The most prominent 5th c. philosopher of the School of Athens; an indefatigable commentator of Plato and the Chaldaean Oracles, theurgist, poet, mathematician, astronomer, and above all, an incomparable systematizer of ideas. His work determined the mode of reception of Platonic philosophy, up to, and including, the Renaissance.

Life and works

Thanks to the hagiological biography Proclus or On Happiness, composed by his student Marinus, we know enough about the life and personality of the chief representative of the Neoplatonic school of Athens in the fifth century.

Proclus was born in Constantinople in 412 to pagan parents hailing from Lycia. Having studied rhetoric, Aristotelian logic, and mathematics in Alexandria, at the age of eighteen Proclus arrived at Athens to study philosophy. Head of the School of Athens was then Plutarch the Athenian, who was impressed by the young man’s gifted nature and offered to teach him Aristotle’s On the Soul and Plato’s Phaedo. Following Plutarch’s death in 432, Syrianus became the head of the school, exerting a deep and permanent influence on Proclus’ philosophical development. Plutarch and Syrianus initiated Proclus into theurgy and convinced him of the esoteric agreement between the doctrines of Orpheus, Pythagoras, the Chaldaean Oracles, and Plato’s philosophy. After Syrianus’ death in 437, and despite his relative youth –he was only twenty five years old–, Proclus became the school’s new head: this is how he received the sobriquet diadochus (= successor, i.e. of Plato) that accompanies his name in the manuscripts preserving his works.

Proclus remained in charge of the school until his death in 485. During his half-century long career, Proclus was forced to abandon Athens for a year to protect himself from Christian aggression (Pr. 15.14-35). Proclus’ austere daily routine included prayers to the sun at sunrise, during its zenith, and at sunset; five or more philosophical lectures, seminars, discussions with students and other members of the school, as well as the composition of seven hundred lines of commentary or systematic text (Pr. 22.29-37).

Roughly one third of Proclus’ voluminous authorial output is extant today: it includes five commentaries on Platonic dialogues (the Alcibiades [up to 116b]; the Cratylus [up to 407c, fragmentarily extant]; the Parmenides [up to 142a]; the Republic [various autonomous studies on themes such as the relation between philosophy and poetry, the Allegory of the Cave, the myth of Er, etc.]; and the Timaeus [up to 44d]); a commentary on the first book of Euclid’s Elements; four systematic works (Elements of Theology, Platonic Theology, Elements of Physics, On Astronomical Hypotheses); various minor works (on providence, fate, evils, theurgy, etc.); and seven hymns to gods. Proclus also composed commentaries, now lost, on other Platonic dialogues (Gorgias, Theaetetus, Sophist, Symposium, Phaedrus, Phaedo, and Philebus). Worthy of mention is also a (now also lost, but according to testimonies quite extensive) commentary on the Chaldaean Oracles.

The Platonic commentaries

As a commentator, Proclus remained true to Iamblichus’ principle that each Platonic dialogue has a single aim or goal (skopos). In this vain Proclus, while still only twenty eight years old, provided an interpretation of the entire Timaeus, including the first part on Atlantis and the proper polity, as a work of physiology. In the same spirit, and following a long-standing Neoplatonic tradition, Proclus discovered in the Parmenides a full reflection of Plato’s “theology” (which in his jargon meant both theology and metaphysics). In the interpretation introduced by Plutarch and elaborated by Syrianus, Proclus held that in the second part of the dialogue the first five deductions really do hold true, for they refer to distinct levels of existences (ranging from the One to matter), while the following four deductions constitute reductiones ad absurdum (In Parm. 1058.17-1064.14). In general, Proclus is quite methodic as a commentator. Before putting forth his own interpretation he presents the views of earlier thinkers and rounds off his review with the opinion of his teacher, Syrianus, which he buttresses with any appropriate argument he can come up with. His aim is not just to illustrate the dogmatic consistency that pervades all Platonic dialogues, but also the absolute correspondence of this coherent teaching with the truth of reality.

At the same time, Proclus’ is constantly concerned with showing the agreement between Plato’s writings, provided they are interpreted correctly, with Orphic theogonies, Homeric and Hesiodic theology, and the doctrines of the Chaldaean Oracles.

The systematic works

Of Proclus’ systematic works, two stand out: the Elements of Theology, which could be loosely described as a primer on metaphysics; and the Platonic Theology.

In the former, probably an early work revised later, Proclus presents his entire metaphysical system articulated in 211 propositions, each of which is proven by adducing elementary logical axioms. The work’s structure is modeled after Euclid’s Elements and its form is reminiscent of Spinoza’s Ethics. Proclus was the first ancient philosopher to systematize his metaphysical theory in a mathematical manner – or, as the expression goes, more geometrico. This original work can function as an excellent introduction to his philosophy. It is worth quoting its opening sentence together with its proof (El. Theol. 1):

Proposition 1: Every manifold in some way participates unity. For suppose a manifold in no way participating unity. Neither this manifold as a whole nor any of its several parts will be one; each part will itself be a manifold of parts, and so on to infinity; and of this infinity of parts each, once more, will be infinitely manifold; for a manifold which in no way participates any unity, neither as a whole nor in respect of its parts severally, will be infinite in every way and in respect of every part. For each part of the manifold – take which you will – must be either one or not-one; and if not-one, then either many or nothing. But if each part be nothing, the whole is nothing; if many, it is made up of an infinity of infinites. This is impossible: for, on the one hand, nothing which is is made up of an infinity of infinites (since the infinite cannot be exceeded, yet the single part is exceeded by the sum); on the other hand, nothing can be made up of parts which are nothing. Every manifold, therefore, in some way participates unity (transl. by E.R. Dodds).

The Platonic Theology, on the contrary, is a work of his mature period and summarizes Proclus’ entire output as a commentator of Plato’s dialogues. In this lengthy treatise all the inconsequential, at first glance, references to gods and demons found in the Platonic dialogues are combined into a majestic theological and metaphysical system of emanation, in which independent intelligible beings (henads, intellects, and souls) are identified with traditional Hellenic deities and are depicted as holding specific ranks in the multilayered hierarchical structure that is ultimately generated by the highest rank of the supra-essential One. In this manner, the ancient mythology of the Orphic, Homeric and Hesiodic gods is harmonized with the abstract thinking on the first principles developed by Late Neoplatonism, and the gap between traditional religion and theoretical philosophy becomes decisively bridged. In this ambitious synthesis, Proclus purposely incorporates symbolic images of Pythagorean mathematics and instances of theurgical theophany (Pl. Theol. Ι.4, 20.1-20 Saffrey-Westerink):

For [1] those who treat of divine concerns in an indicative manner (δι᾽ ἐνδείξεως), either [1.1] speak symbolically and fabulously, or [1.2] through images. But [2] of those who openly (ἀπαρακαλύπτως) announce their conceptions, some [2.1] frame their discourses according to science (κατ᾽ ἐπιστήμην), but others [2.2] according to inspiration from the Gods (κατὰ τὴν ἐκ θεῶν ἐπίνοιαν). And he who desires to signify divine concerns through symbols [1.1] is Orphic, and in short, accords with those who write fables concerning the Gods. But he who does this through images [1.2] is Pythagoric. For the mathematical disciplines were invented by the Pythagoreans, in order to a reminiscence of divine concerns, at which, through these as images they endeavour to arrive. […] But the entheastic character, or he who is under the influence of divine inspiration (ἐνθεαστικῶς) [2.2], unfolding the truth itself by itself concerning the Gods, most perspicuously ranks among the highest initiators (παρὰ τοῖς ἀκροτάτοις τῶν τελεστῶν). For these do not think proper to unfold the divine orders, or their peculiarities to their familiars, through certain veils (διὰ δή τινων παραπετασμάτων), but announce their powers and numbers, in consequence of being moved by the Gods themselves. But the tradition of divine concerns according to science (κατ᾽ ἐπιστήμην) [2.1], is the illustrious prerogative of the philosophy of Plato (transl. by Thomas Taylor, parentheses added).

Proclus’ philosophy is premised on the triadic first principles of Iamblichus’ Neoplatonism, which he further systematized and developed. The triptych “unparticipated - participated - participant” is one characteristic such example. Through it, Proclus seeks to underline both the transcendent nature of intelligible hypostases and the impassible way in which they are causally related to the sensibles. Also characteristic is the triptych “abiding – procession - return” by which Proclus, in essence following Plotinus, illustrates the dialectical process through which effects, once distanced from their causes, first acquire some relative autonomy, and then desire to return to the roots of their existence in order to achieve “salvation”.

Historical significance

Proclus has exerted significant historical influence. In the ninth century, his Elements of Theology was translated into Arabic; two centuries later this Arabic translation was employed to produce a Latin version (entitled Liber de causis = Book on Causes), which was considered a work by Aristotle that purportedly complemented the Stageirite’s Metaphysics. Enjoying the aura of Aristotelian authority, the Elements of Theology was disseminated in the West and deeply influenced Medieval scholastic theology.

On the other hand, inspired by Proclus’ multilayered philosophico-theological system, the unknown author of the so-called Pseudo-Dionysian corpus created a Christian theological counterpart to Proclus’ pagan/Hellenic hierarchy of the intelligible world. In this manner, mediated by Proclus’ Neoplatonism, Platonic philosophy was grafted onto the main body of Eastern Orthodoxy. Proclus, however, was also directly known in Byzantium. Scholars such as Michael Psellus, Nicholas of Methone, George Pachymeres and Cardinal Bessarion had first-hand knowledge of Proclus’ work and were influenced by it.

In later times, the revivalists of Platonism in the Italian Renaissance saw in Proclus an authentic interpreter of Plato’s thought. Proclus’ importance as an exegete of Plato began to be gradually questioned only in modern times, when the Platonic dialogues got extricated from the hermeneutical distortions of Plato’s successors. Today Proclus is studied more as an emblematic figure of late antiquity and a historical source for late Neoplatonism than as an authentic exponent of Plato’s thought. His value as an independent thinker is also celebrated, though. Hegel admired the dialectics of procession and return of Proclus’ system.

Author: Spyridon Rangos
  • Saffrey, H.D., Westerink, L. G. Proclus: Théologie platonicienne, 6 τόμοι. Παρίσι, 1968-1997.
  • Saffrey, H.D., Segonds, A.P. Marinus: Proclus ou sur le bonneur. Παρίσι, 2002.
  • Steel, C. "Proclus." Gerson, L.P. ed. The Cambridge History of Philosophy in Late Antiquity,τόμος 2ος. Cambridge, 2010.
  • Helmig, C., Steel, C. "Proclus." Zalta, E.N ed. The Stanford Encyclopedia of Philosophy .. 2012.
  • Rosán, L. J. The Philosophy of Proclus: The Final Phase of Ancient Thought. Νέα Υόρκη (ανατ. Dilton Marsh χ.χ. 2008), 1949.
  • Chlup, R. Proclus: An Introduction. Cambridge, 2012.
  • Siorvanes, L. Proclus: Neo-platonic philosophy and science. New Haven, 1996.
  • Dodds, E.R. Proclus: The Elements of Theology. Οξφόρδη, 1963.
  • Rangos, S. "Proclus on Poetic Mimesis, Symbolism and Truth." Oxford Studies in Ancient Philosophy 17 (1999)
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