Christian elements. There is always the primitive all-perfect Æon, the fountain-head of divinity, and a co-eternal companion Æon. From these emanate a second pair who, in turn, engender others, generally in pairs, or in groups of pairs, in keeping with the Egyptian idea of divine couples. One of these inferior Æons, desiring to know the unknowable, to penetrate the secrets of the primal Æon, brings disorder into the Æon-world, is exiled, and brings forth a very imperfect Æon, who, being unworthy of a place in the Pleroma, brings the divine spark to the nether world. Then follows the creation of the material universe. Finally, there is evolved the Æon Christ, who is to restore harmony in the Æon-world, and heal the disorder in the material world consequent upon the catastrophe in the ideal order, by giving to man the knowledge which will rescue him from the dominion of matter and evil. The number of Æons varies with different systems, being determined in some by Pythagorean and Platonic ideas on the mystic efficacy of numbers; in others by epochs in, or the duration of, the life of Christ. The Æons were given names, each Gnostic system having its own catalogue, suggested by Christian terminology, and by Oriental, or philosophical and mythological nomenclature. There were nearly as many æonic hierarchies as there were Gnostic systems, but the most elaborate of these, as far as is known, was that of Valentinus, whose fusion of Christianity and Platonism is so completely described in the refutation of this system by St. Irenæus and Tertullian. (See Gnosticism, Valentinus and Valentinians, Basilides (1), Ptolemy the Gnostic.)
The best description of æonic systems is to be found in the refutations of Gnosticism by early Christian writers:—Irenæus, Adv. Hæreses, in P.G., VII, I. II, tr. in Ante-Nicene Fathers (New York, 1903), I, 315 sq.; Tertullian, Contra Valentinianos, in P.L., II, 523. The introduction contains graphic schemata illustrating the Æonic genealogy, vi sq. (tr. As above III, 503); Hippolytus, Philosophumena, in P.G., XVI, 3, attributed to Origen, tr. Refutation of all Heresies, as above V, 9; Baur, Christliche Gnosis (Tübingen, 1835); De Faye, Introduction à l'étude du gnosticisme, in Revue de l'histoire des religions, (1902, 166 sq.); Dufourcq, La pensée chrêtienne, Saint Irenée (Paris, 1905), 41–112; Duchesne, Histoire ancienne de l'Eglise (Paris, 1906), I, 153–194; Mead, Fragments of a Faith Forgotten (London, 1900). See also works on Gnosticism and on the heresiarchs referred to above.
Æquiprobabilism. See Probabilism.
Aër (Greek, ἀήρ, the air), the largest and outermost covering of the chalice and paten in the Greek church, corresponding to the veil in the Latin rite. It is slightly larger than the veil used to cover the chalice and paten in the Latin rite, and is beautifully embroidered in the same style and colour as the vestments of the officiating priest. It takes its name either from the lightness of the material of which it was formerly made or from the fact that the priest during the time of the recital of the Nicene Creed in the Mass holds it high in the air and waves it slowly towards the chalice. Its use, like that of the veil, was originally to cover the chalice and to prevent anything from falling therein before the consecration and before the sacred vessels were brought to the altar. It is first mentioned by name in an explanation of the liturgy (Mass) by a writer of the sixth century, and is also alluded to as "the so-called air" in the Acts of the Council of Constantinople. In the Greek Orthodox church the veil is put on the shoulders of the deacon who brings the paten to the altar at the great entrance, and the same rite is preserved in the Greek Catholic church, where the aër usually has a couple of short strings to secure it over the shoulders. A similar ceremony is still preserved in the Roman rite, where the deacon at high Mass brings the chalice and paten to the altar and places a special veil over his shoulders.
Clugnet, Dict. grec-français des noms liturgiques (Paris, 1895), 4.
Aërius of Pontus, a friend and fellow ascetic of Eustathius, who became Bishop of Sebaste (355), and who ordained Aërius and placed him over the hospital or asylum in that city. Aërius fell out with Eustathius, upbraided him for having deserted ascetic practices, and began to preach new doctrines, insisting that there was no sacred character distinguishing bishop or priest from laymen, that the observance of the feast of Easter was a Jewish superstition, and that it was wrong to prescribe fasts or abstinences by law, and useless to pray for the dead. According to some, Aërius was inspired to teach these doctrines by his jealousy of Eustathius. For a time, he had many followers in Sebaste, but he could not make his tenets popular, and gradually he and his sect became an occasion of abuses, which made them odious. His movement is considered important by Protestants as indicating a tendency to some of their views even at this early period; but it also shows how strongly the Christians of his day were opposed to the teaching of Aërius.
St. Epiphanius, Adv. Hæres, 75, P. G., t. XLII; Hemmer, in Dict. théol. cath.; Venables, in Dict. Christ. Biog.
Æsthetics may be defined as a systematic training to right thinking and right feeling in matters of art, and is made a part of philosophy by A. G. Baumgarten. Its domain, according to Wolff's system, is that of indistinct presentations and the canons of sensuous taste (αἰσθητικὴ τέχνη, from αἰστθάνεσθαι, to preceive and feel). It has, however, developed into a philosophy of the beautiful in nature and art, and, finally, into a science of the (fine) arts based on philosophical principles. Natural beauty, particular works of art, pure, that is, not sensual, beauty, and philosophical questions are sometimes treated thoroughly, sometimes merely touched upon. Applied æsthetics is the accurate description and valuation of particular works of art; technical æsthetics, the training of the art-student in individual productions; art-history, the continuous record of the development of art, according to a definite plan. It is the duty of æsthetics always to seek the deepest grounds of the pleasure derived from art, not only in the laws of nature, but, above all, in those of the mind, and thus to come in touch with philosophy; but the fruitful source of sound judgment is to be found in a correct view of the world of art itself. The student of æsthetics, though he cannot wholly dispense with an insight into the technique of artistic production, or with a knowledge of the varied manifestations of beauty in nature and life, or even with an actual exercise of one kind of art or another, must rely chiefly on a quick perceptive faculty, systematizing talent, and an intelligent appreciation. In this respect æsthetics will, on the one hand, offer more, on the other hand, less than technical treatises on any one art, practical instruction in the exercise of the same, or illustrated art books for everyone.
The Philosophy of Æsthetics.—Æsthetics, as a general science, takes no account of the individual arts. It investigates the physiological and psychological principles of art, the conceptions of art, of beauty, and of the beautiful in art, and develops the universal laws of artistic activity. Clear and orderly thinking, the presupposition of all scientific discussion, is indispensable in æsthetics, the more so because, otherwise, aimless circumlocution and serious errors are unavoidable. All ideas, moreover, concerning æsthetic beauty and the aim of art need to be carefully examined into. Finally, the subjective conditions of the artist, his relation to nature, and the division and classification of the material that lies to his hand must be taken into account.
The Science of the Arts.—In a history of art only the imitative arts and, possibly, music are, as a rule, included; æsthetics, on the other hand,