Iamblichus

(b. Chalcis, Syria, ca. A.D. 250; d. ca. A.D. 330)

philosophy.

Iamblichus’ parents were Syrian and he taught philosophy in Syria. Otherwise almost nothing is known of his life. It is clear from later writers that he was of major importance in the elaborate systematization of Neoplatonism that occurred after Plotinus. He wrote an encyclopedic work on Neopythagorean philosophy which included arithmetic, geometry, physics, and astronomy. But what has survived of this work has virtually no philosophical or scientific interest. We have only the traditional “Pythagorean” claims that all sciences are based on Limit and the Unlimited, that numbers are generated form the One and a principle of plurality, and that geometric solids are generated form unit points, lines, and surfaces. Because this “procession” of the One generates also beauty and then goodness, the study of mathematics and of the sciences based on mathematics is said to be the path to true virtue; individual numbers moreover are symbols of individual gods of the Greek pantheon. But Iamblichus makes all these claims in only a compressed and dogmatic manner. His Life of Pythagoras has no historical value.

Iamblichus’ commentaries on Aristotle are lost. They contained some acute, if unoriginal, defenses of Aristotelian doctrine as well as some less welljudged attempts to incorporate Neoplatonic metaphysics. For example, he correctly defended Aristotle’s definition of motion as incomplete or potential against the claims of both Plotinus and the Stoics that motion was activity and actuality (energeia). He argued that Aristotle was concerned with the concept of “being potentially (possibly) so and so” as opposed to “being actually so and so,” while his opponents confused this notion with the concept of possibility itself, as opposed to actuality or activity (see simplicius, “In Aristotelis Categorias,” pp. 303 ff.). Historians have perhaps failed to notice the significance of Iamblichus’ influential commentary on Aristotle’s psychology. By sharpening the distinctions that his Neoplatonic forerunners had blurred between soul and intellect and between a human soul and a pure or disembodied soul, he showed how Platonic prejudices need not stand in the way of separating psychology from metaphysics.

Like most Platonists of his age, Iamblichus was attracted by the prevalent Gnostic and sometimes magical practices that were supposed to lead to salvation. His work On the Egyptian Mysteries is a characteristic attempt to reconcile these practices with Platonic philosophy. Although it rationalizes them (more than has been recognized), the work is without scientific significance. In the Renaissance, however, it was partly responsible for the fascination with hieroglyphics and other supposed symbols of the East.

BIBLIOGRAPHY

I. Original Works. E. Des Places, ed., Les Mystéres d’Égypte (Paris, 1966), contains Greek text with French trans. and intro. De vita pythagorica, Protrepticus, Theologumena arithmeticae, and De communi mathematica scientia are in various eds. of Teubner Classics (Leipzig & Hildesheim)

II. Secondary Literature Simplicius’ commentaries on Aristole’s On the Soul and Categories are in Commentaria in Aristotelem graeca, II (Berlin, 1882), and VIII (Berlin, 1907), respectively—see indexes under Iamblichus.

See also A. H. Armstrong, ed., Cambridge History of Later Greek and Early Medieval Philosophy (Cambridge, 1967), pp. 295-301.

A. C. Lloyd

IAMBLICHUS

Neoplatonist philosopher; b. Chalcis in Coele Syria, c. a.d. 250; d. c. 325. He was a student of porphyry, the successor of plotinus, and later conducted his own school, possibly at Apamea. He is credited by his successors with important elaborations within the scheme of Neoplatonist emanation, with the promotion of theurgy and with the dethronement of the human soul from its Plotinian perpetual union with the intellect. Unfortunately, his commentaries upon various dialogues of plato have not survived, and one is left to conjecture what his system may have been from quotations and testimonies in later writers, especially proclus and Damascius.

See Also: neoplatonism.

Bibliography: His extant works form part of a Pythagorean collection: De vita pythagorica, ed. l. deubner (Leipzig 1937); Adhortatio ad philosophiam or Protrepticus, ed. h. pistelli (Leipzig 1888); De communi mathematica scientia liber, ed. n. festa (Leipzig 1891); In Nicomachi arthmeticam introductionis liber, ed. h. pistelli (Leipzig 1894); Theologoumena arithmeticae, ed. v. de falco (Leipzig 1922), authorship disputed; De mysteriis liber, ed. g. parthey (Berlin 1857), probably correctly attributed to Iamblichus. Grouped together with commentary are fragments of his lost treatise De anima, in La Révélation d'Hermès Trismésiste, ed. and tr. a. j. festugiÈre, 4 v. (Paris 1950–54) v.3. Lost are works on the gods and on the Chaldean oracles. g. faggin, Enciclopedia filosofica, 4 v. (Venice–Rome 1957) 2:707–708. f. ueberweg. Grundriss der Geschichte der Philosophie, ed. k. praechter et al., 5 v. (12th ed. Berlin 1923–28) 1:612–618. p. merlan, From Platonism to Neoplatonism (2d ed. The Hague 1960). aristotle, Protrepticus, ed. i. dÜring (Göteborg 1961).

[w. h. o'neill]

Iamblichus

fl. c. 320

Syrian philosopher whose work emphasized the mystical aspects of Pythagorean number theory. According to Iamblichus, Pythagoras (c. 580-c. 500 b.c.) himself had discovered "amicable" numbers, pairs in which each is the sum of the other's proper divisors. By expanding on the nonscientific aspects of Pythagorean mathematics—aspects that indeed did go back, in many respects, to ideas of Pythagoras himself—Iamblichus helped perpetuate interest in numerology, magic, and astrology.