Semi-Arianism

Like in substance: the formula explained simply

The whole debate turns on two Greek words that differ by a single letter, the iota — the smallest letter of the Greek alphabet^[8]. Nicaea had defined that the Son is homoousios with the Father: homos, "same", + ousia, "substance, essence" — of the same substance, consubstantial. The Semi-Arians proposed homoiousios: homoios, "like", + ousia — of like substance^[9].

In other words: for Nicaea, the Father and the Son share one single Godhead, like two torches lit from one flame that is never divided. For the Semi-Arians, the Son possesses a Godhead like the Father's — very close, almost identical, but his own. The difference seems slight, and their leaders swore it safeguarded both the Father's transcendence and the Son's dignity^[10]. But it changes everything: if the Son's substance is only like and not the same, then there are two divine substances — and, intentions notwithstanding, one falls back either into two unequal gods or into a diminished Son, that is, a luxury creature^[11].

The very name "Semi-Arians" comes from Saint Epiphanius of Salamis, who reserves the title for the party of reaction gathered around Basil of Ancyra in 358, in the seventy-third heresy of his Panarion^[12]. The word is somewhat unjust — these bishops anathematized the true Arians — but it has the merit of stating their real position: halfway between Arius and Nicaea, closer to Nicaea than to Arius, yet halted before the final step^[13].

The table of the four parties

After Nicaea, the East was divided not into two but into four families, distinguished by their answer to a single question: what is to be said of the substance of the Son?^[14]

The Anomoeans are the hard-liners: Eunomius pushes the logic so far as to maintain that man can know God's essence as adequately as God knows Himself. The Homoeans are the skilful ones: their formula of 359–360 — the Son "like" the Father, without the word ousia — lets everyone hear what he wishes, and it is this formula the emperors impose as the state religion. The Homoiousians, for their part, are almost Catholic: a single iota separates them from Nicaea, and many will end by crossing it^[15].

Tyre (335) and the conservative majority of the East

The Semi-Arian party was not born in a day: it is the heir of the great conservative majority of the East, those bishops who accepted the deposition of Saint Athanasius at Tyre in 335 and received the Arians into communion at Jerusalem after their repentance — without being Arians themselves, yet far from all being orthodox^[16]. These bishops held the traditional faith of their Churches, distrusted novelties — including, in their eyes, the new word of Nicaea — and wanted the peace of the Empire as much as the truth^[17].

The Dedication Creed (Antioch, 341)

The council of the Dedication, assembled at Antioch in 341 for the consecration of the great church begun under Constantine, brought this middle theology to light: it published a creed faultless within a single word — it said all that Nicaea said, except the word consubstantial^[18]. It is the matrix of all the Semi-Arian creeds to come: an almost complete orthodoxy, amputated of the one bolt that shut the door on Arius.

At this date, even disciples of Arius such as George, bishop of Laodicea (335–347), and Eustathius of Sebaste (c. 356–380), joined the moderate party; and after the death of Eusebius of Nicomedia, the leaders of the court faction — Ursacius, Valens, Germinius — were bound to no formula at all, for Constantius himself detested Arianism, although he detested Athanasius still more^[19].

Marcellus deposed, Basil installed (336–350)

The history of the see of Ancyra, in Galatia, sums up the crisis: when Marcellus of Ancyra was deposed in 336 for a theology redolent of Sabellianism — one God dilating in turn into Father, Son and Spirit — it was Basil who succeeded him^[20]. Marcellus was rehabilitated by the council of Sardica and by the pope in 343, but Basil was restored in 350 by Constantius II, over whom he gained considerable influence: the future leader of the Semi-Arians became the emperor's theologian^[21].

Sirmium 351 against Photinus, then the "blasphemy" of 357

Basil proved himself as champion of middle orthodoxy: he presided over the council of Sirmium in 351 against Photinus — a former deacon of Ancyra become bishop of Sirmium, who reduced the Word to an impersonal virtue — and the canons of this synod begin by condemning Arianism, without however rising quite to the level of Nicaea^[22]. After the defeat of the usurper Magnentius at Mursa in 351, Valens, the bishop of that city, became Constantius' spiritual director; in 355, Valens and Ursacius obtained the exile of the Western confessors — Eusebius, Lucifer, Liberius — and Hilary's followed^[23].

In 357, the same men had the second creed of Sirmium voted, nicknamed the "formula of Hosius": homoousios and homoiousios were rejected together in it, and even the word substance was banished from confessions of faith^[24]. Meanwhile, the violent Eudoxius seized the see of Antioch and supported Aetius and his disciple Eunomius — the Anomoeans, who proclaimed the Son dissimilar to the Father^[25]. It was this flaunted blasphemy that woke the moderates: Basil of Ancyra decided to react, and the Semi-Arian party entered history.

A church dedication turned synod

In Lent 358, Basil gathered many bishops for the feast of the dedication of a new church he had just built at Ancyra^[26]. In the midst of the rejoicing came a letter from George of Laodicea: Eudoxius of Antioch had just publicly approved Aetius; George begged Macedonius of Constantinople, Basil and the assembled bishops to decree the expulsion of Eudoxius and his supporters from Antioch, failing which that great see was lost^[27].

The name of Father implies a Son of like substance

In reply, the synod of Ancyra published a long letter addressed to George and the other bishops of Phoenicia: it took up the creed of Antioch (341), adding explanations against the "dissimilarity" of the Son taught by the Arians — the Anomoeans, from anomoios — and it demonstrated that the very name of father implies a son of like substance: homoiousios, or homoios kat'ousian, "like according to substance"^[28]. Appended anathemas explicitly condemned Anomoeism and imposed the teaching of "likeness of substance"^[29].

Legates were at once dispatched to Sirmium to see the emperor: Basil himself, Eustathius of Sebaste, a venerated ascetic, Eleusius of Cyzicus, a supporter of Macedonius, and Leontius, priest of the imperial chapel^[30]. They arrived just in time — Constantius was lending his ear to a Eudoxian — and the emperor turned about: in a letter preserved in the history of Sozomen (IV, 14), he declared the Son "like in substance" to the Father and condemned the Arians of Antioch^[31]. Never was the party so close to winning the Empire.

The anathemas — and the nineteenth canon

The synod joined to its letter a series of anathemas striking the Anomoean theses one by one^[32]. But the nineteenth of these canons goes further: it also forbids the use of homoousios and tautoousios ("of the same substance")^[33]. This anti-Nicene sting is perhaps a late addition owed to Macedonius' insistence — Basil himself does not seem to have held to it afterwards — but it reveals the party's permanent temptation: from wanting to bar the road to both extremes, forbidding the word of Nicaea on the same footing as that of Arius^[34].

The "dated" creed of 22 May 359

Buoyed by imperial support, Basil persuaded Constantius to convene a general council to settle the faith of the Empire: Ancyra was proposed, then Nicomedia — but that city had just been destroyed by an earthquake^[35]. Basil thus found himself at Sirmium in 359, where the Arianizers had meanwhile regained ground: with Germinius of Sirmium, George of Alexandria, Ursacius, Valens and Mark of Arethusa, he held a conference lasting into the night^[36].

From it emerged a confession of faith drafted by Mark on 22 May — mocked as the "dated creed", because it bears the consular date as its heading instead of opening with the anathema (Hilary, Fragment XV)^[37]. Arianism was rejected in it, of course, but homoios kata ten ousian was not admitted: in its place was substituted the vague kata panta homoios — "like in all things"^[38]. Basil, disappointed, signed only by adding in his own hand that these words mean not only in will, but in existence and in being — kata ten hyparxin kai kata to einai^[39]. And, not content with this patching, he published with George of Laodicea and others a common explanation (preserved by Epiphanius, Panarion, 73, 12–22): "in all things" must include substance^[40].

Rimini in the West, Seleucia in the East

To have the compromise ratified, the court party organized two separate councils: one at Rimini for the Latins, the other at Seleucia for the Orientals^[41]. At Seleucia, assembled on 27 September 359 in the church of Saint Thecla, the Semi-Arians held the majority — supported by men such as Saint Cyril of Jerusalem, his friend Silvanus of Tarsus, and even Saint Hilary, exiled in Phrygia and present on the spot^[42]. But the Homoeans' manoeuvres — divide and rule — kept them from obtaining what they wanted, in the East as in the West^[43].

It was then that Saint Jerome, years later, would write the sentence that has remained famous about that terrible year:

"The whole world groaned, and was astonished to find itself Arian." — Saint Jerome, Dialogue Against the Luciferians, 19^[44]

The council of Rimini, with its some four hundred Latin bishops, ended by yielding under imperial pressure; that of Seleucia dispersed having concluded nothing. Within months, the Homoean compromise — the Son "like", without the word substance — became the official faith of the Empire, and the Semi-Arians, who thought they had inspired it, found themselves excluded from their own victory^[45].

The outstretched hand of Athanasius and Hilary

It was at that precise moment that Saint Athanasius performed one of his most magnanimous gestures. At the end of 359, after the dispersal of Seleucia (1 October) and even before learning of the final disaster, he wrote his De Synodis — On the Councils of Rimini and Seleucia — conceived, by history's own admission, as a formal offer of peace addressed to the Homoiousian party^[46]. Far from treating these bishops as enemies, he treats them as brothers mistaken over a word: those who sincerely confess the Son "like in substance", who reject the Arian blasphemies and hold all the rest of the faith of Nicaea, must not be repelled — they must be helped across the final iota rather than excommunicated over a vocabulary^[47].

A few months earlier, Saint Hilary of Poitiers had made the same move from his exile: at the beginning of 359, he addressed to the bishops of the West his Book on the Councils, to explain the Eastern formulas to them loyally and prepare reconciliation^[48]. The Latin West, which swore only by Nicaea, thus discovered that the East was not wholly Arian — and the East discovered that Athanasius was no inquisitor. This double outstretched hand would save, in the twenty years that followed, half of the Semi-Arian party^[49].

Fear of Sabellianism

To understand the Homoiousians' obstinacy, one must hear their fear — and it was no imaginary one. The East had seen Marcellus of Ancyra and then Photinus of Sirmium slide from the consubstantial toward a theology in which the Father, the Son and the Spirit are but three successive names of a solitary God^[50]. To Greek ears, homoousios — "of the same substance" — sounded like tautoousios — "of the same person": to affirm a single substance was, they believed, to confound the Persons and fall back into the opposite error, the one that denies any real distinction in God^[51]. It is the error refuted by Sabellianism and Modalism: the Semi-Arians wanted to guard against it at all costs, and the word homoiousios seemed to them the rampart — two like substances, hence two really distinct Persons^[52].

Refusal of unscriptural words

A second argument, more respectable still: neither homoousios nor homoiousios figures in Scripture. The second creed of Sirmium (357) had rejected both at a stroke, and many sincere bishops held that no word forged by men should divide the Church^[53]. The Semi-Arians shared this scriptural scruple — while keeping their own unscriptural word, a contradiction Athanasius does not fail to point out gently: if homoiousios, itself forged outside Scripture, is accepted, why refuse homoousios, which alone shuts the door on Arius?^[54]

What Nicaea answered them

The Catholic answer holds in a simple grammar, the one Nicaea had received from the Fathers: to beget communicates nature; to create produces from nothing another nature. A son receives from his father what his father is; a creature receives existence without receiving the essence^[55]. To call the Son "like in substance" is therefore, whether one wills it or not, to make of Him a second, diminished god or a first creature — and to reopen exactly the breach Arius had dug with his slogan: "there was a time when he was not"^[56].

The final stake is salvation itself: only God reconciles humanity with God. If Christ is not true God, born of the Father before all ages, He cannot divinize man — He is but a luxury intermediary between God and us^[57]. It was for this reason, and not from a taste for dispute, that the Church held Nicaea's word for the bolt of the whole faith — and it is this reason that would finally convince the best of the Homoiousians^[58].

Constantinople (January 360): the triumph of the Homoeans

Basil, Silvanus and Eleusius went as a delegation to Constantinople, where the council that was to ratify Seleucia met in January 360^[59]. The reverse happened: the assembly, led by Acacius of Caesarea — gone from the extreme Arian side to the new party of the Homoeans — followed Rimini's example, condemned homoiousios and homoousios together, and authorized only homoios, "like", without any precision^[60]. The formula was Acacius' invention; the council procured the exile of Macedonius, Eleusius, Basil, Eustathius, Silvanus, Cyril and the other Semi-Arian leaders^[61]. The party that had thought to lead the Empire was beheaded in a single day.

Julian, Jovian and the Pneumatomachian temptation

Constantius died at the end of 361; Julian recalled all the exiles — to divide the Church, not to heal it — and Basil, probably, was already dead^[62]. Macedonius then organized what remained of the party: he confessed the Son kata panta homoios, "like in all things", but declared the Holy Spirit servant and minister of the Father — a creature^[63]. Eleusius joined him, Eustathius for a time too; this remnant of the Semi-Arian party held synods at Zele and elsewhere^[64]. The slide was complete: for want of having fully confessed the Son, they came to diminish the Spirit — and it is under the name of Macedonians, or Pneumatomachi, that history would henceforth remember these heirs^[65].

The accession of Jovian, an orthodox emperor, produced an ironic reversal: the versatile Acacius, with Meletius of Antioch and twenty-five bishops, accepted the formula of Nicaea, explaining that the Fathers of Nicaea had meant by homoousios simply homoios kat'ousian — Acacius was taking up the Semi-Arians' original formula^[66]. In 365, the Macedonians assembled at Lampsacus under Eleusius' presidency condemned the councils of Rimini and Antioch (360) and reaffirmed likeness in substance; but the threats of the Arian emperor Valens made Eleusius sign an Arian creed at Nicomedia in 366 — he returned to his diocese full of remorse and asked that another bishop be elected, which his faithful refused^[67].

The embassy to Liberius and the synod of Tyana

The West lived in peace under Valentinian: the Semi-Arians sent deputies there — Eustathius and Silvanus — to the emperor and the pope to ask for help^[68]. Liberius refused to receive them before they presented him a confession of faith including the formula of Nicaea; he seems to have been unaware that the party now rejected the divinity of the Holy Spirit — which was perhaps not true of the envoys themselves^[69]. On the legates' return, the documents they brought back were received with great joy by a synod assembled at Tyana, which embraced the faith of Nicaea; but another synod, in Caria, still refused the homoousion^[70]. The party split before our eyes: some returned into the Church, others locked themselves in refusal — and only the former still belong to our narrative, the latter belonging to the history of Macedonianism.

Constantinople (381): the final anathema

The Second Ecumenical Council, assembled at Constantinople in 381 by Theodosius, closed the dossier in a single sentence of its canon 1:

"And let every heresy be anathematized, particularly that of the Eunomians or Anomoeans, that of the Arians or Eudoxians, and that of the Semi-Arians or Pneumatomachi, and that of the Sabellians, and that of the Marcellians, and that of the Photinians, and that of the Apollinarians." — First Council of Constantinople (381), canon 1^[71]

Note the wording: the council names the "Semi-Arians" a final time — and at once identifies them with the Pneumatomachi, those who war against the Spirit^[72]. Basil of Ancyra's party no longer existed under that name: its best sons had become Nicenes, its worst heirs had become Macedonians. The anathema strikes the name to close history — and rightly so, for history itself was already closed: the final iota had been crossed by some, and definitively refused by the others.

Semi-Arianism leaves the Church a threefold lesson, valid for every doctrinal controversy. First, words guard the faith: an iota can carry the salvation of the world, and to refuse a word on the pretext that it is not in Scripture is sometimes to refuse the one dyke protecting the meaning of Scripture^[83]. Second, fear of one error leads into the opposite error: from dreading the Sabellianism that confuses the Persons, the Homoiousians failed the one God by multiplying substances — proof that one never defends a truth well by sacrificing another^[84]. Finally, the charity of Athanasius and Hilary saved more souls than a hundred anathemas: by treating the Semi-Arians as erring brothers rather than enemies, they brought back to Nicaea half of a party that rigour alone would have lost entire^[85].

That is why the Church, which anathematized the name in 381, never despised the men: Basil of Ancyra was a loyal adversary, Eustathius of Sebaste an ascetic venerated even in his errors, and those who rallied at Tyana were received with joy^[86]. Firmness on the word and gentleness toward persons — such has been, since that crisis, the Catholic way of treating almost-believers^[87].

• Arianism
• Arius (c. 256–336)
• The Arian controversy
• Nicaea I (325)
• Saint Hilary of Poitiers
• Saint Basil the Great
• Sabellianism
• Modalism
• Macedonianism
• The heresies of the early centuries

To dig deeper: R. P. C. Hanson, The Search for the Christian Doctrine of God, Edinburgh, T&T Clark, 1988 — the modern reference study on the whole Arian crisis; J. N. D. Kelly, Early Christian Creeds, London, Longman, 3rd ed. 1972 — on the fourth-century creeds; M. Simonetti, La crisi ariana nel IV secolo, Rome, Institutum Patristicum Augustinianum, 1975 — the Italian synthesis; L. Ayres, Nicaea and its Legacy, Oxford, 2004 — the contemporary re-reading.