This text is adapted from a forum dialogue conducted in 2006. While I have reworked and refined my responses, the interlocutors' statements remain largely as originally posted, with minor editorial adjustments made to ensure thematic clarity and logical flow.

The Eastern and Western bishops at Florence sadly were talking past each other, rather than with each other at the council, and so, it was not simply because of some type of pressure from Muslim leaders that the union failed.  The union failed because the decree of Florence did not represent the faith of the Eastern Church.

That said, it is true that the Eastern Church accepts a shining forth (proeinai), or — to be more accurate — a manifestation (phanerosis), of the Holy Spirit through the Son in the divine energy, but Byzantine theologians reject anything that would make the Son a cause (aitia) of the Spirit's hypostasis (i.e., person).  Thus, in Eastern theology a distinction is made between the Holy Spirit's hypostatic origin, which is from the Father alone, and His manifestation (phanerosis / ekphansis) as divine energy, which comes from the Father through the Son.  That is why Eastern Christians speak of the Spirit as proceeding (ekporeusis) from the Father, but they refuse to use the term ekporeusis in connection with the Son; instead, using the term proeinai, which means to issue forth, in order to refer to the energetic outflowing of the Spirit as grace (i.e., as divine energy).  In other words, the Eastern tradition holds that the Spirit proceeds (ekporeusis) as person from the Father alone; while He (i.e., the Spirit) progresses (proeinai) through the Son and is made manifest (ekphansis) as divine energy.

Sadly, theological problems arose between the two sides on this issue because the West used only one word — the Latin word processio — in order to translate these two Greek words (i.e., ekporeusis and proeinai), and this created a false equivalence between the two terms and resulted in theological differences that continue to affect relations between East and West to this day, both in connection with understanding the "mode of existence" (tropos hyparxeos) proper to each of the divine persons in the Trinity, and in connection with the doctrine of grace.

It is nice to see a clear assertion that the Father alone is the source of the Godhead, but the East holds that the Father is not merely the "first" principle within the divinity; rather, He is the sole principle (arche), and that is why the East holds to the doctrine of the monarchy of the Father.  This teaching was confirmed by St. Maximos in his letter to Marinus, for in that letter when speaking about the Western "filioque" of his time he said that Westerners, ". . . have not made the Son the cause (aitia) of the Spirit — [because] they know in fact that the Father is the only cause of the Son and the Spirit, the one by begetting (gennatos) and the other by procession (ekporeusis)."  Thus, there is only one cause (aitia), one source (pege), one principle (monarchia) of Godhead within the Trinity, i.e., the Father, and these characteristics (idiomata) are hypostatically proper to the Father alone, and so they cannot be shared with the Son or the Spirit.

The word ekporeusis means procession in the proper sense of the term, i.e., it means procession in the sense of receiving existence or taking origin from another.  Thus, the Holy Spirit receives His existence, i.e., He receives His hypostasis from the Father alone, and not from or through the Son, because as the Nicene-Constantinopolitan Creed says, "Kai eis to Pneuma to Agion, to Kurion, to zoopoion, to ek tou Patros ekporeuomenon."  Now it is important to note that the word ekporeuomenon found in this part of the creed can only be used in reference to the Spirit's origination from the Father (see John 15:26) and must not be confused with His progression (proeinai) from the Father through the Son in the divine energy.

In other words, the Spirit can only be said to progress (proeinai) from the Father through the Son, and this eternal manifestation (aïdios ekphansis) does not concern the Spirit's hypostatic origin; instead, it concerns the Spirit's outflowing from the Father through the Son in the divine energy (i.e., as uncreated grace).

Thus, ekporeusis, which is the specific word used in the Nicene creed, concerns the Spirit's hypostatic origin; while proeinai, which is not used in the Nicene creed, concerns His energetic manifestation (phanerosis / ekphansis) from the Father through the Son, and these two things should not be confused or blended into a single spiration or procession.  The addition of the filioque to the normative and irrevocable creed of the Fathers of Constantinople I (A.D. 381) involves the confusion of the Spirit's hypostatic origination from the Father alone, with His energetic manifestation (ekphansis) — both temporally and eternally — in the divine energy from the Father through the Son.

Yes, as long as one understands that the word ekporeusis is used in connection with the Holy Spirit's hypostatic procession from the Father alone, i.e., that it concerns the Spirit's procession of origin; while the word proeinai concerns the Spirit's manifestation (phanerosis / ekphansis) from the Father through the Son, not as person (hypostasis), but as energy (i.e., as grace).

First, it should be noted that the word homoousios — used by the First Council of Nicaea to describe the communion between the Father and the Son — affirms the dependence of the Son upon the Father within the immanent Trinity. Crucially, this relational dependence implies that the Son receives His hypostatic existence from the Father and remains dependent upon Him for His consubstantial nature.  St. Athanasios the Great understood this and used this idea, along with the distinction between essence and will, the will being a natural energy of a hypostasis, in order to refute the heresy of Arius.  In Ad Serapionem St. Athanasios speaks of the energy of the Trinity and refers to the Spirit in relation to creation as the energeia of the Son.  His understanding of the divine energy is that it comes from the Father, through the Son, and rests upon creation in the power of the Holy Spirit.  Thus, St. Athanasios makes a distinction between things natural to the Father (e.g., the generation of the Son, and the spiration of the Spirit), and things which are a result of the divine energy, i.e., the created order.

In addition, if you read the writings of the Cappadocian Fathers (e.g., St. Basil's Adversus Eunomium, and his Letters 234, 235, etc., and his treatise On the Holy Spirit; St. Gregory of Nyssa's Contra Eunomium, his treatise On Not Three Gods to Ablabius; and St. Gregory Nazienzen's Orations, etc.), you will see that they never speak of a procession from the Son; moreover, they explicitly deny causality to the Son within the inner life of the Trinity, holding instead that the Father is the sole principle (monarche) of origin for the Son and the Spirit.  I would add to this the fact that the distinction between essence and energy is fundamental to understanding the Cappadocian arguments against Eunomius, and if one fails to make this distinction, the result is an inexorable tendency to Eunomian essentialism.  In addition to the Cappadocian Fathers, St. Maximos and St. John Damascene make the distinction between essence and energy, and both of them also deny any causal power to the Son within the inner life of the Trinity.

Now of course, following in line with the teaching of St. Maximos the Confessor and the Cappadocian Fathers, the Sixth Ecumenical Council of Constantinople III taught that there is a distinction between essence, energy, and hypostasis, because — as the council decreed — in Christ there are two natures, two natural wills and energies, and to say otherwise is to fall into the heresies of Monophysitism and Monothelitism.  Moreover, the doctrine of the Incarnation falls apart if you fail to make a real distinction between essence and person, because it is only the Second Person of the Trinity who became man, but if you say that essence and hypostasis are really the same thing then the whole Trinity became incarnate and that proposition is clearly false.  Thus, to fail to make a real distinction between essence, energy and hypostasis leads to problems in both Triadology and Christology.

Thus, in conclusion, I do hold that this distinction is a dogma, and it is a dogma of the first millennium, and not simply of the second millennium.  Moreover, in response to your comment that for one thousand years the West has recited the creed with the filioque, I would simply point out that for more than one thousand six hundred years the East has not recited it that way, and that the filioque is not to be found in the original version of the Niceno-Constantinopolitan Creed, which the Holy See itself has declared to be normative and irrevocable for the whole Church.  So the fact that a Pope, after more than four hundred years of papal resistance to the pressure to add the filioque to the creed, finally gave in to the pressure of the German Emperor Henry II to add it, does not make it normative for the whole Church; in fact, as I have already pointed out, the Vatican itself (in the mid 1990s) has indicated that it is not normative, and this decision is even reflected in the document Dominus Iesus, which was issued without the filioque by the Congregation for the Doctrine of the Faith back in August of 2000.

Manifestation vs. Procession:  Why Florence Failed

by Steven Todd Kaster

Original Version:  11 May 2006 (from a thread at the Phatmass Phorum)

This essay was edited together from several forum posts, and was revised and expanded on:  16 February 2026

Copyright © 2006, 2026 - Steven Todd Kaster