East and West on the Spirit

The doctrinal core of the Filioque debate at Florence: the Eastern teaching that the Holy Spirit proceeds from the Father alone, grounded in the monarchy of the Father as sole cause within the Trinity, and the threefold distinction — eternal hypostatic procession, eternal manifestation “through the Son,” and temporal mission — that lets the Orthodox affirm the patristic “through the Son” without conceding the Latin doctrine; against the Latin, Augustinian teaching of a double procession from Father and Son “as from one principle.” It sets out the Palamite and Maximian background of Mark’s case, the dispute over the patristic florilegia and the charge of textual corruption, and the measured both-sides assessment of the modern scholarship.

Tradition: Pan-Orthodox / Byzantine

From the Father Alone: The Monarchy of the Father

The doctrine that Mark defended at Florence — the teaching the Orthodox Church confessed before the council and confesses still — is summed in a single phrase: the Spirit proceeds from the Father alone (ἐκ μόνου τοῦ Πατρός, ek monou tou Patros). Its foundation is the monarchy of the Father — the teaching that the Father alone is the cause (αἰτία, aitia), principle (ἀρχή, archē), and fount (πηγή, pēgē) of both the Son (by generation) and the Spirit (by procession). This is a personal monarchy, the principle of unity within the Godhead, and it implies no subordination or inequality: the Son and the Spirit are fully and coequally God, but they have their origin, eternally and without beginning, from the Father (Lossky, The Mystical Theology of the Eastern Church; Meyendorff, Byzantine Theology; see Pneumatology).

St. Gregory the Theologian had given the principle its classic form: the Son possesses all that the Father has except causality — “in respect of being the Cause the Father is greater than the Son” (Gregory of Nazianzus, Oration 29.15; cf. 30.7). For the Orthodox this is the hinge: to make the Son, with the Father, a cause of the Spirit’s being is to introduce a second principle into the Godhead, to compromise the Father’s unique role as the one source, and so to dissolve the very thing that holds the Trinity in unity (Lossky; Photius, Mystagogy; see St. Photius the Great).

The Threefold Distinction

The Orthodox case turns on a distinction the Latins did not draw, and the failure to draw it is, on the Eastern reading, the root of the whole error. There are three things to be distinguished (Lossky; Meyendorff, Byzantine Theology):

The eternal hypostatic procession (ekporeusis, the verb of John 15:26): the Spirit’s origin of being, His coming-to-be as a divine person — and this is from the Father alone.
The eternal manifestation or shining-forth (ekphansis / eklampsis) “through the Son” (dia tou Huiou): the Spirit eternally rests in and shines forth through the Son, in the common manifestation of the Godhead — a real and eternal relation, but one of manifestation, not of origin.
The temporal mission: the Spirit sent by the risen Son into the world in time — the economy, not the eternal life of the Trinity.

The Latin error, on this analysis, is to confuse (2) and (3) with (1) — to take the “through the Son” of manifestation, and the temporal sending of the Spirit by the Son, and transfer them into the order of origin, making the Son a cause of the Spirit’s very existence. The distinction is what allows the Orthodox to affirm, with the Fathers, that the Spirit proceeds “through the Son” — in manifestation — while denying absolutely that He proceeds “from the Son” in His being.

The Latin Doctrine

The Latin doctrine the Greeks faced was the developed Augustinian theology of double procession. St. Augustine, in the De Trinitate, taught that the Spirit proceeds from the Father principaliter (principally) and from the Father and the Son as from one principle (tamquam ab uno principio), and conceived the Spirit as the bond of love (vinculum amoris) between the Father and the Son (Augustine, De Trinitate; Siecienski 2010: 57). In the Latin frame, as Meyendorff describes it, the divine persons are distinguished by relations of opposition within the one essence, so that the Filioque appears not as an addition but as a logical necessity: the Son must be distinguished from the Spirit by some relation of origin, and that relation is the Son’s part in the Spirit’s procession (Meyendorff, Byzantine Theology). The union decree Laetentur Caeli enshrined this in the formula that the Spirit proceeds from the Father and the Son “as from one principle and a single spiration” (tamquam ab uno principio et unica spiratione) — the “one principle” being precisely the Latin guard against the charge of positing two causes (Gill 1959, appendix; cf. Second Council of Lyons, 1274, which had already condemned those who say the Spirit proceeds “as from two principles”).

[Disputed: whether the Latin “one principle” preserves or compromises the monarchy of the Father. Rome itself rejects the charge of two principles (Lyons 1274 condemns tamquam ex duobus principiis). The Latin reading holds that ab uno principio fully preserves the divine unity. The Orthodox reading (Lossky) holds that “one principle” merely relocates the difficulty, subordinating the persons to the common essence and so still displacing the Father’s unique causal role. Some Orthodox, however, treat the difference as one of theological idiom rather than heresy: Bulgakov called it “a difference of theological opinions,” and Kallistos Ware spoke of “semantics rather than… basic doctrinal differences.” The sharpness of the Lossky-style “two opposed triadologies” is itself contested in the modern scholarship as overdrawn (Siecienski 2010; Lossky; Bulgakov; Ware, The Orthodox Church).]

The Palamite and Maximian Background

Mark fought the doctrinal debate at Florence (in March 1439, against John of Montenero) as a self-conscious Palamite, and the essence–energies theology of St. Gregory Palamas stands behind his reading of the patristic texts. The Palamite distinction between the divine essence (ousia) and the uncreated energies supplied the conceptual key: the “through the Son” of the Fathers denotes the eternal energetic manifestation and radiance of the Spirit, not the procession of His hypostasis. The Spirit shines forth eternally through the Son in the divine energies — which are eternal — while having His existence from the Father alone (Meyendorff, A Study of Gregory Palamas; see St. Gregory Palamas).

The immediate Byzantine background is the teaching of Gregory II of Cyprus and the Council of Blachernae (1285), which had repudiated the earlier Union of Lyons and coined the formula of the Spirit’s eternal manifestation (aidios ekphansis) through the Son: the Spirit shines forth through the Son eternally, as light through the sun’s rays, while having its existence from the Father alone — the rays transmit the light but do not cause it (Papadakis, Crisis in Byzantium: The Filioque Controversy). This tradition — Photius to Gregory of Cyprus to Palamas — is what let Mark concede the patristic dia tou Huiou in Cyril of Alexandria and Maximus without conceding the Latin causality.

[Disputed: whether the “eternal manifestation” of Gregory of Cyprus is to be understood as energetic or hypostatic. The energetic reading (Lossky, Meyendorff, Papadakis) treats it as part of the single Photius–Gregory–Palamas tradition; a hypostatic reading (Stăniloae; Vivier-Mureșan, Byzantinische Zeitschrift 113 [2020]: 1041–1068) argues the formula concerns the Spirit’s hypostasis and even questions whether Palamas himself taught an eternal energetic procession. The debate is internal to Orthodox theology and does not affect Mark’s core claim that the Son is not the cause of the Spirit’s being.]

The decisive patristic text for Mark — as for the whole later Orthodox tradition — was St. Maximus the Confessor’s Letter to Marinus (c. 645–646; PG 91, 134D–136C; see St. Maximus the Confessor). Defending the Roman use of “through the Son” to his Eastern correspondents, Maximus had insisted that the Latins “have not made the Son the cause (aitia) of the Spirit — they know that the Father is the only cause” — the Latin formula expressing only the Spirit’s coming-forth (proienai) through the Son, a manifestation of the unity of essence (Maximus, Letter to Marinus, PG 91, 134D–136C). Maximus exploited the very distinction the Orthodox urged at Florence: ekporeuesthai (causal procession, from the Father alone) versus proienai (mediated coming-forth, through the Son).

[Disputed: the meaning of Maximus’s Letter to Marinus. Both sides invoked it. The Orthodox reading (Mark’s) takes it to teach only energetic or consubstantial manifestation, with the Father as sole cause; a pro-union reading took the Father as the “originating cause” with the Son sharing a mediated causality — a soft Filioque. At Florence, strikingly, the unionists led by Bessarion rejected the letter as possibly a forgery rather than rest the Latin case on it; modern scholarship (Sherwood, Alexakis) has upheld its authenticity. Siecienski concludes that Maximus remains “the most promising tool for bringing East and West closer together” (Siecienski 2010, ch. on Florence and conclusion).]

The Florilegia and the Charge of Corruption

Because both sides agreed to be bound by the Fathers, the doctrinal debate at Florence became, in large part, a contest over patristic texts — and over their authenticity. John of Montenero’s concluding florilegium leaned heavily on Greek Fathers, on the calculation that Greek authorities would move the Greeks. Its most contested item was a passage of (Pseudo-)Basil, Against Eunomius III.1, which made the Spirit “dependent on [the Son] as cause” — “the basis of the Latin defense.” Across the sessions of March 1439, Mark charged that the passage was an interpolation, accepting only texts agreeing with Maximus and Cyril; the Latins produced ancient manuscripts with the disputed reading, and — to the visible “stupefaction” of the Greeks — even the manuscript of the Greek metropolitan Dorotheos of Mytilene was found to contain it (Acta Graeca, ed. Gill 1953; Gill 1959, ch. 7; Alexakis, Revue des Études Byzantines 58 [2000]: 153–162).

[Disputed: the authenticity of the (Pseudo-)Basil passage and who “won” the textual argument. Modern scholarship vindicates Mark’s conclusion while correcting his accusation: the disputed words are indeed an interpolation — but an early (c. seventh-century), Greek, probably Eunomian one that predates the Filioque controversy, not a Latin forgery (Van Sickle; Alexakis 2000; Kappes, The Epiclesis Debate at the Council of Florence [2019]). Bessarion’s own later manuscript search found tampering by Greek hands as well, so neither side was guilty of conscious forgery. Kappes further argues that Montenero’s use of the passage was inconsistent even with Aquinas, who had softened it — so the popular “Mark versus Aquinas” framing is historically imprecise.]

The Measured Verdict

The modern scholarship, at its most careful, declines to award the patristic argument to either side. A. Edward Siecienski concludes that “it would be inaccurate to claim that the Greek patristic corpus explicitly addressed the procession of the Spirit from the Son… as later theology would understand it,” and equally that the claim “that the Eastern fathers explicitly… condemned the filioque cannot be sustained” — both sides could find “explicit and implicit support for and against the doctrine” in the Fathers, because the question they were asking had not been put in those terms before the controversy arose (Siecienski 2010, ch. 1 and conclusion). On this reading Florence “demonstrated all the arguments” but resolved nothing substantively; the way forward, Siecienski suggests, lies through Maximus’s distinction rather than through a declaration of patristic victory for either party. That measured conclusion belongs to the source-critical register, where the methodology §4.2 keeps the treatment strictly evidential: what the patristic corpus explicitly addressed is a historical question, and it is reported here as the scholarship finds it. It does not reopen the dogmatic one. The Orthodox Church confesses the procession of the Spirit from the Father alone and has never received the Filioque; Mark’s stand rests where the Church places it — not on a scholars’ victory in a contest over texts, but on the confession of the faith the Church had received, which he refused to let an unfree council redefine.

References

Siecienski, A. Edward. The Filioque: History of a Doctrinal Controversy. Oxford: Oxford University Press, 2010. (The procession; the threefold distinction; the Latin doctrine; the florilegia; the measured conclusion.)
Lossky, Vladimir. The Mystical Theology of the Eastern Church. London: James Clarke, 1957; and “The Procession of the Holy Spirit,” in In the Image and Likeness of God. (The monarchy of the Father; the two triadologies.)
Meyendorff, John. Byzantine Theology: Historical Trends and Doctrinal Themes. New York: Fordham University Press, 1974; and A Study of Gregory Palamas. (The personal monarchy; the Palamite manifestation.)
Papadakis, Aristeides. Crisis in Byzantium: The Filioque Controversy in the Patriarchate of Gregory II of Cyprus (1283–1289). Crestwood, NY: St. Vladimir’s Seminary Press, 1997. (Blachernae 1285; the eternal manifestation.)
Maximus the Confessor. Letter to Marinus (PG 91, 134D–136C). (The Father as sole cause; ekporeuesthai vs. proienai.)
Alexakis, Alexander. “The Greek Patristic Testimonia Presented at the Council of Florence (1439) in Defense of the Filioque Reconsidered.” Revue des Études Byzantines 58 (2000): 149–165. (The (Pseudo-)Basil interpolation.)
Kappes, Christiaan W. The Epiclesis Debate at the Council of Florence. Notre Dame, IN: University of Notre Dame Press, 2019. (Montenero, Aquinas, and the textual question.)
Acta Graeca. Ed. J. Gill. Rome, 1953; and Gill, The Council of Florence (1959), ch. 7. (The doctrinal sessions and the manuscript dispute.)