Calcidius

(fourth, possibly fifth, century a.d.),

Platonist Commentary.

Calcidius’ Latin translation of the first two-thirds of Plato’s Timaeus was the only extensive text of Plato known to western Europe for 800 years. Latin cosmology, throughout the early Middle Ages, was based upon the Timaeus; and Calcidius’ version, together with his commentary upon it, provided scholars with their best contact with the master.

Nothing is known of Calcidius’ life. Hosius, or Osius, the close friend to whom he dedicated his work, has generally been identified with the bishop of Córdoba who was prominent at the First Council of Nicaea (a.d. 325). Waszink, the latest editor of Calcidius, prefers to identify Osius with a Milanese patrician and official at the end of the fourth century. Waszink also regards Calcidius as certainly Christian.

Calcidius’ commentary is eclectic in character. His Platonic concepts appéar to have been derived from Porphyry and from writers of the Middle Platonist school, his Aristotelianism from Adrastus, and his Christian doctrines from Origen. An extended section on astronomy closely follows and at times translates the second half of Theon of Smyrna’s commentary on Plato, but it is agreed that both Calcidius and Theon were using Adrastus here.

Calcidius’ commentary is six times as long as his translation of the Timaeus and deals almost exclusively with passages in the middle third of Plato’s treatise. The opening chapters are devoted to explicating enigmatic passages about the creation of the universe (31c–32c) and the origin and constitution of the World Soul (34c–35b). Chapters 3 and 4 deal with the numerical ratios of the harmonic intervals in the musical scale used in the fabrication of the World Soul (36a–36c). Chapter 5, ostensibly commenting upon two passages in the Timaeus about intelligibles and sensibles (37a–37c), turns out to be a conventional handbook treatment of astronomy. The highlight of Calcidius’ discussion comes in the following chapter, when he explains the epicyclic motions of Venus (presumably of Mercury too) and attributes the system to Heraclides Ponticus. Although mistaken in assuming that Heraclides was using a geometrical demonstration instead of hypothesizing actual orbits of those planets about the sun, Calcidius was the most influential authority in keeping alive geoheliocentric views in the Middle Ages and thus laying the foundations for Copernicanism. His Latin version of Plato’s account of Atlantis (24d–25d) was also vital in preserving that myth of a lost continent. Calcidius’ theory of matter is a conflation of Platonic and Aristotelian concepts. Silva to Calcidius has the character of both “space in which” (Plato) and of “matter out of which” in qua, Calcidius also struggles to avoid the Aristotelian “merely possible” concept of matter.

Manuscripts of Calcidius are abundant. Few were the medieval libraries of any standing that did not have a copy of his work. His part in transmitting classical cosmology to the Latin West culminated with the Scholastics of Chartres in the twelfth century.

BIBLIOGRAPHY

The definitive ed., Timaeus a Calcidio translatus commentarioque instructus, J. H. Waszink and P. J. Jensen, eds. (London-Leiden, 1962), includes exhaustive discussions of MSS (about 150 are filiated) and of Calcidius’ sources.

J. H. Waszink, Studien zum Timaioskommentar des Calcidius I (Leiden, 1964), deals mostly with the sources of the first half of the commentary. Waszink believes that Calcidius drew from both Adrastus and Porphyry. J. C. M. van Winden, Calcidius on Matter; His Doctrines and sources (Leiden, 1959), prefaces his exhaustive discussion of matter with a running account of the contents of the commentary. W. H. Stahl, Roman Science; Origins, Development, and Influence to the Later Middle Ages (Madison, Wis., 1962), places Calcidius in the traditions of Latin cosmology and digests his account of mathematics and astronomy. T. L. Heath, Aristarchus of Samos (Oxford, 1913), discusses Calcidius’ imputations of epicyclic concepts to Heraclides. Pierre Duhem, Le système du monde, III (Paris, 1954), devotes 119 pages to Calcidius, Macrobius, and Martianus Capella as transmitters of the “Heraclidean” system to the medieval world.

William H. Stahl