception

6th century

Damascius

There was a notably quick reaction to Proclus' work in the 6th century by a mostly favourable response from the Neoplatonist Damascius. The structure of Damascius' philosophy was so close to Proclus', that it would have been inconceivable without Proclus' influence; however, he held fundamental differences to Proclus on key doctrines, criticized Proclus' doctrines frequently, and developed his own innovative doctrines of Neoplatonism. The transmission of Proclus' Neoplatonic doctrines by Damascius' works is mainly relevant after the Renaissance, since Damascius' works were largely forgotten throughout the Middle Ages.

John Philoponus

Early in the 6th century, 529, the Byzantine-Greek Christian theologian John Philoponus published a refutation of Proclus' treatise On the Eternity of the World, in his lengthy Greek work, now known by its Latin title, De Aeternitate Mundi Contra Proclum. That work is not only important philosophically, but it also preserves 17 of 18 arguments verbatim by Proclus from On the Eternity of the World, arguments that are not preserved as a group by any other extant manuscripts of Proclus. Philoponus' work, originally published in Greek, was translated into Latin at least three times. It is through the collections of Philoponus' work by: the 15th century Catholic cardinal Bessarion, the 15th century Catholic priest and scholar Marsilio Ficino, and the 15th century Italian Christian philosopher Pico della Mirandola, that Proclus' arguments from On the Eternity of the World became known. Philoponus' work De Aeternitate Mundi Contra Proclum was first translated into Latin in 1551 by Gaspare Marcello Montagnese.

Pseudo-Dionysius the Areopagite

A very important 6th century and later centuries transmission of Proclus' 'great cosmic system of divinity' was through Pseudo-Dionysius the Areopagite. Early in the 6th century Pseudo-Dionysius was weaving Proclus' Neoplatonic theology into Christian theology, and was probably the first Christian theologian to attempt merging Proclus' Neoplatonic doctrines into Christian doctrines. Pseudo-Dionysius was a Christian writer in whose works can be found a great number of Proclus' important Neoplatonic doctrines.

The extent that Pseudo-Dionysius' Christian doctrines in his Corpus Dionysiacum Areopagiticum depended on Proclus' Neoplatonic doctrines were independently revealed in the late 19th century by the German church historian and Jesuit J. Stiglmayr, in his work Dionysius Areopagita in der Lehre vom Uebel, and especially by the German Catholic theologian and church historian Hugo Koch in is detailed work Pseudo-Dionysius Areopagita.

It is through commentaries on Pseudo-Dionysius' works that Proclus was received in later centuries by: the 7th century Christian theologian Saint Maximus the Confessor, the 8th century Byzantine-Christian monk Saint John of Damascus, the 9th century Irish Catholic theologian John Scotus Eriugena, the 12th century Saxon theologian Hugh of St. Victor, the 13th century English theologian Robert Grosseteste, the 13th century German bishop Saint Albert the Great, the 13th century Italian philosopher and theologian Saint Thomas Aquinas, and others.

Boethius

Illustration from a 15th century manuscript of Consolation of Philosophy by Boethius. Consolation of Philosophy is an important source for the diffusion of Proclus' Neoplatonic doctrines.

Another important transmission of Proclus' Neoplatonic doctrines in the 6th century and throughout the Middle Ages was through the Roman Christian senator and philosopher Boethius in his 524–525 Latin work Consolation of Philosophy, which contains a number of Proclus' doctrines and motifs. In that work of Boethius, the poem in III.9 is an extraordinary 50 hexameter line summary of Plato's Timaeus and Proclus' Commentary on Timaeus. Consolation of Philosophy IV.6 and V.6 contain important aspects of Proclus' Neoplatonic doctrines on Providence, Fate and Eternity.

In particular, Boethius' doctrines of Providence and details of his cosmology in Consolation of Philosophy uses and sometimes takes directly from Proclus' Commentary on Timaeus and Proclus' treatises Tria Opuscula, and hence Consolation of Philosophy is an important transmission of Proclus' doctrines in later centuries. Boethius' Consolation of Philosophy was also translated from Latin to Greek and so becomes an important example of the mixing between Byzantine and Latin traditions that diffused Proclus' doctrines. Proclus' axiomatic treatment of theology in Elements of Theology also influenced Boethius' theological treatise Quomodo Substantiae. The close relationship between Proclus' Neoplatonic doctrines and Boethius' Consolation of Philosophy is demonstrated by the works of 20th and 21 century scholars, notably: by the German Classical Philologist Friedrich Klingner in 1921, by the German Professor Werner Beierwaltes in 1983, by the French Professor Jean-Luc Solère in 2003 and by the American Professor Stephan Gersh in 2012.

Others

Important doctrines of Proclus' Neoplatonism were transmitted through the 6th century by the Neoplatonist Simplicius of Cilicia, in a refutation of John Philoponus' criticisms of Proclus; by the Neoplatonist Olympiodorus the Younger, who used a triad developed by Proclus derived from Plato's Philebus 20d; and by the Neoplatonist Priscian of Lydia. Further, the 6th century Byzantine administrator and writer on antiquarian subjects John of Lydia, in his work De Mensibus, quoted a lengthy passage from an important treatise by Proclus.

Middle Ages Byzantine reception

7th and 8th century

In the 7th century, the Byzantine-Christian monk and theologian Saint Maximus the Confessor in his works Ambigua 7.3 and Ambiguum ad Thomam 5 echoes language and employs theological principles used by Proclus in Elements of Theology propositions 14, 98 and 143. Early in the eighth century, Proclus' Neoplatonic doctrines, merged into Christian doctrines through the writings of Pseudo-Dionysius the Areopagite, were quoted extensively by the Byzantine-Christian monk Saint John of Damascus.

9th and 10th century

There are references to Proclus in the 9th century work Bibliotheca by the Byzantine Patriarch of Constantinople Photius. In 10th century Byzantium, Proclus' philosophy was well known to non-specialists as is evidenced by a reference to him in the extant 10th century encyclopedia called the Suda.

11th century

11th century Byzantine philosophy received Proclus' Elements of Theology, treatises, and commentaries on the Timaeus and Chaldaean Oracles through extensive references made by the Byzantine-Greek philosopher, imperial courtier and historian Michael Psellos in his works Philosophica Minora and De Omnifaria Doctrina; and also by his student John Italus in his work Problems and Solutions. Psellos is regarded by some as the major transmitter of Proclus' philosophy in the 11th century, and though he read many Neoplatonic works, he preferred Proclus over other Neoplatonists and used Proclus' philosophy to build a legal case, in speeches at the imperial court of Constatine IX and to solve theological questions.

Statue of Ioane Petritsi who made an important extant Georgian translation of the work Elements of Theology by Proclus.

12th century

12th century Byzantine philosophy received Proclus' doctrines by way of his treatises and specifically his axiomatic work Elements of Theology, whose wide circulation in the century is demonstrated by an important extant Georgian translation, from a Greek manuscript, by the 11th–12th century Georgian Neoplatonist philosopher Ioane Petritsi, working in the Gelati monastery. Petritsi's translation allows scholars to reconstruct the transmission of Proclus' Elements of Theology from the 13th century, as that is the oldest version of his manuscript that is extant. Petritsi might have been a student of Michael Psellos or John Italus, and he also wrote an extant commentary on Proclus' Elements of Theology called Kommentar zur Elementatio theologica des Proklos, in which he attempts to show points of agreement between Proclus' doctrines on the One and Christian doctrines of the Trinity.

Also in the 12th century, Proclus' Elements of Theology was received into Byzantine philosophy and theology by way of the criticisms of Byzantine-Greek Christian theologian Nicholas of Methone. Further, conspicuous similarities in key theological concepts have been found by 21st century scholars between Proclus' Elements of Theology and the works of the 12th century Byzantine-Greek Christian bishop Eustratius of Nicaea.

13th century

In 13th century, 1248, Ioane Petritsi's 12th century Georgian translation of Elements of Theology was translated into Armenian by the monk Simeon of Garni (Svimeon Petrizis). The Arabic work Kalām fī maḥḍ al-ḫayr, which contained Proclus' Neoplatonic doctrines from his Elements of Theology, was also translated into an extant Armenian version by Simeon of Garni and also translated by anonymous translators into at least four Hebrew versions that are extant, and three commentaries on one of those Hebrew versions. Traces of Proclus' Commentary on Parmenides are also found in works of the 13th century Byzantine-Greek historian and philosopher George Pachymeres. Also in the 13th century there was a Greek manuscript discovered by William of Moerbeke, when he was the Latin archbishop of Corinth, that was later used in his 1280 Latin translation of Proclus' treatise On the Existence of Evil.

14th century

Early in 14th century Byzantium, Greek manuscripts of Proclus' treatise On the Existence of Evil were in circulation, which is evidenced by fragments from a extant 1311 florilegium into which parts of that treatise were copied. In the middle of the 14th century, references to Proclus' commentary on the Chaldean Oracles were in the writings of the Byzantine-Greek astronomer, historian and theologian Nicephorus Gregoras. Also in the 14th century, the Byzantine-Greek theologian Saint Gregory Palamas employed theological principles used by Proclus in Elements of Theology propositions 20 and 143 in his works Triads 1.3.8.10 and Contra Acyndinum 7.9.26. And in the same century, the Bishop of Gerace, Barlaam of Calabria, used Proclus at length in his dispute with Saint Gregory Palamas.

Middle Ages Islamic reception

9th to 12th century Arabic translations of parts or all of Proclus' Elements of Theology are generally referred to by scholars working in that field as Discourse on the Pure Good, but there is a 10th-century Arabic translation of parts or all of Proclus' Elements of Theology referred to by scholars as The Book of Chapters on Divine Subjects. Two of the three of those Arabic translations name the author as Buruqlus (i.e. 'Proclus').

8th and 9th century

In the 8th century, Proclus' Elements of Theology was known to the Islamic historian Muhammed ibn Ishaq. In the 9th century, the transmission of an Arabic translation of Proclus' Elements of Theology into 9th century Islamic theology is demonstrated by an extant 9th century manuscript. Importantly, in the 9th century, some of Proclus' Elements of Theology were translated from Greek to Arabic by Arabic translators (possibly by Ibn al-Bitṛīq) and Christian translators convened by the Islamic philosopher al-Kindī so as to be acceptable to Islamic philosophy and theology. Further, it is known that in the 9th century, Arabic physician and translator Isḥāq ibn Ḥunain translated into Arabic nine of the eighteen arguments in Proclus' treatise On the Eternity of the World.

10th century

In the 10th century, a second-generation student of Islamic philosopher al-Kindī named al-ʿĀmirī (d. c. 922) revised and incorporated Islamic doctrines of theology into an Arabic translation of part of Proclus' Elements of Theology titled Kitāb al-Fuṣūl fī l-Maʿālim al-Ilāhīya (The Book of Chapters on Divine Subjects). Also in the 10th century, Proclus' works Commentary on Republic Book 10, Commentary on Gorgias, Commentary on Phaedo and Commentary on Golden Verses are known to have been translated into Syriac. Further, in the 10th century, Persian physician al-Razi wrote the work Concerning Doubt, in connexion with (or against) Proclus, and there are references to Proclus in the 10th century Arabic encyclopedia Kitab al-Fihrist compiled by the Muslim bibliographer Ibn al-Nadim.

12th and 13th century

First page of a 15th century Latin translation of Liber de Causis from a manuscript in the library of the Catholic cardinal Bessarion. Liber de Causis is and important source of transmission of Proclus' work Elements of Theology.

In the 12th century, Ioane Petritsi's Georgian translation of Proclus' Elements of Theology was translated several times into Arabic and was modified to be acceptable to Islamic theology. One of those Arabic translations, called Kalām fī maḥḍ al-ḫayr (Discourse on the Pure Good), was subsequently translated into the important Latin work Liber de Causis (Book of Causes) by the 12th century Italian translator Gerard of Cremona.

The Latin work Liber de Causis is frequently misattributed to Aristotle, but was found to be essentially derived from Proclus' Elements of Theology in a commentary by Saint Thomas Aquinas. The Arabic work Kalām fī maḥḍ al-ḫayr (Discourse on the Pure Good), also known as the Arabic Liber de Causis, comprises 31 propositions that paraphrase and modify 30 or more propositions in Proclus' Elements of Theology.

Also in the 12th century, Proclus' treatise On the Eternity of the World was paraphrased by the Persian scholar Aḥmad Al-Šahrastānī in his work The Book of Religions and Sects (Kitāb al-milal wa l-niḥal) II.6. Further, 21st century scholars have found growing evidence that arguments from Proclus' treatise On the Eternity of the World can also be found in the 12th century Hispanic Jewish philosopher Maimonides in his work The Guide for the Perplexed II.14, II.18 and II.21. In the 13th century, a summary of an Arabic translation of part or all of Proclus' Elements of Theology was incorporated in a work on metaphysics by the Islamic philosopher ʿAbd al-Latị̄f al-Baghdādī.

Middle Ages Latin reception

9th century

In the 9th century, through the works of Pseudo-Dionysius the Areopagite, important Proclean Neoplatonic doctrines can be seen in the Latin translation of Hilduin who was the Bishop of Paris and chaplain to Louis I and one of the leading scholars and administrators of the Carolingian empire. Again, through Pseudo-Dionysius, important Neoplatonic doctrines originally written by Proclus can be seen in the 9th century work De Divisione Naturae by the Irish Catholic theologian and Neoplatonist philosopher John Scotus Eriugena. The work De Divisione Naturae by Eriugena described a detailed Neoplatonic world-system that also appears in the works of the 12th century French professor Simon of Tournai and the 12th century English translator Alfred of Sareshel and influenced the 13th century Italian philosopher and theologian Saint Thomas Aquinas and the 17th century French philosopher and mathematician Descartes.

12th century

By way of the writings of Pseudo-Dionysius the Areopagite, Neoplatonic doctrines originally written by Proclus are in the Latin translations of the 12th century scholar John Sarrazin, who is known only from his translation of the writings of Pseudo-Dionysius from Greek into Latin. In the 12th century and later centuries, Proclus' Elements of Theology was transmitted into Christian Europe by the Latin work Liber de Causis (Book of Causes, frequently misattributed to Aristotle) translated from Arabic by Gerard of Cremona between 1167 and 1187. 20th and 21st century scholars have shown that more than 30 propositions of Proclus' Neoplatonic doctrines in his Elements of Theology are in the Arabic version of Liber de Causis translated by Gerard of Cremona.

The first clear reference to Liber de Causis is in the work De Fide Catholica by the French Christian theologian and poet Alan of Lille, most likely written before April 1187. Between the late 12th century and early 13th century, manuscripts of Liber de Causis arrived in England were it was cited in the work De Motu Cordis by the 12th century English translator Alfred of Shareshill; cited in the work Speculum Speculationum by the 12th century English Christian theologian Alexander of Neckam; and was also included in the late 12th century to early 13th century manuscript Selden Supra 24, the oldest known manuscript containing the Aristotelian Corpus Vetustius and Liber de Causis. Further, 21st century scholarship has identified text from Liber de Causis in 18 manuscripts of the work De Articulis Fidei by the 12th century French Christian theologian Nicholas of Amiens.

13th century

The 12th century translation of the Arabic Kalām fī maḥḍ al-ḫayr (Discourse on the Pure Good) to the Latin Liber de Causis by Gerard of Cremona was frequently copied (about 237 times). The work Sapientiale composed by the 13th century English Franciscan theologian and philosopher Thomas of York between 1250 and 1260, contains more than 100 clear references to Liber de Causis that use more than 20 of the more than 30 propositions in the Liber de Causis derived from Proclus' Neoplatonic doctrines in his Elements of Theology. Thomas of York did not attribute Liber de Causis to Aristotle, as he believed it belonged to a Platonic tradition due to the hierarchy of intermediary causes between the divine mind and the material universe, a hierarchy rejected by Aristotle. Further, in 1255, a statute of the Faculty of Arts from the University of Paris prescribed the teaching of Liber de Causis and at the end of the 12th century and throughout the 13th century, Liber de Causis and Proclus' Elements of Theology were read and cited at Oxford and Cambridge Universities.

Late 13th century manuscript from northern Italy of part of a treatise by Proclus translated from Greek to Latin by William of Moerbeke. William's translations are an important dissemination of Proclus' Neoplatonic doctrines

A very important dissemination of Proclus' Neoplatonic doctrines in the latter parts of the 13th century, and later centuries, was through the Flemish Catholic bishop (also Latin archbishop of Corinth and translator) William of Moerbeke, who finished his precise literal translation from Greek manuscripts to Latin of Proclus' Elements of Theology (Elemntatio Theologica) in Viterbo on June 15, 1268. He also translated into Latin, Proclus' Commentary on Parmenides (1280s), Proclus' Commentary on Timaeus (1280s) and some of Proclus' treaties (February 1280).

It was through William of Moerbeke's precise Latin translation of Proclus' Elements of Theology that indirect and direct traditions of Proclus' Elements of Theology merged, as William's Latin translation from Greek manuscripts (a direct tradition) was used by Saint Thomas Aquinas to make his observations about Proclus' doctrines in Liber de Causis (an indirect tradition). Saint Thomas Aquinas, in his commentary on Liber de Causis, was the first to find that much of the content of Liber de Causis was from Proclus' Elements of Theology, thus leading to an important transmission of Proclus' doctrines into the 13th century and later centuries. Both William of Moerbeke and Saint Thomas Aquinas were working in Viterbo in 1268.

Proclus' doctrines in the Liber de Causis were also diffused in the 13th century through commentaries by the 13th century Belgian philosopher Siger of Brabant and the 13th century German Dominican friar Saint Albert the Great, who, in his commentaries, used at least six of the more than 30 Neoplatonic doctrines of Proclus in Liber de Causis. 21st century scholarship has discovered a presence of Liber de Causis and Proclus' Elements of Theology in Saint Albert the Great's commentary on the Sentences, his treatises De Incarnatione and De Resurrectione and sacramental Christian theological discussions about the order of sacraments.

Further, in the 13th century, German theologians and philosophers Heinrich Bate (friend of William of Moerbeke), Theodoric of Freiberg, and Meister Eckhart, in his Work of Propositions, continued the dissemination of Proclus' Neoplatonic theology through the Latin translations of the Liber de Causis, Elements of Theology and Commentary on Parmenides by Proclus. Parts of Bate's encyclopedic work Speculum Divinorum et Quorundam Naturalium harmonized Plato and Aristotle through Proclus and provided a simplified version of Proclus' late Athenian Neoplatonic theology and contains many references to Proclus' Elements of Theology.

14th century

Early in the 14th century, the Italian poet, writer and philosopher Dante Alighieri also integrated Proclus' Neoplatonic doctrines found in the Liber de Causis in several of his works, notably in the Convivio (III.6.11), written between 1304–1307, when describing Beatrice's physical beauty as caused by her soul, and in his works De Monarchia, Divine Comedy, and Epistle to Cangrande. In his work De Monarchia (I.11 and III), written between 1312–1313, Dante uses Proclus' Neoplatonic doctrines of Causes and Effects found in Liber de Causis proposition 1, to provide a metaphysical basis of a political order between princes and the people and as a basis for his defence of papal supremacy over government.

In 14th century Germany there was an enthusiastic engagement and integration of Proclus' Elements of Theology and his treaties into German mysticism in the Bavarian city of Regensburg (1327–1335) and then in the German city of Cologne (1335–1361) led by the German Dominican theologian and Neoplatonist Berthold of Moosburg in his enormous commentary on Proclus' Elements of Theology. Berthold's commentary Expositio Super Elementationem Theologicam Procli, written between 1327 and 1361, is a defence of Proclus in which he assumes Platonism is superior to Aristotelianism and that the rigorous dialectical form of Proclus' Elements of Theology is superior to the figurative language used by all other Platonists to explain Platonic doctrines. The sources Berthold used in his commentary are Plato, Aristotle, Corpus Hermeticum, Cicero, Seneca, Apuleius, Macrobius, Proclus, Avicenna, Al-Farabi, Al-Ghazali, Averroes, Maimonides and the Liber De Causis. Berthold's commentary was the first Middles Ages document to clearly cite Proclus' Elements of Physics and Tria Opuscula (three treatises).

Renaissance reception

15th century

During the 15th century, the Catholic cardinal Bessarion (student of Georgius Gemistus Pletho) had in his possession numerous manuscripts in Greek brought back from his time in Greece, and after becoming a cardinal in 1439, Bessarion made annotations and revisions to Greek manuscripts of Proclus' Elements of Theology and Commentary on Parmenides. Also in 1439, the Roman Catholic cardinal Nicolas of Cusa had in his possession Greek manuscripts of Proclus' Elements of Theology that he had brought back from Constantinople, and asked the Italian monk and theologian Ambrogio Traversari to translate them into Latin, a task completed by the Italian translator Pietro Balbi in 1462. During the middle of the 15th century, in 1450 and 1455, Nicolas of Cusa also authorized two copies of Proclus' Commentary on Parmenides, of which he held three of the six Greek manuscripts, and used the one he heavily annotated while writing his treatises. Also near the middle of the 15th century, the Dutch theologian Heymeric de Campo was influenced in his work Theoremata Totius Universi by Proclus' axiomatic treatment of theology in Elements of Theology.

The 15th century Italian Catholic priest and scholar Marsilio Ficino translated many of Proclus' works into Latin.

During the late 15th century, the Italian Catholic priest and scholar Marsilio Ficino was reading Greek manuscripts of Proclus' works and displays a detailed understanding of Proclus' Neoplatonic doctrines in his Latin translations of Proclus' Platonic Theology and On the Immortality of the Souls, written between 1469 and 1471. By the 1490s, Ficino had the following Greek manuscripts of Proclus' Neoplatonic doctrines available to him: Commentary on Timaeus, Commentary on Republic (a more than 400 leaf codex dated from the 9th or 10th century), Commentary on First Alcibiades, a commentary by Nicholas of Methone on Proclus' Elements of Theology, Proclus' Platonic Theology, and Elements of Physics, the last of which contain his notes. Ficino also translated Proclus' Hymns, Elements of Theology, selections from Commentary on Republic and Elements of Physics, the last is lost, however the other two were printed in Venice by Aldus Manutius in 1497. Ficino's Latin excerpts from Proclus' Commentary on First Alcibiades and treatise On Sacrifice and Magic were all that were available of these Proclean texts until the original Greek manuscripts were rediscovered in the 20th century. In 1492, Ficino also translated into Latin excerpts from Commentary on Republic by Proclus which were included in a collection of his letters in 1495.

Further, commentaries on the Liber de Causis and Proclus' Elements of Theology were composed by many Central European Universities from the 14th century to the 16th century. In the last year of the 15th century, Thomas Linacre's Latin translation of a spurious work by Proclus called The Sphere was printed, which became very popular and was frequently reprinted.

16th century

At the turn of the 16th century, around 1501, Italian academic, mathematician, philologist and translator Giorgio Valla translated Proclus' Commentary on the First Book of Euclid's Elements and Proclus' Outline of Astronomical Hypotheses into Latin and incorporated much of that text into his colossal encyclopedia Seek and Shun. Early in the 16th century in northern Italy, Proclus' Commentary on Timaeus was translated into Latin by an anonymous translator. Between 1520 and 1526, Proclus' Platonic Theology, Commentary on Republic, Commentary on First Alcibiades and Commentary on Parmenides were translated by the Italian Augustinian friar and Platonist Nicholas Scutelli.

A monument to the 16th century Prussian-Polish mathematician and astronomer Nicolaus Copernicus in Toruń, Poland. Copernicus used parts of Proclus' work Outline of Astronomical Hypotheses in his work On the Revolution of Celestial Spheres.

During the early 16th century, there is evidence that the Prussian-Polish mathematician and astronomer Nicholas Copernicus had read Proclus' Commentary on the First Book of Euclid's Elements and that parts of Proclus' Outline of Astronomical Hypotheses, from Valla's encyclopedia Seek and Shun, were used by Copernicus in his 1543 work On the Revolution of Celestial Spheres. Also, early 20th century scholars thought that the cosmology discussed in Proclus' writings were the source of fundamental doctrines in the works of 16th century Italian Dominican friar, philosopher and cosmological theorist Giordano Bruno.

From 1531 to 1540 the German Protestant theologian and scholar Simon Grynaeus edited a Greek manuscript of Proclus' Elements of Physics, and printed the first Latin editions of Proclus' Elements of Physics, Commentary on Republic, Commentary on Timaeus and Outline of Astronomical Hypotheses. Although written in 1505, it wasn't until 1539 that a new Latin translation of Proclus' Commentary on the First Book of Euclid's Elements was published by the Italian humanist and translator Bartolomeo Zamberti. In 1541, Giorgio Valla's Latin translation of Proclus' Outline of Astronomical Hypotheses was published in Ptolemy's Opera. In the middle of the 16th century, 1551, Copernicus' student, the Rhaetian mathematician, astronomer and teacher Georg Joachim Rheticus in his work Canon of the Science of Triangles, concludes that Proclus' Outline of Astronomical Hypotheses be introduced into schools because of its sound theory of celestial motions.

In 1560, the Italian mathematician, astronomer and humanist Francesco Barozzi published a Latin translation of Proclus' Commentary on First Book of Euclid's Elements. Important parts of the prologue of Proclus' Commentary on the First Book of Euclid's Elements were translated by the Swiss professor of mathematics Konrad Dasypodius and printed in his work Mathematicum Volumen II. from 1570. In 1583, Proclus' Elements of Theology and Elements of Physics was translated into Latin by the Italian Platonist philosopher and scientist Franciscus Patricius (Italian: Francesco Patrizi). Patricius' work Nova de Universis Philosophia is based on Proclus' Elements of Theology. From 1548 to the early 17th century, the prologue of Proclus' Commentary on the First Book of Euclid's Elements stimulated a large debate amongst scholars on the classification of mathematical sciences. Those that contributed to the debate were: the Italian philosopher Alessandro Piccolomini, the French logician Pierre de la Ramée, the Swiss professor of mathematics Konrad Dasypodius, the Spanish philosopher Benito Pereira, the Belgian mathematician Adrian van Roomen and the German Calvinist minister Johann Heinrich Alsted, all of whom relied on Proclus' Commentary on the First Book of Euclid's Elements.

Modern reception

17th century

At the turn of the 17th century, 1596–1609, Proclus' influence is seen in the Latin work Harmonice Mundi of the German astronomer and mathematician Johannes Kepler, who quotes at length, in Harmonice Mundi 218.33–221.39, from Proclus' Commentary on First Book of Euclid's Elements 12.2–18.4. Early in the 17th century, in 1618, the first printed Latin editions of Proclus' Platonic Theology and Elements of Theology were published, they were prepared earlier in the century by the Italian philologist and university professor Aemilius Portus. After Portus' first printed editions of Proclus, there were no first editions of Proclus' works published until the early 19th century, some 200 years later. Also, in 1651, a commentary in Armenian of Proclus' Elements of Theology was written by the Armenian bishop Simeon of Djulfa (Svimeon Dshughaezi).

Late in the 17th century, the Georgian writer and diplomat Sulchan-Saba Orbeliani added propositions and references from Proclus into his Georgian Dictionary that was both an encyclopaedia and dictionary. Further, 20th and 21st century scholars think there is a close relationship or similarities between Proclus and 17th century Dutch philosopher Baruch Spinoza, through the mediating role of 17th century religious philosopher Abraham Cohen Herrera and other indirect sources, specifically with regards to Spinoza's idea of geometric method and Proclus' understanding of Platonic dialectic.

18th century

In the 18th century, a commentary of Proclus' Elements of Theology by the Armenian bishop Svimeon Dshughaezi was translated from Armenian into Georgian at least twice, one of these translations was in 1757. Also in the 18th century, the Catholicos–Patriarch of the Georgian Orthodox Church Anton I of Georgia, in his work Spekali, cited and commentated on the 12th century Georgian translation of Proclus' Elements of Theology by Ioane Petritsi.

In his Elements of Theology, propositions 28 and 29, Proclus introduces a metaphysical law of Continuity that seems very probable to scholars to historically descend into the doctrine on Continuity of Leibniz in his early 18th century essay la nature ne fait jamais des sauts. It was thought by at least one leading Neoplatonic scholar of the early 20th century that Neoplatonism contains an early representation of Leibnizian monadism.

19th century

Georgia

Early in the 19th century, Prince Ioane of Georgia (Joane Bagrationi) in his Georgian work Kalmasoba, explained 86 of the 211 propositions of Proclus' Elements of Theology, basing his work on Armenian commentaries of Proclus' works.

France

In 1820 the first published version of Proclus' Commentary on Cratylus was published in Latin by the French classical scholar Jean François Boissonade de Fontarabie. From 1820–1827, the French philosopher Victor Cousin published his Latin translation Procli Philosophi Platonici Opera in six volumes, revised and re-edited in 1864, that included three treaties by Proclus, Proclus' Commentary on First Alcibiades and Proclus' Commentary on Parmenides, all dedicated to F. J. W. Schelling and G. W. F. Hegel. In 1839, the French statesman and philosopher Jules Simon, in his work Du Commentarie de Proclus sur le Timée de Platon, provided a comprehensive summary of Proclus' Commentary on Timaeus. In 1840, influenced by Cousin's Procli Philosophi Platonici Opera, the French philologist Adolphe Berger wrote a thorough description of Proclus' cosmology in his doctoral thesis Proclus: Exposition de sa doctrine. And in 1846, the French philosophical writer Étienne Vacherot wrote a historical account of Proclus' philosophy.

Germany

19th century German church historian and Jesuit Josef Stiglmayr who, in 1895, was the first to reveal the extent that Pseudo-Dionysius' Christian doctrines depended on Proclus' Neoplatonic doctrines.

In 1820, Proclus' Commentary on First Alcibiades was published in Latin by German philologist and archaeologist Georg Friedrich Creuzer. Proclus was a particular favourite of the German philosopher Hegel, who regarded Neoplatonic philosophy as the peak of Greek philosophy as a whole, and praised Proclus as 'the peak of Neoplatonic philosophy' in his Lectures on the History of Philosophy, which details lectures given by him from 1802–1830. Hegel drew on Proclus' Elements of Theology and Platonic Theology and integrated Proclean concepts into his philosophy. However, the German philosopher and Protestant theologian Eduard Zeller was less praiseworthy in his 1844–1852 work Die Philosophie der Griechen in ihrer Geschichtlichen Entwicklung, but nonetheless Zeller recognized Proclus' importance in the history of philosophy. During the mid 1860s, the German philosopher and historian Friedrich Ueberweg lauded Proclus in his 1863–1886 work Grundriss der Geschichte der Philosophie and, with Hegel, called Proclus' works the peak of Neoplatonic philosophy.

Late in the 19th century, in 1895, the German church historian and Jesuit Josef Stiglmayr, in his work Dionysius Areopagita in der Lehre vom Uebel, and later in 1900, the German Catholic theologian and church historian Hugo Koch, in is detailed work Pseudo-Dionysius Areopagita, independently revealed the extent that Pseudo-Dionysius the Areopagite slavishly followed Proclus' doctrines. They revealed that the works of Pseudo-Dionysius reproduced the whole structure of late Athenian Neoplatonism, and took over technical Neoplatonic theological terminology, with a thinly veiled disguise of Christianity. Since the late 19th century, there have been many other proofs that demonstrate the close link between works of Pseudo-Dionysius and the late Athenian Neoplatonic works of Proclus and Damascius, notably, a study by the 20th–21st century Italian academic and philologist Eugenio Corsini, three studies by the 20th–21st century French philosopher Henri-Dominique Saffrey, and a study by the 20th–21st century Italian Hellenist Salvatore Lilla.

England

In the late 18th century and early 19th century, between 1792–1833, the English translator and Neoplatonist Thomas Taylor was overwhelmed by Proclus and published the following English translations on and by Proclus:

Cover page of Proclus on the First Book of Euclid's Elements translated into English by Thomas Taylor 1792 Volume I.

• Marinus's Life of Proclus, or Concerning Felicity in 1792;
• The Philosophical and Mathematical Commentaries of Proclus on the First Book of Euclid's Elements and Proclus's Theological Elements in 1792 in 2 volumes;
• Five Hymns, by Proclus in 1793;
• Commentary on The First Alcibiades from his English translation of The Works of Plato (which included English translations of certain dialogues by Floyer Sydenham) in 1804;
• The Six Books of Proclus on the Theology of Plato in 1816 in 2 volumes;
• Proclus' The Elements of Theology in 1816;
• Proclus' Commentary on the Timaeus of Plato in 2 volumes and 2 editions, 1810 and 1820;
• The Fragments that remain of the Lost Writings of Proclus in 1825;
• Select Theorems on the Perpetuity of Time, by Proclus in 1831;
• Two Treatises of Proclus (Ten Doubts Concerning Providence and On the Subsistence of Evil) in 1833.

Taylor also published four articles on Proclus in the Classical Journal in 1821, 1822, 1824 and 1825, that were a response to Jean François Boissonade de Fontarabie's first published Greek text edition of Proclus' Commentary on Cratylus and Victor Cousin's Greek text editions of Proclus' commentary on First Alcibiades and Parmenides (three articles).

United States of America

Taylor's translations of Proclus inspired Ralph Waldo Emerson, who declared in 1847:

"When I read Proclus, I am astonished at the vigor and breadth of his performance. Here is no...modern muse with short breath and short flight, but Atlantic strength, every where equal to itself, and dares great attempts because of the life with which it is filled."—Ralph Waldo Emerson, Journals

Contemporary reception

20th and 21st century

Between 1900 and 2021 there have been more than 30 modern versions published of Proclus' works in Greek text and two new editions of Moerbeke's Latin translation. There have also been over 100 published translations of Proclus' works that are considered by scholars as a standard, or important for Proclean studies. Those translations include 32 in English (including 8 reprints of Thomas Taylor's translations) 23 in Italian, 20 in French, 18 in German, six in Spanish, two in Hungarian, one in Russian and one in Polish.

A nearly complete list of Proclus' works in Greek text and translations published after 1900 may be found at De Wulf-Mansion Centre for Ancient, Medieval, and Renaissance Philosophy. Below is a chronological listing of modern editions of Proclus' works in Greek text and first edition translations that are in the bibliographies of All From One, edited by d'Hoine & Martijn 2017, and Proclus On Plato's Cratylus, translated by Duvick 2014. Where there is more than one volume published for a work, the year is taken from the last published volume.

Modern Editions in Greek Text and Translations from Bibliographies of All From One 2017 and Proclus On Plato's Cratylus 2014

Year Finished	Language, Editor and/or Translator	Title	Work by Proclus
1873	Greek text edited by G. Friedlein	Procli Diadochi In Primum Euclides Elementorum Librum Commentaria	Commentary on First Book of Euclid's Elements
1901	Greek text edited by W. Kroll	Procli Diadochi In Platonis Rem Publicam Commentaria, 2 volumes	Commentary on Plato's Republic
1906	Greek text edited by E. Diehl	Procli Diadochi In Platonis Timaeum Commentaria, 3 volumes	Commentary on Plato's Timaeus
1908	Greek text edited by G. Pasquali	Procli Diadochi In Platonis Cratylum Commentaria	Commentary on Plato's Cratylus
1909	Greek text edited by C. Manutius	Procli Hypotyposis astronomicarum positionum	Outline of Astronomical Hypotheses
1933	Greek text and English translation by E. R. Dodds	Proclus. Elements of Theology	Elements of Theology
1965	English translation by W. O'Neill	Proclus: Alcibiades I	Commentary on Plato's First Alcibiades
1968	French translation by A. J. Festugière	Proclus. Commentaire sur le Timée, 5 volumes	Commentary on Plato's Timaeus
1970	English translation by G. R. Morrow	Proclus: Commentary on the First Book of Euclid's Elements	Commentary on the First Book of Euclid's Elements
1986	French translation by A.-P. Segonds	Proclus: Sur le Premier Alcibiade de Platon	Commentary on Plato's First Alcibiades
1987	English translation by G. R. Morrow and J. M. Dillon	Commentary on Plato's Parmenides	Commentary on Plato's Parmenides
1997	Greek text and French translation by H.D. Saffrey and L.G. Westerink	Théologie Platonicienne, 6 volumes	Platonic Theology
2001	English translation by H. S Lang and A. D.Macro	On the Eternity of the World. De Aeternitate Mundi	On the Eternity of the World (from Arabic)
2003	English translation by J. Opsomer & C. Steel	On the Existence of Evils	On the Existence of Evil
2007	English translation by C. Steel	Proclus: On Providence	On Providence and Fate
2007	English translation by B. Duvick, Edited by H. Tarrant	Proclus On Plato's Cratylus	Commentary on Plato's Cratylus
2009	Modern Greek translation by Oi Ymno iand P. Kalligas	Proklou, H Ieratikê Technê	Hymns
2012	English translation by R. Lamberton	Essays 5 and 6 of his Commentary on the Republic of Plato	Commentary on Plato's Republic
2013	English translation by H. Tarrant, D. T. Runia, M. Share and D. Baltzly	Commentary on Plato's Timaeus, 6 volumes	Commentary on Plato's Timaeus

Further, in the early 20th century, Proclus' philosophy can be seen in the process philosophy of the English mathematician and philosopher Alfred North Whitehead. Also in the early 20th century, in 1909, the American editor of The Platonist Thos. M. Johnson published Proclus' Elements of Theology in a work titled Proclus' Metaphysical Elements. And in 1918 the English metaphysician Thomas Whittaker published his work The Neoplatonists, which provides complete summaries of Proclus' commentaries and describes many propositions in Proclus' Elements of Theology. In c. 1932, the German scholar Ansgar Josef Friedl, in his work Die Homer-Interpretation des Neuplatonikers Proklos, wrote an analysis of Proclus' Commentary on Republic that discussed Proclus' theology and his literary criticism of Homer's myths.

In 1949 the American philosophical instructor Laurence Jay Rosán published The Philosophy of Proclus, a work that provided a significant reassessment of Proclus in 20th century scholarship. In the late 20th century, the writer Richard A. Smyth's 1997 book Reading Peirce Reading explores the Neoplatonic link from Ralph Waldo Emerson, a very passionate reader of Proclus, to the 19th century American philosopher Charles Sanders Peirce. And in 2012, a conference was held in Turkey, at Fatih University, celebrating the 1600th anniversary of Proclus' birth.

List of Influence

This topic provides a chronological listing of Proclus' influence on philosophy and theology. The century ascribed to people in the list is based on the year they flourished, traditionally that is when they were 40 years old.

Proclus' Influence

5th century	Ammonius Hermiae	Greek Neoplatonist philosopher and Proclus' student
6th century	Damascius	Greek Neoplatonist philosopher
6th century	Priscian	Roman Latin grammarian
6th century	John Philoponus	Byzantine-Greek Christian commentator
6th century	Simplicius of Cilicia	Greek Neoplatonist philosopher
6th century	Olympiodorus the Younger	Greek Neoplatonist philosopher
6th century	John of Lydia	Byzantine-Greek administrator and writer on antiquarian subjects
6th century	Boethius	Roman philosopher, senator and consul
6th century	Pseudo-Dionysius the Areopagite	Greek Christian theologian and Neoplatonic philosopher
7th century	Saint Maximus the Confessor	Byzantine-Christian monk, theologian and scholar
8th century	Muhammed ibn Ishaq	Islamic historian
8th-9th century	Ibn al-Bitriq	Syrian scholar
9th century	Hilduin	Catholic bishop of Paris
9th century	John Scotus Eriugena	Irish Catholic Neoplatonist philosopher, theologian and poet
9th century	al-Kindī	Islamic philosopher
9th century	Isḥāq ibn Ḥunain	Islamic physician and translator
10th century	al-ʿĀmirī	Islamic philosopher. Second-generation student of al-Kindī:
10th century	anonymous Syriac translators	Syriac translations
10th century	al-Razis	Persian physician, philosopher and alchemist
11th century	Michael Psellos	Byzantine-Greek philosopher
11th century	John Italus	Byzantine-Greek philosopher
12th century	Eustratius of Nicaea	Byzantine-Greek Christian bishop of Nicaea
12th century	John Sarrazin	French scholar
12th century	Isaac Sebastocrator	Byzantine-Greek scholar and patron of learning and the arts
12th century	Nicholas of Methone	Byzantine-Greek Christian theologian, philosopher and commentator
12th century	Ioane Petritsi	Georgian Neoplatonist philosopher
12th century	anonymous Arabic translators	Arabic translations of Ioane Petritsi's translation
12th century	Aḥmad Al-Šahrastānī	Islamic scholar, philosopher and theologian
12th century	Gerard of Cremona	Italian Catholic translator
13th century	ʿAbd al-Latị̄f al-Baghdādī	Islamic philosopher.
13th century	St Albert the Great	German Catholic Dominican friar, philosopher, scientist and bishop
13th century	William of Moerbeke	Flemish Catholic bishop and translator
13th century	St Thomas Aquinas[279]	Italian Christian theologian, philosopher and jurist
13th century	Siger of Brabant	French Averroist philosopher
13th century	Heinrich Bate	Flemish Christian philosopher, theologian, pupil of St Thomas Aquinas
13th century	Theodoric of Freiberg	German Christian Dominican friar, theologian and physicist
13th century	Simeon of Garni. (Svimeon Petrizis)	Armenian Christian monk
14th century	Nicephorus Gregoras	Byzantine-Greek astronomer, historian and theologian
14th century	Saint Gregory Palamas	Byzantine-Greek theologian
14th century	Meister Eckhart	German Christian theologian
14th century	Dante Alighieri	Italian poet, writer and philosopher
14th century	Berthold of Moosburg	German Christian Dominican theologian and Neoplatonist
15th century	Nicolas of Cusa	German Catholic cardinal and theologian
15th century	Ambrogio Traversari	Italian monk and theologian
15th century	Pietro Balbi	Italian translator
15th century	Bessarion	Byzantine-Greek Catholic cardinal and theologian
15th century	Marsilio Ficino	Italian Catholic priest and scholar
15th century	Giovanni Pico della Mirandola	Italian Christian philosopher
15th century	Giorgio Valla	Italian academic, mathematician, philologist and translator
16th century	Anonymous Italian translator	Translation of Commentary on Timaeus
16th century	Nicholas Scutelli	Italian Augustinian friar and Platonist
16th century	Simon Grynaeus	German Protestant theologian and scholar
16th century	Publication	Outline of Astronomical Hypotheses in Ptolemy's Opera 1541
16th century	Francesco Barozzi	Italian mathematician, astronomer and humanist
16th century	Franciscus Patricius	Italian Platonist philosopher and scientist
16th century	Aemilius Portus	Italian philologist and university professor
16th century	Nicholas Copernicus	Prussian-Polish mathematician and astronomer
16th century	Giordano Bruno	Italian Dominican friar, philosopher and cosmological theorist
17th century	Johannes Kepler	German astronomer, mathematician, astrologer, natural philosopher
17th century	Simeon of Djulfa (Svimeon Dshughaezi)	Armenian Christian bishop
17th century	Jacob Boehme	German philosopher
17th century	Gottfried Wilhelm Leibniz	German polymath, mathematician, philosopher, scientist, and diplomat
17th century	Sulchan-Saba Orbeliani	Georgian writer and diplomat
18th century	Thomas Taylor	English Neoplatonist and translator
18th century	Anton I of Georgia	Catholicos–Patriarch of the Georgian Orthodox Church
19th century	Prince Ioane of Georgia (Joane Bagrationi)	Georgian prince, writer and encyclopaedist
19th century	Georg Friedrich Creuzer	German philologist and archaeologist
19th century	Jean François Boissonade de Fontarabie	French classical scholar
19th century	Victor Cousin	French philosopher
19th century	Hegel	German Christian philosopher
19th century	Schelling	German philosopher
19th century	Ralph Waldo Emerson	American essayist, lecturer, philosopher, abolitionist and poet
19th century	Charles Sanders Peirce	American philosopher, logician, mathematician and scientist
20th century	20th century scholars	Scholars and translators
20th century	International Astronomical Union	Named the crater Proclus on the Moon after him.
21st century	21st century scholars	Scholars and translators

Late Athenian Neoplatonic theology

Late Athenian Neoplatonic theology is formalized and systematized in Proclus' Elements of Theology and elaborated in his works Platonic Theology, Commentary on Timaeus and Elements of Theology. Proclus was a great systematizer of late Athenian Neoplatonic theology; however, little of what he wrote was original. He formalized, systematized, elucidated and elaborated on the main sources of Neoplatonic theology that were already in the writings or teachings of Orpheus, Homer, Hesiod, Pythagoras, Socrates, Plato, Plotinus, Porphyry, the Chaldaean Oracles, Iamblichus and Syrianus.

Propositions

Proclus' doctrines of Neoplatonic theology are based on 211 propositions, and proofs of those propositions using his authorities, in his systematic work Elements of Theology that formalized, systematized and elaborated the early and loosely systematized Neoplatonic theology of Plotinus, Porphyry and Sallustius, into a later Athenian Neoplatonic theology.

The structure of the propositions in Elements of Theology has two major subdivisions, the first, propositions 1–112, introduce typical Neoplatonic metaphysical antitheses consecutively. Some important examples of typical Neoplatonic metaphysical antitheses are, multiplicity and unity, cause and effect, progression and return, and potentiality and actuality. The second subdivision, propositions 113–211, uses the results of propositions 1–112 to construct theories about the realm of henads and the essential hypostases of Nous and Soul. The propositions result in a more complex and more dynamic theology than that of early Neoplatonic theology, with the complexity due to a much greater formalization and systematization of Neoplatonic hypostases, and hierarchies of beings in those hypostases.

Eternity

Eternity is the cause of life, power and energy in late Athenian Neoplatonic theology.

"eternity is the cause of never-failing life, of unwearied power, and [resolute] energy"—Proclus, Platonic Theology III.18.59.16–26

The late Athenian Neoplatonic doctrine of Eternity is formalized in Proclus' Elements of Theology propositions 52–55. Those propositions are a formalization of the early Neoplatonic understanding of eternal existence and eternal activity, otherwise known simply as eternity. Proclus' understanding of eternal existence had its roots in Plato's Timaeus 37e ff. and ultimately to the early fifth century BC philosopher Parmenides On Nature v. 66.

"But that which is ever changeless without motion must not become elder or younger in time, neither must it have become so in the past nor be so in the future..."—Plato, Timaeus 38a

Proclus' understanding of eternal activity had its roots in Aristotle's Nicomachean Ethics 1154b27.

"This is why God always enjoys a single and simple pleasure; for there is not only an activity of movement but an activity of immobility, and pleasure is found more in rest than in movement."—Aristotle, Nicomachean Ethics 1154b27

In the early Neoplatonism of Plotinus, Enneads 3.7.4, eternal existence and eternal activity were combined into a Neoplatonic understanding of eternity.

"And eternity may be properly denominated a God unfolding himself into light, and shining forth, such as he essentially is, viz. as immutable and the same, and thus firmly established in life."—Plotinus, Enneads 3.7.4

The Neoplatonic understanding of eternity was passed into Christian theology through St Augustine in Confessions XI.11 and On the Trinity XII.14, Boethius in The Consolation of Philosophy V.6 and St Thomas Aquinas in Summa Theologica First Part, Q.10, Article 5.

"Eternity therefore is a perfect possession altogether of an endless life"—Boethius, The Consolation of Philosophy V.6

One and Many

Proclus begins his Elements of Theology with the systematical exploration of the antithesis of the One and the Many, an opposition that was fundamental to Greek philosophy for about 1000 years, as it was a search for the First Principle of every thing immaterial and material. In his Commentary on Parmenides 696.33 ff., Proclus finds four solutions for the First Principle, (a) pure multiplicity, or the Many (b) explicit multiplicity with implied unity, (c) explicit unity with implied multiplicity, and (d) pure unity, or the One. Solutions (b) and (c) are known as partial unities. The last of these solutions, (d) pure unity, or the One, was the traditional Neoplatonic belief that had its roots in the first hypothesis of Plato's Parmenides 137c ff.

"Well then, said Parmenides, if there is a One, of course the One will not be many. Consequently it cannot have any parts or be a whole. For a part is a part of a whole; and a whole means that from which no part is missing; so, whether you speak of it as 'a whole' or as 'having parts', in either case the One would consist of parts and in that way be many and not one. But it is to be one and not many. Therefore, if the One is to be one, it will not be a whole nor have parts."—Plato, Parmenides 137c-d

Elements of Theology propositions 1–6 try to prove the existence of solution (d) pure unity, or the One, by finding contradictions, to the other three solutions (a), (b) and (c). The arguments used in the proofs of Proclus' propositions are supported by his authorities in Plato's dialogues Parmenides and Sophist, Plotinus' Enneads, Aristotle's Metaphysics, and Syrianus' Commentary on Aristotle's Metaphysics.

The One and Partial Unities

In Elements of Theology proposition 1, of the four solutions for the First Principle of every thing immaterial and material, the only solution Proclus found a contradiction to, or found not to exist, was (a) pure multiplicity, or the Many. His authority for the basis of the contradiction was Plato's Parmenides 157c ff.

"Yet the Others are not wholly destitute of the One, but partake of it in a way."—Plato, Parmenides 157c

However, Proclus' formal argument in proposition 1 against pure multiplicity, or the Many, was different to Plato's and is elaborated on in his Platonic Theology II.1 The other three solutions to the First Principle (b) explicit multiplicity with implied unity, (c) explicit unity with implied multiplicity, and (d) pure unity, or the One were supported by arguments from his authorities. The thesis that any thing that is, immaterial or material, must have unity to some degree was also supported by Plotinus in Enneads 6.9.1 and 5.6.3. In the proofs of propositions 2–4, he was able to establish the existence of (d) pure unity, or the One, and distinguish it from both the partial unities (b) and (c) and show (d) pure unity, or the One, is necessary for both the partial unities (b) and (c) to exist.

Also, in Elements of Theology, in the proof of proposition 5, the two types of partial unity (b) and (c) were determined not to be the source of the One and so, because the One was necessary for (b) and (c) to exist, and since there was nothing else, they had to progress from the One. Further, in the proof to proposition 6, both types of partial unities (b) and (c) were found to be composed of the same indivisible units, or henads. Hence, the One, and the two types of partial unities, (b) and (c), that progressed from the One, formed a hierarchy that Proclus used as a basis of his next set of propositions, the doctrine on Hierarchy of Causes.

Causes

In Proclus' Elements of Theology, propositions 7–13 begin to formalize and systematize causes and culminate in linking the First Cause to the One, the Final Cause to the Good, and finally identifying the One to be identical to the Good. Proposition 7 is fundamental to the entire structure of Neoplatonic theology and asserts: a cause is superior to its effect.

Proposition 7 has its roots in Plato's Philebus 27b, is stated clearly in Cicero's De Natura Deorum II.33.86, and is fundamental to the early Neoplatonism of Plotinus, Enneads 5.4.1, Porphyry, Sententiae xiii, and Iamblichus, On the Mysteries III.20.

"Socrates. The agent or cause always naturally leads, and the patient or effect naturally follows it?

Protarchus. Certainly.

Socrates. Then the cause and what is subordinate to it in generation are not the same, but different?

Protarchus. True."—Plato, Philebus 27

Proclus is the only ancient philosopher to prove the assertion: a cause is superior to its effect, using arguments from his authorities in the proof, one of those authorities being Aristotle's Nicomachean Ethics 1094a1.

A Transcendent Final Cause

Proclus' Elements of Theology proposition 8 argues for the existence of a transcendent final cause of the universe, or a transcendent Good, like propositions 4–5 argued for the existence of a transcendent One. In proposition 8, in the proof of the existence of a transcendent Good, Proclus uses the Neoplatonic theological belief that the Good is the good that all things desire, a belief that has its roots in Plato's Republic 509b, Philebus 20d, Aristotle's Nicomachean Ethics 1094a1 and Plotinus' Enneads 5.5.13.

"Every art and every inquiry, and similarly every action and pursuit, is thought to aim at some good; and for this reason the good has rightly been declared to be that at which all things aim."—Aristotle, Nicomachean Ethics 1094a1

Self-Sufficient

In Elements of Theology, propositions 9 and 10 claim self-sufficient is a mean term, or intermediary term, between the Good and the good things of sense experience. Hence, the term self-sufficient forms a bridge between immaterial levels of reality and the material level of reality. Proposition 9 asserts that things that are self-sufficient, or derive their well-being from themselves, are more similar to the Good than things that are not self-sufficient, and hence are more like the Good and superior to those that are not self-sufficient. Proposition 10 asserts: everything that is self-sufficient is inferior to the Good. Proclus' arguments for the fine difference between self-sufficiency and the Good in a monistic system are seen in his Commentary on Timaeus II.90.9 ff. that has its roots in Plato's Timaeus 33d.

"For by design was it created to supply its own sustenance by its own wasting, and to have all its action and passion in itself and by itself: for its framer deemed that were it self-sufficing it would be far better than if it required aught else."—Plato, Timaeus 33d

A Transcendent First Cause

In Proclus' Elements of Theology, proposition 11 claims all things proceed from a single first efficient cause of the universe, thereby assigning a transcendence to the first efficient cause of the universe. The arguments in the proof of Proposition 11 reject any views that deny efficient causality, reject doctrines of Bi-causality, reject assumptions of an infinite chain of unilateral causation, and reject Empedoclean pluralism. In proposition 12, Proclus identifies the first efficient cause of the universe with the final cause of the universe, an argument that has its roots in Plato's Republic 509b.

"In like manner the good may be said to be not only the author of knowledge to all things known, but of their being and essence, and yet the good is not essence, but far exceeds essence in dignity and power."—Plato, Republic 509b

Proposition 12 argues that in the chain of causes, there is nothing higher than the final cause of the universe and there is nothing higher than the first cause of the universe, where higher means both morally better and more unified.

The Good is Identical to the One

In Elements of Theology, the propositions 7–13 culminate in proposition 13 in which Proclus links the first cause, of everything immaterial and the material universe, to the One, identified by propositions 1–6, and then links the One to the final cause, of everything immaterial and the material universe, to the Good, and hence deduces the Good is identical to the One.

Scholastic opinion is that Proclus' authorities for his proofs of propositions 7-13 include, Plato's Timaeus, Republic, Phaedo, Philebus and Meno, Aristotle's Physics, Metaphysics, Nicomachean Ethics and Eudemian Ethics, Aristoxenus' Elementa harmonica, Plotinus' Enneads, the Pythagorean philosopher Euryphamus, Philo and Plutarch.

"Of those who maintain the existence of the unchangeable substances some say the One itself is the good itself; but they thought its substance lay mainly in its unity."—Aristotle, Metaphysics 1091b13

It is generally agreed by scholars that Aristotle is mainly referring to Plato in Metaphysics 1091b13.

Hypostases

Proclus' Elements of Theology propositions 14–20 formalize and systematize Neoplatonic hypostases. Propositions 14–20 systematically build a hierarchy of hypostases, culminating with proposition 20 that concludes with the claim that there are three hypostases and one material level of reality. The three hypostases in hierarchical order are: the One, the hypostasis of Nous and the hypostasis of Soul. The One is the most essential hypostasis, the hypostasis of Nous descends from the One, the hypostasis of Soul descends from the hypostasis of Nous and the material level of reality, or the material universe, descends from the hypostasis of Soul. Proclus elaborates on the Neoplatonic hypostases of Nous and Soul in his Commentary on Timaeus II.243.19 and II.251.5, in his Commentary on Cratylus 118, in his Platonic Theology III.24.164 and II.5.93 and in his Commentary on Parmenides 703.12 ff., and 1069.23 ff.

The three Neoplatonic hypostases: the One, Nous and Soul, also known as a trinity, have their roots in:

• Plato's Parmenides, which was identified by Moderatus with the Form of the Good (hypostasis of the One);
• the Demiurge of Plato's Timaeus, which was identified by Poseidonius, Antiochus or the Old Platonic Academy with Aristotle's doctrine of Nous in Metaphysics Λ.7 (hypostasis of Nous);
• the World Soul of Plato's Timaeus and Laws Book X (hypostasis of Soul).

The Neoplatonic doctrine of the Trinity, comprising the hypostases of the One, Nous and Soul, was known to the Middle Platonist Plutarch, but was given its established pattern and structural cohesion by the early Neoplatonist Plotinus in his Enneads 2.9.1–18, 3.8.9, 4.4.11, 4.3.5 and 5.3.10–12.

"Consequently there are no principles other (than the three divine hypostatic substances); and the first rank will have to be assigned to Unity [the One], the second to Intelligence [Nous], as the first thinking principle, and the third to the Soul."—Plotinus, Enneads, 2.9.1

Series

Marble bust of Homer. Homer is an important authority for Proclus

In late Athenian Neoplatonic theology, hypostases are progressions, or a series of causations, from distinct unifying principles, or henads. Progression from henads is achieved through a likeness of members to themselves and ultimately to the henad that is at the summit of a series of causation. Within each hypostasis there are also progressions, or a series of causations from unifying causes, or monads. Similarly, progressions from a monad is achieved through a likeness of members to themselves and ultimately to the monad of that series of causation.

In Elements of Theology, Proclus' first uses the word 'series' (Ancient Greek: 'σειρά') in proposition 21 when writing about a monad and a series, or order, that is a unity derived from the monad. For example, the generic attributes of the monad Helios, progresses (where progressions imply likeness) into the material universe through a series of causation resulting in the Sun itself, people with a sun-like soul, sun-like animals, e.g. a rooster, sun-like plants, e.g. heliotropes and stones like sunstones. The roots of representing a progression from the heavens to the material world as a series, or a chain, (Ancient Greek: σειρά), are Orphic, from Homer's Iliad Book 8 (Θ), 19–20 where 'σειρὴν' is translated as 'a chain':

"Make ye fast from heaven a chain of gold, and lay ye hold thereof, all ye gods and all goddesses;"—Homer, Iliad Book 8 19–20

Vertical Series and Transverse Series

Scholars of the late Athenian Neoplatonic theology of Proclus represent progressions from a hypostasis as two types of series, a vertical series and a transverse (or horizontal) series. Scholars use multiple vertical series to represent progressions of generic characteristics that give a fundamental character to beings in the distinct hypostases of the One, Nous and Soul, and scholars use multiple transverse series to represent progressions of specific characteristics that give an individualistic character to beings through Neoplatonic hypostases. Vertical series develop from henads, which are unifying principles, while transverse series develop from monads, which are unifying causes. Tracing a transverse series from the monad to its members, is moving from cause to effect, while tracing a transverse series from its members to the monad, is moving from effect to cause.

Series of Causation

The late Athenian Neoplatonic theology of Proclus, Elements of Theology propositions 110, 111 and 132, provides a continuous transverse series of causation from the unifying cause of the One through the hypostases, Nous and Soul and the material universe. It also provides a continuous transverse series of causation from the unifying causes, or monads, in the hypostasis of Nous through the hypostasis of Soul and the material universe. Finally, it provides a transverse series of causation from the unifying causes, or monads, in the hypostasis of Soul through the material universe. In each series of causation, there are no gaps, or no vacuum.

The late Athenian Neoplatonic theology of Proclus, Elements of Theology propositions 162–165, also provides a continuous vertical series of causation from unifying principles, or henads, within each division of the hypostasis of Nous, within each division of the hypostasis of Soul and within the subdivisions of the material universe, leaving no gaps, or no vacuum.

Further, Elements of Theology propositions 108, 109, assert a continuous vertical series of causation that connects a monad in a transverse series of causation to a monad in a subsequent transverse series of causation, thereby vertically linking all transverse series, leaving no gaps, or no vacuum. Hence, in late Athenian Neoplatonic theology, there is a continuous vertical and transverses series of causation from the One to the material universe that forms a great 'chain', or series, of beings leaving no gaps, or no vacuum.

Multiplicity from Unity

A fundamental principle in Proclus' doctrines is stated in Elements of Theology proposition 11, which asserts: all that exists proceeds from a single first cause. The first cause can be seen like a root of a tree from which progresses the trunk and branches, the trunk being near the root while the branches are distant. From Plotinus onwards, it was essential to explain how a multiplicity of things could proceed from a totally transcendent and Simple One.

Law of Emanation and Law of Undiminished Giving

Plotinus' doctrines to explain multiplicity from unity are discussed in Enneads 2.9.3, 3.8.10 and 5.3.12, where he explains the universe is produced from the One like a limitless fountain that is undiminished by its giving and in which there are no gaps. That limitless undiminished fountain is known as Plotinus' law of Emanation, in Enneads 5.1.6. and law of Undiminished Giving, in Enneads 5.4.2:

"What conception are we then to form of this generation of Intelligence by this immovable Cause [the One]? It is a radiation of light which escapes without disturbing its quietness, like the splendor which emanates perpetually from the sun, without affecting its quietness, which surrounds it with out leaving it."—Plotinus, Enneads 5.1.6

which has its roots in Plato's Timaeus 42e.

"So when [the One] had made all these ordinances for them [the One] was abiding after the manner of [its] own nature..."—Plato, Timaeus 42e

What Plotinus meant by 'no gaps' in his limitless and undiminished fountain is more precisely stated in his Enneads 6.9.8 where he claims immaterial beings are not separated by a quantitative interval, but by a qualitative interval. However, Plotinus did not only leave a qualitative gap, but a qualitative gulf, between the One, the first hypostasis, which is pure unity, and the immediate consequent hypostasis of Nous, which has a multiplicity of entities. This is significantly evident in Enneads 6.5.9 where he cannot explain how to get multiplicity from the One, without first putting multiplicity into it, thereby negating the pure unity of the One.

"If then this Essence may justly be called one, if unity may be predicated of its being, it must, in a certain manner, seem to contain the nature opposed to its own; that is, the manifold; it must not attract this manifoldness from without, but it must, from and by itself, possess this manifold; it must veritably be one, and by its own unity be infinite and manifold"—Plotinus, Enneads 6.5.9

Law of Continuity

Plotinus' law of Emanation was formalized by Proclus in Elements of Theology proposition 25, and Plotinus' law of Undiminished Giving was formalized in propositions 26 and 27. To attempt to fill the qualitative gulf, left by Plotinus' law of Emanation and law of Undiminished Giving, between the One, the first hypostasis, and the immediate consequent hypostasis of Nous, Plotinus' laws were elaborated by Proclus by the addition of a third law, the law of Continuity, formalized in Elements of Theology proposition 28.

"Every producing cause constitutes things similar to itself, prior to such as are dissimilar."—Proclus, Elements of Theology Proposition 28

The law of Continuity, in late Athenian Neoplatonic theology, means there is only the minimum qualitative difference between the distinctness of an entity and its immediate consequent entity in a progression of entities. E. R. Dodds, in his Elements of Theology, compares Proclus' proposition 28 with Saint Thomas Aquinas' Summa Contra Gentiles I.29 written about 800 years later, and with The Confessions of Jakob Boehme written about 1100 years later.

"...it is of the nature of action that a like agent should produce a like action,"—Saint Thomas Aquinas, Summa Contra Gentiles I.29

"Eternity bringeth to birth nothing but that which is like itself"—Jakob Boehme, The Confessions of Jakob Boehme

Progressions from Unifying Principles

To explain how late Athenian Neoplatonists generated multiplicity from the One, scholars represent progressions (where progressions imply likeness) from unifying principles of Neoplatonic hypostases as a vertical series of causation (vertical linkages), where the vertical series of causation is generated from a henad at the summit of a Neoplatonic hypostasis. By the late Athenian Neoplatonic law of Continuity, Elements of Theology proposition 28, each being, or monad, in a vertical series of causation has either the minimum qualitative difference from the distinctness of the henad from which the series progresses (i.e. the monad is like the henad) or the monad has the minimum qualitative difference from the distinctness of the immediate consequent monad in the same vertical series (i.e. the monad is like the immediate consequent monad).

Progressions from Unifying Causes

Scholars of late Athenian Neoplatonism represent progressions from unifying causes of Neoplatonic hypostases as a transverse series of causation (transverse linkages) through hypostases, where each transverse series of causation is generated from a member of a vertical series of causation, or monad. By the late Athenian Neoplatonic law of Continuity, Elements of Theology proposition 28, each being in a transverse series of causation has either the minimum qualitative difference from the distinctness of the monad from which the series progresses (i.e. the being is like the monad) or the being has the minimum qualitative difference from the distinctness of the immediate consequent being in the same transverse series (i.e. the being is like the immediate consequent being). Further, each transverse series is causally linked to another transverse series by a particular member of either transverse series.

Progressions from the One

In late Athenian Neoplatonic scholarship, there is no vertical series of causation progressing from the Neoplatonic hypostasis of the One, indicating the unifying principle of the One does not progress from the One. In the case of the One, only a transverse series of causation progresses from the One, indicating a unifying cause progresses from the One that causes a multiplicity of unifying principles, or a realm of henads. In the late Neoplatonic doctrine of Henads, henads are like a bridge between the pure simplicity of the One and the multiplicity of beings, and are the transcendent sources of individuality. The doctrine has its roots in Plato's Philebus 15a.

"...but when the assertion is made that man is one, or ox is one, or beauty one, or the good one, then the interest which attaches to these and similar unities and the attempt which is made to divide them gives birth to a controversy....for how can one and the same thing be at the same time in one and in many things?"—Plato, Philebus 15a-b

The henad immediately subsequent to the One has a minimum qualitative difference to the One by the Law of Continuity formalized in Elements of Theology proposition 28, whereby it is closely linked to the One, but it is not part of the One, nor is it an attribute of the One, which has the sole attribute of goodness. The henads progressing from the One unfold other facets of the goodness of the One. Similarly, each subsequent being has a minimum qualitative difference to its antecedent henad or antecedent being, which results in a continuity of beings. Hence, Proclus explained how to generate multiplicity from the One while not violating the transendency of the One.

Causes and Effects

In Proclus' Elements of Theology proposition 28 there is a fundamental Neoplatonic law that asserts: first, a producing cause brings into existence, through its effect, things that are similar to it, and afterwards, things are brought into existence that are dissimilar to it. That proposition led to the fundamental subject of relations between causes and effects that is systematically explained in Elements of Theology propositions 25–29, 56, 57 and 75. Propositions 25–29 assert: the late Athenian Neoplatonic theological laws of Emanation, Undiminished Giving and Continuity.

Efficacy of Causes

Proclus' Elements of Theology propositions 56 and 57 assert: things produced by lower beings are produced in greater measure by higher, or more essential beings.

"Every thing which is produced by secondary natures is produced in a greater degree by prior and more causal natures, by whom those which are secondary were also produced."—Proclus, Elements of Theology proposition 56

Propositions 56 and 57 means the production of things by higher, or more essential beings, is not limited to their immediate productions, it extends down through the production of their immediate productions, and further, to entities not caused by the more essential being's immediate production. Specifically, with respect to causes, propositions 56 and 57 mean that the ultimate cause of something is responsible for the entire series of causes that branch out from it.

Proclus' Elements of Theology propositions 56 and 57 mean, for example, that the level of Matter, placed on the lowest grade of reality by Neoplatonic theological doctrines, is totally dependent for its subsistence on the highest, or the most essential hypostasis, called the One. And in another example, the hypostasis of Nous, which is placed by Neoplatonic theological doctrines on a higher, or more essential hypostasis than Soul, is the cause of subsistence for all beings in the hypostasis of Soul. The theory resulting from propositions 56 and 57 is elaborated in Proclus' Platonic Theology III.6 and applied, in his Commentary on Parmenides 691.5 ff., to the relationship represented allegorically between Parmenides, Zeno, and Socrates.

Further, Proclus' Elements of Theology proposition 75 asserts: causes transcend their effects, effects are in some manner inferior to their causes, causes are not in their effects, effects are in their causes. Propositions 25–29, 56, 57 and 75 qualified the early Neoplatonic doctrine on Emanation into the later Neoplatonic doctrine on Illumination of the lower by the higher, or more essential.

Rest, Progression and Return

Proclus' Elements of Theology propositions 30–39 are the formalized and systematical doctrine on Cyclic Creativity that explain the late Athenian Neoplatonic understanding of the cyclic process: rest, progression and return. The earlier Neoplatonic understanding of the cyclic process is recognizable in Plotinus' Enneads 5.2.1 and 6.5.7.

Law of Immanence

In Proclus' Elements of Theology proposition 30, the law of Immanence, he asserts: the effect of a cause, simultaneously progresses from the producing cause and also remains in the producing cause.

"Everything which is produced...abides in its producing cause, and proceeds from it."—Proclus, Elements of Theology proposition 30 (abridged)

The law of Immanence allows a being or monad in one Neoplatonic hypostasis to participate in the Neoplatonic hypostasis immediately subsequent to it, whilst still remaining in its hypostasis. The early Neoplatonic doctrine of the law of Immanence can be found in Plotinus' Enneads 5.2.2 and 5.5.9.

"All that is begotten by anything else resides either in the begetting principle, or in some other being, in the case of the existence of any being after or below the generating principle"—Plotinus, Enneads 5.5.9

The late Athenian Neoplatonic law of Immanence was used by St Thomas Aquinas in Summa contra Gentiles I.49, to show that God knows not only himself (like Aristotle's God) but also all the creatures in Creation.

"The likeness of every effect pre-exists somewhat in its cause: since every agent produces its like."—Saint Thomas Aquinas, Summa Contra Gentiles I.49

Progression and Return

In Elements of Theology proposition 31, Proclus asserts: effects are reunited to their cause, or anything produced by a principle, returns to the principle that produced it. In general terms, the given metaphysical (Greek: ἀρχή) implies the ethical (Greek: τέλος). Proposition 30, the law of Immanence, is necessary for the progression to be timeless and a return to the producing principle to be possible. Proposition 31 has its roots either in Middle Platonism or the Stoic school of the philosopher Poseidonius.

According to Proclus, in Elements of Theology proposition 15, only what is incorporeal and without parts is reunited, or returns, to its cause, and in so doing becomes identical to its cause. Proposition 15 implies there is no resurrection of a material body, as it can be divided into parts and since it is impossible for these parts to be identical it means that a material body cannot be identical to its cause. That belief was also held by the Christian theologian Origen, Saint Gregory of Nyssa and the Christian monk Evagrius Ponticus. Thus in late Athenian Neoplatonic theology, for inanimate bodies, plants and animals, only phantasms of souls return to their cause, whilst for a human, only the soul is reunited, or returns, to its cause.

Briefly, in Elements of Theology propositions 32-38 assert: [32] as likeness is a condition of progression, so is return; [33] progression and return are a single movement (like diastole-systole); [34] the given ethical implies the metaphysical, the converse of proposition 31; [35] trinity in unity comprised of (1) immanence, (2) progression, and (3) return to a cause that unifies and is a unity. The triad of: immanence, progression and return, governs Proclus' dialectic; [36 and 37] progression is from better to worse, return is from worse to better; [38] the return is through Neoplatonic hypostases in reverse order to that of the progression.

In Elements of Theology proposition 39, Proclus claims there are three types of return. (1) The phantasm of a soul in a simple material entity that only exists, like a stone, is reunited to its cause simply by participating in the cause. Here the return is by way of existence. (2) The phantasm of a soul in a more complex material entity that is alive, like a plant or an animal, is reunited to its cause by participating in the cause and by developing. Here the return is by way of life. (3) The soul of a material being that is capable of thinking, like a human, is reunited to its cause by participating in the cause, by developing, and by knowing the goodness of the cause. Here the return is by way of cognition.

Cyclic Creativity

The Neoplatonic doctrine on Cyclic Creativity is formalized and systematized in propositions 30-39 of Proclus' Elements of Theology. The doctrine on Cyclic Creativity has its roots in Plotinus' Enneads 5.2.1 and 6.5.7 and was fundamental to Neoplatonism thereafter. The cyclic process is rest in the principle producing the cause, progression from the principle that produced the cause, and return to the principle that produced the cause. The cyclic process governs all activity for immaterial and material entities.

In late Athenian Neoplatonic theology, principles that produce things through a cause are said to be at rest because all activity, immaterial and material, is governed by a progression through a cause from the productive (Greek: ποιητικόν) principle and a return back to the productive principle. The initial state of rest in a productive principle's cause is the potential, i.e. the potency, of the cause. In Proclus' Neoplatonic theological doctrines, both progression from and return to the productive principle are required for actuality, i.e. for any kind of reality to subsist or exist. If there was only a progression from the producing principle, the result would be uncertain. The essence of an entity; where an entity can be a producing principle or an entity can simply be a person; is fixed only by reflecting back on the entity's cause. Hence, the cause has a two-fold effect, as it is the producer of the effect and the purpose of the effect, which is to perfect the cause.

Epistrophe

In Proclus' Neoplatonic theology, the cause by which principles produce things has a two-fold effect, the first effect produces something, and the second effect is the return, i.e. the purpose, of the effect, which is to return to the cause, thus perfecting the cause. The Neoplatonic term for this process is called epistrophe (Greek: επιστροϕἠ) and is a process where every cause is both the purpose of the producing principle and every cause is also returning to its own higher, or more essential cause, all ultimately returning to the One.

Potentiality and Actuality

In the early Neoplatonism of Plotinus and the late Neoplatonic theology of Proclus, the principles potential (Greek: δύναμις) and actuality (Greek: ἐνέργεια) are concerned with cause and effect. The two principles potentiality and actuality are fundamental and basic to Neoplatonic theology.

In Proclus' Elements of Theology proposition 77 he asserts the thesis: all things that exist potentially progress to actuality by a medium that is actually what the other is potentially. The proof of this proposition relies on proposition 7 which is the fundamental Neoplatonic principle that states: a cause is superior to its effect. The involution of proposition 77 required Proclus to use two terms for potential, perfect potency and imperfect potency, to form a logical basis for the Neoplatonic theory of involution. Perfect potency and imperfect potency can also be regarded as creative potency and passive potency, respectively.

The essence (Greek: οὐσία) of a causal principle implies its creative potency, but its passive potency must come to actuality. For example, the causal principle primal Limit has a creative potency, while its passive potency has come into actuality as matter. And using that example, proposition 77 becomes: the potential that is matter, progresses to actuality by the principle primal Limit that is actually what matter is potentially. In Proclus' Neoplatonic theology, the One is exempt from the laws of potentiality and actuality and hence primal potentiality and primal actuality originates in a principle immediately following the One, the primal Limit.

The roots of the thesis formalized by proposition 77 are in Aristotle's Metaphysics Θ.8 The early Neoplatonic discussions of the terms potential and actuality are found in the discussions of Plotinus' Enneads 5; 1.7.9; 3; 6.1.26 and 8.10.1. The late Athenian Neoplatonic understanding of the terms potential and actuality are elaborated in Proclus' Platonic Theology Book 3 chapter 9 31.14 ff. and his Commentary on Parmenides 979.1 ff.

The One

See also: Neoplatonism § The One

The overarching doctrine in Neoplatonic theology is of the One (Greek: τοῦ ἑνός). The Neoplatonic doctrine of the One has its roots in the first hypothesis of Plato's Parmenides (137c ff). The late Athenian Neoplatonic doctrine of the One, in Proclus' Elements of Theology propositions 8, 11, 12 and 20, assert that: that the One is the first principle of all things that exist and the One is identical to the Good; beyond the One there is no further principle; the One is the formal and final cause of the material universe and that is why it is the Good; and qualifying it further would diminish it; the last assertion being from the doctrine on the One in Plotinus' Enneads 3.8.11.

"Other beings, indeed, aspire to the Good, as the goal of their activity; but the Good itself has need of nothing; and therefore possesses nothing but itself. After having named it, nothing should be added thereto by thought; for, to add some thing, is to suppose that [the One] needs this attribute."—Plotinus, Enneads 3.8.11

A Dyad

A development by Iamblichus, that the late Athenian School of Plato headed by Proclus adopted, was the postulation of the antithetical principles Limit and Limitlessness, called a dyad, immediately following the One. That a dyad is the first level of reality that progresses from the One is an assertion that has its roots in Plato's Philebus 16c. Proclus' Elements of Theology propositions 90–95 and Platonic Theology Book 3 chapters 7–9 develop the Neoplatonic theological doctrine on A Dyad. Briefly, the doctrine asserts that: All Being proceeds from the One as first cause, every level of existence and every individual is held together and given form by the One, immediately following the One there are two principles, primal Limit and primal Limitlessness. The two principles, primal Limit and primal Limitlessness, are derived from Plato's Philebus 23c ff. Further expositions of a dyad, a distinguishing characteristic of late Athenian Neoplatonic theology, are found in Syrianus' Commentary on Aristotle's Metaphysics 112.14 ff., Proclus' Commentary on Timaeus I.176 and Proclus' Commentary on Parmenides 1119 ff.

Henads

The late Athenian Neoplatonic doctrine on Henads (Greek: ἑνάδες), that had its origins in Plato's Philebus by way of Neopythagoreanism, was the invention of either Proclus or Syrianus and is regarded as a fascinating modification of the early Neoplatonic doctrines of Plotinus. The doctrine on Henads systematized and elaborated by Proclus were found by Syrianus to be represented allegorically in Greek mythology by the traditional Greek gods. The doctrine was needed to fill a qualitative gap between the One and the hypostasis of Nous that was left by the early Neoplatonic doctrines of Plotinus, especially evident in Enneads 6.5.9.

"If then this Essence may justly be called one, if unity may be predicated of its being, it must, in a certain manner, seem to contain the nature opposed to its own; that is, the manifold; it must not attract this manifoldness from without, but it must, from and by itself, possess this manifold; it must veritably be one, and by its own unity be infinite and manifold"—Plotinus, Enneads 6.5.9

The late Athenian Neoplatonic doctrine on Henads introduces henads as a source of transcendental individuality, thereby introducing plurality into the hypostasis of Nous, but in such a way as to leave untouched the perfect unity of the One, and so minimizes the qualitative gap between the One and the hypostasis of Nous.

The fullest systematized exposition of the complex Neoplatonic doctrine on Henads, held by Proclus' School of Plato in Athens, is found in his Elements of Theology propositions 112–165 and Platonic Theology Book 3, chapters 1–6. Proclus' Elements of Theology propositions 113–127 systematically define general characteristics of henads; propositions 128–150 systematically expound the relationship between henads and the universe of Being; propositions 133 and 151–159 systematically explain the relationship between henads and the One; and propositions 160–165 systematically classify henads according to the principles that can participate in them.

Briefly, the doctrine of Henads asserts: the henads are more unified than beings in the hypostasis of Nous, are individual, are the transcendent sources of plurality, are without internal differentiation, are the measures of essence, have a hierarchy without being divided into genera and species, are limited in number, are the source of providence, are the unifying principles at the summit of the divisions of the hypostasis of Nous, the divisions of the hypostasis of Soul and the divisions of Nature, and are allegorically represented by distinctive properties of particular gods in Greek mythology, which are then reflected in different levels of reality.

The doctrine on Henads explain that the henads are participated entities, unlike the One, and are subsequent to a dyad and form a chain of beings between the One and all multiplicity. A major argument in the doctrine on Henads is that a cause brings forth that which is most like itself before anything else. The doctrine on Henads also has roots in Plato's Parmenides (see Proclus' Commentary on Parmenides Book 6 1043.9 ff.) and Timaeus (see Proclus' Commentary on Timaeus III.12.22 ff.)

Nous

See also: Neoplatonism § Nous

To the late Athenian School of Plato headed by Proclus, the Neoplatonic doctrine on Nous describes a complex hypostasis subsequent to the One. A detailed systemization and explanation of the complex Neoplatonic doctrine on Nous is in Proclus' Platonic Theology Books 3–5. That doctrine has its roots in Plato's Parmenides and in Plato's Timaeus.

Hierarchy

In late Athenian Neoplatonic doctrines, the Plotinian hypostasis of Nous is divided into three levels: Intelligible, Intelligible-Intellectual, and Intellectual. The Neoplatonist doctrine on Nous by Iamblichus' had already explained that the Plotinian hypostasis of Nous can be divided into an Intelligible level and an Intellectual level. The Late Neoplatonists, Syrianus and Proclus, by applying the Neoplatonic doctrine of Plenitude, in Proclus' Elements of Theology proposition 112, to Iamblichus' doctrine of Nous, elaborated their doctrine of Nous to include a third level, the Intelligible-Intellectual level (intelligible and at the same time intellectual), between the Intelligible level and Intellectual level.

In the late Athenian Neoplatonic doctrine of Nous, elaborated on in Proclus' Platonic Theology Books 3–5, each of the divisions of the Neoplatonic hypostasis of Nous, i.e. Intelligible, Intelligible-intellectual, or Intellectual, was further divided into triadic moments, or triads, by Syrianus where each triad is composed of a moment of Being, a moment of Life and a moment of Intellect.

The Demiurge

The late Neoplatonists doctrine on Nous, elaborated on in Proclus' Platonic Theology Books 3–5, explains that the Intellectual level of the hypostasis of Nous is the domain of the Demiurge. That doctrine explains that the Demiurgic level is composed of a demiurgic monad, demiurgic gods and the Demiurge itself. A major activity of the Demiurgic level is the transmission of Forms to the Neoplatonic hypostasis of Soul, where the Forms progress into souls through the World Soul, the soul of the material universe, an then into the material universe proper. The roots of the Neoplatonic doctrine on the Demiurge are in Plato's Timaeus 28c, which is discussed in great detail, including an examination of Middle Platonic and Neoplatonic views, in Proclus' Commentary on Timaeus I.99–319.

Forms

The early Platonic understanding of a Form (Greek: εἶδος) likened it to an immaterial principle with an intrinsically characteristic immaterial pattern, from which were produced material entities in the Form's likeness. In late Athenian Neoplatonic theology, a Form is more than an immaterial pattern that produces material entities in its likeness, a Form also perfects and conserves the immaterial and material entities it produces. Nor are the immaterial and material entities simply the likeness of a Form that produced them, but also the produced material entities are protected by the Form and gain all their completeness and coherence from the Form. Hence, in late Athenian Neoplatonic theology, Forms are not just inert immaterial paradigmatical principles for the material entities they produce, but they are also living and active immaterial beings.

The late Athenian Neoplatonic doctrine on Forms is discussed in great detail in Proclus' Commentary on Parmenides. In Book 1 of Commentary on Parmenides the discussion is allegorical, Book 2 discusses the structure of Forms, Book 3 details arguments for the existence and nature of Forms, Book 4 discusses the participation of Forms in particulars.

Divine and Transcendent Forms

Late Athenian Neoplatonic theology has an understanding of divine and transcendent Forms as living and active immaterial beings with potency and power that are at once patterns and creators of secondary Forms in their likeness. The hypostasis of Nous is a plenitude of divine and transcendent Forms where divine and transcendent Forms exist primordially together and in unity in the Demiurge. In Neoplatonic theology, the purpose of a soul is to be like to beings in the hypostasis of Nous, or the level of the Demiurge, and the purpose, or good, for beings on the level of the Demiurge is to be like divine and transcendent Forms, on the summit, or Intelligible level antecedent to the hypostasis of Nous.

Genus and Species

In late Athenian Neoplatonic theology, a divine and transcendent Form is the genus transmitted through many separate secondary Forms and existing in each of them. Forms are organized through a hierarchy of genera and species, the genus is not a group of species, like a whole of parts, but is active in each species and exists before each species. Species are different forms that are comprehended by a unique divine and transcendent Form, which is the genus that transcends its species and encompasses the causes of its species.

Proclus' view is that secondary Forms produce only species, not individuals. Human souls progress from a divine and transcendent Form, under which they are grouped, through a collection of Forms. In late Athenian Neoplatonic theology, things that exist only in parts have no corresponding Form, e.g. eyes or fingers, accidental attributes like colour, objects made by humans (despite Plato's Republic Book X), arts and crafts like weaving, and there is no corresponding Form of evil.

Hierarchy

In late Athenian Neoplatonic theology, a dyad of Limit and Limitlessness is the foundation of Forms. Forms are the first clear manifestation of a dyad of Limit and Limitlessness, whereas henads are the first implied manifestation of a dyad of Limit and Limitlessness. Henads are not Forms, they are principles of unity ingrained in Forms by the One. As henads are more unitary than traditional Platonic Forms, they are the foundational principles of Forms. For Proclus, henads transcend Forms and are the unities or Limit-elements within Forms. For each henad there is only one corresponding Form, i.e. there is a one to one correspondence between henads and Forms, and due to the continuity between henads and Forms, henads are knowable. The late Athenian Neoplatonic doctrine on Henads bridges the gulf between the One and the hypostasis of Nous, where the hypostasis of Nous is the highest realm of Forms. The Neoplatonists Syrianus and Proclus thought the number of Forms is finite.

Late Athenian Neoplatonic theology organized Forms by the following hierarchy:

• primal Forms are in the late Neoplatonic level of Intelligible;
• secondary Forms upon the late Neoplatonic level of Intelligible-Intellectual (intelligible and at the same time intellectual). Secondary Forms bring cohesion to all Forms subordinate to them and they also bring to completion the late Neoplatonic level of Intellectual.
• assimilative Forms through which secondary Forms are made like intellectual Forms;
• intellectual Forms upon the late Neoplatonic level of Intellectual;
• transcendent Forms that unify those forms that are divided in the hypostasis of Soul;
• immanent Forms that participate in the material universe.

In late Neoplatonic theology, forms that arrange and define matter, or measure material generation, are called immanent Forms. Immanent Forms are a whole of parts; the other Forms, or transcendent Forms, are wholes before the parts.

Plato depicted in the fresco The School of Athens by Raphael carrying a bound copy of Timaeus. Plato is an very important authority for Proclus.

Allegory in Plato's Timaeus

In a famous passage of Plato's Timaeus (30a) there is a hint of dualism where the material universe was in disorder before the Demiurge brought it into order.

"For God desiring that all things should be good, and that, so far as this might be, there should be nought evil, having received all that is visible not in a state of rest, but moving without harmony or measure, brought it from its disorder into order, thinking that this was in all ways better than the other."—Plato, Timaeus 30a

Proclus explains that the disorderly motion did not come from any evil principle residing in matter, but through the explicit effect of primal Forms, which are antecedent to the Demiurge. In Platonic and Neoplatonic scholarship, the God that generates the material universe is identical to the Demiurge. The disorderly motion caused by the primal Forms was lacking order until the Demiurge established harmony and measure.

Participation

The Platonic and Neoplatonic doctrine on Participation (Greek: μέθεξις) is the theological explanation of how an immaterial being, known as a Form, can remain undiminished in its hypostasis and simultaneously be present in a material body. A rigorous theological explanation of the doctrine on Participation was keenly sought by scholars of Platonism, Middle Platonism and Neoplatonism since the time of Plato. To elaborate the question is to ask, how can a Form in the hypostasis of Nous; which means the Form is eternal, immobile and an indivisible cause, remain in its hypostasis and simultaneously be manifested in the material universe as a number of material bodies that are temporal, mobile and divisible? The question is regarded by scholars as an objection to Platonism and was raised by Plato himself, through the character Parmenides in his dialogue Parmenides (131a4–e4), and also raised by Aristotle in one of his principal works Metaphysics (Met. Α 9, 991a20–b9 and Met. Ζ 14).

Immanent Forms

The Middle Platonist Alcinous, in his Handbook of Platonism, records a theological explanation of the Platonic doctrine on Participation. In Alcinous' Handbook of Platonism (IV 155.39–41) a distinction is made between primal Forms in the late Neoplatonic level of Intelligible and immanent Forms that arrange and define matter, or measure material generation, in the material universe. For the distinction to be made, a merging of Platonic Forms with Aristotelian formal causes was required and achieved by treating Aristotelian formal causes as equivalent to immanent Platonic Forms. A similar distinction between primal Forms and immanent Forms was made by other Middle Platonists. And also, Proclus in his Commentary on Parmenides and Commentary on Timaeus, thought Plato himself had employed the distinction in his dialogue Parmenides (130b3–5), where Parmenides talks about the Form of likeness as opposed to likeness, and in Timaeus (51e6–52b5), where Timaeus talks about a likeness of the Form of likeness existing in receptacles such as fire, air, water and earth.

Double Activity

In the late Neoplatonic theology, the doctrine on Double Activity provides a rigorous theological understanding of the relationship between Forms and material bodies. The doctrine has its origins in Plotinus' discussion of double activity in his Enneads. The doctrine on Double Activity formally and systematically explains the relationship between a Form and material bodies in such a manner so as to leave the Form undiminished in its transcendence, while simultaneously accounting for production of numerous participants in the hypostasis of Soul. The doctrine on Double Activity rigorously explains that when a Form produces a cause it results in no change to the producing Form itself, i.e. the cause that is produced by the Form in no way diminishes the producing Form, and is simultaneously present in the material world as images of the Form that impose a likeness of the Form upon the material participants.

The late Neoplatonic theological doctrine on Double Activity is formalized in Proclus' Elements of Theology propositions 23 and 24 and elaborated on in Proclus' Commentary on Parmenides (Book VI 1069.21–1070.12) and Proclus' Commentary on Timaeus I.240.6–248. The formalization is in terms of the triad unparticipated, the participated and the participant. The doctrine on Double Activity distinguishes between the object of participation, the participant, the attributes it receives from the participated Form, and the attributes of the eternal transcendent unparticipated Form. The hierarchy of Forms allows the unparticipated Form to preserve its transcendent unity and allows the explanation of the unchanged character of formal principles in material bodies.

Specifically, Elements of Theology proposition 23 claims if immaterial Forms are to participate in the material world, they must be immanent Forms, and therefore divided. However, if one undivided immaterial Form is participated by divided immaterial Forms, the undivided immaterial Form must be a transcendent Form, or a Form that is not directly participated, i.e. an unparticipated Form. The transcendent Form, or unparticipated Form, is related to immanent Forms as a monad is to other members of its series as it gives unity to the many immanent Forms and only affects the material world like Aristotle's God, i.e. it is strictly unparticipated. Logically, the word intension is equivalent to the metaphysical term unparticipated; the word extension is logically equivalent to participants, and the link between intention and extension is participation. Hence, the participated Form receives the intention of the unparticipated Form and creates, through it, the extension, or participants.

Principles of Reason

For early Platonists, it was through principles of reason (Greek: λόγοι or logoi), housed in a soul, that enabled a soul to have an innate conception of Forms. Principles of reason are a corollary to the Platonic theory of Memory of the Forms, or Platonic anamnesis, where a human soul brings forth principles of reason from within itself and so has a memory of Forms that caused the principles of reason. The roots of the early Platonic understanding of principles of reason are in Plato's Phaedo and in Plato's Meno and elaborated on in Plato's Phaedrus.

Early Neoplatonic doctrines of Plotinus in Enneads (2.3.17 and 3.5.9) identify the creative power of a Form with principles of reason in a soul, or logoi in a soul. Plotinus' early Neoplatonic doctrine on Principles of Reason held that principles of reason progress from Forms that are in the hypostasis of Nous, specifically the level of Intellect, and are the formative and organizing principles of material bodies. Plotinus' doctrine on Principles of Reason were a modification of the Stoic theory of seminal principles of reason (Greek: λόγοι σπερματικοὶ or logoi spermatikoi) and were further advanced by the late Athenian Neoplatonic theology of Proclus.

Proclus' doctrine on Principles of Reason (Commentary on Parmenides Book III 795.25-796.9and Elements of Theology proposition 177) claim the hypostasis of Nous is a plenitude of Forms (Greek: πλήρωμα εἰδῶν). These Forms are present in the three divisions of the hypostasis of Nous called: (1) Intelligible, (2) Intelligible-Intellectual and (3) Intellectual, in a suitable manner. As the Forms progress from Nous, they are further divided and multiplied and are finally participated by a number of temporal and material particulars that disperse the productive power of the Forms into images of the Form in the material world, and hence natural material bodies are images of their Forms.

Progression of Forms

In late Neoplatonic theology, Soul is a hypostasis between the hypostasis of Nous and the natural material world, whereby souls govern and generate natural material bodies through principles of reason. Soul actively receive Forms from the hypostasis of Nous and animate them, thereby giving motion to the stable being of Nous. Souls progress into Nature and generate natural principles of reason, or immanent Forms, that are manifested in natural material bodies, where here Nature is an irrational agent operating as an internal principle that is inseparable from natural material bodies.

Late Athenian Neoplatonic theology divides Forms in the hypostasis of Nous according to their idiosyncrasies, each acting as a monad for a series of participant Forms in the subsequent hypostasis of Soul. This provides a multitudinous variety of Forms, all progressing from one transcendental monad at the summit of the hypostasis of Nous.

In the late Neoplatonic theological understanding of a series of Forms, each participant of the series shares the particular (Greek: ἰδίωμα) characteristic of the Form that is at a higher level in the series. However, the further removed a participant is from the monad of its series, the less powers (Greek: δυνάμις) it will retain from the monad of the series. For example, all participants of the Form of Human will share the particular characteristic of being human, however only the unparticipated transcendental Form will have the power to be indivisible, eternal, and changeless. It is Proclus' understanding that powers determine the different appearances of Forms in participated material bodies.

Proclus' doctrine on Progression of Forms (Elements of Theology propositions 99-101 and 108–110) formalizes and systematizes the participation of Forms in the hypostasis of Nous, and is elaborated on in Commentary on Parmenides Book III 795.25–796.9.

Paradigmatic Causes

In late Neoplatonic theology, everything in the material world is an image of Forms caused by the level of Intellect, hence the fundamental purpose of Forms is to be a paradigmatical cause of the material world. The treatment of Forms as a paradigm has its roots in Plato's Timaeus (30c and 31b) and Parmenides (132d3). That treatment of Forms as a paradigm was extended to become a paradigmatical cause by heads of Plato's Old Academy Speusippus, and Xenocrates, and popularized among Platonists of the New Academy. By the time of the Middle Platonists, Aristotle's theory of four causes (efficient, material, formal and final) was commonly extended to include a fifth cause, the Platonic paradigmatical cause. The late Athenian Neoplatonists Proclus and Hermias sometimes complemented the five causes by a sixth cause, the instrumental cause, that transmitted the efficiency of causes from higher levels to causes on a subsequent levels.

A central proposition of the late Neoplatonic theology of Proclus is that a cause is immaterial and that it transcends its effects (Elements of Theology proposition 75). Hence the immanent Forms, which are equivalent to Aristotelian formal causes, and material causes that form material bodies from material substances, are not regarded by late Neoplatonists as primary causes. Proclus treated Aristotelian material causes and formal causes as secondary causes, similarly he regarded instrumental causes as secondary causes. Thus, for late Neoplatonists, the primary causes were the Final cause, paradigmatic causes, and efficient causes and it is primarily these three types of causation that encompass the activity of Forms in the hypostasis of Nous.

In the theology of the late Neoplatonists, the Final cause is the One and the Good and is antecedent to the Intelligible level, paradigmatical causes are in the intermediate level Intelligible-Intellectual (intelligible and at the same time intellectual) and efficient causes are in the Intellectual level, where the Demiurge is the primary efficient agent. For late Neoplatonists, the Final cause is the One and the Good and is thus antecedent to Forms, whilst paradigmatical causes that govern progression, are inferior to Forms, and hence Neoplatonic Forms, at their highest level, are a median between the Final cause and paradigmatical causes, i.e. between the One and the Good and the summit of the Intelligible-Intellectual level, whereby Forms strive for the Final cause whilst struggling with paradigmatical causes.

Soul

The Neoplatonic theological doctrine on Soul describes the hypostasis Soul, which is between the hypostasis of Nous and the material universe. The roots of the doctrine are in Plato's Timaeus. The Platonic theory of Soul claimed a soul was an immaterial being that settled into a material body and animated that body through its hierarchy of faculties: rational intellect, motion, nutrition and growth. In the Platonic theory of Soul, the soul's faculty of rational intellect is separable from its material body and is immortal. Further the theory claimed gods, humans, animals, plants and stones had certain faculties of a soul, but only gods and humans had all the faculties of a soul, specifically, only gods and humans had the soul's faculty of rational intellect.

The late Athenian Neoplatonists formalized and systematized the early Neoplatonic doctrine on Soul in Proclus' Elements of Theology propositions 21, 109, 164–166 and 184–211 and elaborated the doctrine in Proclus' Commentary on Timaeus. Propositions 184–211 systematically explain the late Neoplatonic arguments for the generation of human souls from the Neoplatonic hypostasis of Nous, their progression from to the Neoplatonic hypostasis of Soul, their subsequent generation into the material universe, and their return from the material universe to the hypostasis of Soul.

A fundamental difference between the hypostasis of Nous and the hypostasis of Soul is that the movement of souls in lower divisions of the hypostasis of Soul is temporal, whereas Forms conceived in the hypostasis of Nous are eternal and unmoving and their progression into higher divisions of the hypostasis of Soul is instantaneous. Ancient scholars had a saying about Forms and souls, specifically mentioned by Hippolytus of Rome in his Refutation of All Heresies, which says that "Forms are called souls, having been cooled down..." In that saying, there is a pun between the ancient Greek word for soul, ψυχή, and the ancient Greek word for cold, ψῦχος.

Characteristics of Soul

In Neoplatonic scholarship, the ancient Greek word 'ψυχή' is translated to the English word 'soul'. Originally, since at least the time of Anaximenes, the meaning for the ancient Greek word 'ψυχή' was 'life-breath', and similarly the ancient Greek word for 'alive' was 'ἔμψυχή', that is literally translated by scholars to 'ensouled'; hence there has been a long tradition in Greek thought for the close association between the concepts of 'soul' and 'life'.

Immortal

In Plato's Phaedo, the argument for immortality of the soul turns on the impossibility of conceiving a dead soul and rests on the assumption that a soul possesses life, not by chance, but by its own right and that a soul cannot be destroyed after its separation from a body. That traditional definition of a soul was fundamental to the Neoplatonists Plotinus, Porphyry, Iamblichus, and Proclus, who uses his authorities to once again argue in favour of that definition in Elements of Theology propositions 188–189, which assert that every soul is a principle of life and a living being. Also in proposition 188, Proclus distinguishes a soul from the Form of Life (from Plato's Phaedo 106d) which in late Athenian Neoplatonic theology is a being upon the Intelligible level, antecedent to the Neoplatonic hypostasis of Nous. Proclus' Elements of Theology propositions 186–187 summarily explain, by applying the results of propositions 15–17 and 47–49 to the late Neoplatonic doctrine on Soul, that every soul is immaterial, separable from a material body, indestructible and immortal.

Intermediary

In Proclus' Elements of Theology, proposition 190 claims every soul is an intermediary between the indivisible Forms in the hypostasis of Nous and the divisible material universe. That claim of a soul's intermediary character has its roots in Plato's Timaeus 35a and was also asserted before Proclus by Xenocrates, Eratosthenes, Poseidonius, Philo in De Opificio Mundi XLVI (135), Plutarch, Atticus, Numenius, the Chaldaean Oracles in Corpus Hermeticum I.15, Plotinus in Enneads 4.4.15, and other early and late Neoplatonists, and was subsequently also a claim made by Saint Thomas Aquinas in his Summa contra Gentiles where he writes,

"the human soul...is on the boundary line of corporeal and incorporeal substances, as though it were on the horizon of eternity and time..."—Saint Thomas Aquinas

About 800 years before Saint Thomas Aquinas, Proclus in his Elements of Theology propositions 191–192, asserted that every soul participates of both eternity and time and therefore is a perpetual being whilst also coming-to-be in the material universe. Those assertions were justified by Proclus using Plato as his authority, specifically Timaeus 37a and Laws 904a. Further, in Elements of Theology proposition 193, Proclus claims that the hypostasis of Soul is immediately subsequent to the hypostasis of Nous and is generated by the hypostasis of Nous, the hierarchical aspect being an adoption of Iamblichus' doctrine on Grades of Soul, while the generative aspect retained elements of Plotinus' doctrine on Soul.

Image of all Forms

In his discussion on the early Neoplatonic hypostasis of Soul, Plotinus, in Enneads 6.5.7, claims that each soul possesses all Forms, a claim that has its roots in Aristotle's De Anima 3.8 431b21. However, the late Neoplatonic theology of Proclus, Elements of Theology propositions 194–195, claim that all Forms are only potentially in each soul, but this potentiality is only actualized in the unparticipated First Soul and is not actualized in any other soul. Hence, in late Athenian Neoplatonic theology, each soul, apart from the First Soul, is claimed to possess only reflections, or images, of all Forms, and that also applies to each soul that is embodied in the material universe. So, for Proclus, human science has an imperfect knowledge, or concept, of Forms, as each soul possesses only images of all the Forms and not the Forms themselves. Hence, the late Neoplatonic doctrine on Soul rejects the mysticism of Plotinus, who claimed each soul possesses all Forms and a human could achieve some sort of mystical unification with the hypostasis of Nous.

Indivisible

In his dialogues, Plato discusses parts of a soul, however the Neoplatonic claim, since the time of Porphyry and Iamblichus, was that these parts did not relate to a soul's immaterial essence and the quantitative expressions of the essence of a soul made known through the material body's organs. Despite a soul being an immediate consequent of the hypostasis Nous, that is comprised of indivisible Forms, a soul is also claimed to be indivisible by Proclus, in Elements of Theology proposition 197. In that proposition, Proclus also claims that because of its intermediary location between the Neoplatonic hypostasis of Nous and the material universe, the principles of being, life and intellect in the Neoplatonic hypostasis of Soul are indivisible in a different sense to Forms and are divided differently to material beings and material bodies. As to what exactly the different sense is, Proclus does not make it clear.

Classification of Souls

20th and 21st century scholars of late Neoplatonism have assigned various names to Proclus' hierarchical division of beings in the hypostasis of Soul, those beings in hierarchical order include (a) the Unparticipated Soul, or the First Soul; (b) the transcendent World Soul and the immanent World Soul; (c) the immanent souls of the stars and seven planets, or divine souls (d) souls of sublunary gods, angels, daemons and heroes; and (e) human souls. Particular souls of animal and plant life, and particular souls of material bodies such as stones, are not considered by Proclus as souls, but rather as phantasms of souls, as in late Athenian Neoplatonic theology, animals, plants and material bodies lack the soul's faculty of rational intellect.

First Soul

In late Athenian Neoplatonic theology, each hypostasis, the One, Nous and Soul, progresses into further plurality through a series of causation from a unifying cause, called a monad, The plurality of souls in the Neoplatonic hypostasis of Soul is caused by a progressive series of causation from a monad that is called by Neoplatonic scholars the First Soul, or Unparticipated Soul. The roots of this type of formalization are in the Pythagorean concept of arithmetical series, where each member of the series is generated by the preceding member and the entire series is generated by the first member, or monad.

Replica of a bust of Plato by Silanion c. 370 BC for the Academia in Athens. Plato is a very important authority for Neoplatonic philosophers.

The First Soul is also called the Unparticipated Soul because it does not participate in the hypostasis of Soul, it participates in the hypostasis of Nous. The impetus for including the First Soul, or Unparticipated Soul, in the early Neoplatonic theology of Plotinus and the late Athenian Neoplatonic theology of Proclus is Plato's Phaedrus 247c:

"But the region above the heaven was never worthily sung by any earthly poet, nor will it ever be. It is, however, as I shall tell; for I must dare to speak the truth, especially as truth is my theme. For the colourless, formless, and intangible truly existing essence, with which all true knowledge is concerned, holds this region and is visible only to the mind, the pilot of the soul."—Plato, Phaedrus 247c

To the early Neoplatonist Porphyry there was no distinction made between the Demiurge and the First Soul, or Unparticipated Soul; however, to Iamblichus and the late Athenian Neoplatonists, the Demiurge was distinct from the First Soul, or Unparticipated Soul.

The First Soul is generally discussed by Aristotle in De Amima 2.4 and Porphyry in Enneads 4.3.4 and 2.9.4, and is systematically formalized by Proclus in Elements of Theology proposition 21 (where the First Soul is called Primal Soul), proposition 109 (where the First Soul is called the Universal Soul) and propositions 164–166 (where in proposition 164 the First Soul is called the Unparticipated Soul). The First Soul is elaborated on by Proclus in Commentary on Timaeus II.105.15 ff. where the First Soul is called the Unparticipated Soul and Commentary on Timaeus II.143.21 ff. where the First Soul is called by 21st century scholars the indivisible case of a hypercosmic soul, or hypercosmic intellect.

World Soul

The Platonists thought the material universe was a living being, so it too had a soul, called the World Soul, which animated and provided structure to everything in the material universe, including all living creatures, and therefore had all the faculties of a soul including the soul's faculty of rational intellect. In Timaeus 34b, Plato claimed that the World Soul was an immaterial being that provided reason, movement and structure to the material universe, and that it was generated by the Demiurge who set it in the centre of the material universe.

"All this, then, was the plan of the god who is for ever for the god who was sometime to be. According to this plan he made it smooth and uniform, everywhere equidistant from its centre, a body whole and complete, with complete bodies for its parts. And in the centre he set a soul and caused it to extend throughout the whole and further wrapped its body round with soul on the outside; and so he established one world alone, round and revolving in a circle, solitary but able by reason of its excellence to bear itself company, needing no other acquaintance or friend but sufficient to itself. On all these accounts the world which he brought into being was a blessed god."—Plato, Timaeus 34a–b

In their explanation of the generation of the material universe, the late Athenian Neoplatonists Syrianus and Proclus introduced a double aspect to Plato's World Soul and asserted one aspect of it was transcendent to the encosmic (or mundane) level in the hypostasis of Soul. The encosmic level comprises temporal souls including the immanent World Soul, angels, daemons and heroes and human souls. In the late Neoplatonic theology of Proclus, the aspect transcendent to the encosmic realm is called the transcendent World soul, and the aspect immanent to the material universe is called the immanent World Soul.

In the late Neoplatonic doctrine on Soul, the transcendent aspect of the World Soul is an immediate consequent of the First Soul and is the unifying cause of the encosmic realm. Hence, the transcendent aspect of the World Soul is also called the monad of the encosmic realm and through a continuous series of causation, generates the immanent aspect of the World Soul that encompasses the material universe and imbues it with souls.

In late Neoplatonic theology, the two aspects of the World Soul provide a continuous series of causation throughout the Neoplatonic hypostasis of Soul and into the material universe, thereby providing the material universe with unity, form and animation and hence giving it life, reason, movement, mutability and structure; the structure explained by mathematical ratios and proportions. A detailed discussion of the late Neoplatonic conception of the World Soul is in Proclus' Commentary on Timaeus II.102–317 especially Timaeus II.290.3 ff.

Divine Souls

Plato's belief that stars have divine souls is stated in his dialogue Laws 899b, where the Athenian Stranger says :

"And of the seasons, stars, moon, and year, in like manner, it may be affirmed that the soul or souls from which they derive their excellence are divine; and without insisting on the manner of their working, no one can deny that all things are full of Gods."—Plato, Laws 899b, abridged

The dictum 'all things are full of gods' is explicitly attributed to Thales by Aristotle in De Anima 411a7. Also, Platonists and Neoplatonists believed Mercury, Venus, Mars, Jupiter, Saturn, the Sun, Moon and Earth had divine souls. Plato's claim that divine souls are embodied in stars, planets and the Earth led some 19th, early 20th, and 21st century scholars of philosophy and Neoplatonism to refer to the divine souls of the stars, planets and the Earth as 'celestial gods'. For Platonists and Neoplatonists, the belief the stars, the seven planets, where the Sun and Moon are regarded as planets, and the Earth have divine souls, has its roots in Plato's Timaeus 34a–40c. In those lines, Plato claims the immanent World Soul's reason and intellect is manifested in the axial rotation of the entire spherical universe and that axial rotation causes the forward motion of the stars, planets and Earth, which also have their own axial rotation caused by the reason and intellect of their individual divine souls. The hierarchical order of generation by the Demiurge of the World Soul, then divine souls, is stated in Timaeus 40a.

"The form of the divine kind he made for the most part of fire, that it might be most bright and fair to see; and after the likeness of the universe he gave them well-rounded shape, and set them in the intelligence of the supreme to keep company with it, distributing them all round the heaven, to be in very truth an adornment (cosmos) for it, embroidered over the whole. And he assigned to each two motions: one uniform in the same place, as each always thinks the same thoughts about the same things; the other a forward motion, as each is subjected to the revolution of the Same and uniform."—Plato, Timaeus 40a

In their interpretation of Plato's Timaeus 40a, the late Athenian Neoplatonists regarded the 'intelligence of the supreme' as the intelligence of the World Soul and 'heaven' as the sublunary gods, 'cosmos' as the material universe and 'thoughts about the same things' as an axial rotation. Proclus, in Elements of Theology proposition 201, echoes the three activities of divine souls inferred in Plato's Timaeus 40a, the first being the activity of a soul in its embodiment of stars, the seven planets and the Earth, the second as a recipient of a divine intelligence from the World Soul and the third to impart axial rotation and forward motion to the stars, seven planets and the Earth.

The belief of Plato that stars have divine souls was passed into the broad range of Hellenistic ideas, and into Stoicism by Hierocles, into the early Neoplatonism of Plotinus (in his Enneads 6.9.8), into the Neoplatonism of Iamblichus and into the late Neoplatonic theology of Proclus (in Elements of Theology proposition 184) where he, like Plato, infers the souls of stars, the seven planets and the Earth, are divine souls. Further, the Neoplatonist Iamblichus and late Athenian Neoplatonists Syrianus and Proclus claimed that divine souls were gods in the hypostasis of Soul, but were the attendants (Greek: ὀπαδός; from Phaedrus 252c) of gods in the hypostasis of Nous. That claim, stated formally by Proclus in Elements of Theology proposition 185, has its roots in Plato's Phaedrus 248a.

Such is the life of the gods; but of the other souls, that which best follows after God and is most like him, raises the head of the charioteer up into the outer region and is carried round in the revolution, troubled by the horses and hardly beholding the realities; and another sometimes rises and sometimes sinks, and, because its horses are unruly, it sees some things and fails to see others. —Plato, Phaedrus, 248a

Daemons

In late Athenian Neoplatonic theology, daemons (Greek: δαίμονες) are a realm of souls between divine souls and human souls that are subdivided into sublunary gods, angels, daemons proper, and heroes. In Plato's dialogue Cratylus, his analysis of the Ancient Greek word 'δαίμονες', translated into English as 'daemons' (and sometimes 'spirits', or 'divinities'), leads him to the conclusion that the word was originally used by Hesiod to mean wise and 'knowing'. In Platonism, the introduction of a realm of souls between divine souls and humans has its roots in Plato's Symposium (or The Banquet) 202d–e (from The Speech of Socrates):

"Love is no God.—What! said I, must Love then be a mortal ?—Far from that, replied she.—Of what nature was he then? I asked her.—Of like kind, answered she, with those natures we have just now been speaking of, an intermediate one, between the mortal and the immortal.—But what in particular, O Diotima?—A great daemon replied she. For the daemon-kind is of an intermediate nature between the divine and the human."—Plato, Symposium 202d–e

The Platonic realm of souls called daemons were elaborated on in the Old Platonic Academy dialogue Epinomis (984b, 984d, and 984e), written about by Xenocrates, a head of the Old Platonic Academy, and were specifically studied by Poseidonius and his school. Plotinus, using Poseidonius' formulation, writes briefly about daemons (or spirits) in Enneads 3.5.6 and 6.3.18, while Porphyry writes more extensively about daemons in On the Abstinence of Eating Animals 2.37 ff. However, much of the Middle Ages belief in daemons is from extensive elaborations by Proclus in his Commentary on Timaeus and Commentary on First Alcibiades. Specifically, Proclus, in his Commentary on Timaeus Book V, subdivides the Platonic realm of souls called daemons into sublunary gods, angels, daemons proper, and heroes, the last three subdivisions are consistent with Celsus.

Sublunary Gods

In Timaeus 40d Plato writes: "To speak however, concerning the other daemons, and to know their generation, exceeds our ability." Proclus, in his commentary on that line in Commentary on Timaeus Book IV, claims Plato is writing about sublunary gods, and after an extensive analysis of Plato's Timaeus lines 40d–41a concludes his commentary on sublunary gods with:

"The sublunary Gods therefore, are entirely unmingled with matter; adorning indeed things mingled in an unmingled, and things generated in an unbegotten manner. They likewise contain partibles impartibly, are the causes of life, the suppliers of intellect, the replenishers of power, the givers of soul, the primary leaders of all good, and the sources of order, providence, and the best administration. They also give subsistence to more excellent animals about themselves, are the leaders of angels, the rulers of daemons [proper], and the prefects of heroes; governing through this triple army the whole of generation."—Proclus, Commentary on Timaeus, Book V

Angels, Daemons proper and Heroes

Whilst Plato filled the theological realm between divine souls (or celestial gods) and humans with one order of daemons, Proclus elaborates Plato's hierarchy and subdivides the realm into sublunary gods, angels, daemons proper and heroes. In his Commentary on Timaeus Book V, Proclus expands his theology of angels, daemons proper and heroes, by relating each to one of the three fundamental principles of Neoplatonic theology, being, life and intellect.

"For the angelic is analogous to being, or the intelligible, which is first unfolded into light from the ineffable and occult fountain of beings. Hence also it unfolds the Gods themselves, and announces that which is occult in their essence. But the daemoniacal is analogous to infinite life. On which account it proceeds every where, according to many orders, and is of a multiform nature. And the heroic is analogous to intellect and conversion. Hence also, it is the inspective guardian of purification, and is the supplier of a magnificent and elevated life."—Proclus, Commentary on Timaeus, Book V

For the late Athenian Neoplatonists, divine souls too had attendants, these attendants are called angels and are a subdivision of the Neoplatonic grade of souls called daemons. A formalization of that claim is in Proclus' Elements of Theology proposition 202 where he states that the attendants of divine souls are subsequent to divine souls, but antecedent to particular souls of daemons proper, particular human souls that are heroic, and particular human souls. Further, in his Elements of Theology proposition 203, Proclus states that divine souls are greater in power, but more unified and hence less in number than daemons proper which are themselves greater in power but more unified and less in number to particular souls of heroes and particular human souls. Here, the general late Neoplatonic argument, formalized by Proclus in Elements of Theology proposition 204, is that as a monad progresses into plurality, it makes up in numbers what it loses in power. A similar argument was used by the 11th century Byzantine philosopher Psellus in De Omnifaria Doctrina 19 in his claim that humans are more numerous than angels. For Proclus, the roots of his argument for proposition 203 are in Plato's Timaeus 42d in which the interpretation for 'instruments of time' is planets:

"When he had delivered to them all these ordinances, to the end that he might be guiltless of the future wickedness of anyone of them, he sowed them, some in the Earth, some in the Moon, some in all the other instruments of time. After this sowing he left it to the newly made gods to mould mortal bodies, to fashion all that part of a human soul that there was still need to add and all that these things entail, and to govern and guide the mortal creature to the best of their powers,..."—Plato, Timaeus 42d

Scholars think that Plato in Timaeus 42d intended souls sowed into planets to be its eventual denizens; however, Proclus, in Commentary on Timaeus III.280.20, regards them as human souls on the Earth placed under the leadership of particular planetary souls, that are their saviours and special patrons, and where each human soul acquires particular natural abilities from the soul of their divine patron planet, arbitrated by the souls of daemons sown into that planet.

Embodied Daemons

As to where embodied daemons (i.e. the embodied souls of angels, daemons proper and heroes) are generated in the material universe, the late Neoplatonists drew their ideas from interpretations of Timaeus 39e10–40a1:

"So many forms then as Mind perceived to exist in the ideal animal, according to their variety and multitude, such kinds and such a number did he think fit that this universe should possess. These are fourfold : first the race of the heavenly gods, next the winged tribe whose path is in the air, third whatso dwells in the water, and fourth that which goes upon dry land."—Plato, Timaeus 39e10 - 40a1

There have been important interpretations of Timaeus 39e10–40a1 by the Neoplatonist Iamblichus and late Neoplatonists Syrianus and Proclus. Proclus' interpretation agrees with his teacher Syrianus in preserving the hierarchical order of the regions, i.e. heavenly, aerial, watery, and dry land regions, but without assuming that the hierarchical order of the regions corresponded to an order of preference by daemons. The immaterial heavenly regions were only the realm of souls of sublunary gods, angels and daemons proper. The material aerial and watery regions could be inhabited by material angels, daemons proper, heroes and other material beings that in the case of aerial regions, lead their lives in the air, such as birds or in the case of watery regions, that thrived in water, such as fish; and the dry land could be inhabited by material angels, daemons proper, heroes, humans and other material beings that arose from the land and grew in it.

Ókhēma-Pneûma

In his Elements of Theology proposition 196, Proclus claims that since every soul that participates in the Neoplatonic hypostasis of Soul has a perpetual existence, and since the invariable essence of those souls is to animate a body, then for every such soul there is a body that is animated perpetually, and consequently that body is also perpetually existent.

Proposition 196 is a formalization by Proclus of a long held Greek theory called by scholars 'ókhēma-pneûma' (Greek: ὂχημα-πνεῦμα) where 'ókhēma' means chariot and 'pneûma' means spirit. The use of the term 'astral body' (Greek for 'astral': ἀστροειδες) to describe ókhēma or pneûma or ókhēma-pneûma, (i.e. a body that is perpetually animated by a soul), seems to come from Proclus. Scholars also use the terms 'first body' or 'vehicle of a soul' when referring to an astral body.

Plato and Aristotle

For early and late Athenian Neoplatonists, the origin of the ókhēma-pneûma doctrine came from the Platonic dialogues Phaedo 113d where boats return souls of the dead on Acheron, Phaedrus 247b which contains the chariot allegory, Timaeus 41e where stars are compared to chariots, and Timaeus 44e and 69c where the mortal body is called the soul's chariot; but especially from Laws 898e:

"Athenian Stranger: If soul drives round the sun, we shall be tolerably sure to be right in saying that it does one of three things.

Clinias: What things?

Athenian Stranger: That either it exists everywhere inside of this apparent globular body and directs it, such as it is, just as the soul in us moves us about in all ways; or, having procured itself a body of fire or air (as some argue), it in the form of body pushes forcibly on the body from outside ; or, thirdly, being itself void of body, but endowed with other surpassingly marvellous potencies, it conducts the body."—Plato, Laws Book X 898e

In Plato's Laws 898e, the second possibility proposed by the Athenian Stranger of a soul "having procured itself a body of fire or air, it in the form of body pushes forcibly on the body from outside" suggested to late Athenian Neoplatonists the beginnings of a doctrine for an astral body. Together, the six Platonic references formed the basis of what late Neoplatonists and modern Neoplatonic scholars term the ókhēma doctrine.

Plato (left) and Aristotle depicted in the 1509–1511 fresco The School of Athens by Raphael. Both Plato and Aristotle are very important authorities for Proclus.

In his development from ókhēma doctrine to the late Athenian Neoplatonic ókhēma-pneûma doctrine, Proclus, in his Commentary on Timaeus III.28.20, uses as his authority, Aristotle's doctrine of pneûma (Greek: πνεῦμα), which is stated in Aristotle's De Generatione Animalium 736b27 ff. In the philosophy of Aristotle, pneûma is the basis for every nutritive and sensitive soul as well as a basis for the physiological condition of imagination (Greek: φαντασία), and further, pneûma is made of a material similar to the stars.

"Now it is true that the faculty of all kinds of soul seems to have a connexion with a matter different from and more divine than the so-called elements; but as one soul differs from another in honour and dishonour, so differs also the nature of the corresponding matter. All have in their semen that which causes it to be productive; I mean what is called vital heat. This is not fire nor any such force, but it is the spiritus included in the semen and the foam-like, and the natural principle in the spiritus, being analogous to the element of the stars."—Aristotle, De Generatione Animalium Book II.3 736b30 ff.

Although Aristotle's doctrine of pneûma theorized pneûma was a material element in a body common to humans and animals, and its means of transmission was biological reproduction, there were definite aspects in common with the late Athenian ókhēma-pneûma doctrine. Aristotle's doctrine of pneûma and Proclus' doctrine of ókhēma-pneûma both agreed that pneûma was the carrier of the irrational aspect of a soul, and also agreed on its important association with imagination and its intuitive quality.

After Aristotle and before late Neoplatonism, scholars have found theories of ókhēma or pneûma in the works of Poseidonius, Alexander Polyhistor, Atticus, Albinus, Galen, Ptolemaeus Chennus, Numenius, Hippolytus of Rome, Origen, the writers of the Corpus Hermeticum, Plotinus, Porphyry, Iamblichus, and the Chaldean Oracles.

Neoplatonism

The early Neoplatonism of Plotinus attached little importance to the theory of pneûma, although in Enneads 4.3.15 he echoes Poseidonius theory of pneûma by suggesting that soul's acquire a body from the heavens (called sublunary gods by the late Athenian Neoplatonists) before their embodiment in the material universe and in Enneads 4.3.24 he also echoes Poseidonius by suggesting that the body acquired from the heavens returns to the heavens before the soul's progression to more divine realms. Porphyry was more elaborate than Plotinus in his writings on the theory of pneûma, but still echoed Poseidonius' theory of pneûma; however he closely connected pneûma with the irrational soul (which St. Augustine calls 'anima spiritalis') and seems to have originated the idea that daemons have a misty pneûma that can change form at will, thus causing them to appear as ever changing shapes in the material universe, sometimes acting as gods, higher spirits or the souls of the dead.

Late Neoplatonism

The late Roman Neoplatonist Macrobius in his Commentarii in Somnium Scipionis 1.2.13, 1.11.12 and 1.12.13, writes that a soul acquires a starry or luminous body in its progression from the sublunary gods into the material universe. Also, the late Alexandrian Neoplatonist Hierocles of Alexandria writes about his ókhēma doctrine in his Commentary on the Golden Verses of Pythagoras 478, which scholars think is derived from Plutarch of Athens.

In late Athenian Neoplatonic theology, Syrianus and Proclus combine the earlier traditions of ókhēma and pneûma into their ókhēma-pneûma doctrine. The traditions they combine are (a) the theory of ókhēma ascribed to Ptolemaeus Chennus and Iamblichus, where an astral body is the permanent embodiment of each soul, and (b) the theory of pneûma ascribed to Plotinus, Porphyry and the Chaldean Oracles, were the soul acquires an astral body from the sublunary gods before it is embodied in the material universe, which subsequently returns to the sublunary gods before the soul's progression to more divine realms.

In the ókhēma-pneûma doctrine of Syrianus and Proclus there are two aspects to an astral body, (a) the transcendent aspect that is immaterial, incapable of suffering, imperishable and is the perpetual source of irrationality in a human soul, and (b) the immanent aspect that is a temporary accumulation made of fire, water, air and earth (in agreement with Plato's Timaeus 42b) that carries the irrational soul proper, survives bodily death, but is eventually purged. In the ókhēma-pneûma doctrine, souls are always embodied, agreeing with Plato's Phaedo 113d and Phaedrus 247b, and the irrational soul proper is perishable, agreeing with Plato's Timaeus 69c and Republic 611b ff.

Formalization and Systemization

The ókhēma-pneûma doctrine of Syrianus and Proclus is formalized and systematized in Elements of Theology propositions 196 and 207–210 and elaborated on in Commentary on Timaeus III.236.31 ff. and III.298.12 ff. In late Athenian Neoplatonic theology, the transcendent aspect of the astral body is the ókhēma, or chariot into which the Demiurge of Plato's Timaeus 41d–e places a human soul:

"And when he had compounded the whole, he portioned off souls equal in number to the stars and distributed a soul to each star, and setting them in the stars as though in a chariot..."—Plato, Timaeus 41d–e

Plato's Timaeus 41d–e is the foundation for Elements of Theology proposition 207, where Proclus formalizes his claim that every astral body, like every soul, is generated from the principal monad in the Neoplatonic hypostasis of Nous, also known as the Demiurge of Plato, and is, like the soul which it embodies, perpetual. That proposition is elaborated on in Proclus' Commentary on Timaeus III.282.2. In Elements of Theology proposition 208, Proclus builds on previous propositions, especially the important proposition 196 where it is argued that every astral body is perpetual, by claiming that every astral body has a transcendent aspect that is immaterial, imperishable and incapable of suffering. Those properties of the astral body are elaborated on in Plato's Theology III.5 and Commentary on Timaeus II.60.2 ff.

In his penultimate proposition on the ókhēma-pneûma doctrine, Elements of Theology proposition 209, Proclus claims that like souls that progress into the material world thus acquiring irrational principles, so too the immaterial, or transcendent, aspect of the astral body becomes immanent and more materialized. That proposition also claims that an astral body experiences all manner of changes in empathy with the soul it embodies including being divested of its immanent and materialized aspect, like the soul is divested of its irrational principles, when it, together with the soul it embodies, returns to the Neoplatonic hypostasis of Soul.

The last proposition by Proclus of his ókhēma-pneûma doctrine is stated in his Elements of Theology proposition 210, where he uses the results of propositions 207 and 209 to argue that the immaterial transcendent aspect of an astral body is invisible perpetually, but the immanent aspect of the astral body changes shape as it acquires and sheds its materiality in its progress into and out of the material universe. Proposition 210 is elaborated on for the class of daemon souls, which includes the souls of angels, daemons proper and heroes, in Commentary on Cratylus 35.22 and Plato's Theology III.5.

Ruled by a Divine Soul

Further, in the late Athenian ókhēma-pneûma doctrine, the personality of an astral body is ruled by a divine soul, specifically, the divine soul of a planet from which it inherits its characteristics. That aspect of the ókhēma-pneûma doctrine is formalized by Proclus in Elements of Theology proposition 205 and elaborated on in Commentary on Timaeus III.305.4 and Commentary on Parmenides 822.16 ff. The roots of this feature of the ókhēma-pneûma doctrine are Plato's Timaeus 42d, where Plato writes about souls being sowed into the Earth and planets, and in Aristotle's De Generatione Animalium Book II.3 736b30–31. There Aristotle writes: "Now it is true that the faculty of all kinds of soul seems to have a connexion with a matter different from and more divine than the so-called elements". In his ókhēma-pneûma doctrine, Proclus extends Aristotle's meaning of matter to the astral body.

Periodicity of Souls

In Timaeus 37d, Plato, indicating his claim that time is infinite, writes:

"time is an image of eternity"—Plato, Timaeus 37d

Plato also claimed that time is infinite in Republic Book 6 499c, Laws 782a and 676b, likewise, Aristotle also claimed that time is infinite in Physica 3.7 207a33–208a4; however the space which the material universe fills was claimed to be finite by both Plato and Aristotle in De Caelo 1.5 271b28–272a19 and Physica 3.7 207b19–20, and orthodox science of Late Antiquity.

Proclus adopted Aristotle's theorem (in Physica 8 (Θ) 8 and 9) that movement in a finite space must return to its starting point if the movement is continuous through an infinite time, and he also adopted Aristotle's theory that the continuous and perpetual movement was circular. In Elements of Theology propositions 198 and 199, Proclus not only applied Aristotle's theorem to the material universe, but also to immaterial planetary souls and immaterial human souls, with his authorities being Plato's Phaedrus 246b and Timaeus 36b ff. For Proclus, the periodicity of a human soul, or its cyclic period, is not one human life, but rather it encompasses the entire time from a soul's initial progression from the Neoplatonic hypostasis of Soul into a human body, to the time of the soul's return to its original purity upon the Neoplatonic hypostasis of Soul.

Further, in Elements of Theology proposition 200, Proclus applies Aristotle's theorem to the immanent World Soul, or the soul of the material universe, and claims it too has a cyclic period, that is much greater than a human soul, and that there are an infinite number of those cycles. The late Neoplatonic doctrine on World Soul Cycles may have its roots in Plato's myth of Er in his Republic. Proclus and Antiochus agree with the Mahabharata in associating one cycle of the immanent World Soul to a conjunction in the constellation Cancer, leading some scholars to believe that the Mahabharata may incorporate astrological ideas from Plato's myth of Er, as the bulk of the Mahabharata was compiled after Alexander's invasion of India.

Human Souls

In late Athenian Neoplatonic theology, the cycle of a human soul progressing from the hypostasis of Soul into the material and temporal universe and returning, can occur an infinite number of times. That aspect of the late Neoplatonic doctrine on Soul is formalized by Proclus in Elements of Theology proposition 206. In the Orphic-Pythagorean and Indian doctrines on Soul, a human soul can attain an ultimate liberation from what is known by scholars as the 'circle of birth', i.e. embodiment of a soul; however the early Neoplatonist Plotinus, in his Enneads, was not definite on this aspect of a human soul, whereas the Neoplatonist Porphyry, in his De Regressu Animae (fragment 11), asserted a human soul will ultimately be liberated eternally from its material and astral bodies.

The Neoplatonists Sallustius, Iamblichus and late Neoplatonists Syrianus and Proclus held a contrary view to Porphyry. This was due to their claims that (a) because the invariable essence of a soul is to be embodied, it would always animate a body, astral or material, and (b) because the number of souls is finite and time is infinite, Porphyry's claim would mean the hypostasis of Soul would eventually have no human souls. The last claim would be a contradiction to the Neoplatonic position that a human soul is eternal, meaning a soul is not created at a point in time nor is it extinguished at a point in time.

Both Syrianus and Proclus, in his Commentary on Timaeus III.278.10 ff., also claim that a human soul will progress into the material universe at least once in every cyclic period of the World Soul. That claim by Syrianus and Proclus is a rejection of the Pythagorean, Gnostic and Plotinian views that the progression of a human soul into the material universe is sinful, rather, it is part of a soul's education. Further, in his Commentary on Cratylus 117, Proclus claims that human souls that are heroic, or souls of heroes like Heracles, could spend many cyclic periods of the World Soul without progression into the material universe.

In his final proposition of Elements of Theology, proposition 211, Proclus claims that every human soul that progresses into the temporal and material universe progresses entirely and does not have an aspect of it that simultaneously participates in the hypostases of Nous or Soul. That proposition is a development of the early Neoplatonic theology of Plotinus in which an aspect of a human soul that has progressed into the material universe simultaneously participates in the hypostasis of Nous.

Plotinus' position was supported by the 4th century Neoplatonist Theodore of Asine and the late 5th century Neoplatonist Damascius, but rejected by the late 3rd century Neoplatonist Iamblichus and most of the other 4th and 5th century Neoplatonists including Proclus. Proclus rejects Plotinus' position because it splits the unity of the soul, one aspect of the soul residing in the material universe and the other aspect in the hypostasis of Nous. Proclus also rejects Plotinus' position because he thinks it is contrary to the experience of human sin and misery. In his rejection of Plotinus' theory, Proclus refers to his authority Plato in Phaedrus 248a and Timaeus 43d:

"...shaking the circuits of the soul, they completely hampered the revolution of the Same by flowing counter to it and stopped it from going on its way and governing; and they dislocated the revolution of the Different."—Plato, Timaeus 43d

The late Neoplatonic interpretation of Timaeus 43d, is that both aspects of the soul, represented by the paradigms of Same and Different, were disrupted by the progression of the soul into the material universe. A similar interpretation was made of Phaedrus 248a, where both aspects of the soul, symbolized by the charioteer and the horses, sank to the Earth.

Following Iamblichus, Plutarch of Athens, and Syrianus, Proclus intricately elaborated the early Neoplatonic philosophy of Plotinus. Whilst Proclus' elaborated doctrines of Neoplatonic theology sometimes agree with Plotinus, there is a very important difference in their respective doctrines on Evil. Plotinus' Neoplatonic doctrine on Evil, in Enneads 1.8 and 3, briefly says that matter was the cause of evil. Proclus' doctrine on Evil, elaborated in his treatise On the Existence of Evil, briefly says that souls are corrupted before they are generated in the material world through matter and therefore matter is not the cause of evil. In Proclus' Neoplatonic doctrine on Evil, there is no single principle that causes evil, as that would lead to a dualism of independent first principles, Good and Evil, and that would contradict fundamental Neoplatonic theological doctrines that claim the One, or the One and the Good is the First Principle and the First Cause, or single cause, or leading cause, of All that exists, or cause of all things (i.e. every thing immaterial and material).

Nature

In scholastic writings on Neoplatonism, Nature can be a series of causation from the unifying principle called Nature or it may be a series of causation from the unifying cause called Nature. When it is treated as a unifying principle it is regarded as a henad and when it is treated as a unifying cause it is regarded as a monad, and so may be described as effecting beings on Neoplatonic hypostases, depending on the context of the text.

In Neoplatonic scholarship, usually when Nature is treated as a unifying principle, it is the henad of the material universe, or the summit of the material universe, and effects all material beings and material bodies. However, when Nature is treated as a unifying cause, it is a monad that can also effect immaterial beings across all Neoplatonic hypostases, excluding the One, and can even be the monad from which the Demiurge modelled the material universe. Also, 19th, 20th, and 21st century Neoplatonic scholarship also uses the terms 'sublunary region', or 'sublunary realm', to refer to material beings and material bodies on Earth.

Works

Proclus' surviving works suggest that his major activity was writing commentaries on Plato's dialogues but that he also spent some time writing on mathematics, astronomy, treatises of philosophical expositions and hymns to deities. Hellenistic Neoplatonism treated Homer and Plato like sacred scriptures, with Orphic poems and Chaldaean oracles for addenda and also incorporated the distinct theologies of Orphicism and Neopythagoreanism. With Proclus, the treatment was more a philosophical method of discursive reasoning, going back to the method used by Socrates and Plato, as Proclus was more in contact with mathematical, astronomical and physical sciences. His commentaries on Plato's dialogues reveal his depth and originality, more so than his systematic works and treatises, as they elucidate and illuminate new thoughts from ancient philosophers.

There are more than sixty known works by Proclus which are either complete, partially complete, in fragments, inauthentic or spurious. Of these, more than half are lost and only known because they are mentioned in scholarly literature. For a near complete listing of all of Proclus' works; extant, partially complete, fragments, inauthentic, spurious or lost, see the Supplement to Proclus by Stanford Encyclopedia of Philosophy. Scholars generally organize Proclus' works into the categories, systematic, commentaries, treatises, and theurgic, but have difficulty determining the chronological order of the works.

Systematic

Works by Proclus regarded as systematic are Elements of Theology, Platonic Theology, and Elements of Physics. All of these works by Proclus have complete and extant manuscripts. The most systematic of these works are Elements of Theology and Platonic Theology. Proclus' 5th century work Elements of Theology is similar to the 17th century work Ethics by Spinoza, as Proclus presents the elements of Neoplatonic theology as a systematic series of propositions with proofs. Platonic Theology is a massive six book systematic discourse on the dialogues of Plato paralleling their agreement with the theologies of Orphism and the Chaldean Oracles. Elements of Physics is a smaller work where Proclus systematizes Aristotle's arguments from Physics Book VI, De caelo, and Physics Book VIII.

From the 12th century, scholars studied the Latin book Liber de Causis (Book of Causes) translated from Arabic to Latin by Gerard of Cremona and eventually found that it contained more than 30 propositions from Proclus' Elements of Theology. Liber de Causis was mistakenly attributed to Aristotle, but it was first recognised by St Thomas Aquinas in the 13th century to contain Proclus' Neoplatonic doctrines and was thus exposed as a reworking of Proclus' Elements of Theology to suit a different theology.

Commentaries

Of major importance are the five lengthy, but only partially complete, extant manuscripts of commentaries by Proclus on Plato's dialogues in, Commentary on First Alcibiades, Commentary on Cratylus, Commentary on Parmenides, Commentary on Republic, Commentary on Timaeus and Commentary on the First Book of Euclid's Elements. The logical order for commentaries of Plato's dialogues suggested by Whittaker 1918 is, Commentary on First Alcibiades, Commentary on Parmenides, Commentary on Timaeus, and Commentary on Republic. That order begins with psychology, the centre of the system; then moves on to the theory of knowledge; then on to ontology and cosmology; and lastly through the aesthetic and practical aspects of philosophy. The Commentary on Cratylus can be treated as an introduction or preliminary to the larger works, Commentary on Parmenides and Commentary on Timaeus, as it unfolds the Neoplatonic interpretation of mythology.

Scholars also know of lost commentaries by Proclus on Plato's Theaetetus, Philebus, Phaedo, Gorgias, and Phaedrus, and lost commentaries on the Chaldaean Oracles and Enneads of Plotinus.

Treatises

There are also three treatises, or monographs that are complete, Ten Doubts Concerning Providence, On Providence and Fate and On the Existence of Evil; together called Tria Opuscula (three treatises). The Tria Opuscula survives as 13 manuscripts dating from the early 14th century to the 17th century. The manuscripts of these treatises were thought to only survive in the 14th–17th century Latin translations of William of Moerbeke until scholars in the 20th century rediscovered copies of them in Greek text, in the works of the 12th century Byzantine-Greek Isaac Sebastocrator.

Theurgic

Of the theurgic, or religious works of Proclus, there a seven complete hymns of the many he wrote, and other works on religious symbolism, and on the Greek myths of Hecate and Cybele that exist as fragments of extant Greek manuscripts or Middle Ages Latin translations or Middle Ages Arabic translations. Marinus of Neopolis thought very highly of Proclus' theurgical knowledge and says it was taught to him by Asclepigeneia, the daughter of Plutarch of Athens, who had learned the wisdom from Nestorius, the hierophant of the Eleusinian mysteries.

Elements of Theology

Cover page of the 1583 Latin translation of Elements of Theology and Elements of Physics from Procli Lycii Diadochi Elementa Theologica, et Physica by Franciscus Patricius

The Elements of Theology (Greek: Στοιχείωσις θεολογική) by Proclus is an elucidation of systematic Neoplatonic theology. Due to its intricacy and systematic qualities, its standing amongst scholars is similar to The Enneads by Plotinus but differs from Plotinus' work of essays that came from discussions and assumed knowledge of Neoplatonic doctrines. Even philosophical works by Porphyry and Salutius, following Plotinus' Enneads, did not detail Neoplatonic doctrines with the theoretical logic and organization of Elements of Theology. Proclus' Elements of Theology is regarded as an attempt to supply an in-depth theory of reality wished for by Plato in his seventh book of his work Republic and whilst Elements of Theology is not a complete summary of Neoplatonism, it is a complete system of Neoplatonic theology.

The Elements of Theology consists of 211 propositions, each followed by a proof using Proclus' authorities, beginning from the existence of the One (divine Unity) and ending with the progression of individual souls into the material world. The first 112 propositions sequentially establish contrasting theological ideas that characterize Neoplatonic theology, such as unity and plurality, whole and part, eternity and time, unmoved and self-moved. The remaining propositions are a theory of three primary Neoplatonic theological orders and their relation to orders of realities that proceed from them. The modern standard edition of the Greek text is The Elements of Theology, edited by E. R. Dodds, 1933. Scholars today still, after nearly ninety years, describe Dodds' 1933 edition of The Elements of Theology as a masterpiece of scholarship.

Platonic Theology

Platonic Theology (Greek: Προκλου Διαδοχου Πλατωνικου εις την Πλατωνος θεολογίαν) is a voluminous work by Proclus in six books. The work establishes a complete parallel between Platonic philosophy in the dialogues of Plato and the divinities of Orphic theology and the theology in the doctrines of the Chaldaean oracles. In the work, and generally, Proclus' treated the philosophy of Plato as a theology and so the work seeks to coordinate it to those ancient theologies. Hegel praised the work as a more systematic and mature demonstration (an Intellektualsystem) of Platonic philosophy than given by Plotinus.

Cover page of the 1618 Greek and Latin translation of Platonic Theology from Procli Successoris Platonici in Platonis Theologiam Libri Sex by Aemilius Portus. The edition remained the only complete standard edition of the Greek text for nearly 380 years.

Thomas Taylor's English translation of Proclus' Platonic Theology in The Six Books of Proclus on the Theology of Plato, 1816 in 2 volumes, remains, more than 200 years later, the only complete English translation of the work. The edition of the Greek text published by A. Portus in 1618 in Procli Successoris Platonici in Platonis Theologiam Libri Sex, remained the only complete standard edition of the Greek text for nearly 380 years, until the modern standard Greek text by Saffrey & Westerink was completely finished in 1997. The modern standard edition of the Greek text and French translation is Proclus: Théologie platonicienne, edited by H. D. Saffrey & L. G. Westerink, 1968–1997 in six volumes that took about 30 years to complete and is regarded by scholars as one of the most momentous editorial accomplishments in modern Proclean scholarship.

"The most beautiful and orderly development of this philosophy, which endeavours to explain all things by an analysis of consciousness, and builds up a world in the mind out of materials furnished by the mind itself, is to be found in the Platonic Theology by Proclus."—Samuel Taylor Coleridge

Commentary on Cratylus

Proclus' commentary on Plato's Cratylus (Greek: Προκλου Σχόλιών εις τον Κραττλον Πλατωνος) is the only commentary of that dialogue by Plato that exists from the writings of ancient philosophy. The large work is regarded as special by scholars because it is the work of both Proclus, who was based in Athens, and another later Neoplatonist who is thought to have been based in Alexandria, and so it has the knowledge of two major late ancient centres of Platonic philosophy. The commentary is separated into the subjects of language-theory and theological etymologies of names of Greek gods, with Proclus relating the names to the theologies of Orphism, Chaldean oracles and Homer.

What has survived of Proclus' Commentary on Cratylus is partially complete, being a commentary of Plato's Cratylus from the beginning (383a) to 407e, whilst the dialogue itself finishes at 440e. The modern standard edition of the Greek text is Proclus Diadochus in Platonis Cratylum Commentaria, edited by G. Pasquali, 1908.

Commentary on First Alcibiades

Proclus' commentary on Plato's First Alcibiades (Greek: Προκλου Διαδοχου εις τον Πλατωνος Πρωτον Αλκιβιαδην) is a lengthy commentary that clearly distinguishes between what the dialogue is about, its theme, and the purpose of understanding it, or its goal. Throughout the commentary it is clear that Proclus was very interested in Aristotelian logic and that becomes evident in his use of ten syllogisms to structure the dialogue between Socrates and Alcibiades. In the dialogue, Proclus makes it comprehensively clear that despite not being completely cognizant of our intuitive logic, we still use it unconsciously.

What has survived of Proclus' Commentary on First Alcibiades is partially complete, being from the beginning (103a) to 116b whilst the dialogue itself finishes at 135e8. The modern standard edition of the Greek text is Proclus: Sur le premier Alcibiade de Platon edited by. A.-P. Segonds, 1985–1986, in two volumes.

Commentary on the First Book of Euclid's Elements

Cover page of the 1560 Latin translation of Proclus' Commentary on the First Book of Euclid's Elements by Francesco Barozzi.

Proclus' Commentary on the First book of Euclid's Elements (Greek: Προκλου Διαδοχου εις το Πρωτον των Ευκλειδους Στοιχειων Βιβλιον Πρωτον) is one of the most valuable sources we have for the history of ancient mathematics, and its Platonic account of the status of mathematical objects was influential. In this work, Proclus also listed the first mathematicians associated with Plato: a mature set of mathematicians (Leodamas of Thasos, Archytas of Taras, and Theaetetus), a second set of younger mathematicians (Neoclides, Eudoxus of Cnidus), and a third yet younger set (Amyntas, Menaechmus and his brother Dinostratus, Theudius of Magnesia, Hermotimus of Colophon and Philip of Opus). Some of these mathematicians were influential in arranging the Elements that Euclid later published. The modern standard Greek text for the commentary is Procli Diadochi in primum Euclidis Elementorum Librum Commentarii edited by G. Friedlein, 1873.

Proclus, the scholiast to Euclid, knew Eudemus of Rhodes' History of Geometry well, and gave a short sketch of the early history of geometry, which appeared to be founded on the older, lost book of Eudemus. The passage has been referred to as "the Eudemian summary," and determines some approximate dates, which otherwise might have remained unknown.

Commentary on Parmenides

Proclus' commentary on Plato's Parmenides (Greek: Προκλου Διαδοχου των εις τον Πλατωνος Παρμενιδην) in seven books was written by Proclus when he was about forty years old. It is an expression of the peak of Proclus' accomplishment in commentary writing in a mature period of his philosophical development. In his Preface to the commentary, Proclus gives an illustrative description of the historical understanding of Plato's Parmenides from the Middle Platonists through Porphyry and Iamblichus and finally to Syrianus. After the Preface, he starts the commentary with an explanation of the entire Neoplatonic theological order, acknowledges his debt to his teacher Syrianus, and dedicates the work to his pupil Asclepiodotus of Alexandria. In the remainder of work, he discusses the dramatic setting, explains allegories in the dialogue including the allegorical representations of the three main characters Parmenides, Zeno, and Socrates and then turns to the examination of the subject matter of the dialogue.

What has survived of Proclus' massive Commentary on Parmenides is partially complete, being a preface and a commentary of Plato's Parmenides from the beginning (126a) to 142a10, whilst the dialogue itself finishes at 166c5. The commentary is extant in the Greek up to 141e10, the remainder (to 142a10) is from William of Moerbeke's Latin translation. From 1864 until 2009, the standard edition of the Greek text was Procli Philosophi Platonici Opera Inedita, edited by V. Cousin, 1864. Since 2009, there are two standard editions of the Greek text: the first is Procli in Platonis Parmenidem Commentaria, edited by C. Steel, with the collaboration of C. Macé, P. d'Hoine, A. Gribomont, and L. Van Campe, 2007–2009 in three volumes; and the second is Proclus. Commentaire sur le Parménide de Platon, edited by A.-P. Segonds and C. Luna, 2007–2021, in five volumes.

Commentary on Republic

Proclus' commentary on Plato's Republic (Greek: Πλατωνικου Διαδοχυ εις τας Πολιτειας) is a voluminous work that comprises 17 essays of varying length. Essay 16 on the Myth of Er accounts for about 40 percent (263 pages) of the commentary, while essays 5 and 6 on poetics and Homer in the Republic account for about a quarter of the commentary. Essays 6, 9, 15, 16 and 17 may be regarded as independent. The modern standard Greek text for the commentary is Procli Diadochi in Platonis Rem Pvblicam Commentarii, edited by Gvilelmvs (Wilhelm) Kroll, 2 volumes, 1899–1901. Below is a summary of the seventeen essays and their page numbers in the Kroll 1899–1901 standard Greek text.

Summary of Essays in Proclus' Commentary on Republic

Essay	Description	Kroll vol:page
1	Principle topics to understand before teaching Republic.	1:5
2	Socrates arguments on Justice against Polemarchus. [missing]
3	Arguments on Justice in Republic against Thrasymachus [missing beginning]	1:20
4	Neoplatonic theology in Book 2 of Republic	1:27
5	Poetics in Republic	1:42
6	Homer in Republic	1:69
7	Soul and Virtues in Book 4 of Republic	1:206
8	Virtues and Education in Book 5 of Republic	1:236
9	Arguments of Socrates and Theodorus of Asine on Virtue	1:251
10	Love of Knowledge in Book 5 of Republic	1:258
11	The Good in Republic	1:269
12	The allegory of the Cave in Book 7 of Republic	1:287
13	Muses in Republic	2:1
14	Arguments on the Just and Unjust	2:81
15	Main topics in Book 10 of Republic	2:85
16	Myth of Er	2:96
17	Aristotle's objections to Republic	2:360

In the commentary on Plato's Republic, Proclus presents his own philosophical system as a faithful interpretation of Plato, and in this he did not differ from other Neoplatonists, as he considered that "nothing in Plato's corpus is unintended or there by chance", "that Plato's writings were divinely inspired" (ὁ θεῖος Πλάτων ho theios Platon—the divine Plato, inspired by the gods), that "the formal structure and the content of Platonic texts imitated those of the universe", and therefore that they spoke often of things under a veil, hiding the truth from the philosophically uninitiate. Proclus was however a close reader of Plato, and quite often makes very astute points about his Platonic sources.

Commentary on Timaeus

Proclus' commentary on Plato's Timaeus (Greek: Προκλου Διαδοχου εις τον Τιμαιον Πλατωνος) is a massive work in five books, and is regarded by scholars as possibly the greatest commentary on a dialogue by Plato and gives an exceptional understanding of eight centuries of Platonic exposition. It supplies crucial information of preliminary examinations of Plato's Timaeus and demonstrates Proclus' perspective on the sense and importance of Platonic philosophy. Plato's dialogue Timaeus has demonstrated its significance historically because it has endured as a central philosophical text from the end of Plato's life (347 BC) and across Hellenistic philosophy, Philo of Alexandria, Middle Platonism, the Christian fathers, the Neoplatonists, and further. Plato's dialogues Timaeus and Parmenides were regarded by Neoplatonists as the two most important texts for philosophical study.

Proclus' Commentary on Timaeus is the pinnacle of centuries of explanatory studies and has earlier thoughts ingrained within it. The commentary reveals the type of interpretive debates that thrived in prior ages and the point of view held by Proclus and Syrianus when they each headed the School of Plato in Athens. Historically the commentary is the most prolific of Proclus' legacy and reveals meanings of the Platonic dialogues Republic and Critias that Proclus thought likely to belong to the same series. What has survived of Proclus' voluminous Commentary on Timaeus is only partially complete, being a commentary of Plato's Timaeus from the beginning (17a) to 44d, whilst the dialogue itself finishes at 92c. It is thought that the sudden termination of the commentary is possibly due to an exhausted scribe. The modern standard edition of the Greek text is Procli Diadochi In Platonis Timaeum Commentaria, edited by E. Diehl, 1903–1906 in three volumes. Modern scholarship uses Diehl's volume, page and line numbers for citations, so for example, the citation "in Tim. I.260.20" means volume 1, page 260, line 20 in the 1903 standard edition of the Greek text of Proclus' Commentary on Timaeus (Latin: Procli Diadochi In Platonis Timaeum Commentaria) by E. Diehl.

Extant Commentary on Timaeus in Five Books

Book	Notes
I	Summary of Plato's Republic and myth of Atlantis
II	Timaeus 27c–31b: gods and the material universe
III	Timaeus 31b–37c: body of the world and generation of the soul
IV	Timaeus 37c–40e: heavenly bodies and traditional gods
V	Timaeus 40e–44d: genealogy of gods, Demiurge, souls

Other Works

Other Works by Proclus from KU Leuven and All From One 2017

Work	Modern Standard edition of the Greek Text and Comments
Elements of Physics	Procli Diadochi Lycii institutio physica, edited by A. Ritzenfeld, 1912. Proclus' summary of Aristotle's Physics Books VI and VIII.
Epigrams	Procli hymni accedunt hymnorum fragmenta, edited by E. Vogt, 1957
Hymns	Procli hymni accedunt hymnorum fragmenta, edited by E. Vogt, 1957
Tria Opuscula (three treatises): Ten Doubts Concerning Providence On Providence and Fate On the Existence of Evil	Procli philosophi Platonici opera inedita, edited by V. Cousin, 1864 S. Thomae Aquinatis in librum beati Dionysii De divinis nominibus expositio, edited by C. Pera, 1950 Procli Diadochi tria opuscula (De providentia, libertate, malo) Latine Guilelmo de Moerbeka vertente et Graece ex Isaacii Sebastocratoris aliorumque scriptis collecta, edited by H. Boese, 1960 Proclus: Trois études sur la providence, I. Dix problèmes concernant la providence, edited by D. Isaac, 1977 Proclus: Trois études sur la providence, II. Providence, fatalité, liberté, edited by D. Isaac, 1979 Proclus: Trois études sur la providence, III. De l'existence du mal, edited by D. Isaac, 1982
Treatises: On the Eternity of the world On Sacrifice and Magic	Ioannes Philoponus: De aeternitate mundi contra Proclum, edited by H. Rabe, 1899 Catalogue des manuscrits alchimiques grecs, VI. Michel Psellus, Épître sur la Chrysopée. En appendice Proclus, Sur l'art hiératique; Psellus, Choix de dissertations inédites, edited by J. Bidez, 1928, volume 6, pp. 148–151
Outline of Astronomical Hypotheses	Procli Diadochi hypotyposis astronomicarum positionum, edited by C. Manitius, 1909. There is no translation of Outline of Astronomical Hypotheses in any modern language
Commentaries on Aristotle	Proclus de Lycie, by Luna & Segonds, 2012, pp. 1556–1562. There is growing evidence for existence of commentaries of Proclus on Aristotle's On Interpretation and Prior and Posterior Analytics
Commentary on the Chaldean Oracles (fragments)	Eclogae e Proclo de philosophia chaldaica sive de doctrina oraculorum chaldaicorum, edited by A. Jahn, 1891. Extent works remain the major source for Proclus' elucidation of the Chaldean oracles.
Commentary on Hesiod's Works and Days (fragments)	Poetae minores Graeci, edited by T. Gainsford, 1823 Scholia vetera in Hesiodi Opera et dies, edited by A. Pertusi, 1955 Der Kommentar des Proklos zu Hesiods 'Werken und Tagen in Übersetzung und Erläuterung der Fragmente (Classica Monacensia 33) by P. Marzillo, 2010
Commentary on Enneads (fragments)	Exzerpte aus Proklos' Enneadenkommentar bei Psellos in Byzantinische Zeitschrift, 52, pp. 1–10, by Westerink, 1959.
On Plato's Three Proofs for the Immortality of the Soul (fragments)	Proclus on Plato's Three Proofs of Immortality in Zetesis: Album Amicorum door vrienden en collega's aangeboden aan Prof. Dr. E. de Strycker, by Westerink, 1973, pp. 296–306 Deux textes en arabe sur les preuves platoniciennes de l'immortalité da l'âme by Hasnaoui, 1997 Il Monobiblon di Proclo sull'immortalità dell'anima: Atene, Ctesifonte, Corbie, Bagdad: secoli V–X by Chemi 2014
Chrestomathia (dubious)	Libanii Opera, edited by R. Foerster, 1927, volume IX, pp. 1–47
Commentary on Pythagoras' Golden Verses (dubious)	Proclus' Commentary on the Pythagorean Golden Verses, edited by N. Linley ( ibn at-tayyib), 1984
On Epistolary Style (dubious)	Libanii Opera, edited by R. Foerster, 1927, volume IX, pp. 1–47
Commentary on Ptolemy's Tetrabiblion and Paraphrasis of the Tetrabiblion of Ptolemy (dubious)	Procli diadochi Paraphrasis in Ptolemaei libros IV sive De siderum affectionibus, edited by Allatius, 1635
On the Sphere (spurious)	Procli sphaera. Ptolemaei de hypothesibus planetarum liber singularis, edited by J. Brainbridge, 1621

Further reading

Monographs

• Proklos: Grundzüge seiner Metaphysik, by Werner Beierwaltes
• L'Un et L'Âme selon Proclos, by Jean Trouillard
• La mystagogie de Proclos, by Jean Trouillard
• KINESIS AKINETOS: A study of spiritual motion in the philosophy of Proclus, by Stephen Gersh
• From Iamblichus to Eriugena. An investigation of the prehistory and evolution of the Pseudo-Dionysius tradition, by Stephen Gersh
• L'architecture du divin. Mathématique et Philosophie chez Plotin et Proclus, by Annick Charles-Saget
• Proclus: Neoplatonic philosophy and science, by Lucas Siorvanes
• The Philosophy of Proclus – the Final Phase of Ancient Thought, by L J Rosan
• The Logical Principles of Proclus' Stoicheiôsis Theologikê as Systematic Ground of the Cosmos, by James Lowry

Collections of essays

• Proclus et son influence, actes du Colloque de Neuchâtel, Juin, 1985. Zürich: Éditions du Grand Midi, 1987.
• Proclus lecteur et interprète des anciens. Actes du Colloque internationale du C.N.R.S., Paris 2–4 October 1985. J. Pépin et H.-D. Saffrey. Paris: C.N.R.S., 1987.
• On Proclus and his Influence in Medieval Philosophy, ed. by E.P. Bos and P.A. Meijer (Philosophia antiqua 53), Leiden-Köln-New York: Brill, 1992.
• The perennial tradition of neoplatonism, ed. by J. Cleary (Ancient and medieval philosophy, Series I, 24), Leuven: Leuven University Press, 1997.
• Proclus et la Théologie platonicienne: actes du colloque international de Louvain (13–16 mai 1998) en l'honneur de H. D. Saffrey et L. G. Westerink, éd. par A.-Ph. Segonds et C. Steel (Ancient and medieval philosophy, Series I 26), Leuven-Paris: Leuven University Press / Les Belles Lettres, 2000.
• Stephen Gersh (ed.), Interpreting Proclus from Antiquity to the Renaissance, Cambridge: Cambridge University Press, 2014.

Studies on particular aspects of Proclus' philosophy

• Gertz, S.R.P., "A Testimonium on Proclus' Views about the Rationality of Animals", Classical Quarterly 68.1, 352–357.

Bibliographic resources

• Proclo, negli ultimi quarant' anni. Bibliografia ragionata delle letteratura primaria e secondaria riguardante il pensiero procliano e i suoi influssi storici (anni 1949–1992), by Nicoletta Scotti Muth
• "Proclus Bibliography (covering the years 1990–2016)".

See Also

• Allegorical interpretations of Plato

External links

• Helmig, Christoph; Steel, Carlos. "Proclus". In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy.
• Helmig, Christoph; Steel, Carlos. "Bibliography: Proclus' Complete Works (extant, lost, and spurious)". In Zalta, Edward N. (ed.). Stanford Encyclopedia of Philosophy.
• Article by Encyclopædia Britannica
• O'Connor, John J.; Robertson, Edmund F., "Proclus", MacTutor History of Mathematics archive, University of St Andrews
• Editions and Translations Proclus – Hoger Instituut voor Wijsbegeerte
• Article at "The Encyclopedia of Goddess Athena"
• The Six Books of Proclus, the Platonic Successor, on the Theology of Plato Thomas Taylor translation.
• Five Hymns of Proclus Thomas Taylor translation.
• Fragments that Remain of the Lost Writings of Proclus Thomas Taylor translation.
• Commentaries of Proclus on the Timaeus of Plato, in Five Books Thomas Taylor translation.
• Ten Doubts Concerning Providence and On the Existence of Evils Thomas Taylor translation.
• Proclus's Life and Teachings
• Index page of the Proclus section for the "Plato Transformed" project at the University Leuven, Belgium.
• Commentary on Plato's Parmenides – (Greek text, scans of Cousin's edition)
• Catalogue of the Prometheus Trust "Thomas Taylor Series" which includes translations of many of the works of Proclus. The site has lengthy extracts of these.
• Proclus's Commentary on Euclid, Book I. PDF scans of Friedlein's Greek edition, now in the public domain (Classical Greek)
• On the Signs of Divine Possession – (partial translation of Proclus's work)
• On the Sacred Art – (translation and discussion of this surviving extract from a larger work by Proclus)
• On the Sacred Art (French introduction and Greek text)
• On the Sacred Art – Greek text and English translation
• Hypotyposis Astronomicon Hypotheseon – Greek text
• Proclus in English and Greek, Select Online Resources
• Works by Proclus at LibriVox (public domain audiobooks)
• Guide to Proclus, Elementa theologica. Manuscript, 1582 at the University of Chicago Special Collections Research Center